World Environmental and Water Resource Congress 2006: Examining the Confluence of Environmental and Water Concerns

IWRM is well recognised globally and needs not much of introduction and recently adaptive management of water resources has gained popularity in tune with other fields where adaptive management has shown encouraging results. This paper gives an introduction of Integrated Water Resources Management in Adaptive Management context and focuses on Information and Communication Technology (ICT) Scenario that can be effectively used for Adaptive Integrated Water Resources Management. It also examines the practical issues that are involved in implementation of ICT for adaptive IWRM. The paper briefly discusses recent advancements that have made it possible to address rural areas and scattered locations that have major share of water consumers and tries to establish that most of the underlying problems in effective adaptive IWRM are due to inability to capture data from remote scattered locations over large geographical areas and also in effective implementation of communication that makes core of feedback and participation mechanism. Recent advancements in communication technology have made it possible to effectively use adaptive management practices for integrated water resources use.

Long-term pumping from the Upper Floridan Aquifer (UFA) in the Savannah region, Georgia has lowered groundwater piezometric heads significantly. This resulted in salt water intrusion and brackish water contamination of the aquifer at Hilton Head Island, S.C. The aquifer is a primary source of drinking and industrial process water in the region, thus, various categories of users apply for groundwater withdrawal permits. The Georgia Environmental Protection Division (EPD) wants to develop a long term groundwater management plan which will protect the UFA from further salt water intrusion and also allow additional groundwater withdrawals from the aquifer. To achieve this goal, EPD first developed an "Interim Strategy for Managing Salt Water Intrusion in the Upper Floridan Aquifer of Southeast Georgia (EPD 1997)". In this interim strategy, EPD has identified an area for enforced protection near the City of Savannah. Thus, since 1997, EPD has not issued permits for groundwater withdrawal from the UFA in the northern-capped area unless such water is reallocated from a permit reduction elsewhere within the northern-capped area (EPD 2004). EPD also initiated a program called Coastal Sound Science Initiative (CSSI) to generate data and information for developing a plan for managing salt water intrusion (EPD 2005). EPD's goal was to find answers for various questions related with the salt water intrusion problem in the region. Two of these questions were: (1) Can areas having minimal impact on salt water intrusion be identified and what amount of water can be obtained from them?, and (2) What are the other fresh water sources in coastal Georgia and what amount of water can be obtained from them? In this study, we proposed a coupled simulation-optimization model to determine spatial distribution of additional groundwater availability within the Savannah region. We used this model to investigate spatial distribution of groundwater availability for various management scenarios, such as groundwater is withdrawn from the Lower Floridan Aquifer (LFA) from the UFA, or from the LFA and the UFA simultaneously (UFA+LFA). The results obtained from this analysis will be useful in answering the two questions posed by EPD and also will provide preliminary guidance in long term management and planning goals.

This paper outlines an approach to the development of adaptive management as a tool in the environmental and economic sustainability of community water supply systems by providing a framework to incorporate information into critical policy decisions. Adaptive management seeks to provide optimal management scenarios of water systems. The specific elements in the development of this approach rely on the deployment of a real-time monitoring and predictive modeling framework using sensor networks, soft computing and information systems; the development of risk-cost analysis methodology for water systems management under uncertainty; and the development of a conceptual approach for multi-scale adaptive management of wastewater treatment facilities. The approach relies heavily on the definition of the role of emerging sensors and sensor networks, soft computing, uncertainty analysis, and advanced information systems.

This paper examines evidence of the factors affecting the adoption of water markets within Australia's largest irrigation district, the Goulbum-Murray Irrigation District in Northern Victoria. The district is unique for the purpose of this analysis for a number of reasons: (1) irrigators are supplied by two main systems with very different supply reliability, (2) parts of the district have a high proportion of land suffering from soil degradation and salinity with low value production while other areas have better soils and higher value production, (3) market restrictions have been eased over time and varies across the district, (4) the district has experienced severe drought over the last six years, and (5) there are two different types of irrigators within the district, those supplied by the district infrastructure and those pumping their own water directly from the rivers with slightly different entitlements. The paper uses the trading and entitlement registers to analyze the trading behavior of all farm businesses during the first 13 years of trading both in the market for water entitlements and water allocations. Originally markets were adopted most extensively in the area with the largest potential financial tradeoffs between high and low value water users and irrigators with poor and good soils, while in the other parts of the district the main driver of market participation has been scarcity and policy changes.

In this paper, the effect of the construction strategy on the final cost (of a shoreline protection system) and the shoreline shape, was investigated. A protection measure, which was designed to protect Sama El-Arish village, along the Mediterranean Sea at El-Arish, Egypt, was considered. This system is a 3-graded length permeable rubble groins spaced at different distances supplied with nourishment at the down-drift, at the East, Balah and El-Serafy. Different strategies were planned. Each strategy was simulated. The simulation modeled the construction phases of each strategy. Based on the modeled construction phases, the strategies were economically evaluated and compared to the originally proposed designed system. Also, the effects of the different construction strategies on the shoreline shape were evaluated and compared to the originally proposed designed system. The comparison showed the effect of the construction strategy on the final cost of the structure and the shoreline shape.

Historically, evaluations of stormwater Best Management Practices, (BMPs), have focused on dissolved and suspended pollutants because the sampling methods were adapted from people's experience with wastewater treatment plants. Therefore, pollutants were sampled in the influent and effluent water column using grab samples or autosamplers, and flow measurements were made using velocity or weir measurements. But, stormwater pollutants differ from wastewater by being intermittent in nature and often having high volumes of gross pollutants in the storm runoff that can not be measured using autosamplers and standard techniques. New methods are being developed that measure gross pollutants in addition to the pollutants in the water column.

Rapid expansion of urban area since 1970's in Korea has caused the difficulties to discharge the flood in urban area watershed. Building the rational and optimal urban sewer network in urban area is very important to overcome the flood disaster. Sewer network installation needs two important requisites; the first is runoff analysis including design discharge and the second network layout design optimized economically. Many researches for runoff analysis as well as efforts to attenuate peak flows in urban watershed have been doing well. But layout design technology, relatively, has less devoted to develop network system or assessment methodology. What is interested in sewer layout design nowadays is not only how to discharge peak flow but also how to set up economic layout condition with results of simulated design discharge. This study aims at developing simulation model which might come up with the optimal condition of pipe capacity, slope, water depth and return cost in terms of least cost optimization in urban sewer layout design according to design discharge. In order to evaluate the risk at each state, first order second moment approximation was adopted to uncertainty analysis in the risk-reliability relationship, which would be able to calculate the risk cost of the element. And DDDP (Discrete Differential Dynamic Programming) which is application of DP (Dynamic Programming) is used as an optimization technique in the sewer layout design. C-language was used to code the model and analyzed node-link structure for manhole-sewer pipe. This model was applied to a newly developed resident area in Ulsan, Korea to assess the installed sewer network layout. As a result, the method in this study could suggest the more optimal condition to about 9% attenuation in terms of return cost considering risk.

Previous experimental investigations on the issue of flow regime transition from free surface to pressurized flow in stormwater sewers have introduced extreme conditions to generate pipe-filling bore fronts. These conditions include the admission of large inflow into still water conditions and sudden flow blockage in a pipeline. It is unclear whether the results of these experiments are representative for flow regime transition events in actual flowing sewers. This paper summarizes an experimental investigation in which pipe-filling bore fronts were generated by introducing large inflows in sewers initially in flowing conditions with drawdown profiles due to a free overfall at the downstream end. This condition is perceived as a more representative scenario in which flow regime transition events would occur. Pressure and velocity measurements were performed and the results compared well with predictions from a flow regime transition model.

The behavior of stormwater systems can be greatly altered by the presence of air pockets within the pressurized portion of the flow. While rapid filling conditions in stormwater storage tunnels can result in air pocket entrapment, the mechanisms for this phenomenon have not been studied systematically to date. This paper summarizes an investigation conducted at the University of Michigan on an experimental setup that reproduces the essential features of a below grade storage tunnel. Various filling scenarios were tested in which the filling rate, initial water depth and ventilation configurations were varied. Different and previously unreported mechanisms for air pocket entrapment were identified. For the conditions investigated in the experiments, the formation of air pockets was relatively common.

The Tunnel and Reservoir Plan (TARP) is a system of 175 kilometers of deep underground tunnels and large reservoirs designed to capture and store combined-sewer overflows of greater Chicago. Conveyance studies in sewer systems often discretize the sewer into reaches delimited by manholes or junctions, effectively ignoring the water-surface profile within a pipe. Another approach is to performing backwater calculations, on small spatial steps, for every flow condition in the system. This is not unreasonable for problems such as flood-plain studies, where only a few flows are considered. However, a much larger range of flows is possible when considering operational decisions for a sewer system. Previous research demonstrated the effective use of the hydraulic performance graph (HPG) for open-channel capacity determination. The HPG stores the results of backwater calculations for a reach so that these calculations do not need to be repeated. The HPG has been extended from that for open-channels to also describe pressurized flow in sewers. This paper describes a procedure that uses the HPGS for each reach of a sewer system, along with a description of the junction losses, to describe the conveyance of any bottlenecks in a system of sewers or tunnels for free-fsurface, pressurized, or mixed flow conditions. This method has been integrated into a geographic information system (GIS). The GIS stores the topology and geometric description of a pipe network, the HPGs for all reaches in the system, and coefficients needed to estimate junction losses. This allows for visualization of bottleneck locations and flow conditions throughout the system for any flow configurations and operation plan.

The rainfall runoff process is one of the most complex and non-linear real world problems in water resources and hydrology. The same amount of precipitation could generate different runoff over the same watershed depending on, for example, soil humidity conditions. An attempt was made in this paper to develop a fuzzy rule-based routine. The main objective was to develop a fuzzy rule-based system to forecast the peak flow rate (Q_max) over a watershed for six different storm events. The developed fuzzy rule system was applied to a drainage basin in North Carolina, in which SWMM (EPA Storm Water Management Model) simulations provided training sets to develop the fuzzy rule system. Geographic Information Systems (GIS) were employed to get the information on watershed characteristics. The resulting fuzzy-rule system was assessed by comparing its responses with the modeling results in EPA-SWMM 5.

The Tunnel and Reservoir Plan (TARP) is a system of 175 kilometers of deep underground tunnels and large reservoirs designed to capture and store combined sewer overflows of greater Chicago. Construction of the system began in the 1970's and currently, the tunnels are nearing completion and excavation of the reservoirs is underway. The hydraulic behavior of the system is inadequately understood, particularly the transition from gravity to surcharged flows. Because of the potential to form hydraulic transients under these conditions, an improved description of the hydraulic behavior of the system is a prerequisite to determining operational rules that better utilize the capacity of the system. In order to gain a better understanding of the hydraulic behavior in the tunnels, models are currently under development to model steady flow, unsteady flow, and hydraulic transients in the as-built system. A geographic information system (GIS) has been developed to provide a framework that facilitates managing the data, visualizing the output, and integrating the different modeling tools needed to describe this system. Of particular interest in this work is use of the GIS to store model results describing the steady-flow hydraulics of the system for the range of possible flow conditions. These stored descriptions of the hydraulics are used by more sophisticated models of the hydrodynamics of the system, thereby eliminating repetitive calculations that otherwise would be necessary for every time step in the unsteady-flow models. In addition, the GIS makes the modeling process more efficient by allowing multiple models to obtain necessary information, such as geometry and hydraulic coefficients, about the entire network from a single database. This allows changes made to the database to be quickly reflected in the models. Finally, the GIS provides an effective means of storing and displaying the model output clearly and concisely so that an assessment of the system performance can quickly be made.

The hydraulic performance graph (HPG), which consolidates all the backwater profiles of a channel reach into a family of delivery curves, provides a summary of the momentum of flow for the entire range of conditions. Earlier research by Gonzalez-Castro (2000) demonstrated that the approximation to the momentum of flow provided by the HPG can be coupled with an implicit finite-difference solution of the continuity equation to route unsteady flows through simple, unbranched channel reaches with accuracies approaching those of dynamic wave models. The model described in this paper adds to the earlier work by introducing the volumetric performance graph (VPG), which describes the volumetric water storage in the reach for the range of flow conditions computed in the HPG. The VPG provides a summary of the conservation of mass in the reach, replacing the finite-difference solution used in the earlier work. Instead of numerically solving the Saint-Venant equations in a coupled manner, as is typically done in unsteady flow-routing, the momentum equation is solved a priori and summarized in the HPGs, which are then used to describe the momentum at each time step. The description of momentum from the HPGs is coupled with the description of continuity from the VPGs to simulate the routing in a stepwise-steady manner. Benefits of this type of modeling include: (1) computation time — the momentum equation is solved for a range of conditions and summarized, as opposed to solving at each time step, and (2) precision — momentum is solved at fine resolution, but summarized to a coarser spatial resolution.

The handling of wastewater sludge is a significant challenge, because the amount of wastewater sludge is large, the handling, processing and final disposal of sludge are difficult and expensive, which could count for 40% of total operational costs of a wastewater treatment facility. It is important to determine rapidly the performance of sludge dewatering (solids recovery and sludge cake dryness) and to optimize timely the dosing of the conditioning chemical, so the operational cost can be reduced. This paper reports findings from a recent study that investigated the feasibility of using capillary suction timer (CST) as a tool to determine the performance of sludge dewatering. This laboratory research studied sludge samples taken from three different sludge treatment processes: mesophilic aerobic, mesophilic anaerobic, and thermophilic aerobic digestion. Two polymers, carrying high and low cationic charges, were used to condition a thermophilic aerobically digested sludge sample. Conditioned sludge was centrifuged at 2,000 rpm for 20 minutes. Experimental results revealed that when unconditioned sludge samples of various sources are compared, CST was not an appropriate indicator to predict quantitatively dewatering performance of sludge samples; when conditioned sludge samples (dosed by polymer at various rates) from a single source are considered, quantitative relationship exists between the solids concentration in the supernatant of the centrifuged sludge and CST of the uncentrifuged samples. Findings from this study suggest that CST can be used as an efficient tool to assist wastewater operators to assess rapidly the performance of dewatering process and make prompt decision for efficient and cost-effective operation of the dewatering process, which would help to reduce the costs of wastewater treatment facility operation.

The aim of this research was to study the utilization of bagasse (sugar industry waste) as adsorbents for removal of red and violet dyes. The dyes namely red C4G and violet 5BN used in textile industry for polyester and silk coloring respectively. The sorption of these dyes to bagasse and the characterization of the adsorptive property of the biomass for color removal were investigated by batch experiment. The influence of operating conditions like time, initial dye concentration and pH on process performance was also evaluated. Dye removal by bagasse was influenced by the pH of the solution, initial dye concentration, and time. Kinetic studies showed that the concentrations of C4G decreased very rapidly initially and remained nearly constant after 80 minutes but for 5BN rate of reaction was comparatively slow and after 240 minutes the concentration reached constant value. The maximum removal of C4G and 5BN on low-cost bagasse adsorbent was at pH 5.5 and pH 2 respectively. Maximum C4G and 5BN removal capacity of the bagasse was found 3.24 mg / g and 0.51 mg / g at 200 mg / l initial dye concentration. Kinetic experiment was conducted and validated for Lagrange's pseudo-first and second order system. It was observed that for C4G dye the reaction follows pseudo-second order rate constant and for 5BN dye reaction follows pseudo-first order rate constant. The Langmuir and Freundlich adsorption isotherm model were used to describe the equilibrium behavior of the system. The efficiency of the sorption was 99% and 76% for C4G and 5BN respectively.

Wastewater contains organic matter, nutrients like nitrogen and phosphorus, pathogens and other pollutants and its discharge in water bodies causes environmental problems like eutrophication, fish kills and odours. Research has been carried out over the years to find effective biological treatment methods to remove nutrients and in this direction the sequencing batch reactor (SBR) has demonstrated good potential for complete removal of phosphorus and nitrogen from domestic wastewater. Bench scale studies on SBR were carried out to assess its ability to develop phosphorus accumulating organisms (PAOs) in short period of time with seed material taken from sludge of septic tank and feed used was synthetic wastewater. Various researchers had reported that several months were taken to develop enhanced biological phosphorus removal (EBPR) sludge whereas in this study it was found that in a short duration of 21 days, the COD removal was 73.4% in anaerobic phase while the phosphorus removal yield (PRY) was 92%, which indicated that PAOs were grown in sufficient numbers. After enrichment, the SBR was fed with raw domestic wastewater which contained COD (260 mg/l), ammonia nitrogen (59 mg/l) and phosphorus (15.3 mg/l). The effluent at the end of the SBR cycle contained less than 15 mg/l of COD, ammonia nitrogen of less than 1 mg/l, nitrate nitrogen in the range of 10 to 11 mg/l and phosphorus in the range of 0 to 1.5 mg/l. The denitrification observed was 100% in the anaerobic phase. To remove nitrate nitrogen completely, an anoxic batch reactor was started and the final effluent contained COD of less than 20 mg/l, nitrate nitrogen less than 1 mg/l, phosphorus concentration less than 2.2 mg/l and ammonia nitrogen concentration of less than 2 mg/l. Kinetic study was done to determine the rate at which microbes treat wastewater to remove nutrients and it was observed that COD uptake was 0.058 mg COD/mg VSS within one hour from the start of anaerobic phase and corresponding phosphorus release was 3.49*10^–4 mg phosphorus/ mg VSS. The denitrification rate observed was 3.40*^–4 mg nitrate nitrogen/ mg VSS. The kinetic study also showed the phosphorus uptake was 5.04*10^–3 mg phosphorus/ mg VSS and the nitrification was 3.33*10^–3 mg ammonia nitrogen/ mg VSS in the first one hour of aerobic phase.

Four, 1-L bench-scale digesters were operated for 25 days to evaluate the effectiveness of oxygen and ozone on sludge stabilization. Each digester contained waste activated sludge generated from the Rocky Creek Wastewater Treatment Plant (WWTP) in Macon, Georgia. Two of the digesters were sparged with air and the remaining two digesters were sparged with ozone. The following parameters were measured frequently during the bench-scale study: pH, total and soluble chemical oxygen demand (COD), temperature, total and volatile solids, and total suspended and volatile suspended solids. The kinetics of volatile suspended solids (VSS) reduction was determined and average first order degradation constants (K_D) for the aerobic and ozonated digesters were 0.0824 days^–1 and 0.108 days^–1 respectively, indicating that ozone was more effective at destroying VSS than oxygen. Total chemical oxygen demand (COD) removals averaged 37% and 64%, respectively for the aerobic versus ozonated digesters. Soluble COD (SCOD) concentrations in the digesters increased from 0 to 15.5 mg/L in the aerobic digesters and from 0 to 293.5 mg/L in the ozonated digesters due to solubilization of the biological sludge solids. Approximately 1.82 mg of oxygen was required per mg of total volatile solids (TVS) destroyed. Average ozone dosages observed in this study were 2.6 and 2.8 mg of O₃ per mg of total solids (TS) destroyed for ozonated digesters 1 and 2, respectively.

With the increasing of the sewage delivery of housing estate, the quantity of residual sludge was increasing at the same time. The proportion of investment and operation cost used for treatment of residual sludge was higher in total cost. That brought many difficulties in treatment of housing estate sewage. In this paper, the non-residual sludge hydrolytic acidification process was taken to treat housing estate sewage. This internal cycle system was composed of medium-temperature anaerobic acidification reactor, hydrolytic acidification tank and contacting oxidation tank. Aerobic and anaerobic microorganism died and can be degraded continuously through a variable anaerobic-aerobic process. In this way, residual sludge produced in aerobic process could be digested thoroughly. Test showed that operation of acidification reactor had better effect under condition of temperature 34 degrees C, HRT 1.5 day, PH 5.5~6.0 and residual sludge can be decreased or zero emission. In this paper design and effective control of acidification reactor are also discussed.

Geographic Information System (GIS) is quickly becoming a critical component to develop and sustain asset management for today's wastewater utilities as most of their data is geographically referenced. This technology offers sophisticated data management and spatial analysis capabilities that can greatly improve and facilitate urban drainage infrastructure modeling and analysis applications. This paper presents a comprehensive GIS-based decision support system that integrates several technologies for use in the effective management of urban stormwater collection systems. It explicitly integrates ESRI ArcGIS geospatial model with advanced hydrologic, hydraulic, and water quality simulation algorithms, nature-based global optimization techniques including genetic algorithms for design and calibration of stormwater management models, automated dry weather flow generation and allocation, and automated subcatchment delineation and parameter extraction tools to address every facet of urban drainage infrastructure management. The geocentric interface allows seamless communication among the various modules. The resulting decision support system effortlessly reads GIS datasets, extracts necessary modeling information, and automatically constructs, loads, designs, calibrates, analyzes and optimizes a representative urban drainage model considering hydrologic and hydraulic performance requirements. It also makes it easy to run, simulate and compare various modeling scenarios,' identify system deficiencies, and determine cost-effective physical and operational improvements to achieve optimum performance and regulatory compliance. These combined capabilities provide favorable geospatial environment to assist wastewater utilities in planning, designing, and operating reliable systems and in optimizing their capital improvement programs.

Sewage in India is treated to primary or secondary level of treatment. Recently, standards for the indicator micro-organisms for the effluents from the sewage treatment plants (STPs) have been proposed. Selection of appropriate technology for the augmentation of the existing STPs is under consideration. Many of these plants are based on the Upflow Anaerobic Sludge Blanket Reactor (UASBR) technology. The fecal coliform count in UASBR effluent was found to be of the order of log cycles of six, which exceeds the WHO guidelines by an order of 3. The evaluation study of pilot plants had been carried out at two different UASBR based sewage treatment plants in India. One of the pilot plants is based on chlorination (2 MLD), and other is based on fixed film aerobic process (1 MLD, biotower). Evaluation study consisted of onsite monitoring of the COD and fecal coliform over a period of 3 months. Samples were collected from the inlet and outlet of the plant. It is contemplated to select an appropriate disinfection technology for the treatment of the effluents from UASBR based sewage treatment plants so as to meet the biological quality standards. The results show that the fecal coliform removal is up to 98.2 and 100% for biotower and chlorination respectively. Removal of COD has also been determined.

To deal with uncertainties in wastewater treatment plants (WWTPs), high safety factors are commonly adopted in the traditional plant design procedure, which may lead to an over-designed plant. In this paper, the Monte Carlo method is applied in both steady-state and dynamic simulations of the activated sludge model No.1 (ASM1) to quantify the uncertainty of the plant performance. Statistical analysis of the plant effluent indicates that it has a wider distribution, which demonstrates the motivation for using conservative design assumptions in the first place. However, we suggest that a better design approach is proposed based on an acceptable risk of effluent violations. To support this design approach, we will present methodologies for estimating the frequency of occurrence effluent violation based on 7-day and 30-day average effluent permit levels. Armed with this type of information, engineers, regulators and the community can more realistically evaluate the trade-off between risk and cost.

This paper describes an investigation into the treatment effectiveness and feasibility of constructed wetland (CW) system as a secondary wastewater treatment system, as an economic agricultural producer, and as a pretreatment phase for an ultrafitration/reverse osmosis UF/RO tertiary treatment plant. The treatment system consists of one vertical-flow infiltration CW cell (150 m² in surface area, 112.5 m³ in volume) and two settling basins (one before and one after the CW); gravel, coastal sand, and almond shells were used as CW media. The CW was vegetated with various plants including spineless cactus. Samples were analyzed for total plate count, turbidity, total nitrogen, total phosphorus, total suspended solids, biochemical oxygen demand, chemical oxygen demand, temperature, conductivity, and pH. The CW operation indicated a significant reduction in influent water quality and proved to be of suitable for smooth operation of the UF/RO pilot plant. High biomass growth was observed on the spineless cactus and banana and little or negative growth was obtained on other planted crops.

The role of wetland plants in the treatment of wastewater was investigated. The research was carried out in the backdrop of conflicting reports about the role wetland plants play in wastewater treatment. The plants' ability to release oxygen through their roots in wastewater environment was investigated in subsurface flow wetlands. The research investigated the role of aerobic and anaerobic processes in constructed treatment wetlands. Oxygen release by the wetland plants has been reported by researchers. One of the most recent studies have reported quantification of wetland plant oxygen release through the use of microelectrodes. However, the microelectrode measurement method had its inherent drawback of possible under or over estimation of oxygen release by wetland plants. This research is an endeavor to model a field wetland based on the assumption that wetland plants do not release enough oxygen for use in biochemical oxygen demand (BOD) removal. The wetland was modeled as an aerobic-anaerobic system. The model takes into account all the possible mechanisms of oxygen addition and consumption. These mechanisms include atmospheric reaeration, plant oxygen release, wastewater oxygen demand, and biomass oxygen demand. The modeling results indicated that ~ 65% BOD removal occurs aerobically and rest is removed anaerobically.

Currently, a reliable method for predicting the remaining life expectancy (RLE) of a land treatment system is not available. Hu (2005) concluded column studies by intermittently loading columns with a high influent P concentration to simulate P adsorption capacity and the low hydraulic loading rate conditions in the field. The objectives of this study were to: (1) further verify Hu's methodology, (2) evaluate P fate and transport in these columns, and (3) improve the existing model for predicting the RLE. Column tests were conducted under different influent P concentrations (e.g., 3000, 1000, 500, and 100 mg-P/L), and P breakthrough in each column was monitored. The results indicate that the predictions of the RLE of the Muskegon system were very similar for the three different influent P concentrations, but varied with soil types. Therefore, loading a short column packed with field soil intermittently with a high influent P concentration may be an efficient way to accelerate the process that might occur in the field and to predict the life expectancy of a wastewater land treatment system.

A review of modeling approaches for simulation of wastewater treatment in vegetated subsurface bed (VSB) systems is presented. A multi-scale biofilm-based model that includes substrate utilization both in bulk liquid and the biofilm is formulated and described. The model accounts for transport of substrate in the liquid phase, and growth and decay of biomass in suspension and in the biofilm. Dynamic changes in porous media hydraulic flow, combined with attachment and detachment of biomass are considered. Natural precipitation and evapotranspiration are also considered. Field application of the model along with a survey of the parameters is presented and performance of the model for simulation of organic matter removal and clogging is assessed. The mechanistic model simulates the performance of a constructed wetland treating wastewater very well, and has potential for use in design of constructed wetland systems.

In this study, a model has been developed to optimize the operation of flow control valves according to variable demands under a selected water leakage percentage. A non-linear optimization objective function is used to minimize the differences between the available nodal pressures and those required. This objective function is subject to constraints; represent assigned minimum and maximum limits for both valve settings and allowable head deviations, in addition to constraints represent the application of the continuity equation at each node and the application of energy conservation law at each loop of pipes. The objective function is further modified by adding penalty of the statistical coefficient of variation of nodal pressures. This model has been verified using a network example presented by previous researchers in the same field and then applied on a case study network in Iraq. The results of the case study indicate the capability of the system to obtain optimal valves settings for the selected input data.

Leakage control is one of the most important issues in water networks. This paper presents leakage management and how to organize and analyze a water distribution system for leakage purposes. Also various aspects of management of water supply networks are depicted in order to provide integrated hydraulic model in (Geographical Information System) GIS. These consist on determination of required data structures and, how to supply and reintegrate the information in GIS. The specification and applicability of the hydraulic model, in GIS for leakage management in urban water system, is studied with practical project in Saveh city of Iran. These are accomplished using Arcview as GIS base and EPANET software for hydraulic modeling and link between the above programs is DC water extension. Based on the analyses carried out and using the relationship between hydraulic and physical characteristics of distribution system, leakage indices have been calculated. The results can provide valuable management guidelines to identify leakage location in the system. Also a flowchart of data management and analyzing hydraulic systems in GIS environment has been obtained that can be useful in any other process of such analysis.

Water accountability standards are increasing for many water utilities as supplies are progressively strained. Water demand for San Antonio, Texas, the eighth largest city in the United States, is expected to double by 2050. At this time, San Antonio is solely dependent upon groundwater, the majority of which comes from a capped withdrawal of the Edwards Aquifer. In addition to a full portfolio of water conservation policies, San Antonio Water System (SAWS) is undergoing a water audit using the standards and methodology of the International Water Association (IWA). This audit is being completed in anticipation of the Texas Water Development Board (TWDB) requiring audits of water purveyors starting in 2006. Successful application of the IWA method to SAWS infrastructure and management practices requires some adaptations to the audit procedure. Changes to the water audit methodology and new techniques for calculating audit components are presented.

Water systems' vulnerability to natural disaster and terrorist attack has prompted extensive study of the probability and consequences of their potential failure. These systems are vital in their own right because they provide water for drinking, but they are also indispensable components of many cities' fire response plans. Water systems are also dependent on — or key inputs to — many of the other infrastructures that support daily life and efficient emergency response. Any risk assessment of water systems must therefore consider the importance of water systems' interdependence with fire response and other affected infrastructures. More investigation is needed on the effects of infrastructure interdependence on water systems' vulnerability. To highlight the importance of infrastructure interdependencies, a coupled model of water system performance and urban fire spread and suppression will be presented. The system's ability to suppress an urban fire under moderate damage to the water system will be modeled, and the consequences of this multi-mode failure — disabled water system and urban fire spread — will be discussed. This coupled modeling approach allows diagnosis of water systems' potential vulnerabilities to multi-mode attacks or failures (MMAFs) and development of possible mitigation strategies.

Nitrogen removal capability of bio-reactor systems were investigated in the laboratory in order to extend the treatment process for river basin management. Biomass from activated sludge was immobilized using gel and bio-pellets were prepared. Three upflow bioreactors R1, R2 and R3 were packed with bio-pellets, anaerobic granules, and mixture of bio-pellets anaerobic granules and biodegradable plastic respectively. Comparing the performance of reactors, R1 demonstrated well at nitrification while R2 showed its capability in denitrification and R3 showed good performance in both nitrification and denitrification. Moreover, results showed that R3 removed 80% of incoming total nitrogen where as reactors R1 and R2 removed less than 60% of total nitrogen. Despite the effluent total organic carbon in all reactors was almost same, N removal process and rate in each reactor was different. It suggests that sources of biomass define the diversities of biomass in the reactors which ultimately guides the N removal process and rate as well. The developed system is wide applicable and has operational advantages in terms of efficiency, aeration cost, and biomass handling.

It is impressive how lengthy the list of chemical technologies based on redox phenomena is and the treatment objectives one can achieve based solely on redox chemistry. This paper provides an overview of oxidation-reduction processes used for the transformation and destruction of targeted water contaminants. The most important oxidation-reduction reagents are further discussed here and classified in three general categories. Key characteristics of each technology are also underlined.

Presented in this paper was a numerical model for the Petroleum hydrocarbons transported in sediment laden flows. The model was developed base on the basic equations of the two-fluid model for sediment laden flows so that the fate and transport of either dissolved or particulate phase of PHs can be simulated without introducing partition coefficient. More important was that by invoking the two-fluid model the model longer need the assumption that the particulate phase of PHs was under the same convection and diffusion effect as dissolved phase. Verifications by flume experiments were also presented in this paper. Comparisons between simulations and observations indicated that the model presented in this paper has a fairly good accuracy so far as the flume data were considered.

High level concentration of fluoride affects human health by causing incurable skeletal and dental fluorosis, non-skeletal manifestation and combinations of above. Defluoridation techniques have been developed and implemented are not continuous and cost effective. At present there is an urgent need of having economically viable continuous flow defluoridation units for rural areas. This study evolves with a noval modification in the popular Nalgonda technique as a continuous flow economical defluoridation unit. Experiments on horizontal and vertical flow defluoridation filter baffles comprising of locally available materials like wood charcoal, medium coarse sand & brick jelly with Nalgonda chemicals revealed that the fluoride removal efficiency of 68% in the pH range of 7 to 8.5 for the maximum 4 mg/l of fluoride concentration has been observed. The economical analysis performed between the assumed extension of a particular comprehensive water supply scheme and the water supply scheme designed with the evolved continuous flow defluoridation unit costs only 26% of the general comprehensive water supply scheme. The independent defluoridation unit costs only 13% of the total cost of the proposed water supply scheme.

The impact of low pressure UV lamps on the oxidation of ammonia (NH₃) in the presence of individual halide ions (bromide (Br^–), chloride (Cl^–) and iodide (I^–) was investigated and revealed that the ions have the potential to accelerate ammonia photo-oxidation. The process was found to be dependent on solution pH, the type of halide ion and the concentrations of halide ion and aqueous ammonia. Protons are released during the reaction while the halide ion concentrations remain unchanged. Nitrite (NO₂^–) and nitrate (NO₃^–) are produced as final stable nitrogen species, with the yield being dependent on the initial pH of the irradiated solution. NH₃ oxidation occurred with Br^– and Cl^– at all pH levels, but in the presence of I^– it proceeded only at basic pH. Sulfur hexafluoride (SF₆) was used as an electron (e^–) scavenger to demonstrate that ammonia oxidation generates e^– in solutions containing halide ions. The process was confirmed with the formation of fluoride (F^–) and sulfate (SO₄^2–) ions.

This paper focuses on the formulation and assessment of a second-order accurate Finite Volume (FV) shock-capturing scheme for modeling two-phase water hammer flows using the single-equivalent fluid approximation. The FV formulation of the proposed scheme ensures that mass and momentum are conserved. For achieving a second-order rate of convergence for smooth transients (i.e., flows that do not present discontinuities), a second-order boundary condition is implemented using virtual cells and the theory of Riemann invariants, which is similar to that used for the Method of Characteristics (MOC). Since the two-phase flow governing equations when using the single-equivalent fluid approximation are the same as the one-phase water hammer equations (with exception that the pressure-wave celerity is constant in the latter case), and because analytical solutions are available for the latter case, the numerical efficiency of the proposed model is tested using the one-phase water hammer equations with constant pressure-wave celerity. The validity of the single-equivalent fluid approximation and the proposed scheme herein are verified with laboratory experiments. For one-phase transient flows, numerical tests were performed for smooth and strong transients. For smooth transients, the results show that the efficiency of the proposed scheme is highly superior to the fixed-grid MOC scheme with space-line interpolation and another second-order FV scheme. For one-phase strong transient flows, the results show that the efficiency of the proposed scheme is highly superior to the MOC scheme, and significantly superior to the other FV scheme for coarse grids. For fine grids, the accuracy of the proposed scheme converges to that of the other FV scheme. For two-phase water hammer flows, the results show good agreement between experimental data and the results of numerical simulations.

Microbial As (III) oxidation was investigated for 204 days in a continuous stirred tank reactor (CSTR) with a pure culture of Alcaligenes faecalis strain O1201 under a range of hydraulic retention times (12.8, 25.6, 51.9, 67.4, and 90.7 hours) and influent As (III) concentrations (1,000, 2,000, 4,000, and 8,000 mg/L ). Air was supplied through a gas diffuser to maintain a minimum level of dissolved oxygen of 2 mg/L throughout the entire operation. NaOH was fed into the CSTR to neutralize hydrogen ions produced during As (III) oxidation and maintained pH at 7±0.1. Temperature was maintained at 30±2 degrees C using a heating tape equipped with a temperature controller. Nine steady-state operation conditions were obtained with near-complete oxidation of As (III) for each phase.

Changes in annual reservoir inflow and flood release volumes due to persistent multi-year dry or wet periods were investigated for the Fort Cobb Reservoir. A time-series analysis of the 1940–2004 annual precipitation revealed three dry and one wet period, called decadal variations. Corresponding strong variations were found in the reservoir inflow and flood release records. The sensitivity of watershed response, reservoir inflow and flood release volume to decadal precipitation variations suggested that water resources and water quality assessments in central Oklahoma should account for decadal precipitation variations. Along the same lines investigations based on numerical model simulations need to consider such climatic variations in the calibration, validation and application phase.

A study of the influence of interdecadal and interannual Pacific oceanic / atmospheric variability on the Wind River Range (WRR), Wyoming is presented. The WRR is an unbroken 160-kilometer barrier that is host to 63 glaciers, the largest concentration of glaciers in the American Rocky Mountains. Glacial recession over the past half century has resulted in an increased interest in the region. Instrumental datasets were obtained for unimpaired streamflow and snow water equivalent for stations in the Green River Basin (GRB — west slope of WRR) and the Wind-Bighorn River Basin (WBRB — east slope of WRR). The phases (cold or warm) of Pacific [El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] oceanic / atmospheric phenomena were identified. Statistical significance testing of the datasets, based on the interdecadal and interannual oceanic / atmospheric phase (warm or cold), was performed applying the parametric t-test test. The results show that the interannual ENSO phase influences streamflow and snow variability in the WRR and the interdecadal PDO phase influences snow variability during La Niña events.

The effects of El Nino and La Nina periods on the maximum daily winter period depths of precipitation are examined using records from five precipitation gages on the Nevada Test Site. The potential implications of these effects are discussed.

The National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center issues total precipitation and average temperature forecasts for 3-month periods for relatively large areas (forecast divisions are about 9 x 10⁴ km²). Incorporation of the climate forecasts into farm level decision support systems necessitates downscaling the forecasts to local and daily time scales. Since any measure of the skill of seasonal climate forecasts is expected to depend on scale (specifically, more skillful for larger areas and longer time periods), there is concern that downscaling will dilute current forecast skill, possibly to the point of non-utility. As an initial exploration, this study will determine any change in die dependability of precipitation and average temperature forecasts downscaled to local and monthly time scales for several locations in Oklahoma. Dependability is a skill measure that assesses only those forecasts that are discernibly different from climatology. Downscaling to daily time scales is done in two steps, first to monthly forecasts, and then to generated ensembles of daily forecasts. This initial study will examine only the first step, the monthly downscaling. In order to assess the relative impact of downscaling in space versus time, forecasts will be downscaled separately in each, and then downscaled in both. Current forecast dependability for Oklahoma at the larger scales is limited compared to regions of the US that experience stronger ENSO impacts, so any degradation from downscaling to monthly forecasts and specific locations should be readily apparent.

This paper for the Proceedings is due well before we will have results of workshops on problems which may arise from new forms of water transfer, so the paper describes the larger context and the new forms. These materials focus on Colorado, but applications are not limited to Colorado. The presentation will report on later progress; both will be available on a website to be established. The organization of the paper is (1): Abstract of the Presentation, (2) Changing Demands for Water — Additional Context, (3) Under-represented Interests, (4) New Forms of Transfer Under Discussion, (5) Potential Benefits of Better Management: The Big Vision, and (6) Getting There. The desirability of increased flexibility in agricultural water management in the Western U.S. has been long established. The pressures of changing demands for water interact with very fast urban and peri-urban population growth to threaten transfer of irrigation water away from rural areas and traditional uses with minimal benefit to the areas of origin, and with significant threat to environmental and recreational interests. In a thin, disorganized water market, transfers have been generally large, carried high adverse impacts, and been arranged in secretive fashion. Leasing, water banking, and other flexible management techniques have increased in recent years, partly in response to high interest in the preservation of agriculture and its landscapes. Improved flexibility in management includes increasing opportunity to respond to climate information. Work on barriers to use of climate information applications led to envisioning use of water transfers to create means for non-market interests to enter water rights markets and to stimulate improvements in agriculture and rural viability. This paper includes a concise presentation of the author's formulation of three kinds of transfers needed, and principles important for water transfers.

Complex watershed models with decision support systems (DSS) have been developed to aid in integrated water resources management (IWRM) and sustainable water supply planning. Detailed simulation models are important in determining operations policy but there is also a need for screening models that can compare a full range of management options before developing detailed site specific IWRM models. This study is an initial effort to develop a generic, optimization model and DSS that considers a comprehensive set of options for managing the quantity, quality, routing and use of water throughout the watershed including traditional water sources, direct and indirect water reuse, groundwater banking, demand management and land use management. The model is developed in accessible, familiar software with a user interface to facilitate the application of the model. A DSS is integrated in the interface to provide extensive output analysis to aid in recognizing and understanding relationships and tradeoffs, thereby supporting informed decision making.

It is well recognized that hydrologic time series, like rainfall, streamflow etc. are modulated by various large-scale atmospheric circulation patterns, like El Niño Southern Oscillation (ENSO) etc., throughout the globe by climatic teleconnection. Indian summer monsoon rainfall (ISMR) is proved to be significantly influenced by ENSO. Recently, it is established that relationship between ISMR and ENSO is modulated by the influence of atmospheric circulation pattern over Indian Ocean region, like, Equatorial Indian Ocean Oscillation (EQUINOO). Thus, for Indian subcontinent, hydrologic time series are significantly influenced by ENSO along with EQUINOO. Though influence of these large-scale atmospheric circulations on rainfall is investigated, their influence on streamflow is yet to be investigated. In this paper, information of ENSO from tropical Pacific Ocean and EQUINOO from tropical Indian Ocean are used in terms of their corresponding indices for streamflow forecasting. To model the nonlinear, time-varying and dynamic relationship between streamflow and such large-scale atmospheric circulation information, Artificial Neural Network (ANN) methodology has been opted for the present study. Efficient optimization of ANN architecture is obtained by using evolutionary optimizer based on genetic algorithm. This study concludes that use of such large-scale atmospheric circulation information potentially improves the performance of streamflow prediction which, in turn, helps in better management of water resources.

The study presented here focuses on the changes/trends in U.S. streamflow from 639 unimpaired stations for the period 1951 – 2002. This is particularly relevant since the issue of climate change is of interest to many and studies have also indicated an abrupt change in climate around the year 1976/77. Trends in U.S. streamflow were evaluated using three statistical tests: Spearman's Rho, Mann-Kendall, and Linear Regression. Step changes in the streamflow data were evaluated using the Rank Sum and Student t test. The multiple tests provide robust results in which areas of the U.S. have experienced significant changes in streamflow data. The number of stations experiencing an increasing or decreasing trend/step change in any given water year were evaluated at a 95% confidence level. Results indicated that the Upper and Middle Mississippi River basin has an increasing trend in streamflow quantity. For the Pacific Northwest and some stations in Florida, the streamflow quantity is decreasing.

Concern over changes in global climate has increased in recent years with improvement in understanding of atmospheric dynamics and growth in evidence of climate link to long-term variability in hydrologic records. Climate impact studies rely on climate change information at fine spatial resolution. Towards this, the past decade has witnessed significant progress in development of downscaling models to cascade the climate information provided by General Circulation Models (GCMs) at coarse spatial resolution to the scale relevant for hydrologic studies. While a plethora of downscaling models have been applied successfully to mid-latitude regions, a few studies are available on tropical regions where the atmosphere is known to have more complex behavior. In this paper, a support vector machine (SVM) approach is proposed for statistical downscaling to interpret climate change signals provided by GCMs over tropical regions of India. Climate variables affecting spatio-temporal variation of precipitation at each meteorological sub-division of India are identified. Following this, cluster analysis is applied on climate data to identify the wet and dry seasons in each year. The data pertaining to climate variables and precipitation of each meteorological sub-division is then used to develop SVM based downscaling model for each season. Subsequently, the SVM based downscaling model is applied to future climate predictions from the second generation Coupled Global Climate Model (CGCM2) to assess the impact of climate change on hydrological inputs to the meteorological sub-divisions. The results obtained from the SVM downscaling model are then analyzed to assess the impact of climate change on precipitation over India.

This paper presents the development and application of a three-dimensional numerical model for simulating the cohesive sediment transport in water bodies where both currents and wind-driven waves are important. The model was verified by a simple test case with an analytical solution (nonconservative tracer in a prismatic channel with uniform flow) and applied to Deep Hollow Lake, a small oxbow lake in Leflore County, Mississippi. The model produced predictions within 2% of the analytical solution. The bottom shear stresses induced by currents and waves were calculated, and the processes of resuspension, deposition and settling were considered. The primary forces associated with sediment transport were caused by wind-induced currents and waves. Simulated sediment concentrations were compared with limited field observations available, with generally good agreement. Simulated concentrations for a scenario with wind-driven waves were about one to three times greater than for a simulation without wind-wave processes.

Integrated numerical models are developed to simulate irregular wave deformations, wave-induced currents, sediment transport, and morphodynamic changes around detached breakwaters in coasts. The models are capable of taking into account various wave deformations, e.g. diffraction, transmission through permeable structure, breaking, etc. The computed morphodynamic changes around a detached breakwater, including deposition/erosion behind the structure, local scours at tips of the structure, and bars in offshore, are in good agreement with the measurements.

The Altamaha River has the largest watershed among Georgia's rivers and the second largest one among the eastern United States. Despite its importance, die Altamaha River sound and its hydrodynamics are not studied extensively. This study is composed of two parts. In the first part we investigated hydrodynamics in the Altamaha River sound using a numerical model in order to understand the basic behavior of contaminant transport in this region. This numerical study is carried out using EFDC (Environmental Fluid Dynamics Code), which is a widely used 3-D hydrodynamics and transport model. To simulate a realistic case, various data such as history of wind and river discharge is obtained and applied. Result shows that the tides are the major forcing factor in contaminant transport in the sound. A three-dimensional structure of salinity, a salt wedge, is also observed to influence the transport process. The second part of this study deals with impacts of possible hurricanes in the region. A hypothetical long wave as a storm surge is assumed and its effects are simulated using the same techniques and tools used in the first part. No significant delay of wave is observed. The transport of contaminants released by this flooding is studied as well with drifting particles in the simulations. The movement of particles depends on where they are initially released and geographical configuration of the release point. Some particles settle on ground and others stay in bays several days before they are discharged into the ocean.

This study compares experimental data taken from a submerged hydraulic jump to results from a k – ε and RNG numerical simulation. The internal flow structure of the jump is investigated by comparing longitudinal and vertical velocity profiles along a vertical direction as well as water surface profiles. The maximum turbulent kinetic energy and longitudinal velocity distribution along the length of the jump are also investigated. The characteristics of the recirculation eddy are investigated by locating the reverse flow in the longitudinal direction. Previous research done on hydraulic jumps has relied on assumptions about the turbulent flow field whereas in this study the turbulence is a part of the solution. The computational grid is based on the experimental set up. The CFD program FLOW-3D was used to simulate the experimental conditions with k – ε and RNG turbulence closure schemes. The results showed that the RNG model performed better in the near bed regions. Also, mean flow conditions returned more quickly in the experiment than either model.

The generating capacity of a power plant is being increased through the addition of another power block at the facility. The plant utilizes a once through cooling system with a large onsite pond for water storage. The new power block will require additional pumping capacity. A large intake structure containing eight 6.31 m³/s circulating water pump in separate bays is located on the pond. One proposed approach for supplying cooling water to the new power block was through the addition of six 3.15 m³/s pumps within the existing intake bays. This approach would reduce the construction schedule and the project cost. A commercial computation fluid dynamic (CFD) model was used to investigate the pump approach hydraulics, and evaluate the likelihood of traditional design modifications to improve the flow conditions approaching the pump intakes. Traditionally, physical hydraulic models have been used to evaluate pump intake design modifications. A CFD model was used for this study because it could demonstrate the feasibility of the project more quickly and at a lower cost than it would take for performing a physical model study. Results from the CFD model demonstrated that traditional intake design modifications could improve the intake hydraulics.

Several software programs have been developed to assist in the hydraulic design and analysis of culverts. Of the available programs, HY8 is the most widely used and distributed. The first version of HY8 was provided by the Federal Highway Administration (FHWA) for distribution in the 1980s. Since that time, understanding of culvert hydraulics has increased significantly and acceptable modeling techniques have been further developed. Computer capabilities have also advanced to facilitate better graphical displays and post processing options. As a result, modernization of HY8 is timely. This paper will provide a brief overview of the existing HY8 software in order to understand its capabilities and limitations. Further, the need for and status of an updated version of HY8 will be presented, including a comparison of the old and new HY8 interfaces.

We present a complete analytical model for mean velocity profile in turbulent boundary layers. The model integrates the conventional log-wake law and the Barenblatt power (scaling) law in the intermediate region so that it includes the effects of the Reynolds number. Furthermore, it includes the effects of the wall and the boundary layer edge so that the model can describe the entire turbulent boundary layer mean velocity profile analytically. The model has been confirmed with recent laboratory experimental data of Osterlund.

A three-dimensional (3D) computational fluid dynamics (CFD) model of an outfall system, discharging cooling water to a reservoir through an existing outfall structure and a proposed diffuser, is presented in this paper. A repowering of the plant would increase the discharge from 55 m³/s to 76.5 m³/s. The CFD model used for the study consisted of over 1.3 million computational cells, with grid spacing varying from 0.05 m to 2.5 m. For the existing conditions, the model results indicated that a high velocity jet from the outfall structure was deflected southward and the jet impinged the southern embankment. To minimize potential erosion, the ports of the diffuser were designed to discharge water towards the water surface with a northward velocity component. With such a diffuser, model simulations indicated a significant reduction in velocities near the southern embankment. The 40 percent increase in the outfall discharge did not significantly increase the maximum near bed velocities in the reservoir.

Mercury is a hazardous metal in the environment that in many cases is concentrated in riverine and estuarine bed sediments, from which mercury can be mobilized due to erosion of the top layer. In this research, a one-dimensional flow and transport sub-model representing the transport of mercury in the river is coupled with several one-dimensional sub-models incorporating diffusive transport, transformation and sorption of mercury species in the bed sediments. Transport of dissolved and particle-associated mercury in the water, and thus the effect of erosion and resuspension of particles on the transport process, is taken into consideration. A set of one-dimensional reactive transport sub-models are utilized to represent the release, adsorption, and burial of mercury species to the bed sediments. This transport model is coupled with a detailed biochemical reaction network that includes main mercury species as well as major components which are effective in production of Methyl-Mercury. The goal of this coupling is to quantify methylmercury production using basic principles. Model parameters are obtained using available literature data and by calibration of the one dimensional-reactive transport model to available column and batch study data. The model can be used for simulating transport of mercury and production of methylmercury, examining various remediation scenarios, and evaluating the effect of anthropogenic activities on resuspension or burial of mercury species in water systems after doing appropriate calibrations.

South Florida Water Management District (SFWMD) manages man-made and natural systems including the Kissimmee River, Lake Okeechobee, constructed wetlands and the Everglades. Water within this complex hydrologic system is conveyed through a network of canals and controlled by over 200 major and 2000 smaller hydraulic structures (i.e., gated culverts, gated spillways and weirs) and about 25 pumping stations. Accurate estimate of the quantity of water passing from one component of the system to the other is inevitably vital for water resources planners as well as decision makers in meeting the SFWMD's main goals including flood protection, environmental restoration and water supply. As a result of this, the SFWMD continuously monitors water levels and operation settings (gate openings and pump engine speeds) at water control structures and subsequently computes flow employing appropriate flow equations derived from governing hydraulic principles. These flow equations, however, need to be calibrated in an attempt to generate optimal values of flow equation parameters that minimize the error between computed and measured flow. For successful calibration of flow equations, however, measurements need to spread over the entire range of operation settings of the hydraulic structures and should cover all possible flow types. Planning streamgauging to minimize data redundancy and in turn cut monitoring cost entails extracting near-realtime water levels (head water and tail water) and operation conditions, identifying data gaps and determining the suitability of current conditions for taking measurements. In order to automate the flow analysis and streamgauging planning processes, a comprehensive computer tool is developed by integrating flow computation and data gap identification algorithms with flow measurement, near-realtime, and structure information databases. The developed tool including a graphical user interface has the capability to calibrate flow ratings, compute flow, summarize flow types, visualize flow parameters, depict current flow condition and identify streamgauging opportunities. The developed tool was tested on hydraulic structures including pumps, gated spillways, and gated culverts. It has subsequently applied in planning regular streamgauging as well as emergency streamgauging during the hurricane season.

Simulation of best management practice (BMP) and low-impact development (LID) effects on stormwater quality is discussed with reference to the EPA Storm Water Management Model (SWMM), version 5. Many such treatment facilities demonstrate a lognormal distribution of effluent event mean concentrations (EMCs). Methods for use of SWMM5 to produce simulated EMCs with similar frequency characteristics are discussed in this paper. Model output was not available at the time of preparation of this paper and will be shown when the paper is presented.

The mechanisms responsible for contaminant removal from a bottom rectangular cavity in a channel are investigated using fully three-dimensional (3D) Large Eddy Simulation (LES) simulations. The aspect ratio (length/depth) of the 2D cavity is L/D=2 and the neutrally buoyant contaminant (passive scalar) is introduced instantaneously inside the cavity once the flow has developed. The flow upstream the cavity is fully turbulent. The large scale coherent structures in the shear layer region induce large scale pressure fluctuations at the trailing cavity edge and convection of patches of vorticity inside the cavity, parallel to the trailing edge. These patches modulate the intensity of the jet like flow that develops along the trailing edge and bottom cavity walls. It is shown that the eddies convected from upstream of the cavity can play an important role in accelerating the extraction of contaminant from inside the cavity. It is found that the contaminant ejection can be described using simple 1D dead-zone theory models in which a single-valued global mass exchange coefficient can be used to describe the contaminant mass decay inside the cavity over the whole extent of the ejection process.

Large Eddy Simulation (LES) is used to numerically investigate the horseshoe vortex (HV) system around a vertical bridge abutment located on a flat bed in a straight channel with vertical lateral walls corresponding to conditions at the initiation of the scour process. The simulation is performed with upstream fully turbulent flow including the turbulent fluctuations obtained from a precalculated LES simulation. The dynamics of the instantaneous coherent structures associated with the HV system around the base of the abutment and the spectral content of the flow in this region are analyzed. Due to the flat bed conditions, for which the HV system is not stabilized by the presence of the scour hole, very large random variations in the structure, position, size and overall intensity of the turbulent HV system are observed. In particular, the HV system appears to oscillate between a zero-flow mode in which the main HV is situated closer to the abutment and the near-bed jet flow beneath it is weak and separates early, and a back-flow mode in which the near-bed jet flow is stronger and separates at a larger distance from the abutment, and the main HV eddy is larger. It is observed that the legs of the horseshoe vortices can interact, at times, with the eddies shed inside the detached shear layer (DSL). The distribution of the bed shear stress shows that the largest values are present in the strong acceleration region near the tip of the abutment, but high bed shear stress values are observed beneath the HV system. It is found that the bed shear stress fluctuations around the local mean values can be very high, especially in the region beneath the separated shear layer. The pressure fluctuations and resolved kinetic energy levels are found to be very high inside the HV region compared to the surrounding flow. These high values are produced primarily by the low-frequency chaotic switching of the HV system between the zero-flow mode and the back-flow mode.

A numerical model for local scour with free surface and automatic mesh deformation is constructed and numerical simulation is carried out to compare with experimental results. The kappa-epsilon model is used to simulate the turbulent flow field. Two interfaces (water and air, water and sediment) in the domain are captured with different approaches. The free surface of the flow is captured by Volume of Fluid (VOF) scheme which is a Eulerian approach. The water-sediment interface (bed) is captured with moving mesh method which is a Lagrangian approach. The flow field is coupled with sediment transport using a quasi-steady approach. Good results have been obtained using current model. The flow field is comparable with the experiment. Scour patterns are similar to the experimental data.

The objective of this research project was to develop a 1-dimensional hydrodynamic/ sediment transport model to simulate flows and sediment transport in rills. The present paper focuses on only the hydrodynamic component of this research. There are many challenging issues that need to be addressed regarding flow in rills. The most important issue is that flow under certain conditions can become transcritical. In this case, step and pool sequences become ubiquitous features of the geomorphology of a rill. In order to address this issue an enhanced TVD-MacCormack scheme was employed. The sensitivity and validity of the code, named 3ST1D (steep stream sediment transport 1-D), was tested for two cases. Because the emphasis here was on the hydrodynamic component of the model, the bed was fixed for the two test case scenario considered here. The model results satisfied the continuity equation for the stream reaches considered and provided and adequate mapping of the water surface profile and the depth averaged velocities.

The gravity currents formed by instantaneous releases of a fixed volume of a suspension of fine sediment into a rectangular channel filled with tap water are studied numerically. The numerical model based on the filtered Navier-Stokes equations and mass transport equation is used to model dynamics of the flow and sediment transport. The effects of subgrid eddies on flow and sediment transport were calculated based on the modified Smagorinsky model that takes into account the effect of buoyancy on turbulence. The sediment transport is computed by the dispersion model. The governing equations are solved based on the operator-splitting algorithm and the third-order CCS scheme, which employs the Crank-Nicolson scheme for time advancing and the cubic spline to fit the spatial distributions of physical variables such as velocity components and concentration. Such a numerical scheme has been proven stable and almost free of numerical diffusion. The paper presents the comparisons between the numerical results and the experimental data such as propagation speed and areal sediment deposit. It is found that the numerical model is capable of correctly reproducing the flows and the associated sediment transport processes.

A higher-order accurate numerical scheme is developed to solve the advection-dispersion equation. A staggered-grid system is introduced with the first-order spatial derivatives being approximated by the fourth-order accurate finite-difference scheme, thus keeping all truncation errors to a smaller order of magnitude than that of the dispersion term. The dispersion term, a second-order spatial derivative, is discretized by the second-order accurate finite-difference scheme. For the time derivative, the fourth-order accurate Adams predictor-corrector method is used. The numerical method is validated against available analytical solutions for a one-dimensional problem. The stability analysis is carried out using the Van Neumann method. It is shown that the proposed algorithm has a good stability property and there is no need to add a numerical dispersion term. As a result, the model can provide more accurate and stable results for long-term simulation. The model is demonstrated to be a useful and accurate modeling tool for a wide range of transport problems.

Many existing river morphological models are limited by their inability to account for erodible banks. In this study, the sediment continuity equation was solved to determine the rate of bed degradation and aggradation. The rate of bank erosion was calculated by determining bed degradation, lateral erosion, and bank failure. To be applicable to the West Jordan River, two layers in the bank surface were considered herein. This bank erosion mode distinguishes itself from other models by relating bank erosion rate with not only flow but also sediment transport near the bank. Additionally, bank height, slope, vegetation, and thickness of each layer in the bank surface were considered. For the purpose of long-term simulation, decoupling technique is used among the flow, sediment transport, and bank erosion models. Furthermore, a new technique of computational mesh adjustment was also put forward. The developed model was then applied to simulate the processes of meandering migration in the study reach from 1981 to 1992. The reasonable agreements between simulated results and the available observations indicate the capability of this model in simulating channel morphologic change in the West Jordan River, Utah.

Evolution of meandering channels, a complex morpho-dynamic process, has been the focus of research challenging geomorphologists and river engineers for decades. The evolution of meandering channel is a result of the complex interactions between flow, sediment transport, and bank erosion. A numerical model including a depth-averaged two-dimensional hydrodynamic flow model, a sediment transport model, and a bank erosion model was developed to simulate the evolution of a low sinuous meandering channel into a high sinuous one. The sediment transport model calculates both bed load and suspended load assuming equilibrium sediment transport. Bank erosion simulation consists of two interactive processes: basal erosion and bank failure. The mass conservation equation where sediment from basal erosion and bank failure is considered as a source term, was solved to obtain the rate of bank erosion. Then, this model was applied to simulate the evolution of free meandering channels in laboratory experimental settings. The model successfully replicated the evolution processes of meandering channel from downstream translation, lateral extension, and then follows by upstream and downstream rotation when sinuosity approaches 3.7. Plots of meandering planforms illustrate the capabilities of numerical model in simulating the evolutions of meandering planform (e.g. downstream translation, lateral extension, upstream and downstream rotation).

This paper presents an experimental study conducted at the St. Anthony Falls Laboratory, University of Minnesota. Flow field at the neighborhood of a spur dike was measured by using a SonTek 10 MHz Acoustic Doppler Velocimeter (ADV). Time-history of velocities in all three spatial dimensions was recorded at 650 nodes near the dike. The time-averaged mean velocity and Reynolds stresses were calculated from the measurements. The results showed two counter-rotating secondary flow cells formed immediately downstream of the dike. The secondary flow cell at one side of the channel having the dike grows gradually, while the other cell decades until separated flows rejoin. These measurements clearly demonstrated the spatial distributions of turbulent normal stresses and Reynolds stresses. Additionally, bed shear stresses were calculated by using mean flow and turbulence Reynolds stresses. Bed shear stresses calculated by using Reynolds' stresses are more accurate for approximating bed shear stresses field around the dike.

A recently developed fully non-hydrostatic model to predict flow, sediment transport and equilibrium bathymetry using RANS models without wall functions and with capabilities to account for bed roughness effects is used to predict the equilibrium flow and sediment transport in a 140° curved channel bend studied experimentally by Struiksma under incoming steady-flow conditions. Additionally, a bed load transport module based on Engelund and Hansen total bed load formula is implemented and tested. In the experiment, the bed load was observed to be dominant, so the suspended sediment component is considered negligible in the simulations. The streamwise variation of the relative water depths at several representative sections are compared with the experimental data. It is found that the best agreement is obtained when the total load (which in the test case considered is equal to the bed load) is estimated using Engelund and Hansen formula with both k-ω and Spalart-Allmaras models. The k-ω predictions, using the originally implemented non-equilibrium bed load transport model based on van Rijn and Wu et al. methodology, are found to overpredict the water depths in the first half of the bend. The main reason for the underperformance of the van Rijn model is its inability to predict the experimentally measured bed load in the initial straight part of the channel.

A 1-D finite-volume model has been established to simulate the morphodynamic processes under dam-break and overtopping flows over movable beds. The effects of sediment transport and bed change on the flow are considered in the flow continuity and momentum equations. An explicit algorithm is adopted to solve the governing equations. The model has been tested against an experiment on dam surface erosion due to overtopping flow and two experiments on dam-break flow over movable beds. The model performs quite well in the case of overtopping flow, but significantly under-predicts the bed erosion due to dam-break flow. A modification has thus been made by considering the effects of sediment concentration on sediment settling and entrainment. The modified model predicts the bed erosion under dam-break flow with much improved accuracy.

A two-dimensional flood simulation model using unstructured grids has been developed to study the hydrodynamics of flooding processes. The model employs the finite volume method to solve the conservative form of the shallow water equations. The HLL approximate Riemann solver is used for computing the intercell fluxes because of its robustness and easiness to implement. The momentum equation used in the model has only one source term representing the driving forces, so that numerical imbalance between source and flux terms can be easily eliminated. In addition to the model formulation, this paper presents the model verifications and validations against analytical solutions and experimental data for a partial dam-break problem and an oblique hydraulic jump test case, respectively. The results show that the model can correctly account for the two-dimensional shallow water flows which may have mixed flow regimes and dry bed problems. These features can allow the model to simulate complicated real-life flooding problems.

An investigation is carried out for numerical computations of dam break hydraulics in Natural Rivers with Explicit Finite Difference (EFD) Schemes. Although computational Dam Break Hydraulics is a topic of interest over more than 100 years, numerical simulations of dam break flow in relatively simple channels are found more often compared to real river flood simulations. Natural River channel with wide floodplains make the computation cumbersome as Natural River channels are highly non-prismatic with significant variations in River bed slope and friction. In this study, first order Diffusive Scheme, second order modified two-step Predictor Corrector scheme and Total Variations Diminishing (TVD) McCormack Predictor Corrector using Venn Leer Flux limiter are analyzed by solving unsteady flow equations in conservative and non conservative forms for simulating a hypothetical dam break situation in a Himalayan River in India. The height of the dam is 245 metres. Upstream length of the channel is 40,000 m and downstream is 64,000 m, the elevation of the bed of the channel changes from 545 m to 126.95 m, change in the channel width ranges from 300 m to 5650 m and Manning's roughness coefficient varies from 0.03 to 0.035 depending on the channel characteristic. The numerical solutions of the EFD are relatively tested for their performances giving special emphasis to some parameters such as the flood depth at different sections and inundated area at different time periods after the failure of the dam and travel time of the flood waves; which are most important for the practicing engineers for efficient flood management. The computational aspects of the numerical models i.e. the implementation efforts of the schemes, run time required are compared. The applicability of the complex numerical corrections such as TVD in the numerical model for refinement in the solutions of dam break hydraulics in Natural Rivers is also examined. The stability and accuracy of the numerical solutions for both conservative and non conservative formulations are analyzed, and it is observed that numerical simulation of flows for complex real River topography in conservative forms with simple EFD schemes are advantageous from practical point of view compared to the higher order Explicit or Implicit Finite Difference or Finite Element schemes which increase the run time significantly and make the implementation complex.

The design of dam body for an earthfill dam is the most important analysis in dam study. The Sonnateh dam is located on an active fault with measured deflections. The dam body analyses are performed based on two methods in order to reach a suitable slope for upstream and downstream of dam body. The upstream and downstream slope of dam body is calculated based on optimal analyses of dam body in different load conditions with linear and nonlinear determination. The two dimensional analysis of dam body with MCL and MDL is performed by GEO-SLOPE program. This analysis was a preliminary determination of dam body dimensions. The amount of safety factor and steady displacement of dam body is calculated during the earthquake. Also, the three dimensional analysis of fault movement is performed using ANSYS finite element based program. This analysis indicated the displacement of dam body which has to compare with allowable displacement of clay core. Based on this analysis, the safety factor of dam body is determined.

The water resources in the northern part of Belgium have been profoundly influenced by anthropogenic activities. Physical deterioration of rivers and their floodplains is common. In general, hydrometeorological disasters have grown to be the most significant natural disaster in terms of frequency, but also in terms of costs to human life and property damage. River valley rewetting is believed to influence the ecology positively, especially during the dry summer months. However, its hydrological influence on the catchment over the annual cycle remains unclear, especially with regard to the winter months. Thus, this research undertook to build an integrated catchment model for a part of northern Belgium in order to study the hydrological influence of rewetting. The paper details the development and testing processes of the model. It highlights the design of a multi-criteria protocol that was used to develop and test the model, the process of determining recession constants corresponding to base flow, interflow, and overland flow components, and the paradox of homoscedascity. It describes WETSPRO, which is a tool for time series analysis which incorporates a recursive digital filter for exponential recessions to split total rainfall-runoff discharges into three components namely, base flow, interflow, and overland flow. The paper presents the results of an implementation of WETSPRO in multi-criteria model development and testing, during which the following plots were utilized: Modeled vs. observed discharge maxima during (nearly independent) quick-flow hydrograph periods; Modeled vs. observed discharge minima during (nearly independent) base-flow or slow-flow hydrograph periods; Cumulative flow volumes; High flow extreme value statistics; Low flow extreme value statistics; and Discharge time series, with and without log-scale for the discharge. Using the multi-criteria protocol, a hydrological model was built. The flow recession constants were determined as approx. 12 hours for quick flow, and 2 months for slow flow. This model is being used to study the effects of anthropogenic changes on the catchment hydrology.

A feasibility study was conducted for wetland restoration alternatives for the Buena Vista Lagoon Restoration Feasibility Study with three different hydrologic regimes — fresh water, salt water, and mixed water (combination of fresh and salt water). The alternatives were evaluated based on flood impacts, maintenance dredging requirements, and habitat distribution. A modeling approach was developed to help compare the three alternatives with the existing condition. Evaluation of each alternative was further complicated due to the different physical processes occurring within each alternative. Physical processes evaluated include watershed loadings (e.g., fresh water flows, fluvial sediments, and nutrient loadings), lagoon hydrodynamics, lagoon salinity, lagoon sedimentation, as well as coastal processes (e.g., tidal inlet/outlet stability and littoral sedimentation) for salt and mixed water configurations. Quantifications of these processes were conducted using a combination of numerical models and analytical methods enabling the linkages of multiple processes.

The Arthur R. Marshall Loxahatchee National Wildlife Refuge is the only remnant of the northern Everglades in Palm Beach County, Florida (USFWS, 2000). It includes 143,238 acres (58,000 ha) and is located seven miles west of the city of Boynton Beach. The U.S. Fish and Wildlife Service (USFWS) has indicated that changes in water quantity, timing and quality are introducing negative impacts to the Loxahatchee Refuge's ecosystem. According to the USFWS (2000) changes in hydroperiod and water depths' pattern affect wading birds feeding pattern, apple snail reproductive output, and alligator nesting, and also alter the distribution of aquatic vegetation and tree islands. In addition, high nutrient runoff causes proliferation of cattails, and other undesirable species that negatively affect the ecosystem's balance. It is a priority for the Loxahatchee Refuge to ensure an appropriate water regulation schedule that will produce maximum benefits for flood control, water supply, fish and wildlife; and also to better understand and minimize the impacts of the excessive nutrients' loading. This study presents the development of water budget and hydrodynamic models that are being used to provide a quantitative framework for management decisions related to inflow and outflow quantities, timing, and quality. The water budget model was developed as a double-box model that predicts canal and marsh stages. This model was calibrated for the 5-year period of record between January 1995 and December 1999, and validated with data for the 5-year period of record between January 2000 and December 2004. Statistical analyses demonstrate the applicability of this model to predict temporal variation of water levels in both the marsh and the Refuge rim canal. A two-dimensional hydrodynamic model was set up for the Refuge using the unstructured finite volume model FVCOM. This model is being used to predict spatial and temporal distribution of water inside the Refuge, and the results show very good agreement between observed and predicted stages at specific locations. Efforts are underway to model the transport of conservative tracer and the dynamics of total phosphorus in the Refuge.

The creation of effective tidal marsh habitat can be streamlined using hydraulic design tools as well as through the proper identification of applicable reference sites. The frequency of inundation corresponding to vegetation zones observed at reference sites can be used to design the elevation zones of proposed tidal marshes. Seasonal fluctuations in salinity levels can affect the suitability of vegetation types in tidal zones. Project success also depends to a large extent on protection from wave action. This paper discusses issues encountered in designing habitat enhancement projects in tidal zones, including analysis of historical tidal records, application of various hydraulic modeling tools, identification of applicable reference sites, establishment of desired elevation zones for plant communities, and accounting for water quality fluctuations arising from freshet conditions. Tidal marsh habitat may be desired in areas previously outside of elevation zones suitable for vegetation establishment. In these cases, the configuration of the inlet channels and project site topography must account for the proper balance of sediment transport through tidal energy and freshwater inflow from landward sources in order to ensure a lasting project life with minimal maintenance.

The Dalles Dam is located at river Mile 192 on the Columbia River, USA. Fish passage is considered one of the important operational functions for the hydropower dams on the Columbia River. The U.S. Army Corps of Engineers, Portland District (CENWP) and the Regional Resource Agencies (Region) have been evaluating fish passage concepts to protect downstream migrating juvenile salmonids at The Dalles Dam. To assist in this evaluation, a three-dimensional (3D) computational fluid dynamics (CFD) model, developed at IIHR-Hydroscience & Engineering, was selected to conduct CFD simulations, providing hydrodynamic flow information for fish passage efficiency assessment. The CFD model solves the Reynolds Averaged Navier-Stokes (RANS) equations closed with the standard k-ε model with wall function. The Dalles Dam forebay CFD model covers approximately 2,134 m from the spillway face to its upstream boundary. GRIDGEN of Pointwise®, Inc. was used to generate the 3D multi-block structured meshes. The model was validated using the ADCP stationary target field data, and then applied to prediction of scenarios corresponding to flow conditions which occurred during 2002 to 2004, referred as FY02, FY03, and FY04.

A numerical modeling study of hydraulic performances of an angled vertical fish screen at a river diversion intake channel that was developed using a porous media numerical scheme. Flow patterns in the intake channel induced by the fish screen were computed with a three-dimensional fluid dynamics computation program solving the Reynolds-averaged Navier-Stokes equations. Screen flow head loss coefficient were simulated and compared with the physical model values converted from the test measurements for the porous media numerical scheme applicability test. For validation of the numerical model, fish screen velocity ratio profiles of sweeping and approach were compared with physical model measurements. Different types of screen face material and baffle installations for uniform approach flow distributions were simulated. The numerical model shows very good agreement with the velocity ratio measurements, and modeling capability for different screen material types and baffle installations by controlling of the numerical model of the porous opening directions and adjustment of baffle porosities respectively.

Water temperature is an important water quality parameter in aquatic ecosystems, impacting dissolved oxygen, chemical and biological reaction rates, and plant and animal mortality. In particular, during summer months, high temperatures in the forebay, gatewells and juvenile fish collection channel at McNary Dam lead to increased stress on fish population. A 3D hydrodynamic and heat transport model was developed to predict the water temperature on McNary Dam. The flow field was solved using an incompressible RANS solver for buoyant flows. The Boussinesq approach and a standard kappa-epsilon model with wall functions were employed. The thermal model takes into account the energy sources due to solar radiation and the convective heat transfer at the free surface, which is function of the air temperature and wind velocity. The equations of the proposed thermal model were implemented into the commercial code FLUENT. The unsteady energy sources, boundary conditions at the free surface and inflows were programmed. A calibration for a typical day was conducted using measured temperature profiles and weather conditions. Comparison shows that the model reproduced general observed trends and daily fluctuations. The multidimensional temperature and velocities fields are presented and discussed.

The Awwa Research Foundation (AwwaRF) is a member-supported, international, nonprofit organization that sponsors research to enable water utilities, public health agencies, and other professionals to provide safe and affordable drinking water to consumers. Mission: Advancing the science of water to improve the quality of life. AwwaRF works to achieve the mission in three ways: By sponsoring research. AwwaRF sponsors an anticipatory and scientifically credible research program that is responsive to the needs of the water supply community. By developing knowledge. AwwaRF identifies the practical benefits of research findings and delivers this knowledge to stakeholders throughout the water supply community. By promoting collaboration. AwwaRF cultivates partnerships with organizations around the world to leverage funding and share expertise. The Awwa Research Foundation was established in 1966 to provide a centralized, practical research program for the drinking water community. Its research program, which is highly respected as being one of the most scientifically credible and best-coordinated in the world, focuses on four main goal areas: (1) High-quality water, (2) Efficient and customer-responsive organization, (3) Infrastructure reliability, and (4) Environmental leadership. Specific research projects focus on the following: (1) Treatment Technologies, (2) Distribution System Operations, (3) Water Resources, (4) Water Quality, (5) Infrastructure, (6) Management, and (7) Health Effects.

National Pollution Discharge Elimination System Phase II construction and Municipal Separate Storm Sewer Systems permits have resulted in the need for education programs. These education programs have many challenges in regards to content, reaching adult audiences, and effectiveness. This paper presents the different ways the University of Minnesota Erosion and Sediment Control Certification Program is evaluating the effectiveness of its storm water pollution prevention education program. Included in this paper are general descriptions of the course structure, audiences, and use of partnerships with other agencies and organizations. Evaluating the effectiveness of reaching the correct audience, getting the information to the class attendees, helping the class attendees retain the information, and increasing compliance with stormwater pollution regulations are all key components of an educational program. Each of these aspects is measured through different means and requires different degrees of effort. The University of Minnesota Erosion and Sediment Control program has attempted to evaluate these components through surveys, testing, and comparisons to compliance records. The attendee surveys, pre-testing, and post-testing have provided helpful information for improving the program and classes. Evaluation of compliance inspections and comparison to training records of construction personnel has possibly provided some insight to the effectiveness of training on regulatory compliance. Of more importance is the understanding of how inspection data collection could be adjusted to provide additional value and more insight to the effectiveness of training on regulatory compliance.

Under an interagency agreement with the U.S. Department of Agriculture, U.S. EPA has coordinated support for several water treatment research demonstrations in China. EPA has demonstrated several treatment technologies to improve water quality in small communities and has installed an immersed membrane water reuse system for a small brewery in China. U.S. EPA has also provided a water quality monitoring buoy and an automated weather station for monitoring of flood conditions (rainfall events) in a remote watershed. The weather station has been designed and built with a remote telemetry system to collect and submit real-time data on an hourly basis. This presentation will focus on interagency cooperation and cooperation between the U.S. and China during implementation and completion of these drinking water demonstrations.

Student feedback from past semesters for the courses Water Resources Engineering and Urban Hydrology and Hydraulics has indicated that out-of-class guidance or coaching from the instructor in solving problems related to the course content was the most effective tool for learning the material from these courses. However, this proved to be an inefficient teaching tool. While similar guidance was commonly repeated to different groups of students, because the student groups progressed through problems at different rates and often all students could not schedule simultaneous time with the instructor. Furthermore, out-of-class coaching is also an inefficient learning tool because the instructor often is not available at the times when the students are working on the problems. The tools described in this paper addressed these inefficiencies by providing asynchronous access to help and guidance on the difficulties that the students commonly encounter while working on out-of-class problems for these courses. The three tools that will be discussed are: (1) a bulletin board that allows students to respond to each other's queries and to see the instructor's responses to the posted queries, (2) a set of daily on-line quizzes that provide feedback and suggestions to the student about their individual results and provide feedback to the instructor about problem areas, and (3) an on-line, help library providing coaching for the most frequently asked questions. This library contains video clips of actual help sessions, and links to additional help tools. These additional tools include animations illustrating the calculations and procedures, reference materials, and solved example problems.

The Departments of Civil and Environmental Engineering and Cinema and Photography at Southern Illinois University Carbondale (SIUC) have collaborated to produce a digital video that highlights careers and other professional opportunities in environmental and water resources engineering. The video is targeted toward high-school students and first- or second-year college undergraduates and, thus, serves as a recruitment and retention tool for related degree programs. The video includes a series of interviews that disseminate answers to questions such as: How much education is required to be an engineer? What is the importance of licensure? Where do environmental and water resources engineers work? What salary is expected? Is engineering difficult? And do I need to be good at mathematics to be an environmental or water resources engineer? Responses are provided by current undergraduate and graduate students at SIUC. The 20-minute video also highlights a number of experiments conducted in the SIUC engineering laboratories. A corresponding website is under construction that will include the majority of interview responses as both text and video clips. Users will be able to click on thumbnail images to hear or see different responses to the same question. The overall project is being supported by a grant from the National Science Foundation, Division of Undergraduate Education that includes the development of a CD-ROM and web-based database of engineering images for classroom use.

Case study use provides for active and discovery-based learning experiences in which students may actively acquire information about an appropriate topic, collaborate with other individuals in problem definition, develop an investigation strategy, choose among alternative problem solving approaches, and negotiate or attempt to convince others of their conclusions. Case study use also potentially engages industry and government in the university educational experience, and may encourage more undergraduate students to pursue graduate degrees. With these educational goals in mind, a set of environmental and water resources systems engineering case studies are being developed for classroom use. For each case study, students are given background information pertinent to a current water or environmental management issue, including geographic, hydrogeological, and other natural resource information; as well as any social, economic, and political information that may be relevant. A series of exercises is provided related to each case study, consisting of additional research, team participation, and computer exercises. Through the computer exercises, students will gain familiarity with technologies commonly used in the profession, including simulation and optimization models, visualization tools, and geographic information systems. This paper provides an overview of some of the case studies developed through these efforts, along with a preliminary assessment of their impact based on student and faculty evaluations. Following case study use, evaluation, and revision, the cases will be made freely available for use in water resource and environmental engineering courses at universities worldwide.

This paper will describe a case study of the installation of scour monitoring devices on the Interstate 10 (I-10) Bridges crossing the San Gorgonio River east of the City of Banning in Riverside County, California. The California Department of Transportation (Caltrans) required that the project area be monitored for a potential headcut resulting from a levee break protecting a large and deep gravel operation that would damage the Interstate 10 bridges upstream. The plan consists of installing monitoring equipment to have three levels of monitoring to provide a high level of redundancy. They include (1) Monitoring the recently constructed engineered levee along the San Gorgonio River, (2) Monitoring cross sections of the San Gorgonio River itself for potential headcutting, and (3) Monitoring the I-10 bridges for scour and water surface elevation. Background information, discussion about these three levels of monitoring, implementation approach, and proposed equipment, lessons learned and construction challenges will also be discussed in the paper.

A Phase I total maximum daily load (TMDL) assessment project for the Cheyenne River Watershed in western South Dakota was initiated in the spring of 2005. A key component of this project was a physical habitat assessment of 48 sites distributed throughout the watershed. The vast amount of field work associated with this project presented an opportunity to refine field data collection methods to work toward a goal of collecting all data electronically in the field in a spatially referenced format for use with a Geographic Information System (GIS). A survey grade Trimble Global Positioning System (GPS) receiver was integrated into the field sampling procedure for sites on the main stem of the Cheyenne River, where data collection is difficult due to the size of the river and the amount of visual obstructions. GPS equipment was used to survey all pertinent stream topography data; e.g., measurements for transect spacing and cross-sectional and longitudinal profiles. This procedure for data collection required slightly less time for postprocessing of data, converting it into a format compatible with other habitat data measurements. Significant gains were made in overall accuracy of the data and the field collection quality assurance/quality control (QA/QC). Total manhours required for data collection and data processing were reduced by up to 50 percent of those required using tape measurers and surveying levels. Additional qualitative estimates were made in the field related to habitat and vegetation as part of the sampling protocols. An ongoing effort, which began at the initiation of this project, involves developing a GIS geodatabase, linked to data entry forms, where the remaining qualitative field data can be entered. This would increase QA/QC of data collection by reducing data entry mistakes while cutting down on time spent on data entry. Once developed, metric calculations will be programmed into the geodatabase allowing for the metrics to be viewed while on location. The current goal is to have this system in place by the 2007 sampling season.

Design of monitoring networks is considered as the main part of the monitoring system design including selection of the water quality variables, location of sampling stations and determination of sampling frequencies. In this study an entropy-based approach is presented for optimal river water quality network design. In this model, the number and location of sampling sites and sampling frequencies are determined so that "redundant information" is minimized. In this methodology, a water quality simulation model is also used to generate the time series of the concentration of the water quality variables at potential monitoring sites along the river. As several water quality variables are usually considered in designing of water quality monitoring networks, pair-wise comparison is used to combine the spatial and temporal frequencies calculated for each water quality variable. The proposed model has been used to design a water quality monitoring network for the Karoon River in the southern part of Iran. The results show that the proposed model can be effectively used for optimal design of monitoring networks. It is also shown that the redundant information can significantly be reduced by using this approach.

The Shadegan Wetland is a Ramsar-listed wetland in the south-west of Iran at the head of the Persian Gulf. It is the largest wetland of Iran covering about 400,000 hectares. The wetland plays a significant hydrological and ecological role in the natural functioning of the northern Gulf. It also supports a very diverse flora and fauna and is the most important site in the world for Marbled Teal. The water regime is threatened by upstream abstraction of water for irrigation and the saline discharge from sugar cane industries and irrigation schemes. This will result in an overall reduction in wetland water quantity and quality, leading to a change in plant community composition. This paper investigates how much water is required to maintain the wetland health and the best management options to fulfill this requirement. Considering the lack of field data, using remote sensing (NOAA_AVHRR images with 1.1 km resolution), wetland monthly water surface and biomass during the 15 years before dam construction were traced. Then using these data wetland environmental water requirements was determined in 3 levels. Also the best hydrological regime that could conserve minimum requirements of vegetation cover, Marbled Teal, and flooding conditions were set as the hydrological regime with exceedance probability of 60% that is equal to 2766 MCM/y (level 3).

In this study, a methodology for conflict resolution for water quality management in a river system is presented. The proposed model maximizes an objective function which is based on the Nash product which includes different utility functions related to the water quality deviations from the standards. Simulation and optimization models are proposed to determine operating policies for river water quality management, based on evaluation of the system performance to derive the most appropriate diffusing strategy for different stakeholders. The proposed model includes an integrated GA-based optimization and a water quality simulation model. Risk-based measures of system performance, termed reliability, resiliency and vulnerability, are calculated for each water withdrawal sector, and are combined into a Nash product, as an objective function. The model is applied to the Karkheh River system in the southern part of Iran. The utility functions are based on the acceptable risk of the allocated water quality by different sectors, especially the environmental protection agency. The results of the proposed model shows that the waste load allocation policies can significantly reduce the number and duration of violations from the standards.

There are approximately 50,000 small community systems and 140,000 non-community systems serving over 25 million transient and non-transient populations of 3,300 people or less. Several of these small systems are having difficulty complying with the ever increasing number of regulations and regulated contaminants and it is estimated that small systems contribute 74% of the Safe Drinking Water Act (SDWA) and its Amendments (SDWAA) violations annually. Nearly 90% of these are for Maximum Contaminant Level (MCL) violations. EPA conducts in-house technology development and evaluation to support the small communities. As part of this research effort, EPA has been evaluating a ceramic filtration system for the production of drinking water. The system is being challenged with various turbidity levels, Cryptosporidium (using polystyrene latex beads as a surrogate) and Bacillus Subtilis (to evaluate bacteria removal). This paper presents the results of studies conducted to date on this system. Future research efforts will include testing the system for removal of total coliforms, MS2 bacteriophage and Cryptosporidium parvum.

Sustainable water resource management requires a "first principles" based understanding of the relationship between environmental stimuli and habitat utilization by target aquatic biota. This understanding is the critical foundation upon which flow management tools are developed that accurately forecast how habitats (and ultimately the aquatic populations they support) change in response to alternative water resource management plans. Emerging methods provide highly resolved descriptions of the physicochemical regimes that influence individual animal movement to supplement methods to accurately track movements of individuals. Emerging methods can be integrated using a Eulerian-Lagrangian-agent method (ELAM) in which (1) the Eulerian framework is used to describe the physical, hydrodynamic, and water quality domains, (2) the Lagrangian framework is used to describe sensory perception and movement trajectories of individuals, and (3) the agent framework is used to describe the behavior decisions of individuals. We discuss a generalized conceptual foundation for describing environmental habitat and stimuli in a manner consistent with animal perception and compatible with ELAM models.

A five-year $20,000,000 study of how Lake Ontario and the St. Lawrence River can be better managed has just come to a conclusion. Three alternative operating policies that balance competing objectives in different ways have been presented to the International Joint Commission for their consideration. After due public discussion, the IJC will be selecting one (or none) of those three to implement, with the primary purpose of improving the environmental and ecological state or quality of the basin over what it is now. At the same time the policy has to meet other objectives such as those related to recreational and commercial boating and navigation, hydropower, shoreline protection, water supply reliability, and flood protection. This paper and talk summarizes the manner in which this joint Canadian and US study arrived at economic, environmental and ecological indicators whose values were functions of what can be managed, namely lake and river levels and river flows. Also of interest is the political process of plan selection and implementation, and the institutional impact of adapting a new policy for managing water in the basin.

Hunter Rouse (1906–1996) is credited and admired as the exemplar researcher and educator who championed the application of fluid mechanics theory, and contemporary experimentation methods, to water flow processes in hydraulic engineering. This application, commonly called hydraulics, placed much of hydraulic engineering on a substantially more rational basis than had prevailed a century ago. This paper is an overview of Rouse's work.

As Hunter Rouse matured, he became increasingly involved in studies of the history of fluid mechanics and hydraulics. Rouse's interest led him to produce two books on the subject, many articles, numerous lectures, and an unusual collection of rare historic books. The collection holds over 500 volumes and spans approximately 500 years. Housed at the University of Iowa, the collection remains a valuable resource for historical research. This paper describes Rouse's history research and writing, as well as the History of Hydraulics Rare Book Collection that he created.

ASCE Manual 54 "Sedimentation Engineering," edited by the late Professor Vito A.Vanoni, provides both qualitative and quantitative guidance to theoreticians and practitioners with respect to sediment issues and processes associated with the development, use and conservation of water and land resources. It describes the nature and scope of sedimentation problems, details methods of investigation, and presents practical approaches to solution and management. As a major contribution to the profession, Professor Vanoni organized, partially wrote, and edited the definitive Manual 54. As chairman of the special Task Committee, established in 1954 with the charge of writing the manual, Vanoni worked for two decades and set a high standard. Many of the sections of the original manuscript for the book were first published in the Journal of the Hydraulics Division ASCE and received considerable discussion, which was taken into account in the final manuscript. Manual 54 received worldwide recognition and widespread use in academia and practice, being recognized with the ASCE Karl Emil Hilgard Hydraulic Prize for best publication in 1976. Since the publication of Manual 54 in 1975, global awareness of sediment erosion, transport and deposition processes and of their impact on the use and development of water and land resources has greatly increased. Manual 54 remains an important reference on many aspects of sedimentation engineering, but in other aspects it has been outdated by advances in knowledge and techniques and by the emergence of new problems and issues.

Congress passed the Flood Control Act of 1944, the Pick-Sloan Plan. It was a marriage of two plans developed by Brig. Gen. Lewis A. Pick of the Army Corps of Engineers and W. Glenn Sloan of the Bureau of Reclamation. The Sloan plan called for irrigating millions of acres of land with water impounded behind dams on the Missouri and numerous tributary rivers, thereby providing construction and farming jobs to encourage people to return to the upper Midwest following years of drought and war. The Pick plan emphasized flood control, navigation, water supply and hydropower generation primarily from reservoirs on the main stem of the Missouri. Signed by President Roosevelt on December 22, 1944, the act authorized the construction of five large dams on the Missouri River to be built and operated by the Corps. In addition, there were numerous tributary structures and giant irrigation projects to be built and operated by the Bureau. In all, it authorized eight purposes: flood control, navigation, irrigation, hydropower, water supply, water quality, recreation and fish and wildlife.

This paper/presentation covers the current operation of the six mainstem dams comprising the Missouri River Mainstem Reservoir System (System) to serve Congressionally authorized purposes. Congress authorized the construction of these dams for flood control, recreation, irrigation, water supply, water quality, navigation, hydropower, and fish and wildlife. The Endangered Species Act also added the requirement to provide special emphasis for Federally listed threatened and endangered species that may be affected by the operation of the System. The System Master Water Control Manual (Master Manual) describes the operation of the six dams as a system to serve the Congressionally authorized project purposes.

We are investigating antibiotic resistance genes (ARG) as emerging contaminants in the environment. The spread of ARG is a growing concern considering the increasing microbial resistance to antibiotics that is being observed world-wide. The development and spread of ARG responsible for imparting antibiotic resistance has been associated with the widespread use of antibiotics in livestock as well as humans. The purpose of this study was to quantify the occurrence of antibiotic resistance in the mixed-landscape Cache La Poudre River watershed, which has previously been studied and shown to have high concentrations of antibiotics correlating with urban and agricultural activity. In order to detect and quantify ARG in various environmental compartments, molecular biological methods were developed and applied to the environmental samples. Polymerase chain reaction (PCR) detection assays were conducted for seven sulfonamide resistance gene families using newly designed primers and eight tetracycline resistance gene families using previously published primers. Sul(I), sul(IT), tet(W), and tet(O) gene families were further quantified by real-time quantitative polymerase chain reaction (Q-PCR). Resistance to four classes of antibiotics (tetracyclines, sulfonamides, ionophores, and macrolides) was also investigated using a culture-based approach on antibiotic media. ARG were found to be present in river sediments, and their concentrations correlated to human and agricultural activity. The quantities of ARG normalized to the 16S rRNA gene copy number were statistically different between the sampling sites with different levels of human and agricultural input, and the pristine site being the lowest in all sampling events. These results suggest the need for increased involvement of environmental engineers to help understand the pathways of ARG in the environment and to develop treatment and mitigation strategies for minimizing the spread of ARG in the environment.

Natural purification of water from rivers and lakes through bank and bed filtration has been shown to be quite effective in the state of Uttaranchal (Longitude 77° 34' 27" to 81° 02' 22" E and Latitude 28° 53' 24" to 31° 27' 50" N), India. The subsurface water under the direct influence of surface water is being tapped by (i) tube-wells in Nainital, (ii) infiltration wells in Hardwar, and (iii) uttaranchal wells in adjoining hilly areas of Dehradun. This paper presents quality of surface and subsurface water at three sites. Cost effective water supply schemes have been developed on the basis of lake, bank filtration, river bank filtration and river bed filtration. At Nainital, five tube-wells of different depths (22.6m – 33.35m) are in use to tap the subsurface water from the unconfined aquifer hydraulically connected to lake water. Lake water as such is not potable as it contains unacceptable levels of organic matter in terms of COD (~ 31 mg/L), coliform (~ 17 x 10⁴ MPN/100 mL) and nutrients. On the other hand coliform bacteria, organics and nutrients have not been detected in any of the well water samples over the years. Sixteen infiltration wells located on the bank of the river Ganga and Ganga Canal at Hardwar get water from the unconfined aquifer hydraulically connected to the river and canal. Distance of the infiltration wells from the river/canal varies from 4 to 90m at different locations. Up to 3 log turbidity reduction and 4 log fecal coliform removal (MPN) is achieved through natural bank filtration. The hilly streams normally have permeable strata just below their bed, saturated with water and having continuous sub-surface flow by gravity. Uttaranchal Well is embedded below the stream bed to tap this continuous sub-surface flow which is in direct connectivity with the surface water above it. It is being used successfully for more than 300 rural water supply schemes in different districts of Uttaranchal. Water quality analysis of samples taken from these wells and source water for Dehradun district is carried out in monsoon, the worst season to assess effectiveness of bank/bed filtration. Fecal coliform count and turbidity of water collected from Uttaranchal Wells is 30 times less than that of stream water. River/stream water is highly turbid particularly during rainy season while well waters are quite clear. These improvised-innovation adapted are operative, almost maintenance free, economical, and sustainable.

High fluxes of sedimentary phosphorus (P) in Spy Pond in Arlington, MA have increased the rate of eutrophication and diminished the recreational value of the pond. The pond sediments are also contaminated with arsenic, which was applied in the 1950s and 1960s to control macrophyte growth. Arsenic (As) is chemically similar to P and remobilizes from the sediments under the same conditions that give rise to P remobilization. The remobilization of P and As are controlled by redox conditions in the bottom waters of the pond: reducing conditions cause P and As adsorbed to sediments to desorb and enter the water column from late spring until fall. To control P remobilization, the pond was treated with alum in May 2004. The goal of our study was to determine whether alum was also effective for controlling As remobilization. Data was collected to monitor the change in average peak concentrations of P and As before and after treatment. The pond is separated into two basins, north and south, by an island and shallow sill. The two basins have unique water chemistry characteristics and the responses to the alum treatment differ. In the south basin, the P concentration ratio before and after treatment was 13:1, while the ratio for As was only 2:1. The ratios for P and As in the north basin were 5:1 and 3:1, respectively. Data collected from Spy Pond indicate As(III) was not significantly inactivated by alum. The effectiveness of the alum to control As remobilization is dependent on the As redox state and competition with P for adsorption sites.

The environmental management of the Three Gorges Project is discussed in this paper. The management experiences and methods during the periods of the feasibility study, construction, and partial operation are described in detail. The pollution control management in the reservoir area is described. The resettlement problems are discussed in brief. Some suggestions for the environmental management are presented from the viewpoint of sustainability management. People-centered management should be promoted in the future operation. The environmental monitoring and investigations should be further made to fully understand the environmental realty related to the dam operation, the reservoir inflow and outflow, sedimentation and the resident's lives around the reservoir. The mitigation measures should be executed to reduce the negative impacts of the Three Gorges Project. The environmental management experiences can be used for other hydropower projects to heighten the management level of the hydropower industry.

Industrial facilities environmental, health and safety (EH&S) audits are accomplished via either self and/or third-party audit(s). The periodic third-party environmental audit of industrial facilities is included to verify the facility compliance with various environmental requirements of a given geographical location, and evaluate facility's routine environmental control practices. The third-party environmental auditor would be responsible for conducting a comprehensive review of facility's operations and confirming whether the facility is in environmental compliance. This paper included: pre-audit communications and the review of facility environmental information; site environmental-audit elements and audit conductance; and, the post-audit review of facility operations information and preparation and submission of the final audit report. The environmental audit should include all applicable environmental regulatory and permitting requirements of state, federal, and local regulating agencies.

Landfills and publicly owned treatment works (POTW) emit pollutants to the air from many sources, most notably fugitive and combustion sources. Flares are commonly used at landfills and POTWs to burn landfill gas and digester gas generated at the plants. Many owners and operators of these facilities are unaware that operation of combustion equipment such as a flare can trigger state air permitting and annual emission reporting requirements. Flares generate a relatively large amount of carbon monoxide (CO), a regulated pollutant. CO is the pollutant that usually exceeds regulatory thresholds. To confuse the situation further, each state enforces different thresholds. Owners and operators of a landfill or POTW should calculate plant emissions and determine their regulatory obligations. Ironically emissions from wastewater treatment systems and solids handling operations at POTWs do not usually exceed regulatory thresholds, even though emissions from these operations are subject to the most public scrutiny. Combustion of digester gas is the activity that typically creates air quality permitting requirements. This paper presents several sources of air emissions common to landfills and POTWs along with typical regulatory considerations that would apply.

Fremont, Nebraska, is a city of approximately 25,000 people located in Eastern Nebraska. The city is served by a wastewater treatment plant (WWTP) originally constructed as a primary treatment plant in the 1960s and subsequently expanded to secondary treatment in the 1970s. Wastewater treatment plants are typically designed for a life of 20 – 25 years for process equipment while structures are expected to serve longer. In the early 1990s, the City of Fremont began planning for the future of wastewater treatment for their community. This planning effort was necessitated for the following reasons: (1) Regulatory agency discharge permit modifications, (2) Implementation of the Part 503 Regulations, (3) Treatment technology changes, (4) Aging of existing systems, and (5) Capacity issues for both liquid and solids stream. In 1991, the City of Fremont retained Jacobson Helgoth Consultants (JHC) to prepare a Facility Plan to address the long-term needs of the City's Wastewater Treatment Plant (WWTP). Once the Facility Plan was completed and approved by the regulatory agency, design of new facilities began. The project was accomplished in phases to meet funding limitations and allow for an orderly flow of construction while still maintaining all treatment processes in operation. The construction was completed in 2002 at a cost of $18,000,000. The plant consistently meets its discharge permit limitations and the requirements for disposal of stabilized biosolids. All systems have been updated to reflect the latest in treatment and equipment technology and the city has treatment capacity to meet it needs for the foreseeable future. As a result of these upgrades and modifications, the City of Fremont has a wastewater treatment plant that will serve it well for the first two to three decades of the 21^st century.

Hydraulic jump is occurred at the transition from supercritical to subcritical flow which is characterized with energy dissipation due to highly turbulent flow, air entrainment, and macro-scale vortices. In this study self-aeration performance of a classical hydraulic jump beyond a sluice gate, has been investigated in a 0.5 m wide flume. Experiments were conducted for a range of upstream Froude numbers 2–6, and unit discharges 2 x 10^–2 – 5.3 x 10^–2 m³/sm. It was appeared that the aeration efficiency of a hydraulic jump was mostly dependent on head loss, and then to the unit discharge positively. Further, turbulence structure of the hydraulic jump, which ensures the entrainment of air into water, was highlighted by using an Acoustic Doppler velocimeter at low Froude numbers. An empirical formula predicting aeration efficiency for hydraulic jumps was developed by using non-linear regression analysis. Good agreement between measured and predicted aeration efficiency values was obtained.

Ancient blockhouses relics are representative culture of Zang nationality in China, which have attracted a great interest of archaeologists around world because of their unique historical, cultural and scientific values. However, the rising water level in Houziyan reservoir may pose threats to the stability of slope and in turn damages to the blockhouses located on the slope. In this paper, the authors characterize the origin of Suopo deposits, analyze structures and failure mechanisms of the blockhouses, and assess current status of slope stability and its change after inundation. Preliminary results indicate that Suopo slope is stable under current condition with localized non-uniform deformation and variable submersion, which had caused collapse of some ancient blockhouses. At a normal pool water level (NPL) of 1852 m, the slope is stable as whole after inundation of Houziyan reservoir. However, some slumps and rock falls may occur near the edge of the rising water or at the toe of slope. With appropriate protection of the slope toe and prevention of slumps and rock falls, impacts of inundation of the reservoir can be minimized, and the blockhouses can be protected.

The Lake Ogallala hydropower tailwater reservoir is subjected to wide fluctuations of the inflow water quality and quantity. These alterations impact lake temperatures, water stage, dissolved oxygen (DO) and nutrients. A two dimensional continuous simulation, hydrodynamic and water quality model, CE-QUAL-W2, was used to simulate the lake's dissolved oxygen. The elements modeled include surges of low DO and temperatures; high chemical oxygen demands and dissolved nutrients; in-lake algae, macrophytes, and epiphytes response; temperature and bathymetric induced circulation patterns; and weather impacts. The epiphyte routine was used to simulate macrophytes, and the model was able to emulate the diurnal DO and temperature fluctuations which ranged from 2 to 12 mg/L and 19.5 to 23 degrees C, respectively. The study found that the chemical demand resulted in an approximately 1.5 mg/L drop in DO across the lake but also found that macrophyte respiration causes approximately a 2 mg/L reduction in DO during dark respiration. Management alternatives were modeled based on controlling the inflow of DO and macrophyte harvesting.

Advances in technology are allowing scientists and engineers to perform their jobs in ways that are both more time-efficient and cost-effective. With the number of abandoned landfills increasing every year, it is essential that the cost of investigation and remediation of such sites remain as low as possible. To achieve this objective, many site investigator teams are choosing to employ the powerful function approximation feature of artificial neural networks (ANN). Once the desired ANN profiling system is trained on existing data, the system can be used to produce efficient predictions for the unexplored regions. Similar ANN profiling systems were utilized herein in the investigation of an abandoned landfill site in Kansas City, KS. The developed ANN systems were trained on existing data and then were used to predict the amounts and distribution of arsenic and lead contaminates within the landfill area. The site investigating team was able to capitalize on the information generated via the developed ANN systems in order to determine the strategic locations for further testing. Therefore, less money was spent since no further testing was needed in the relatively uncontaminated regions.

The purpose of this study was to explore the potential of wetlands for bioremediation of a methyl tert-butyl ether (MTBE) spill at a Colorado refinery where other contaminants present at the site have potential to inhibit MTBE biodegradation. MTBE biodegradation has been observed to be inhibited by the presence of other contaminants that are common at refineries, such as Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX). MTBE biodegradation is also typically limited by availability of oxygen, and only rarely has been observed to degrade under anaerobic conditions. To test the feasibility of MTBE bioremediation, a bench-scale study followed by a pilot-scale study in the field were conducted. The bench-scale studies were performed as batch tests in which two enrichment cultures were compared for their ability to degrade MTBE in the presence of BTEX. It was observed that culture MO (originally enriched only on MTBE) was superior to culture MB (originally enriched on MTBE and BTEX) in terms of its ability to degrade MTBE. However, both cultures showed inhibited degradation of MTBE in the presence of BTEX. Interestingly, when the MO culture was placed in a semi-batch reactor, simultaneous MTBE and BTEX biodegradation was observed. This suggests that metabolic by-products accumulated in the batch tests may inhibit the ability to degrade MTBE in the presence of BTEX. It was thus hypothesized that in a continuous-flow system, such as a wetland, MTBE and BTEX will degrade simultaneously. In the second part of the study, pilot wetlands are now being tested at the refinery. The wetlands consist of 30-gallon aquaria filled with sediments from the Sand Creek near Denver, CO. The feed water to the systems is taken directly from the pre-treated water from an air-stripper that is currently in operation at the refinery. Six different conditions are being tested in which the inoculum, Fe(III) availability are being tested. Molecular analysis will be used to gain insight into the effect of the microbial community and to assess bioremediation potential at the site. The results of the pilot-scale study will thus serve to guide the design of the full-scale wetland study. It is expected that the complex environment and flow-through conditions of a wetland will promote simultaneous biodegradation of MTBE in the presence of multiple co-contaminants.

Sulfate-reducing permeable reactive zones (SR-PRZs), such as anaerobic wetlands, sulfate-reducing bioreactors, and permeable reactive barriers, rely on microbially-mediated processes to treat mining influenced waters (MIWs) contaminated with heavy metals. The remediation is accomplished through the precipitation of metal cations with sulfide produced by sulfate-reducing bacteria (SRB). The microbial communities in SR-PRZs are very complex and include not only SRB but also cellulose degraders and fermenters that provide SRB with the substrates necessary for their growth. Even though microorganisms are the driving force in SR-PRZs, little is known about the microbiology of these passive mine drainage treatment systems. We have recently developed a suite of molecular biology tools in our laboratory for characterizing the microbial communities present in SR-PRZs. In this study our suite of tools is used to characterize two different field bioreactors: Peerless Jenny King and Luttrell, near Helena, MT. Both bioreactors employ a compost-based substrate to promote the growth of SRB. The two bioreactors were sampled at multiple locations and depths in June, 2005, and Peerless Jenny King was sampled again in August, 2005. Cloning of polymerase chain reaction (PCR) amplified 16S rRNA genes followed by restriction digest screening and DNA sequencing provided insight regarding the overall composition of the microbial communities. To directly examine the SRB populations, two approaches were used. In the first approach, a gene specific to SRB, ApsA, was PCR-amplified, cloned, and sequenced. This revealed that two main SRB groups are prevalent in both Luttrell and Peerless Jenny King, both of which are Desulfovibrio spp, and one of which is noted to be particularly aerotolerant. This analysis also revealed the presence of Thiobacillus denitrificans, an organism that oxidizes sulfides in the presence of nitrate or oxygen, which has been considered highly undesirable for bioreactor function. In the second approach, quantitative real-time PCR (Q-PCR) was used to quantify two specific groups of SRB, Desulfovibrio and Desulfobacter. These two SRB groups were found to vary in distribution between the two bioreactors and with depth. The results of this study indicate that two different SR-PRZs also have two very different microbial communities. The ultimate goal will be to develop an improved understanding of the microbiology of SR-PRZs in order to improve design and operation of these treatment systems.

The American Society of Civil Engineers launched the Model Water Code Project in 1990 under the leadership of Ray Jay Davis. I took over direction of the project in 1995 after Professor Davis retired. We have now completed the Regulated Riparian Model Water Code, which is standard 40-03 of the Society. The Appropriative Rights Model Water Code has been completed as a report of the Laws and Institutions Committee of Environmental and Water Resources Institute, with balloting on it as a standard about to begin. While efforts were made to make the provisions of the two model codes the same insofar as possible, the two model codes represent the two very different regulatory approaches to water management issues now prevalent in the United States. A close comparison of the two model codes thus serves as an introduction to the provisions of the codes and serves to introduce the major legal issues regarding water management and possible legal responses to those water management issues. This paper will be the first such comparison since the completion of the report version of the Appropriative Rights Model Water Code.

The Border International Water Quality Standards Committee of EWRI is developing a major document revision that will add two appendices to the previously published "Comprehensive Transboundary International Water Quality Management Agreement." The new version is tentatively retitled "Comprehensive Transboundary Water Quality Management Model Agreement with Guidelines for the Development of Standards, a Management Plan, and Effective Agreements." The document development follows the established process for ASCE standards, as discussed below. The purpose of the upcoming "Comprehensive Transboundary Water Quality Management Model Agreement (model agreement) with Guidelines for the Development of Standards, Management Plan, and Effective Agreements" is to provide a framework for bi- or multi-lateral agreements that form the policy and regulatory structure for establishing a partnership between sovereign countries or nations (Parties) to provide comprehensive water quality management of shared water resources along or across intergovernmental boundaries. This model agreement and the appendices will provide a step-by-step approach to implementation of an agreement of this type is based on the concept of shared sovereignty. It is appropriate only for those situations in which the Parties are prepared to relinquish a significant degree of sovereignty over their portion of the shared water resource. Work describing the development of the model agreement was previously published.

Calibration of hydrologic models has traditionally been performed with respect to a single performance metric. This type of calibration, however, is often inadequate to properly evaluate the simulation of important characteristics of a hydrologic system. This paper presents a multi-objective, automatic calibration model, which is developed using an evolutionary optimization technique known as Strength Pareto Evolutionary Algorithm 2 (SPEA2). SPEA2 is a multi-objective search algorithm that employs the concept of Pareto dominance for selection of better solutions. The calibration model is integrated with the U.S. Department of Agriculture's Soil and Water Assessment Tool (SWAT). SWAT is a physically-based, semi-distributed hydrologic model that was developed to predict the long term impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use, and management conditions. Being a semi-distributed model, SWAT consists of a large number of parameters to capture the various physical characteristics of a hydrologic-defined unit. In order to reduce the number of calibrable parameters to a manageable size, parameterization was performed. In this study, SWAT was calibrated for daily streamflow and sediment. The calibration process was formulated as a multi-objective optimization problem, and it involves parameter specification, whereby sensitive model parameters are identified, and parameter estimation. The methodology is demonstrated using Big Creek watershed in southern Illinois. The model finds Pareto optimal solutions for the calibration problem, which are sets of model parameters. Application results show that model predictions are significantly improved and that the use of multiple calibration objectives results in better model performance.

Computer models are vital for the evaluation and management of urban drainage systems. Usefulness of these models, however, depends on how well they are calibrated. Properly calibrated models can be used to conceive, evaluate and compare various design improvement alternatives. Unfortunately, calibration and design of urban stormwater models, especially with the commonly used trial-and-error approach, are an expensive, time-consuming process and normally represent the most painful step of a modeling exercise. Their success depends mainly on the engineering expertise of the modeler and budget availability. The effort is complicated by the fact that these models normally necessitate the evaluation of a large number of variables and parameters in order to adequately describe the complex relationships that exist between rainfall, runoff, watershed characteristics, and system hydraulics in an urban setting. The trial-and-error evaluation of all calibration and design/improvement options is therefore unlikely to be practically feasible or manageable, and even knowledgeable modelers often fail to obtain good results. In this paper, a rigorous optimal calibration and design methodology is presented, which eliminates the need of the traditional trial-and-error technique. The optimal calibration and design problems are cast as nonlinear optimization problems and solved using genetic algorithms (GA) optimization and particle swarm optimization (PSO). The EPA storm water management model (SWMM5) is employed to perform hydrologic and hydraulic analyses. The optimal calibration model determines the set of calibration parameters that best matches field observations of flow, depth or velocity to accurately mirror actual system performance. The optimal design model determines the set of design parameters that best meets desired system performance requirements at minimum cost. Design parameters can include any combination of pipe slope and size, storage, pumping, and new piping. System performance criteria include explicit constraints on the maximum allowable depth to diameter ratio, minimum and maximum pipe velocities, and maximum head loss for force mains. The proposed optimal calibration and design models are demonstrated by application to an example urban stormwater collection system. Enhancement of urban drainage system planning, design, operation and management is a principal benefit of the proposed methodology.

This paper presents a general mathematical calibration model for the parameterization of CAEDYM, and its implementation to Lake Kinneret as a case study. CAEDYM along with DYRESM form a 1D aquatic ecosystem model that can simulate the physical, biological and chemical processes of lakes and reservoirs. CAEDYM is the biological-chemical model and describes primary production, secondary production, nutrient and metal cycling, oxygen dynamics, and the movement of sediments. Lake Kinneret (the Sea of Galilee) is the most important surface water resource in Israel providing approximately 35% of its annual drinking water, a proportion that is constantly increasing. The lake surface is approximately 212 m below the level of the Mediterranean Sea, its maximum volume is 4.3 Billion Cubic Meters (covering an area of about 167 km²), its maximum length (north to south), width (east to west), and depth, are 24 km, 16 km, and 44 m, respectively. The calibration model, entitled CalKin, couples a genetic algorithm with CAEDYM. The model performance has been shown to be robust and reliable achieving significant improvements over manual calibration.

This paper builds on work done on using interactive multi-objective genetic algorithms (IMOGA) to solve the groundwater inverse problem (Singh & Minsker, 2005) by searching for optimal hydraulic conductivity fields conditioned on field measurements of hydraulic heads and conductivities. The biggest challenge faced when using such interactive systems is that of user fatigue because the user is expected to evaluate many solutions during the search process. This paper discusses a two-step approach to reduce user fatigue. First the user is shown only a fraction of the total population in every generation. To ensure minimum redundancy during evaluation, the solutions are clustered using unsupervised clustering and the expert is shown unique samples from distinct clusters. Next the unranked solutions are ranked using a surrogate model that ‘learns' from the user preferences. This is implemented using a supervised classification algorithm to cluster the solutions based on the 2-D images of hydraulic conductivity. We test ‘content-based' and ‘spectral' algorithms for the clustering and classification as these have been shown to be similar to how humans process images. The work on applying and testing these algorithms is on-going and this paper discusses some preliminary results. Complete results will be shown at the EWRI conference.

The Interactive Genetic Algorithm (IGA) allows water resources and environmental decision makers to become active online participants during the optimization process, and thus provides a method to include qualitative expert knowledge within the search criteria. However, various interfering human factors, especially human fatigue, can limit the extent of the decision maker's participation. In this paper, we propose a mixed-initiative interaction technique for the IGA in which a simulated expert (created by using a machine learning model) can share the workload of interaction with the human expert, while constantly learning her/his preferences. This collaborative framework also allows the system to observe the learning behaviors of both the human and simulated expert, while utilizing their knowledge for search purposes. Many machine learning models can be utilized for creating the simulated experts, in our work we use fuzzy logic modeling that implements a rule based decision making criteria for modeling the human expert's preferences. These methodologies are tested on a field scale groundwater monitoring application to analyze their benefits.

This paper investigates a groundwater source identification problem in which concentrations at observation wells are used to reconstruct the pollution loading scenario. This inverse problem is solved using a simulation-optimization approach using evolutionary algorithms to conduct the search. Varying levels of complexity may be modeled, leading to different levels of accuracy in predictions of source location, size, and concentration. More complex models will increase the computational effort needed to model pollutant transport as part of a search procedure. In addition, the amount of non-uniqueness will typically increase as the complexity of the problem increases. This paper describes an investigation of surrogate modeling procedures and methods to generate very different solutions to characterize groundwater pollutant source under varying degrees of problem complexity.

A methodology for optimizing groundwater long-term monitoring (LTM) is presented. Groundwater LTM is required to assess the performance of groundwater remediation and human being health risk at post-closure sites where groundwater contaminants are still present. Some monitoring wells in the existing LTM network may be redundant, making it possible to remove some of them without compromising data quality. An optimization algorithm based on the ant colony optimization (ACO) paradigm is developed to minimize the overall data loss by identifying a given number redundant sampling locations. The ACO method is inspired by the ability of ant colony to identify the shortest route between their nest and a food source. The algorithm searches for redundant wells from among sampling locations in the monitoring network and follows steps analogous to traveling salesman problem (TSP), which is a cardinal combinatorial problem successfully solved by ACO. Results from the developed ACO-LTM algorithm show global optima or near-optimal solutions were identified. A comparison of the ACO-LTM results to those from complete enumeration indicates that the developed ACO-LTM algorithm is efficient and effective.

Chance-constrained genetic algorithms (CCGAs) can identify efficient solutions to complex water resources and environmental problems that satisfy a criterion with a specified likelihood under uncertainty. However, because they require evaluation of potential solutions numerous times using realizations of uncertain parameters, the computational time requirements can be very large. This paper investigates the effectiveness and efficiency of various strategies for sampling uncertain parameters in a CCGA applied to a watershed management design problem. Various sample sizes, as well as strategies for sampling uncertain parameters in a CCGA, such as using a new set of realizations for each generation, using the same set of realizations for all generations, using a new set of realizations for each potential solution evaluation, and strategies that vary the sample size based on the genetic algorithm (GA) progress, are investigated for a chance-constrained watershed management design problem. The resulting solution quality and computational requirements are compared, and recommendations are made for the most promising sampling strategies and sizes for GA-based chance-constrained watershed management.

Handling constraints in evolutionary algorithms (EAs) is a challenging issue, since an EA does not handle constraints directly. Thus, developing a heuristic that can guide the search toward feasible and good-performing solutions has become a topic of considerable interest in the field of evolutionary computation in recent years. If a heuristic is applied that is not appropriate or properly fine-tuned, the EA may converge on infeasible solutions, or on feasible solutions with poor objective function values. This paper presents a new constraint-handling technique based on stochastic tournament selection (STS). The performance of this technique is compared to various other constraint-handling techniques applied to a genetic algorithm- (GA-) based irrigation canal management problem. The problem involves finding an efficient strategy of irrigation canal network operations that can minimize the total water consumed while preventing problems such as water shortage and flooding. The most common way to handle constraints in EAs is to incorporate penalty functions into the fitness criterion to degrade the fitness of solutions that violate one or more constraints. Alternative techniques have also been reported in the literature, including multiobjective optimization techniques that treat the constraints in single objective problems as additional objectives and stochastic techniques. This paper investigates the performance of five constraint-handling techniques (four techniques from the literature, and the new proposed STS technique). Three scenarios of the case study, with different levels of difficulty and different numbers of constraints, are tested. A comparison of the performances is made to help provide guidelines for the most promising constraint-handling techniques for EA-based management of water supply and irrigation canal operations, based on the level of difficulty of the problem.

In this study, an algorithm combining an ANFIS-based water quality simulation model and a GA-based optimization technique is developed for determining optimal reservoir operating rules. In this paper, the Nash bargaining theory is used to resolve the existing conflict of interests as different decision-makers and stakeholders are involved in the reservoir operation. The utility functions of the proposed models are developed based on the reliability of water supply to downstream demands, water storage, and the quality of the withdrawn water. A numerical water quality simulation model is also developed to simulate the thermal stratification cycle and the reservoir discharge quality through a selective withdrawal structure. As the water quality simulation model has a considerable run-time, an ANFIS-based simulation model is trained using the results of multiple simulation runs of the numerical water quality simulation model. Then the trained ANSIS model is linked with the Dynamic Genetic Algorithm (DGA). DGA can reduce the computational burden of the classical GAs and the ANFIS model reduces the simulation time. Therefore, total model run time is considerably reduced in the proposed model. The developed model is applied to the 15-Khordad Reservoir in the central part of Iran. The results show that the model can reduce the salinity of the allocated water to different water demands as well as the salinity build-up in the reservoir.

There has been a modern confluence of environmental and water systems research towards a design paradigm that emphasizes multiple objectives for computationally intensive applications in areas including groundwater management, water distribution systems, and non-point source pollution. To date there have been very few parallel evolutionary multiobjective applications world-wide. This study seeks to explore new parallelization strategies for the Epsilon-Dominance Nondominated Sorted Genetic Algorithm-II that compare standard Master-Slave and multiple population parallelization approaches. Our analysis focuses on enhancing the efficiency of evolutionary multiobjective optimization by (1) using convergence based dynamic topologies and (2) enhancing search progress using archive-based migration strategies. The long-term goal of this research is to develop parallelization strategies that minimize processor population sizes and communication times while maintaining a proper load balance to achieve optimal speedups. Detailed results of the analysis will be available at the time of the conference.

The potential exists for structural best management practices (BMPs) to be improved by coupling simulation and optimization techniques. This project sought to improve the nutrient trapping ability of a retention pond design by linking a BMP simulation model with a heuristic search algorithm. Hydrologic data from a typical agricultural basin is used to run the Integrated Design and Evaluation Assessment of Loadings (IDEAL) model. The IDEAL model is linked with a genetic algorithm to find the principle outlet elevation and outlet diameter that provides the highest level of removal efficiency. The outlet elevation specified by the search algorithm should provide greater nutrient removal over conventional design methods. Various scenarios are run to test the ability of the approach. Results from those trials demonstrate the capablitiy of the model to improve BMP efficiency.

A water distribution system is an interconnected collection of storage tanks, pipes, and hydraulic control elements (e.g. pumps, valves, regulators) delivering water to the consumers in prescribed quantities and at desired pressures. Reliability analysis of a water distribution system is concerned with measuring its ability to meet consumers' demands in terms of quantity and quality, under normal and low flow conditions. This paper presents an approach to optimal operation of water networks in order to increase reliability by pressure management and adding pipes between nodes in the network. As the decision variables have several attributes, the utility of them could be used by the decision makers in form of Nash products. The developed methodology is used by combination of the Genetic Algorithms (GA) and the Artificial Neural Networks (ANN). Cost of piping, amount of leakage and water network reliability are considered in the objective function of the model. In the proposed methodology, the results of the EPANET hydraulic simulation model are used to train the ANNs based simulation model. This model is then linked to the GA based optimization model to develop the optimized piping extensions and pressure in each node. The proposed model is applied to a hypothetical water distribution network but it can be used in real world problems.

This paper presents a hybrid model tree (MT) — genetic algorithm (GA) scheme for toxic Cyanobacteria predictions in Lake Kinneret. Lake Kinneret (the Sea of Galilee) is the most important surface water resource in Israel providing approximately 35% of its annual drinking water, a proportion that is constantly increasing. For more than 30 years there have been no major problems with respect to the water quality of the lake. However, the appearance of toxic Cyanobacteria blooms in 1994 suggests that the future water quality of the lake might be at risk. A full physical understanding of the reasons for the toxic Cyanobacteria blooms is lacking. This study suggests a data driven modeling approach, relying on the vast existing data base of the lake, to explore the possible major factors causing the toxic Cyanobacteria to bloom, and to predict their possible appearance.

An educational module has been developed to introduce graduate-level students to genetic algorithms and their applications in surface water systems analysis. The module includes a user-friendly graphical user interface that is used to select genetic algorithm heuristics and parameters and explore their effect on the analysis of an irrigation canal network management problem. The simulation model for the canal network is an unsteady flow model that predicts the hydraulic response in the network to changes in boundary conditions and internal sluice gate operations, as well as the irrigation demands in the areas served by the network. This model is incorporated into a genetic algorithm-based search framework to find efficient strategies for scheduling gate operations and boundary conditions that minimize the amount of water consumed while satisfying constraints throughout the network (related to flooding, water shortages, stability of gates, etc.) over a period of time. This module has been developed primarily for use in graduate level water resources systems analysis courses, and is intended to help students visualize and understand the effects of different GA operators, parameters and constraint-handling techniques on the search process and the solution quality.

Understanding of subsurface heterogeneity, e.g., hydraulic conductivity, is inherently difficult in that natural heterogeneity and processes are extremely complex and the available data are limited. Although the parameter structure error in groundwater modeling has been assessed with one parameterization method (zonation or interpolation), with limited information many parameterization methods may interpret the same data satisfactorily. To cope with the non-uniqueness problem of parameterization, we develop a Bayesian multi-parameterization (BMP) method to integrate multiple parameterization methods in a Bayesian geostatistical framework. Moreover, a generalized parameterization (GP) method is adopted to estimate the highly complex spatial distribution of parameter heterogeneity. In this study, we combine BMP and GP as a multi-GP method to better represent the heterogeneity and reduce the model prediction uncertainty. The BMP with GP approach avoids overconfidence in one type of a single parameterization method. The proposed methodology is conducted in a numerical example where the spatially distributed hydraulic conductivity is estimated. The optimal weighting coefficients embedded in GP are identified through the maximum likelihood estimation (MLE) where the misfits between the observed and calculated groundwater heads are minimized. The conditional means and conditional variances of the estimated hydraulic conductivity distribution are obtained to assess the estimation uncertainty.

Integration of various geophysical data is essential to better understand aquifer heterogeneity. However, data integration is challenging because there are different levels of support between primary and secondary data needed to be correlated in various ways. This study proposes a geostatistical method to integrate the hydraulic conductivity measurements and electrical resistivity data to better estimate the hydraulic conductivity (K) distribution. The K measurements are obtained from the pumping tests and represent the primary data (hard data). The borehole electrical resistivity data from electrical logs are regarded as the secondary data (soft data). The electrical resistivity data is used to infer hydraulic conductivity values through the Archie law and Kozeny-Carman equation. A pseudo cross-semivariogram is developed to cope with the resistivity data non-collocation. Uncertainty in the auto-semivariograms and pseudo cross-semivariogram is quantified. The methodology is demonstrated by a real-world case study where the hydraulic conductivity is estimated in the Upper Chicot aquifer of Southwestern Louisiana. The groundwater responses by the cokriging and cosimulation of hydraulic conductivity are compared using analysis of variance (ANOVA).

Watershed studies using a variety of observational parameters are being implemented to assess how pathogen indicators migrate through rural watersheds. The objectives of the research are to examine the presence and persistence of Bacteriodes and E. coli in several east Tennessee watersheds through observations made in the main channel. Evaluation of combined surface water and groundwater inputs should be evaluated when considering possible regulatory actions through establishment of total maximum daily loads. Further, correlations between hydrologic parameters, water quality, Bacteriodes, and E. coli. are being evaluated in order to examine watershed processes in the system and determine their behavioral response to watershed practices and hydrologic stresses. The experimental design includes a preliminary synoptic evaluation of the water chemistry and bacteria during baseflow conditions through repeated measurements. Streams are known to gain and lose flow throughout the watershed, with certain areas being in proximity to karst features. Definitive causation of bacteria at baseflow is speculative at this point. Sinkhole topography is hypothesized to play an important role in the occurrence of bacteria in the channel which may provide rapid hydrologic transport to and from the channel on a seasonal basis, although direct observation from sinkholes and springs have not been made at this point in the study. The study will provide a robust dataset for evaluating landuse input functions for hydrologic inputs to the watershed.

We apply a modified counterpropagation artificial neural network (ANN) that uses multivariate data to several parameter estimation problems: (1) estimation of small scale Berea sandstone geophysical properties, (2) estimation of apparent conductivity at a leaking landfill using electromagnetic data and (3) estimation of hydraulic conductivity field at a landfill in New York State using pumping test and well log data. The counterpropagation algorithm has been enhanced in this research to allow for spatial interpolation that is comparable to traditional kriging methods. This enhanced ANN is data-driven, can incorporate large amounts of multiple data types to produce parameter estimates in real-time and does not require the computation of large covariance matrices associated with traditional geostatistical methods (kriging).

To facilitate the predictions of movement and behavior of chemicals, a one-dimensional analytical model has been developed to predict the solute transport through the unsaturated soil zone. The characteristics feature of this model is that it takes into account the influence of various processes like adsorption, leaching, volatilization, degradation, and plant uptake simultaneously. This could be achieved by introducing a common rate constant term called as total elimination rate, which is the summation of rate constants derived from the degradation, leaching, volatilization and plant uptake processes. It is this feature of the model that sets it apart and excels from that of conventional model or process specific models or site-specific models, which tends to be expensive, time consuming, and data exhaustive. The application of the developed model has been illustrated by considering the agricultural sub soil environment. The breakthrough curves for concentration versus time and depth were generated for nitrates and phosphates and used to determine the input parameters for the developed analytical transport model.

Leaching behavior of seven organic contaminants, including lindane, atrazine, N-nitrosodimethylamine (NDMA), estrone, 17Beta-estradiol, octylphenol, and nonylphenol, found in the wastewater of a treatment plant in Honolulu were evaluated for leaching in an Oxisoil (a red soil with high iron oxide content) of Oahu using both batch sorption and packed soil column experiments. Soils from two depths (0.6 m and 3.9 m) were used for the study. Two column leaching experiments were conducted using a solution of the contaminants in an artificially created ground water (deionized water with small concentrations of calcium chloride) and treated wastewater. The breakthrough curves obtained from the column experiments were used in inverse numerical modeling (HYDRUS 1D) to obtain the transport parameters for the column experiments. Sorption characteristics of each compound were obtained through batch sorption studies with different controlling parameters such as pH, ionic strength, and organic carbon content. The results of the experiments indicated that NDMA possessed the maximum potential to leach through the tested soil. Both atrazine and lindane showed moderate leaching properties. The estrogenic and the phenolic compounds were strongly adsorbed to the soil and were retained in the columns. Transport parameters obtained from the column study will be applied to the field setting to determine the arrival time and extent of contamination of ground water where widespread irrigation with wastewater over potable water aquifers to be practiced. Increases in leaching under different controlling parameters (pH, ionic strength, etc.) will also provide additional information about leaching potential.

Remediation schemes for contaminated sites are often evaluated to assess their potential for source zone reduction of mass, or treatment of the contaminant between the source and a control plane (CP) to achieve regulatory limits. In this study, we utilize a stochastic stream-tube model to explain the behavior of breakthrough curves (BTCs) across a CP. At the local-scale, mass dissolution at the source is combined with an advection model with first-order decay for the dissolved plume. Field-scale averaging is then employed to account for spatial variation in mass within the source zone, and variation in the velocity field. Under the assumption of instantaneous mass transfer from the source to the moving liquid, semi-analytical expressions for the BTC and temporal moments are developed, followed by derivation of expressions for effective velocity, dispersion, and degradation coefficients using the method of moments. Modified definitions of effective parameters are presented for degrading solutes to account for the normalization constant (zero-th moment) that keeps changing with time or distance to the CP. Implications of model results on estimating cleanup times and fulfillment of regulatory limits are discussed.

This paper presents assessment of groundwater resources in Arbuckle-Simpson aquifer located in Southern Oklahoma. This research paper evaluates the response of the aquifer to natural recharge, springs, and stream discharges, and withdrawal of groundwater from pumping wells in the aquifer. Currently, the aquifer is underutilized and the Oklahoma Legislature would like to assess the result of increased pumpage from this aquifer. The demand of groundwater from this aquifer is anticipated to increase over the next thirty years.

This research investigates the applicability of model reduction, through empirical orthogonal functions (EOF's) and the Galerkin projection, to groundwater management. In the past, groundwater models have been coupled with optimization algorithms to solve parameter estimation and groundwater management problems. The solution of a groundwater management problem generally involves finding a set of pumping/recharge rates that maximizes some measure of the system performance while satisfying a set of constraints on groundwater heads, velocities or solute concentrations. Solution of the management problem with an optimization algorithm requires repeated calls to a numerical simulation model for objective function and gradient evaluations. In many practical applications the simulation model may include thousands of nodes, and extensive solution times required to run the simulation model may prohibit the applicability of simulation-optimization schemes to large-scale problems or to real-time decision support. The use of a reduced model for simulation permits a dramatic decrease in running times when the EOF's have been computed in advance. As a result, when quick answers are required, fast execution of the reduced model makes it possible to apply simulation and optimization, such as real-time group decision-making and conflict resolution. Results from the proposed methodology are compared with results obtained with the original groundwater model, in order to assess the effect of the necessary loss of accuracy that stems from using the reduced model over the solution of the management problem for a real-world case study.

The time has passed when witching, drilling a test hole and finding good formation is adequate to site a new well for a drinking water supply. Quality, quantity, and aquifer management must all be thoroughly evaluated when developing or expanding a groundwater supply. Four case histories are described that do just that. New appropriations for groundwater rights in the Garden City, Kansas area have been frozen for several years. A public-private partnership between Wheatland Electric Cooperative and the City of Garden City was used to solve local problems with water rights and water quality. Wheatland converted existing industrial water rights and constructed a 6.5-MGD reverse osmosis blended treatment plant to sell water to potential customers. Several customers are now being served and there has been interest by several industries in buying water. Economic development in the Garden City community is back on track because of the availability of good quality groundwater, properly managed. The water levels in the Equus Beds, a prolific groundwater supply providing the majority of water for Wichita, Kansas, have been dropping for several years. This drop in groundwater levels was causing saline water to be drawn into the aquifer from the north and southwest, causing deteriorating water quality. Several alternatives were evaluated, including aquifer storage and recovery (ASR). Several ASR alternatives were evaluated in this multi-year demonstration project, to determine the best method to store excess flows from the Little Arkansas River. It is planned to store and recover both surface water from induced infiltration and treated surface water, thus blocking chlorides from local supplies. Wichita can continue to develop because of an adequate quantity of good quality groundwater, properly managed for the City and their neighbors. Lake Havasu City, Arizona has provided water to its citizens since it was incorporated in 1973. Their groundwater supply exceeded secondary drinking water standards for manganese, and the taps of water users often flowed black. Citizens voted to develop a new water treatment plant to remove manganese and arsenic, a constituent also found that exceeded drinking water standards. The nation's first manganese removal plant to use biological filtration was built and can provide up to 26-MGD of good quality water. This City of 50,000 can continue their rapid growth partially because they now have good quality water with adequate quantity for many years. Union County, Arkansas had realized for many years that their groundwater supply, the Sparta Aquifer, was rapidly dewatering. A County Groundwater Conservation District was established and a means of financing formulated. The final master plan recommended using surface water from the nearby Ouachita River to supply local industrial users with process and cooling water, leaving the Sparta aquifer for municipal and domestic supply. A countywide sales tax, voted to sunset in seven years, helped pay for construction. Union County now owns and operates a river intake, pretreatment facility, pumping station, and many miles of large water lines. Management of their water resources has saved both Union County and the Sparta from extinction.

Computational cost is a critical issue for large-scale water resource optimization problems that often involve time-consuming simulation models. This issue is compounded when optimizing under uncertainty, since Monte Carlo simulations are often required to evaluate objective function values over multiple parameter realizations. In order to improve computational efficiency, we propose a dynamic surrogate modeling approach to approximate and replace the time-consuming numerical models within a noisy genetic algorithm (GA) optimization framework. The surrogates are trained to predict the distribution of the objectives online, using Monte Carlo simulation results created during the GA run. The surrogates are then adaptively updated to improve their prediction performance and correct the GA's convergence as the search progresses. Latin Hypercube sampling method is used to efficiently sample parameters for the Monte Carlo simulation and the sampling results are archived so that the estimation of the objective function distributions is progressively improved. The GA is modified to incorporate hypothesis tests to produce reliable solutions. The method is applied to a hypothetical groundwater remediation design case study, where the primary source of uncertainty stems from hydraulic conductivity values in the aquifers. Our preliminary results show that the technique can lead to reliable and cost-effective solutions with significantly less computational effort.

Uncertainties in input parameters, such as hydraulic conductivities may result in inconsistencies between simulated and observed groundwater flow and transport data. If a groundwater management model for aquifer remediation design is based upon incorrectly estimated flow and transport parameter data, non-optimal remediation policies may result. To improve upon deterministic management, which is based on a single calibrated input parameter set, previous studies have developed robust optimization models for remediation design. Robust optimization searches for a remediation policy that is likely to perform well over the range of conditions that might be observed in the field. The range of conditions is simulated through generation of multiple realizations of unconditional random fields of the uncertain parameters. These robust optimization studies have explored the relative impact of the degree of uncertainty in various input parameters on the robust management decisions. This study expands upon previous work through incorporation of random fields conditioned on localized field observations. The importance of conditioning on both the final remediation design and on the conclusions about the overall impact of parameter uncertainty is explored by comparison to robust optimization using unconditional random fields and by varying the number of data points utilized for conditioning.

Pump-and-treat (P&T) remediation is a commonly used technology for the cleanup of contaminated groundwater. The long remediation time, high capital and operational costs are the most important problems associated with these systems. One of the determinants that affect the remediation design and its outcome is the spatial heterogeneity in the hydraulic conductivity (K) field. In this study, the effect of correlation scale (length) (lambda) of the heterogeneous K-field on P&T remediation design and costs was investigated. For this purpose, several synthetic K-fields of similar means and variances (sigma²) but different lambdas were generated using a random field generator. Simulation-optimization approach was used in order to conduct the study. For this purpose, BIO2D-KE linked with a genetic algorithm library was used. Runs were conducted in order to determine the best pumping policies and costs for the heterogeneous fields. According to the initial results, lambda of the spatial variation in K impacted P&T remediation design and costs. The number of wells, pumping rates, and costs of remediation varied for different lambdas. This outcome was more pronounced for higher sigma² of the spatially variable K-field.

A methodology has been developed in this study to optimize pumping (extraction/injection) rates in in-situ bioremediation system design with the aid of Artificial Neural Network (ANN). The equation governing in-situ bioremediation system consists of the flow equation and the equation of solute transport coupled with biodegradation kinetics, that results into a highly non linear system of equations. Consequently, the computational effort involved is a significant problem in the design of bioremediation systems. In this study, the computational burden is managed within practical time frame by replacing the BIOPLUME III simulation model with an ANN model. Artificial Neural Network has been considered to be a universal function approximator that generates fast solutions in real time. Besides this, the search for the optimal pumping pattern is directed by a simple genetic algorithm in this study. The results show that the costs involved in the proposed management solution is consistent with those resulting from other non traditional optimization techniques which use embedded bioremediation models. However, it has been observed that one can achieve considerable decrease in the number of simulations involved using the ANN approach.

This paper presents an exact analytical solution of one-dimensional transport of a contaminant undergoing advection, dispersion, sorption, and first-order decay, subject to unique boundary conditions, a first-order decaying contaminant concentration in time at the source with a constant concentration at infinity. This exact solution provides a method to study a new area of physical processes and to evaluate approximate methods and models that have been developed to analyze these problems. Recently two fields have developed interest in modeling physical processes that are best conceptualized using a decaying source boundary condition. These two fields are long-term modeling of recalcitrant non-aqueous phase liquid (NAPL) spills and radioactive waste disposal. Both of which can be approximated using a decaying source term. This paper briefly introduces some general field transport problems that can conceptually be described using a decaying source boundary condition. The paper then describes the governing equations, boundary and initial conditions, and the solution techniques used to develop the analytical solution. Next the analytic solution is provided and discussed along with some example cases. The results of the exact analytical solution are compared to another similar solution from the literature.

This paper describes the planning and design of a constructed wetland that is part of a groundwater remediation project in Murdock, Nebraska. The wetland design attempts to optimize the carbon tetrachloride remediation process while protecting adjacent properties from flooding and channel instability, enhancing wildlife habitat, and creating recreational and educational opportunities for the citizens of Murdock. Features were incorporated into the wetland design that would encourage volatilization of carbon tetrachloride during the non-growing season, as well as phytovolatilization and rhizodegradation during the growing season. As with any constructed wetland, control of the hydrologic regime was an important consideration for water quality improvement, habitat development, and maintenance. The water level is controlled by adjustable stop-logs mounted in a concrete outlet structure. Although typical wetland restoration sites are designed to safely pass 25-year storm events, this outlet structure was sized to safely pass a 100-year storm event. The interpretive trail that winds around the wetland offers opportunities for recreational and educational activities. The wetland is also accessible for water quality monitoring and further scientific investigations. Lessons learned in the design and construction of this polishing wetland should provide valuable insights for future efforts to complement phytoremediation with constructed wetlands.

This paper reviews the hydrologic principles governing the life or flooding-drying cycle of vernal pools. A quantitative method for describing the ponding hydrograph in a vernal pool formed by rainfall or by artificial flooding is proposed. This method can be used for predicting the flooding-drying phases of a vernal pool, and also to achieve desired ponding hydrograph in vernal-pool restoration work.

This paper presents findings from an investigation into catchment hydrological response to changing stimuli, including land use change, climate change, and river valley rewetting. It outlines the central role of groundwater modeling in the development of a physically based, fully distributed catchment model, which role was as a consequence of the stream flow composition. The paper also examines the influence of the catchment's hydraulic characteristics on the discharge. The study area was the Grote Nete catchment, located in the northeast of Belgium. Numerical digital filtration established that base flow constitutes the dominant stream flow of the river network, accounting for over 60% of the flow, followed by interflow with 25%. It was thus, considered paramount that these flow components be modeled accurately. The paper also highlights two issues that were taken into consideration when characterizing the catchment model. Firstly, the experimental procedures for measuring the soil hydraulic characteristics are difficult and not very reliable. Secondly, the use of pedotransfer functions to derive the characteristics from more easily measurable characterizing properties of the soil is equally as unreliable. The Averjanov method was used for the model. This method contains an exponent, whose value had a direct influence on the percolation rate in the soil and thereby influenced the actual evaporation rate. The MIKE SHE model code was adopted to model the temporal and spatial variability of soils. In testing the model hypothesis, the research made use of discharge data. For implementing a multi-criteria calibration protocol, a tool was sought that incorporates a recursive digital filter for exponential recessions to split total rainfall-runoff discharges into its three component sub-flows, and is able to determine the recession constants for each component. WETSPRO, a tool for time series analysis, was adopted. The catchment model is now being used to study trends of anthropogenic changes on catchment hydrology.

Groundwater long-term monitoring (LTM) is required for groundwater remediation projects to assess compliance of active remedial systems and natural attenuation sites where groundwater contamination is still present. LTM can be costly given the large number of sampling locations, frequency of monitoring, and number of constituents monitored at given site. This study uses a Bayesian statistics-based methodology to optimize the scheduling of groundwater long-term monitoring. This method does not rely on pollutant simulated transport models. The technique combines information from different sets of observations over multiple sampling periods with spatial sampling optimization by ant colony optimization algorithm. Instead of binary results (0/1), this methodology will suggest future monitoring schedule of each individual monitoring well on fuzzy probabilistic scale (0–1) and thus facilitating its inclusion into risk assessment procedures.

This paper adds an important case study to the long-term monitoring (LTM) optimization literature and discusses some of the advantages, as well as limitations, of the Geostatistical Temporal-Spatial (GTS) algorithm and software. Application of GTS at Tinker AFB demonstrates that the basic optimization approach now built into GTS can offer substantial cost-savings in LTM costs, and that the re-designed algorithm offers flexibility in its applicability to challenging site environments, and greater simplicity for non-expert users.

This study contributes a detailed assessment of how increased problem sizes impact the computational complexity of using multiple objective evolutionary algorithms (MOEAs) for long-term groundwater monitoring (LTM) applications. Problem size in this study is measured in terms of the number of design decision variables being considered. Computational complexity (or scaling) can be defined as a measure of how increased problem sizes impact the growth rate of the average number of design evaluations required by an MOEA to successfully solve an application. Building on a recent comparative analyses of MOEA effectiveness, this study characterizes the computational complexities of the Epsilon-Dominance Non-Dominated Sorted Genetic Algorithm II (ϵ-NSGAII) developed by the authors. This algorithm has proved to be more efficient and reliable relative to other state-of-the-art MOEAs. This study's computational scaling analysis is based on a suite of long-term groundwater monitoring (LTM) test cases formulated to test a range of problem sizes. The purpose of this study is to provide guidance on the current computational complexity of MOEAs to clarify future research paths that will allow them to solve larger water resources applications efficiently and reliably.

Knowledge of hydrological data at or near the soil surface of "large" areas — a field, catchment or watershed — is of considerable interest for the management of surface and subsurface water resources and environmental research dealing with mass transfer at the earth-atmosphere interface. The gap between the local scale for conceptual modeling and observations, and the much larger application and validation scale is bridged with aggregation procedures. Especially for the vadose zone, aggregation is subject to uncertainty due to cross- and auto-correlation of hydraulic properties and nonlinear flow. This study compares a priori aggregation of hydraulic properties with a benchmark a posteriori aggregation of simulation results. Monte Carlo simulations of evaporation were conducted for a synthetic watershed. First, probability density functions (pdf's) and cross-correlations of hydraulic parameters were established from a set of 126 retention curves and saturated hydraulic conductivities from the UNSODA database. Second, random fields of two hydraulic parameters were generated with imposed auto- and cross-correlation. Third, evaporation was simulated using a stream tube model. Fourth, a posteriori and a priori aggregation were employed to estimate water content and moisture fluxes for different field scales and to quantify the behavior of field-scale mean and variance. A posteriori aggregation yielded the correct mean and a realistic decrease in variance with increasing field scale. On the other hand, a priori aggregation resulted in erratic predictions of the mean and variance of the evaporation flux at the field scale. The cross-correlation between hydraulic parameters enhanced clusters with low or high water contents and evaporation fluxes.

The Edwards Aquifer is located in south-central Texas with a length of about 180 miles, and varying width from 5 to 40 miles. It is one of the most permeable and productive artesian limestone aquifers in the United States and supplies drinking water to more than 1.5 million people in San Antonio and the Austin-San Antonio corridor. Water from the aquifer is vital to the agricultural and light industrial economy of the region. Discharge from the aquifer provides water to many springs in the area, including two large springs, San Marocs and Comal Springs. Flows from the these springs provide water for the tourist and recreation industry, critical habitat for several endangered species and appropriated water use downstream for the Gulf Coastal Plain and the San Antonio Bay ecosystem. A major storm occurred in south-central Texas on October 17, 1998, through October 19, 1998 with most of the precipitation falling within the first 24 hours. The storm had two main centers of rainfall; one with 30 inches of rainfall and a second with about 22 inches of rainfall. This storm provided a unique stress on the Edwards Aquifer that allowed us to study the correlation between the surface water and groundwater systems and infer information about recharge, storage, and flow in the Aquifer. The study found that the initial response of river and stream flow to the precipitation event was very rapid and produced sharp peaks in flow with fast recession curves. Well and spring response was slower, with the well response times significantly longer than those of the springs. The data shows interesting correlations between the surface and ground water systems that are indicative of aquifer characteristics and help provide insight for future management decisions.

Interpolation of spatial variables is of primary importance for hydrogeological applications. Various approaches have been considered in geostatistical literature to address this issue. However, most traditional interpolation methods, including inverse distance weighting, standard kriging and radial basis functions techniques have various limitations. Kernel-based sparse bayesian learning, which has received much attention in the context of regression and classification, can provide a probabilistic framework for spatial interpolation. This study reports the use of the theory of relevance vector machine (RVM), a particular specialization of bayesian learning, for interpolating spatial variables at unknown locations. An important practical question dealing with the selection of the kernel function parameters in the design of RVMs is addressed here. The results indicate that the proposed method of selecting kernel parameters can translate into improved performance of RVMs.

Optimization is useful in water resource and environmental analysis both for design of remediation plans and for calibration. Optimization is used in calibration for selecting the best parameters for models based on comparison of model results to historical data. The main types of nonlinear optimization in use are (1) derivative based algorithms for finding local optima and (2) heuristic methods like genetic algorithms or simulated annealing for global optimization. Function Approximation is a new approach that differs from both derivative based and heuristic evolutionary optimization. Function Approximation is designed for optimization of computationally expensive functions like simulation models for which it is not feasible to run the model a large number of times. In this tutorial we will discuss new methodology to solve problems involving computationally expensive functions, i.e. cases where the times involved in the model simulation prevent a large number (e.g. thousands) of simulations in order to find the best answer.

The AFCEE Monitoring and Remediation Optimization System (MAROS) Software is a Microsoft Access database application developed to assist users with groundwater data trend analysis and long term monitoring optimization at contaminated groundwater sites. MAROS is a collection of statistical and data visualization tools in one software package designed to aid stakeholders in evaluating and developing efficient long-term groundwater monitoring programs. The MAROS methodology is designed to organize large quantities of site data and focus analysis to reveal underlying trends in the data. By reviewing several lines of evidence on plume stability and predictability, the user can optimize a groundwater monitoring network both temporally and spatially while maintaining adequate delineation of the plume. The MAROS software training presents an introduction to the MAROS methodology and software application. The tutorial program is intended to provide users with the basic skills to begin site analysis and to understand the application of the methodology to various regulatory contexts.

Hydroacoustic-based field flow measurements have been applied at the South Florida Water Management District (SFWMD) for the last ten years for rating validation and calibration of water control structures, such as spillways, weirs, pumps and culverts. This paper summarizes recent applications of these types of measurements in calibrating flow rating equations at hydraulic structures maintained and operated by SFWMD for real-time flow monitoring. Selected recent research findings on complex physical processes related to the hydraulics of flow through water control structures are then discussed. The findings include improved rating equations for free and submerged orifice flow at radial gate spillways.

Hydraulic conditions within Reclamation's Tracy Fish Collection Facility (TFCF) were measured using a Nortek BoogieDopp acoustic Doppler current profiler. This instrument is essentially a modified AquaDopp profiler, mounted on the underside of a boogie board, using wireless modem communication with a Pocket PC for control and data collection. These data were collected to support on-going research to track and locate holding areas for large predatory fish (striped bass) within the confines of the facility. The velocity profile data at and near these locations help biologists and engineers better understand the types of flow fields that should be avoided within structures if the goal is to pass fish most expeditiously into a holding facility. The BoogieDopp collects velocity profiles in-line with the axis of the profiler through the depth of the water column. When measured simultaneously with sonic locating of tagged fish, the researchers are given a clearer picture of the types of flow conditions that allow predatory species to hold and feed on other unsuspecting fish passing through the facility. The BoogieDopp's remote operation and ability to collect a velocity profile rather than just a point velocity promotes a much better understanding into the behavior of these predatory fish.

During the winter months, the Chicago River in Chicago, Illinois is subject to bi-directional flows, and density currents are thought to be responsible for these flow variations. This paper presents detailed field measurements using three acoustic Doppler current profiler instruments and simultaneous water-quality measurements made during December 2005. Observations indicate that the formation of density currents within the Chicago River and density differences are mostly due to salinity differences between the North Branch and the main stem of the Chicago River, whereas temperature difference does not appreciably affect the creation of density currents. Sources of higher water temperature, conductivity, and salinity values should be addressed in future studies.

The Loxahatchee River is a small stream that discharges into the Loxahatchee Estuary on the eastern side of South Florida. The river runs through an environmentally sensitive area where the combination of low flows and tidal influence has been subjecting the coastal ecosystem to harmful salinity concentrations. This paper summarizes the bankfull channel capacity analysis of a river reach subject to tidal influence, conducted in support to the development of the Loxahatchee River Restoration Plan (LRRDP). The analysis is based on direct measurements of discharge and stage at four stations between river mile 11.2 and river mile 14.5. The discharge measurements were made with a four-transducer, 2400-kHz Acoustic Doppler Current Profiler (ADCP) with Janus configuration during low flow and high tide amplitude conditions for about half a tidal cycle. Hydraulic analysis of the stage-discharge relations developed from the data collected at each station during this period allowed us to establish that for low flows during high-range tides, the tidal effect propagates upstream up to river mile 12. As a result, the bankfull channel capacity at all stations downstream from this river station is affected by both the tidal range and the base flow from inland. The field data collected at river mile 11.2 shows that, at high tide, the bankfull channel capacity at this station is about 15 percent less than that during low tide.

Improving descriptions of natural stream flow fields is a critical step in restoring aquatic ecosystems. Current methods used for evaluating aquatic habitat rely on simplified representations of the flow field. These methods can be improved by incorporating important spatial and temporal flow field variations and more advanced habitat metrics. However, knowledge of velocity and turbulence distributions in natural streams is limited to laboratory derived empirical equations. Further, only limited experiments have been conducted in natural streams. The objectives of this research were to evaluate the adequacy of existing empirical relationships for describing natural stream flow fields and to investigate spatial distributions of flow variables. In this research, acoustic Doppler velocimeter (ADV) measurements were conducted at the reach scale (approximately 5 stream widths) in two cobble-bed streams. The measurements encompassed riffle, pool, and run stream units. The results showed that velocity distributions were adequately predicted with the log-law for all stream units and transverse locations. However, empirical turbulence intensity and turbulent kinetic energy equations inadequately described measured values. This was likely due to turbulence generation from stream banks, bedforms, obstructions, and other stream features.

Rapids on the Colorado River in Grand Canyon attract over 20,000 white-water enthusiasts a year and are considered one of the premiere collections of rapids in North America. While this collection of rapids is an important recreational resource, relatively little is known of the specific hydraulics of individual rapids. Flow measurements are occasionally made in the low-velocity reaches between rapids, but the turbulent and dangerous nature of rapids makes in-situ data collection challenging. The present study measured hydraulics within a small rapid in Grand Canyon as well as an alluvial reach of the Colorado River in Glen Canyon using a Sontek Argonaut acoustic Doppler velocimeter (ADV)². The ADV was mounted near the center-front of a motor-powered 19-foot J-snout boat; the instrument sample volume was located 80 cm below the surface. The quality of the measurements was best in the slower water above the rapid and in Glen Canyon. Waves, aeration, and high-velocity water rendered specific measurements in the core of the rapid difficult as the ADV instrument could only measure velocities less than about 3.0 m/s. Nonetheless, velocity, bathymetry, and water-surface maps were constructed for the rapid and the reach in Glen Canyon. The compiled data sets can be used for predicting the erosion potential of debris fans forming the rapid and the development of numerical models to better characterize rapids.

The problem of culverts that block fish from freely moving up and downstream is becoming a critical environmental issue. Agencies often retrofit culverts with baffles to aid in fish passage, but little is known about the detailed flow characteristics within a baffled culvert. During August and September, 2005, fine-scaled measurements were taken at the Skookumchuck hatchery near Tenino, WA on the flow field inside a 6-foot diameter corrugated metal culvert fitted with sloped-weir baffles. The culvert was 40 feet long and set at a 1.14% slope, and the data were collected for flow rates 1.5, 2.0, 3.0, 4.0, and 8.0 cubic feet per second. Flow field measurements were collected using a Sontek acoustic Doppler velocimeter at 50 Hz. Preliminary data were used to understand the turbulence characteristics of flow within a culvert fitted with baffles, and to compare the flow field caused by sloped-weir baffles to experiments of other baffle types recorded in literature. It has been found that the turbulent kinetic energy (TKE) dissipates as the flow moves downstream from a baffle. At flows less than 3.0 cfs, the sloped-weir baffles cause higher TKE values on the left side of the flow (looking upstream) due to plunging flow. As the flow rate increases, the TKE becomes equal on both sides of the culvert, and are higher on the edges due to shear stress caused by the culvert boundary. The flow is also described using dimensionless discharge, and data from this experiment are compared to dimensionless discharge equations given by previous researchers. This research provides new information on the turbulence characteristics of flows within culverts retrofitted with sloped-weir baffles, and will be useful in recognizing which areas of the flow field could be too turbulent for fish passage.

Recent evidence suggests that, although their ultimate destination is the sea, juvenile salmonids also travel upstream to locate more desirable habitat and feeding areas. Since many culverts are impassible to juvenile salmonids, baffle systems are being evaluated that will facilitate greater upstream passage. A culvert test bed facility at Washington Department of Fish and Wildlife Skookumchuck Rearing Facility near Tenino, Washington was built to test fish passage success and study the hydrodynamic regimes induced by the baffles. The study involved installing baffles within a 40 foot long, 6 foot diameter corrugated culvert and recording 3-D velocities using an Acoustic Doppler Velocimeter (ADV). The purpose of these tests is to describe the hydrodynamics of the baffle flow and to evaluate how different hydraulic conditions may benefit or hinder fish passage. Baffle generated flow structures such as a jet on the low side of the baffle or a roller wave are identified. Using the 3-D velocity data and surface images, the flow structures are then characterized according to their intensity and size. A scaling equation is analyzed to relate the modification of flow features to the independent study parameters. This paper establishes hydraulic guidance that can help biologists and engineers to improve baffle design and configuration to aid juvenile salmon migration.

A negative bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) is attributed to the movement of sediment near the streambed and is an issue widely acknowledged by the scientific community. The integration of a differentially corrected Global Positioning System (DGPS) to track the movement of the ADCP can be used to avoid the systematic bias associated with a moving bed. DGPS systems, however, cannot provide consistently accurate positions because of multipath errors and satellite signal reception problems on waterways with dense tree canopy along the banks, in deep valleys or canyons, and near bridges. An alternative method of correcting for the moving-bed bias, based on the closure error resulting from a two-way crossing of the river, is presented. The uncertainty in the mean moving-bed velocity measured by the loop method is shown to be approximately 0.6 cm/s. Use of this method to correct the measured discharge is evaluated. For the 13 field measurements presented, the loop method resulted in corrected discharges that were within 5 percent of discharges measured utilizing DGPS to compensate for moving-bed conditions.

In 2004, the U.S. Geological Survey (USGS) Office of Surface Water staff and USGS Water Science employees began testing the StreamPro, an acoustic Doppler current profiler (ADCP) for shallow-water discharge measurements. Teledyne RD Instruments introduced the StreamPro in December of 2003. The StreamPro is designed to make a "moving boat" discharge measurement in streams with depths between 0.15 and 2 m. If the StreamPro works reliably in these conditions, it will allow for use of ADCPs in a greater number of streams than previously possible. Evaluation sites were chosen to test the StreamPro over a range of conditions. Simultaneous discharge measurements with mechanical and other acoustic meters, along with stable rating curves at established USGS streamflow-gaging stations, were used for comparisons. The StreamPro measurements ranged in mean velocity from 0.076 to 1.04 m/s and in discharge from 0.083 m³/s to 43.4 m³/s. Tests indicate that discharges measured with the StreamPro compare favorably to the discharges measured with the other meters when the mean channel velocity is greater than 0.25 m/s. When the mean channel velocity is less than 0.25 m/s, the StreamPro discharge measurements for individual transects have greater variability than those StreamPro measurements where the mean channel velocity is greater than 0.25 m/s. Despite this greater variation in individual transects, there is no indication that the StreamPro measured discharges (the mean discharge for all transects) are biased, provided that enough transects are used to determine the mean discharge.

Time-series data describing the rate of flow of water (discharge), along with a description of the uncertainty in the reported discharges, are essential for most water-resources analyses, designs, and decision making. Direct measurement of discharge, however, is impractical; thus, most discharge records are developed using empirical ratings to estimate the discharge based on measured water stages. For many streams, however, the stage alone is insufficient to determine the discharge. Advances in hydroacoustics over the past decade have resulted in a family of rating methods that use the velocity measured for a subsection of the flow area ("index velocity") as a second parameter to estimate the discharge. While different methods have been utilized to incorporate the velocity data into discharge ratings, the method that is becoming widely accepted is the "Index-velocity method," in which an empirical rating between the index velocity and the cross-section mean velocity is developed. Index-velocity methods are being widely adopted and a few studies have examined the uncertainties in the resulting discharges from a statistical perspective. However, the uncertainties in these ratings have generally been lumped into "goodness-of-fit" statistics such as the standard error of regression. This approach precludes estimating the portion of the discharge uncertainty from different sources (e.g., instrument precision, temporal variations in the flow, percentage of the cross section measured, etc.). Without identification of the sources of uncertainty and quantification of their effect on the discharges, selection of instrument precision, number of sampling points, frequency and duration of index-velocity measurements, frequency and duration of rating measurements, etc. becomes a ‘seat-of-the-pants' exercise rather than a rational scientific design. This paper presents an overview of potential sources of uncertainty in index-velocity ratings and demonstrates use of reliability-analysis methods to synthesize these into an estimate of the uncertainty in the calculated discharges. An example applications to an index-velocity gauging station illustrates the relative significance of different sources of uncertainty.

Previous studies have shown that velocities measured near the Acoustic Doppler Current Profiler (ADCP) transducers are biased low. The error was associated with two causes: acoustic ringing and the flow disturbance created by the submerged part of the ADCP in its vicinity. Acoustic ringing defines the resonance of the transducer and the associated electronics occurring after the acoustic pulse is generated until the vibrations die out. The local flow disturbance is induced by the flow blockage and the drag acting on the ADCP and it is commensurate with the ADCP submergence and its geometry. Given that these errors contaminate the measured velocities in the bins close to the transducers, they are collectively addressed in this paper as the near-transducer error. The paper presents results of a study conducted in a laboratory flume with an ADCP specifically designed for reducing the ringing effect (ZedHed produced by Teledyne RD Instruments). The measurements were conducted in shallow, low-velocity flows (i.e., bulk flow velocities between 0.5 ft/s and 3 ft/s and flow depths between 1 ft and 3 ft) where the near-transducer error becomes increasingly significant. The results show that by operating the ADCP with minimum blanking distance the error in the velocity estimates near the transducers can be up to 8.23% from the mean velocity in the undisturbed channel (for a flow depth of 2 ft and velocity of about 3 ft/s), and up to 27.5% when the flow is very shallow (for a flow depth of 1 ft and bulk velocity of about 1 ft/s). The results of the study also indicate that the major fraction of the near-transducer bias error is due to the ADCP blockage and the drag acting on the submerged part of the ADCP, with ringing playing a secondary role.

The overarching objective of this investigation was to evaluate the role of relative submergence on the formation and evolution of cluster microforms in gravel bed streams and its implications to bedload transport. The methodological component of this study was founded on the recent research findings of Papanicolaou et al. and Strom et al. about cluster formation, disintegration, and the effects of cluster evolution on bedload transport. An enhancement of the methodology was attempted to account for the role of relative submergence on cluster microtopography, a very important feature in gravel-bed rivers that few to none have researched in a systematic way. Specifically, the methodology and experimental design of this research was based on the premise that in natural gravel bed streams, where the height of clast-obstacles is generally of the same order of magnitude with the flow depth, the processes between the interaction of the flow and clasts play a dominant role in eddy taxonomy and flow prevailing mechanisms.

The impact of large streamwise vortices or macroturbulence upon suspended sediment transport and mobility of aquatic species is well recognized. In order to advance the understanding of large streamwise vortices, it is increasingly important to map the turbulent structures on a large scale domain such as for a total river reach. Large Scale Particle Image Velocimetry (LSPIV) serves as a promising experimental tool to map large streamwise vortices due to its extrusive nature and the ability to capture the dynamics of free-surface flows over large areas, potentially from airplanes, helicopters, and satellites. This work explored the ability of LSPIV to capture the characteristics of large streamwise vortices in a controlled experimental setting where a gravel-bed river was modeled. Visualization and statistical techniques were used to measure the largest coherent turbulent scales from LSPIV data obtained for unobstructed flow in a laboratory flume. Results revealed that LSPIV has the ability to capture free surface motion including sweeping and upwelling or ejections which indicate the upstream and downstream extent of the large streamwise vortices. Length scales and frequencies agree with published field and laboratory data for large streamwise vortices. The large streamwise vortices show quasi-stable behavior for the conditions tested.

Movable bed physical models are often used as a tool for the prediction of the morphological behavior of rivers and estuaries. But as a tool they have limitations in their own in terms of so-called scale effects defined as differences between prototype and model due to deviations from some of the scale conditions. The consequences of these scale effects are sometimes serious as some important phenomena might not be reproduced correctly. This paper discusses for scale models of rivers in which suspended load is dominant the derivation of some important scale conditions and their application for the assessment of scale effects in reproducing flow, sediment transport and bed topography. Several numerical simulations were performed for a full scale U-shape prototype bend and five of virtual physical models based on three velocity and two bed material diameter scales using a depth-averaged 2D morphological model (Mike-21C). This allowed to quantify scale effects by comparing the prototype with the "virtual physical models" created in the mind only. The results show that (1) the selection of velocity scale is very important and (2) neither the Froude nor ideal velocity scale is a good choice for movable bed models for rivers with significant suspended load with respect to scale effects.

The flow patterns around large particles in mountain gravel bed streams were examined. An emphasis was placed on the effects of these flow patterns when the relative submergence exceeded 3. To provide an improved understanding of the flow structures around the clasts, an in depth analysis of mean flow measurements was performed. On average, the velocity profiles were characterized by an inner layer that reflected mostly grain/skin resistance and an outer layer that mostly reflected form resistance. With the knowledge gained from these experiments, a practical application is to use strategically placed clast particles in a stream to help trap or entrain incoming particles near spawning grounds, thus helping to make and sustain a cleaner habitat for fish and other aquatic organisms.

A storm runoff simulator is needed to evaluate flow hydraulics, sediment trapping and water quality benefits of grass filter strips, small hydraulic structures such as storm drains, other stormwater management practices and similar bioretention systems. Based on an engineering analysis using MUSLE and HEC2, it was determined that a simulator could be developed for a 1 x 9 m grass filter plot, with resource constraints of 7,580 L stored water, 7.3 L s^–1 peak water flow rate and 0.71 metric tons of soil, for field to buffer area ratios (BAR) greater than 30:1, the maximum design criteria specified for grass filter strips by the Natural Resources Conservation Service. A runoff simulator water output control device operating under gravity flow conditions and using a feedback control system between and a flow meter and an actuated valve was designed, built and tested. A time-compressed 10yr-2hr SCS design hydrograph with a 7.3 L s^–1 peak flow rate was used to calibrate the simulator for optimal performance with large changes in flow rate and for compatibility with a variety of hydrograph shapes. When reproducing the compressed SCS hydrograph, the simulator maintained comparable efficiencies among repetitions; with a 2% error between root means square error and the total flow range. Hydrographs with step changes in flow rate, flow rate plateaus, multiple peaks and flow rates up to 9.8 L s^–1 could be simulated with comparable efficiencies and 4 to 6% error.

We evaluate the use of river velocity and bathymetry data measured with an acoustic Doppler current profiler (ADCP) to estimate the longitudinal dispersion coefficient K. Whenever mixing is controlled by shear dispersion, the dispersion coefficient can be estimated from a theoretical formula that relies on velocity measurements in a cross section. The relative ease and detail with which ADCPs measure velocities allows the dispersion coefficient to be estimated with greater frequency and spatial coverage in U.S. rivers. We conducted simultaneous ADCP and tracer measurements in the Kissimmee River in South Florida under bankfull threshold conditions. The ADCP method underestimates the dispersion coefficient obtained from the tracer study by about 40%. Flow in side channels and over part of the river floodplains likely led to dispersion of the dye cloud that the shear dispersion mechanism does not take into account.

An estimate of apparent bedload velocity (ν) can be derived from the difference between Differential Global Positioning System (DGPS) and acoustic Doppler current profiler (aDcp) bottom track (BT) measurements when BT is biased by moving bottom. A Kalman filter has been developed to integrate GPS and bottom track data to improve estimation of boat velocity during ADCP measurements under moving bed conditions. The boat velocity estimated using the Kalman filter is superior to boat velocity from raw DGPS data. In this paper we assess the improvement in estimation of ν using the Kalman filter as opposed to raw DGPS data. Specifically, a synthetic moving bed bias was generated. The synthetic moving bed bias had mean, variance, and distribution across the section as typically observed during bedload transport conditions, and had the advantage that it was known explicitly. The errors in estimated apparent bedload velocity derived using either raw DGPS data or the Kalman filter boat velocity were compared. It was found that the improved boat velocity from the Kalman filter yielded significantly (alpha=0.05) better estimates of ν, because boat velocity errors were reduced.

The river outlet works at Fontenelle Dam, part of the Seedskadee Project in southwest Wyoming, has a long history of concrete abrasion damage. Consequently, the project manager has requested assistance to identify the cause of the damage. Reclamation's Water Resources Research Laboratory will conduct a physical model study to determine the cause of the damage and to design necessary modifications to prevent the damage from reoccurring. As part of the preparation for the model study, bathymetry data for the river outlet works channel was needed to construct the topography in the physical model. The project manager also requested bathymetry data for the river outlet works structure to verify areas of abrasion damage and material accumulation identified during a recent underwater inspection. The bathymetric data were collected using an acoustic Doppler current profiler (ADCP), depth sounder and a hand-held GPS receiver. This paper presents details on the bathymetric survey techniques, considerations regarding depth and positional uncertainty, and a comparison of the bathymetric data with design data.

The ability to protect bridge piers and abutments from scour is critical to bridge safety. Excessive abutment scour can cause high maintenance costs or even bridge collapse resulting in the interruption of traffic and possibly death. Two approaches to scour mitigation have been taken. These are (1) bank-hardening and (2) flow-altering countermeasures. Bank-hardening methods are composed, among others, of riprap, cable-tied blocks, and geobags. Flow-altering countermeasures include spur dikes, guidebanks, parallel walls, and collars. Selection of a countermeasure involves a life-cycle cost assessment for the particular site in question as well as social and environmental issues. Three new countermeasures include parallel walls, spur dikes located locally to the abutment, and horizontal collar-type plates attached to the abutment. All three of these new countermeasures have been proven successful in the laboratory. This work will be detailed in an upcoming report as part of the NCHRP 24-18A project.

Observations of bridge-abutment scour lead to a practical new approach for estimating realistic scour depths at bridge abutments. Prior design approaches usually lead to unrealistically deep estimates of abutment-scour depth. The observations presented stem from flume experiments conducted with abutments with approach embankments subject to a range of erodibility conditions: fixed embankment on fixed floodplain; riprap-protected erodible embankment on readily erodible floodplain; and, unprotected readily erodible embankment on readily erodible floodplain.

Many equations are available for sizing riprap protection for bridge piers and abutments. These design equations can give significantly different results for protecting the same installation. This paper provides an overview of a review of riprap sizing methods performed as part of the National Cooperative Highway Research Program (NCHRP) Project 24-23, "Riprap Design Criteria, Specifications, and Quality Control." The performance of twelve (12) pier riprap sizing equations was evaluated by comparing the predicted size against three laboratory data sets. Adjustment factors for pier shape were also evaluated because the laboratory data includes tests of square and round nose piers. Flow velocity is the primary variable for determining riprap size. One-dimensional models often do not provide accurate estimates of flow velocity for bridge abutment areas located at the ends of embankments that encroach significantly into floodplains. Therefore, 2-dimensional hydraulic modeling was performed to test methods for estimating flow velocity at abutments and guide banks and additional guidance was developed.

A methodology to predict local scour depth at a complex pier is presented that recognises the relative scouring potentials of the components of complex piers, and the transition of scouring processes occurring for varying pile-cap elevation. Scour depths are predicted over the entire range of possible pile-cap elevations using a combination of existing expressions for scouring respectively at uniform piers, caisson-founded piers, pile groups with debris rafts, and pile groups alone. The validity of the method is confirmed using measurements of local scour at complex piers, and a case study is used to highlight application of the methodology. For design purposes, the method highlights respective pile-cap elevations that maximise (i.e. to be avoided over the pier life) and minimise local scour at complex piers. The method reinforces that where the pile-cap elevation relative to the bed can vary with time at a bridge site, potential local-scour depths need to be assessed over the range of possible pile-cap elevations for the pier.

In 1997, the National Cooperative Highway Research Program (NCHRP) developed a Strategic Plan for research on scour at bridge foundations. The Plan identified, prioritized, and developed problem statements for thirty-five studies in seven topical areas to respond to the most critical research needs. This paper evaluates progress on the Strategic Plan by NCHRP, the Federal Highway Administration (FHWA), the U.S. Geological Survey (USGS), individual State highway agencies, and others. Based on a literature search and evaluation of research activities in stream stability and bridge scour in the 1995–2004 period and a survey of State DOTs, research needs for the next 5 – 10 years are identified.

Research is currently being funded by the National Cooperative Highway Research Program (NCHRP) to develop risk-based guidelines to assist bridge owners in evaluating and prioritizing various courses of action for managing bridges with unknown foundations for scour failure. Currently, over 60,000 bridges over water have unknown foundations. Managing these bridges for failure risk is extremely difficult since a critical scour depth to cause failure cannot be determined in the absence of foundation information. The guidelines being developed under this research project focus on the following: (1) Estimating risk of failure as a function of estimated failure probability and associated economic losses, (2) Setting performance standards for various bridge classifications, (3) Recommending data collection activities (including nondestructive testing of foundations), (4) Recommending scour monitoring activities, and (5) Recommending scour countermeasures. The guidelines being developed will present a logical plan of action for bridges with unknown foundations. Given the large population of such bridges and the potential cost of management options, these guidelines will assist bridge owners in selecting and prioritizing management activities. Once the guidelines are developed, they will be applied to dozens of case studies for validation with real-world examples. After the case studies are completed, the guidelines will be finalized and made available to bridge owners nationwide.

Unsatisfactory features of the equation that is recommended in HEC-18 (Richardson and Davis, 2001) for predicting pressure-flow scour are pointed out. These are found to stem from the basic model of the regression analysis performed by Arneson (1997), and an unfortunate transformation resulting in the final form of the equation. Alternative approaches are examined.

In current practice, inlet loss coefficients for buried-invert culverts are either ignored or approximated using traditional culvert design data due to a lack of data specific to fish passage culvert geometries. This study included the experimental determination of inlet loss coefficients for a circular culvert with an invert burial depth of 50%. Culvert inverts are buried when a simulated streambed is desired in the culvert for fish passage applications. This paper outlines the experimental methods used to determine inlet loss coefficients relative to fish passage culvert geometries and presents the data relevant to the hydraulic design and evaluation of these culverts.

This paper presents results of an experimental investigation to increase roughness within the barrel of a concrete box culvert using trapezoidal-shaped corrugations with a shape similar to pavement underlay on bridge decks. Half-scale corrugations were placed on the bottom and both sides of a tilting flume 21 meters long, 0.90 meters wide, and 0.53 meters deep in Albrook Hydraulics Laboratory at Washington State University. During the experiment, wood cut to the shape of bridge decking simulated the concrete forms expected to be used in the field. Experimental flow rates ranged from 24–144 L/s. Experimental slopes ranged from 0.3–10.1%. Depths were measured with a point gage in several points upstream of corrugations, within the corrugations, and downstream of corrugations. Depths were measured at both the crest and the trough within corrugations. Manning's n was found to be dependent on the submergence ratio in a power function. In a range of submergence ratios between 1.33 and 3.0, the Manning's n ranged from 0.03–0.05 after scaling to full size. This increase in Manning's n would lead to a 40–60% velocity reduction in full scale conditions.

Populations of North American beaver (castor canadensis) have increased in the past decades throughout the Midwestern U.S., leading to an increase in the frequency of beaver dams in small streams. Beaver dams form ponds and slow water velocity. Multiple dams create a stair-step effect on the water surface profile. The hydraulic and geomorphic influence of beaver dams on streams in the focus of this study. The study area, Little Muddy Creek watershed in eastern Nebraska, is predominantly in agricultural land use. Since the early 1900's, streams in the watershed have undergone deep incision, with new floodplains being established. The main reach of this 3^rd-order watershed was surveyed for beaver dams from 2003 to 2005. Dam locations were documented with mapping grade GPS, integrity of dam structure was noted and upstream and downstream water surface elevations were measured. Failure of dam structure was documented following runoff-producing storms. While some dams were repaired within weeks, others were abandoned and left to degrade, causing a significant and transient change in the water surface profile of the stream. Tests were conducted in the laboratory to determine discharge rating curves for a simulated beaver dam. The upstream and downstream slopes and height of the dam were based on field-surveyed characteristics. Initial tests were run using a smoother surfaced dam, followed by tests with sticks attached to the smooth surface mimicking the roughness of a beaver dam. The rating curve of the beaver dam shifted to the right compared to the smooth dam, indicating that the roughness of the sticks significantly altered the stage-discharge relationship. Field observations showed that the spatial arrangement and hydraulic condition of beaver dams were temporally dynamic in both short and long term scales. Field and laboratory results indicate that beaver dam structures were similar to and could be modeled as broad-crested weirs.

The objective of this investigation is to employ the state-of-the-art large scale particle image velocimetry (LSPIV) technique for free surface flow measurements around and within the vicinity of hydraulic structures (e.g. weirs, ladders) used for fish passage in the loess region of Western Iowa, USA. Knowledge of the two dimensional (2-D) free surface velocity allows engineers and biologists to determine the hydraulic performance of the above structures as it relates to fish passage. The magnitude of the velocity will provide unique information about the level of turbulence around and within the vicinity of the structures, the approach velocity magnitude, the dissipation rate and the forces acting on juvenile and adult fish passing through the structures. The LSPIV technique is founded on similar principles with those of the particle image velocimetry (PIV). LSPIV is a powerful and efficient technique for measuring river surface velocities especially in natural -large scale- systems which are of the primary interest of this research. It is a cheap method as it needs, basically, an inexpensive video equipment (camera) and a geodetic survey to describe the region of interest (ROI). The water velocity vector magnitude and direction are calculated by dividing the estimated displacement of the particles with the time interval between two sequential images. The LSPIV technique does not require calibration and it is well-suited for measuring in very shallow flows quickly and accurately; also can be used to estimate the discharge in conjunction with bathymetry information and assumed velocity distribution over the depth. Validation of the LSPIV measurements will be attained with the use of a SonTek flow tracker.

Research at Washington State University is bringing together state-of-the-art and state-of-practice fish passage design criteria from across the nation — covering culvert and bridge installations or retrofits. A Federal Highways manual entitled Hydraulic Engineering Circular 26 "Design of Fish Passage at Bridge and Culverts" (HEC-26) will be the amalgamation of a comprehensive literature review, input from state departments of transportation, non-governmental organizations, and other interested parties. HEC-26 will include a compilation and comparison of design methods, culvert and stream assessment techniques, case studies, and design examples. The manual will provide a set of guidelines to any party interested in the design or retrofit of culverts and bridges to meet fish passage requirements, and is intended to streamline the design process. This paper presents a summary and comparison of design, retrofit and field assessment techniques employed to evaluate the barrier status of existing culverts. A number of alternatives have been developed for the design of fish-crossings, and although the exact specifications of each method vary from state to state, the overarching concepts remain the same. General methodologies fall into two categories, which meet the needs of most crossing structures: Stream Simulation and Hydraulic Design. The appropriateness of the design method is dictated by the level of stream-reach connectivity required and project budget. Fish passage assessment is essential to prioritize culvert improvement projects, and shows many similarities across the nation. The results presented within this paper will be used to shape the discussion of design procedure and culvert assessment techniques within HEC-26.

Many spillway designs form surface jets that discharge in relatively large reservoirs. It has been often observed that strong liquid entrainment is caused by these surface jets. This water entrainment can have important environmental and ecological impacts. Because of this entrainment the Total Dissolved Gas (TDG) produced in the spillway is diluted with low TDG water coming from the powerhouse. In addition, low Dissolved Oxygen (DO) waters from the powerhouse are rapidly oxygenated by mixing with the aerated spillway discharge. A numerical and experimental study of the tailrace flow on Brownlee Dam on the Snake River is presented to study this entrainment. Experimental data was obtained on a 1/48 physical model, where three dimensional velocity fields were measured using an AVD probe. Numerical models were evaluated, including the effect of turbulence models (k-epsilon and Reynolds stress model, RSM), free surface approximation (Volume of Fluid, VOF, surface capturing method or rigid lid) and single-phase or two-phase mixture. The commercial CFD code FLUENT was used. Multi-block structured grids were used to accommodate the complex geometry that includes a spillway deflector, power house units and the bathymetry. The velocity fields at different depths were compared against the experimental data taken on the physical model. The ability of the model to predict the experimental results is discussed. Both experimental and numerical results show a strong water entrainment from the powerhouse to the spillway when deflectors are used. Predicted results of the model will contribute to the understanding of the physics of this entrainment.

The overarching goal of this research is to evaluate the hydraulic performance of different structures found in the Missouri River for creating new shallow water habitat (SWH). Such structures include dikes found in their original form, notched dikes and chevron dikes. The hydraulic performance of the aforementioned structures will be evaluated via detailed field monitoring studies for a range of flow conditions and for different locations within the stream. In addition, a 2-D hydrodynamic model will be used to describe the flow patterns around the hydraulics structures. The code will provide for different flow conditions the flow depth and velocity variation introduced by the structures. This paper presents the first phase of this ongoing research by comparing the numerical simulations with the field measurements.

Many spillway designs form surface jets that discharge in relatively large reservoirs. It has been often observed that strong liquid entrainment is caused by these surface jets. Velocity measurements at both model and prototype scale for Wanapum Dam, Washington, and at model scale for Brownlee Dam, Idaho, indicate that the jet configuration and strength affect the entrainment. This water entrainment can have important environmental and ecological impacts. In the abovementioned power dams, water coming from the powerhouse is attracted to the spillway, causing beneficial phenomena. The Total Dissolved Gas (TDG) produced in the spillway is diluted with low TDG water coming from the powerhouse. In addition, low Dissolved Oxygen (DO) waters from the powerhouse are rapidly oxygenated by mixing with the aerated spillway discharge. The mechanisms causing this entrainment are poorly understood. Most of the studies found in the literature explain the entrainment with turbulent mixing. Aeration and free-surface instabilities contribute to modify the turbulence structure and have an effect on the entrainment. Standard RANS numerical models fail to predict the degree of entrainment observed experimentally. In this work a study of the entrainment in free surface jets, with the objective of reveal the reasons for the poor performance of RANS solvers in predicting water entrainment, was carried out. A numerical model was developed to resolve the free surface using the commercial code FLUENT. A submerged round jet parallel to the free surface was modeled and the effect of turbulence models was analyzed. Following a brief description of the models, the paper discusses the mechanisms involved in entrainment in spillways by comparing models with available experimental results.

It is common in different open channel flow systems, such as cooling tower basins, irrigation systems, and other water distribution systems, for two flows of equal magnitude to collide and then turn 90-degrees into a downstream channel. When this occurs two separation zones are formed in the downstream channel. This separation is often of interest during the design or evaluation of these types of structures to evaluate the potential for a hydraulic jump or choked flow conditions to occur. Numerous studies of open channel junctions have been conducted but very little information exists for the particular case of two opposing flows which collide and turn 90-degrees. This paper presents the results of a physical model study to evaluate the separation zones in this hydraulic phenomenon. The physical model study was used to validate an analytical method of the opposing flow condition. There was good agreement between analytical method and the physical model. The validated analytical method approach can be used to predict the maximum width of the separation zone. This paper summarizes the results of these studies and presents an analytical tool which can be used to asses the potential for hydraulic jumps or choked flow conditions in cooling towers, irrigation channels, and a variety of other water distribution applications.

The United States Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) estimates that nearly half of the small watershed dams constructed with their assistance will reach the end of their planned service life within the next 10 years. While many of these structures were originally built in rural environments, urban communities have encroached upon these structures over the years, making it difficult to address issues such as the maintenance of adequate spillway capacity to meet current dam safety standards. The urban infrastructure surrounding these structures limits the options available for dam rehabilitation. For instance, raising the dam or widening the existing auxiliary spillway to increase spillway capacity is often not a viable option due to land right constraints or changes in topography. Therefore, one of the more popular choices for increasing spillway capacity is the use of roller compacted concrete (RCC) stepped spillways. Two advantages of RCC stepped spillways are that they can be placed over the top of the dam and that they can provide considerable energy dissipation within the spillway chute. When placing an RCC spillway over an existing embankment dam, it is often desirable for the width of hydraulic control section to be greater than the width available to outlet the flow into the downstream channel. A generalized study utilizing a three-dimensional, 1:22 scale physical model was conducted to evaluate the influence converging training walls have on the flow characteristics on a stepped spillway. Vertical walls having convergence angles ranging from 0 degrees to 70 degrees were tested in conjunction with a spillway having a chute slope of 3(H):1(V) and a prototype step height of 0.3 m (1 ft). Water surface profiles in the central area of the chute and along the walls were collected and analyzed for each spillway configuration. Results of the study are presented in a format that will assist engineers in determining the required wall height for this type of a converging chute spillway.

The Friends of the Lower Olentangy Watershed (FLOW) was formed in August of 1997 with a mission to increase public awareness of the extensive environmental, recreational and cultural resources of the Lower Olentangy River Watershed and to promote responsible policies and uses of the river. FLOW drafted a watershed action plan based on water quality data collected by OEPA in 1999 and published in 2001. This plan, the Lower Olentangy Watershed Action Plan, was endorsed by OEPA and ODNR in 2005. One of the nine priorities listed in the plan is restoration of the mainstem through dam removal or dam modifications.

The model study objective is to determine the optimum configuration for a multi-segment cable-deployed vertical gate to block flow through a fish bypass when primary gates are not functional. In such emergency situations, gate segments are subjected to complex three-dimensional flows that vary with gate deployment elevation. The 1:24 scale model incorporated a comprehensive experimental setup controlled by LabVIEW data acquisition and visualization software allowing real-time measurement and visualization of the forces during gate deployment. Thirty gate segments (stoplogs) and lifting beam shape combinations were tested to minimize submerged gate closure weight and measure maximum cable tension. The experimental tests were complemented by companion Computational Fluid Dynamic (CFD) simulations aimed at substantiating the flow features and directing the phasing of the experimental program. This paper describes the experimental setup, procedures, and experimental phasing, as well as synergistic use of laboratory and CFD data.

An emergency closure system using stoplogs was designed to stop the flow through a fish passage when the primary gates are not functional. Physical and numerical hydraulic models were conducted to develop the stoplog design for the Wanapum Future Unit Fish Bypass. Different design alternatives were evaluated to minimize the maximum cable tension during deployment and the hydraulic uplift force that could prevent closure. The hydraulic force on the stoplog and lifting beam were calculated using the commercial code Fluent. The Volume of Fluid (VOF) method was used to simulate the free surface. Structured and unstructured hybrid grids were used to simulate the complex geometry near the stoplogs. The predicted flow field for the stoplogs at different elevations are presented and discussed. Two-dimensional numerical results are compared against experimental data taken on the 1:24 scale laboratory model and used to understand the physics underlying the behavior of each geometric design.

Hydraulic model tests of flow properties of diversion structure gates are presented for the proposed diversion structure on the Rio Grande at Albuquerque, New Mexico. The Rio Grande diversion structure is composed of independently controlled adjustable height gates across the channel, a fish passage through the diversion structure, and an intake channel for 3.7 m³/s of maximum river diversion. A 1:24 scale distorted movable bed hydraulic physical model was constructed at the Water Resources Research Laboratory of U.S. Bureau of Reclamation in Denver, Colorado. The hydraulic performances of the diversion structure that were tested include the gates operation over various flow rates, flow transitions and sediment exclusions at the intake channel. Two-dimensional hydrodynamic numerical model was built to simulate the flow properties around the diversion structure. Velocity vector computations around the intake structure and the diversion gate openings are compared with the physical test measurements. The numerical model shows very good agreements with the physical model measurements.

The placement of bendway weirs (barbs) has beneficial effects on bank stability and river ecology by increasing the conveyance at the center of the channel. This study focuses on the Raccoon River, Iowa, USA, and specifically the stabilization of the north riverbank immediately upstream of the US-169 highway bridge. The integrity of the north bridge abutment, originally built in 1950, is in danger as the river continuously erodes the surrounding soils. The Iowa Department of Transportation (IDOT) proposed solution to the problem is to install a combination of barbs and bendway weirs on the north bank upstream of the bridge to stabilize the bank. Although many recent studies have focused on the flow effects and scour holes produced by the addition of barbs, few detailed design guidelines exist. The objective of this study is to employ fundamental knowledge to evaluate the effectiveness of the proposed IDOT design and eventually produce a comprehensive, non-site specific barb design to increase bank stability. The study utilizes a commercial Surfacewater Modeling System (SMS) software package with a 2-D solver to evaluate the large scale effects of the design. Quantitative and qualitative evaluation based on previous fundamental studies showed the IDOT design effectively reduced the flow-induced shear stress, velocity, and depth along the river bank. Results also showed the current IDOT design will produce adequate sedimentation between structures and effectively move the bank line back towards its historic location. Future results from the continuation of this study will help to further reduce the ambiguity of barb design.

Lazy rivers are popular attractions at modern aquatic centers and water parks. These recreational water channels carry patrons on floating tubes around a meandering loop. The current is maintained by pumps that withdraw a small fraction of the flow from the channel through large bottom grates and return it to the channel in jets directed downstream. This paper presents the hydraulic relationships needed for lazy-river design. These relationships account for the propulsion of the flow by the water jets and the resistance to flow resulting from friction, bends and drag forces on standing persons. The total pump output power is minimized when the downstream component of the jet velocity equals twice the desired current speed. However, other practical considerations generally favor a higher jet speed. Field tests on three lazy rivers indicate that a Manning n value of 0.015 is sufficient to account for boundary friction, bend losses and other local losses. Persons standing in the flow cause added drag, which can reduce the current speed substantially. A design example illustrates the practical application of the relationships and experimental findings. The investigations presented in this paper were conducted for Water's Edge Aquatic Design LLC of Lenexa, Kansas. Water's Edge Aquatic Design is a leading design firm specializing in aquatic centers and water parks. The relationships in this paper have been applied successfully to numerous lazy-river design projects.

The U.S. Army Corps of Engineers, Los Angeles District, and the Office of Water Resources of Marine Corps Base Camp Pendleton contracted with WEST Consultants, Inc. (WEST) to perform watershed analyses of three small coastal basins on the base in southern California. Although this project included hydrologic, hydraulic, and sediment yield studies, the focus of this paper will be the sediment yield estimates. Using subbasin delineations developed for the hydrologic modeling, and extensive geographic information system (GIS) data sets, WEST estimated the amount of sediment yield for these watersheds using four different methods: (1) U.S. Army Corps of Engineers, Los Angeles District (LA Corps), (2) Modified Universal Soil Loss Equation (MUSLE), (3) Dendy and Bolton, and (4) Taylor. Each of the above methods was developed at a different time for slightly different purposes using different input parameters. A brief review of the different methods is provided before results from the different methods for the various subbasins are compared. Sensitivity of the various methods to certain input parameters is explored and recommendations are made regarding the methods presented.

The Illinois River has been significantly altered physically and hydrologically over the last century, resulting in a degraded ecosystem. One of the major changes was the construction of levees in the floodplain to protect agricultural levee and drainage districts (LDDs) from regular flooding from the river. A total of 24 LDDs were established in the lower Illinois River between 1987 and 1916. Removal of a large part of the river's floodplain contributed to more rapid water-level fluctuations during the growing season that inhibit establishment of native vegetation along the river. Major ecological restoration efforts are underway in the Illinois River basin. One of the goals of those restoration efforts is to re-establish the natural hydrology of the river and its floodplain to the extent possible without disrupting economic activities along the river. One of the options under consideration is the reconnection of some of the floodplain with the river. Hydrologic and ecological models are being used to assess restoration potential and to guide restoration efforts along the river. Water budget and unsteady flow models of the Illinois River are being used to evaluate water level fluctuations within the LDD. Modeling results are then used as input to a vegetation model that simulates plant growth based on water depth, fluctuation, and duration. This paper presents research results for a selected segment of the Illinois River.

Typical approaches to the determination of sediment stability generally only consider the influence of applied shear stresses due to advective flow over the sediment bed. However, in the case of fine-grained sediments, it is possible that the pressure gradients created by groundwater discharging to the stream bottom may result in a significant additional de-stabilizing effect. Several previous experimental studies have been conducted to investigate the role of injection or suction through a porous stream bed on the resistance to bed erosion. The results of these studies yield contradictory findings with injection, for example, contributing to bed stability in some studies while stabilizing it in others. A consideration of the fundamental forces acting on a bed particle is presented, providing a framework in which these conflicting results can be understood. The results of a preliminary study with a non-cohesive fine sand, d₅₀ = 500 μm is presented. A constant head water supply is provided at the bottom of the sand bed to provide different rates of vertical water movement through the sediment bed including a few cases with suction through the sediment bed. The influence of the critical shear stress for initiation of motion will be compared to the zero recharge condition to determine the magnitude of vertical hydraulic gradient required to produce a significant change in the critical shear stress.

In this study, a new unmixing model is presented for land-use fingerprinting eroded-soil using delta⁵N and C/N. The model is specified within the Bayesian Markov Chain Monte Carlo framework and is capable of unmixing erosion sources characterized by multiple erosion processes. A unique attribute of the formulation is the use of a truncation parameter to account for uncertainty during the erosion process. The model was applied for fingerprinting soils from forest and agriculture land-uses in Jerome Creek sub-watershed of the Upper Palouse Watershed, Northwestern Idaho. Multiple processes including upland rill erosion and floodplain headcut erosion are represented within the agriculture region of the Upper Palouse. A sensitivity analysis for the unmixing model and comparison of the model with sediment yield estimates for the land-uses add confidence to the accuracy of the model.

We extend the modified log-wake law, which was developed for turbulent pipe and boundary layer flows, to open-channel turbulence. Like those in pipes and boundary layers, turbulent velocity profile in open-channels can be approximated with three components: (1) the law of the wall that results from the constant bed shear stress; (2) the law of the wake that reflects the effects of gravity, secondary currents and bed roughness; and (3) the cubic correction near the maximum velocity. The modified log-wake law compares very well with experimental data from Coleman, Lyn, Kironoto and Graf and Sarma et al. It also replicates the measured velocity profile of cross-section of the Mississippi River. In particular, it can well model the velocity dip phenomenon in open-channels where the conventional log-wake law fails.

The radial basis function neural networks model (RBFNNM), a kind of hybrid neural networks model, is developed and applied to construct the flood forecasting and warning system (FFWS) in small catchment, South Korea. The RBFNNM consists of supervised and unsupervised training performance in the networks system. The parameters of the RBFNNM such as centers, widths, connection weights, and biases are determined by the RBFNNM training performance. The RBFNNM validation performance is also carried out using these parameters. The results of the RBFNNM training and validation performance are compared with those of the two multilayer perceptron neural networks model (MLPNNM). The two MLPNNM are embedded with the one step secant backpropagation (OSSBP) and resilient backpropagation (RBP) algorithm respectively. The RBFNNM shows better results than the MLPNNM-OSSBP and MLPNNM-RBP slightly on the basis of the statistical analysis and flood hydrograph respectively. The constructed FFWS using the RBFNNM spent less time for the training performance and can be easily used by the hydrologists with little background knowledge of the RBFNNM. This system, furthermore, can enable many local officers and engineers to protect large flood disasters and save the private life and wealth in the Wi-stream catchment, South Korea.

Rainfall runoff relation is very complex and depends on so many factors which require numerous assumptions. Misleading results may be obtained due to over simplification of the process. The various formulas developed for estimation of peak flood discharge are generally based on single geometric parameter, the catchment area which does not reflect true discharges on which hydraulic structures like protection gabion walls, weirs, protection embankments, small irrigation weirs built on torrential flood channels, culverts and bridges are designed. This results in loss of precious money of the state and repeated rehabilitations. This paper presents a procedure for estimating the peak flood discharge. A novel regional mathematical rainfall-runoff model was developed by full convolution of the synthetic unit hydrograph known as Snyder Method extended to include design return period of the selected storm and aerial reduction factor analysis. The model was tested against actual stream flow records by incorporating the flow records in the form of a regional flood frequency curve. The Synthetic Unit hydrograph and the design storm are related to find flood hydrograph corresponding to the design storm which may be routed through the hydraulic structure. Finally the developed mathematical model was analyzed for variation with respect to parameters of which it is composed of. The results were found within satisfactory limits of statistical tests.

The concerted flood control operation rules at the upper and lower Jinhu reservoirs on the Bijiasha River in Shenzhen, China were discussed in this study. The upper and lower Jinhu reservoirs play an important role in the flood control in Shenzhen City. The upstream flood forecast and downstream hydrological information were not considered in the present operation modes. In order to improve the reservoir operation modes, the concerted real-time operation rules for the two reservoirs were developed in consideration of the hydrological information of the inflows, and the water level of the downstream river channel. In the new operation rules, the releasing discharges from the two reservoirs were determined according to their regulating capacities, and the downstream water level in the channel from the dams to the Nigang gaging station where the real-time water level and discharge data are available. The uncertainty of the flood forecast and the downstream discharge forecast data is taken into account during the process of determining the releasing discharges. In actual operation, the floodgate opening are adjusted in a define time because of the floodgate mechanical performance. The influence of the downstream water level on the reservoir releases was considered from the safety view of point. The effects of the newly developed operation rules were verified by a 50-year flood. The retention effects performed by the new operation rules are better than those by the present modes. The new operation rules are operated easier than the present ones, and provide higher safety to the reservoirs and the downstream river channel.

An investigation was carried out to develop a flood hazard analysis and flood protection plan for a proposed residential development located in Indio, California. The project area is part of an existing floodplain that straddles portions of the alluvial fans derived from Thousand Palms Canyon and Pushawalla Canyon. Floodwaters emanating from a channel located west of the project area impact the project site. A two-dimensional flood routing model was applied to study the progression of a flood flow in the existing floodplain. Processes simulated included overland flow, infiltration, and bottom boundary roughness. Elevations were based on USGS DEM, rough grading plans, high-resolution LiDAR survey data, and data from a field reconnaissance survey. Model results were analyzed to determine the peak discharges into the proposed development. A channel was proposed to intercept the peak flows crossing the western boundary of the proposed development and convey these floodwaters southward along the western boundary and then eastward along the southern boundary of the project. The U.S. Army Corps of Engineers' River Analysis System (HEC-RAS) was utilized to predict water surface elevations in the proposed channel, and to establish freeboard conditions with respect to pad elevations. To account for the interception of flows along the western boundary, the flows in the proposed channel were progressively increased to the peak flows. To simulate the outflows across the southern boundary, lateral weir flow was assumed to occur. The results of the analysis show that the proposed flood control channel accept and discharge the floodwaters at the historical locations. The U.S. Army Corps of Engineers' HEC-6 model was used to conduct sediment transport simulations in the floodplain and onsite channels to determine the potential for sediment deposition. Model results were analyzed to estimate the sediment deposition for each cross section at the peak flow of the event, and at the end of the event. The results of our model studies indicate that sediment is transported through the system well and does not interfere with the function of the proposed stormwater channel.

The current methodology recommended for flood-frequency analyses by U.S. Federal agencies is presented in Bulletin 17B. Bulletin 17 was first published in 1976; minor corrections were made in 1977 resulting in Bulletin 17A, which was later succeeded by Bulletin 17B published in 1982. The fields of hydrology and flood frequency analysis have substantially advanced since Bulletins 17-17A-17B were published. As Bulletin 17B approaches its 25^th birthday, it is time for the guidelines to be updated. New techniques are now available that correct known problems with Bulletin 17B and improvements should now become part of the Bulletin's recommended procedures. Such changes would provide: (1) statistically appropriate and efficient procedures for the computation of the regional skew and its precision that recognize that sample skewness estimators are relatively inaccurate themselves, (2) statistically effective and flexible methods for employing historical flood data in flood frequency investigations, (3) consistent and straightforward treatment of low outliers, and (4) computation of confidence intervals for quantiles correctly reflecting uncertainty in the skewness coefficient. A computational study demonstrates how Bulletin 17B confidence intervals (correctly computed for known skew) perform when the weighted skew is estimated with at-site and regional information.

CH2M HILL working with the City of Portsmouth conducted a Water Supply Master Plan Study that includes evaluation of the safe yield of the City's reservoirs, evaluation of water quality and treatment issues, and development of system-operating rules. The purpose is to develop an integrated water supply plan that both supports new state requirements as well as assists the City in making decisions involving the future direction of water supply and water sales development. The new state regulations call for "Water Plans" to be developed. Requirements for the Water Plan include an assessment of needs and current supplies, development of a Drought Response and Contingency Plan, description of demand management measures in place and articulation of a Statement of Need. This paper will describe CH2M HILL's efforts to assist the City of Portsmouth in developing its Water Plan, including the application of the dynamic simulation model VOYAGE. One major part of the work involved the development of the drought response plan and reservoir operating rules. The foundation for both the plan and the rules was the testing of different reservoir operating modes. The operating modes consisted of different combinations of withdrawal rates, reservoir routing, and groundwater well pumping. The two limiting factors considered were available useable storage in the reservoirs and fluoride levels in the finished water. Each operating mode was modeled and optimized using CH2M HILL's water system simulation model VOYAGE. This tool is an object oriented model created in the Extend simulation platform. VOYAGE was designed to quickly evaluate numerous potential solutions and identify the optimal combination of water supply sources to meet demands based on given constraints and the operation that will optimize system performance. Input to the model included system configuration data, plant upgrade scenarios, water usage, meteorological data, and the results of an unaccounted-for water study. Twelve mode of operation scenarios were tested using a weekly time step over a four year period that included the 2001 – 2002 drought. The scenarios were divided into three groups. The first group assessed the combination of existing surface supplies and production wells. The second group included only wells as the raw water source during drought. The third group added an emergency pipeline from a neighboring reservoir owned by the City of Norfolk. VOYAGE allowed fast evaluation of changes in operating rules, for example, comparing the advantages of releasing water from upstream reservoirs based on total useable volume of the reservoir system with releases based on only the downstream reservoir's useable volume. Other modes of operation tested the optimal trigger points for well activation during a drought as well discharge location within the system. Efficacy was based both on available water for withdrawal and water quality at the intake.

This study presents an attempt to develop depth-duration-frequency curves for a region including South Carolina, North Carolina, and Georgia by identifying homogeneous regions. Existing methodologies of identifying the homogenous regions are reviewed and utilized in this study. The aim of the study is to update the existing intensity-duration-frequency curves and develop isopluvial maps that can be used to develop these curves at ungauged sites throughout the region. For this study, 17 durations ranging from 15 minutes to 120 hours are analyzed. For each duration, return periods of 2, 10, 25, 50, and 100 years are considered. Data is collected from various sources and the missing daily data is estimated using the surrounding daily stations. Maximum annual precipitation series is computed for each duration at each site. The scale correction factor is applied to correct the maximum precipitation data for clock hour interval recording. The serial and cross-correlation of maximum annual precipitation series are computed to verify the assumption that rainfall is independent of time and space. Outliers in the maximum annual precipitation series are identified and removed. The impact of missing periods on outliers is also investigated. The maximum annual precipitation data at each site is also fitted to candidate probability distributions in order to determine rainfall amount for each return period and duration. The distributions used for this study are normal, lognormal, generalized extreme value, Pearson type III, and log Pearson type III. The goodness-of-fit of each distribution is evaluated with the chi-squared goodness-of-fit test to choose the best fit. Isopluvial maps are developed by performing spatial analysis. The intensity-duration-frequency curves are developed and compared to the existing curves.

Habitat/aquatic impairments in an urban environment are often associated with multiple stressors, including known and unknown pollutants, storm water runoff, hydrologic modifications, riparian corridor encroachment, and channel alteration. These stressors may be acting either individually or cumulatively. In the absence of comprehensive physical, chemical, and biological data it is often difficult to determine each stressor's role and significance in contributing to the impairment. As a result, developing restoration plans or TMDLs and implementing improvements to address these impairments presents unique and complex challenges. This paper presents an approach to restoration plans or TMDL development and implementation planning for data-limited urban watersheds using a manageable watershed model and a flow analysis. Evaluation of data in many New England watersheds has shown that habitat/aquatic impairments are frequently related to excessive urban development and the accompanying increased storm water runoff. Not only does the storm water runoff regime (including changes in the peak and base flows) alone lead to problems, but increased runoff also generally leads to increased pollutant transport capacity and loading. Therefore, using storm water as an "umbrella" surrogate to address a suite of stressors contributing to aquatic life impairments is a plausible option in urban areas (where discrete local problems have not been identified). The use of surrogate indicators expressed as quantitative targets is an important tool for developing TMDLs. This paper demonstrates application of simple watershed models to support flow duration analysis and hydrologic target identification for TMDL development in Maine, Vermont, and Massachusetts. It also exemplifies how the approach can be extended to support storm water implementation planning.

The current SCS dimensionless rainfall distribution patterns (Type I, IA, II, and III) are thought to be over conservative and in need of replacement. This study develops new dimensionless design rainfall patterns for the state of South Carolina for various durations. The rainfall data from various sources dating back to 1971 was collected and analyzed. Different storm separation methods were reviewed and a modification of an existing method was adopted for the study. The rainfall events were combined into 21 different groups ranging from 2 to 51 hours. The top fifty events (by volume) within each group were selected to determine the dimensionless rainfall pattern. Similar dimensionless rainfall patterns for various groups were combined to create representative time-duration patterns for the state of South Carolina. The results showed that two distinct dimensioless rainfall patterns could be established. The new rainfall patterns were compared to the SCS rainfall curves and rainfall patterns developed by other states. The impact of these new dimensionless rainfall patterns on design practice was assessed. The new rainfall patterns were used to evaluate the response of hydraulic structures to rainfall events. In particular, the basin rainfall-runoff volume and detention pond performance were evaluated and compared to the results from the SCS rainfall patterns. For the basin test, the runoff volume, peak discharge, and time to peak were compared. For the pond test, the stage versus time and the ratio of storage volume to runoff volume were compared. The impact of varying the outflow culvert size on pond storage requirement was also investigated. The comparison showed that new rainfall patterns resulted in lower peak flow and different peak time for the runoff hydrograph. The new rainfall patterns resulted in lower peak stage and detention pond storage volume.

This study focuses attention on the examination of the quality of drinking water in Ipetumodu and Yakoyo Communities in Ife North Local Government Area of Osun State, Nigeria. Based on the population, geographical spread and physical observations, structured questionnaires were administered on the residents to determine the various drinking water sources. Nine sources of drinkable water were identified and samples were taken from them to determine their physical, chemical and bacteriological characteristics. The Physical analysis revealed total solid and^turbidity values (of the sampled water) of 100mg/L–860.0mg/L, and 3.5NTU–20.5NTU respectively. The chemical analysis shows hardness, alkalinity, P^H and chlorides values of 13.5mg/L–270.2mg/L, 3.5mg/L–21.2mg/L, 6.3–8.5 and 10.0mg/L–20.0mg/L respectively while the bacteriological analysis revealed the absence of coliform in the water samples collected from three out of the nine drinkable water sources. The paper concluded that imminent outbreak of water borne diseases can not be ruled out and it recommended that both the Local and State Government should work harmoniously towards ensuring the provision of potable water to the nook and crannies of the state because health is wealth.

South Florida was hit by one hurricane, two major hurricanes, and a remnant of a fourth hurricane in less than a seven-week period in 2004. Hurricanes Charley, Frances, and Jeanne along with remnants of Hurricane Ivan had hydrologic impact on South Florida. A similar series of events had not been observed in records dating back to 1871. The property losses from these hurricanes were extremely high. High rainfall, high surface water flows and a rise in lake water levels were experienced. Most of the rainfall occurred on the Upper and Lower Kissimmee Basins, the headwaters of Lake Okeechobee, which is the central component of the South Florida water management system. In these basins, the 100-year return period of monthly rainfall was observed for September 2004. The resulting surface water flow raised the water level in Lake Okeechobee, a 175,304 ha lake, by 1.64 m between August and October 2004 resulting in a storage increase of 292,347 ha-m. It impacted surface water management in South Florida. This paper presents an analysis for the individual and combined hydrologic impacts of the 2004 hurricanes on South Florida.

A combination of RADARSAT-1 and Landsat 5 TM satellite images linking the soil moisture variation with Normalized Difference Vegetation Index (NDVI) measurements were used to accomplish remotely sensed change detection of riparian buffer zone in the Choke Canyon Reservoir Watershed (CCRW), South Texas. The CCRW was selected as the study area contributing to the reservoir, which is mostly agricultural and range land in a semi-arid coastal environment. This makes the study significant due to the interception capability of non-point source impact within the riparian buffer zone. First of all, an estimation of soil moisture using RADARSAT-1 Synthetic Aperture Radar (SAR) satellite imagery was conducted. With its all-weather capability, the RADARSAT-1 is a promising tool for measuring the surface soil moisture over seasons. The time constraint is almost negligible since the RADARSAT-1 is able to capture surface soil moisture over a large area in a matter of seconds, if the area is within its swath. RADARSAT-1 images presented at here were captured in two acquisitions, including April and September 2004. With the aid of five corner reflectors deployed by Alaska Satellite Facility (ASF), essential radiometric and geometric calibrations were performed to improve the accuracy of the SAR imagery. The horizontal errors were reduced from initially 560 meter down to less than 5 meter at the best try. Then two Landsat 5 TM satellite images were summarized based on its NDVI. The SAR data obviously show that soil moisture and vegetation biomass wholly varies in space and time in the CCRW leading to identify the riparian buffer zone evolution over seasons. It is found that the seasonal soil moisture variation is highly toed with the NDVI values and the change detection of buffer zone is technically feasible. Future research focuses on comparison of soil moisture variability within RADARSAT-1 footprints against NDVI variations for studying riparian ecosystem functioning on a seasonal basis. It will contribute to develop more effective management strategies for non-point source pollution control, bird habitat monitoring, and grazing and live stock handlings in the future.

Since the watershed of the Mekong River is situated under the typical monsoon climate, the Mekong River presents a distinct variation in its water levels between the dry and rainy seasons, and causes heavy inundation in the Delta area along the river every year. In order to analyze the flow phenomena and inundation process for agricultural practice in the Mekong Delta, this study tried to establish three models: the combine of "3*4+1-type" model and the ARMA time series model, Tonle Sap Lake Storage Model and Delta Water Balance Model. The "3*4+1-type" Model was employed to calculate the runoff of the Lower Mekong River Basin from Chiang Saen to Kompong Cham and its sub catchments. The ARMA time series model was applied to the residuals of the Tank Model application in order to obtain 1 day to 5 days ahead flow forecasting after the present day based on the available data of the present day. The inflow to the Tonle Sap Lake was also estimated by the "3*4+1-type" Model, whereas outflow of the lake was formulated based on the relationship between storage volumes and water level of the Lake surface. The application of the ARMA to the "3*4+1-type" model was found effective to improve flood forecasting at the outlets point of each sub-catchment. The established storage model for the Tonle Sap Lake could calculate well for simulating the outflow and the seasonal water balance of the Tonle Sap area. Deltaic area was divided into four zones, and water balance of each zone was formulated by considering the zone's inflow/outflow between rivers and flooding areas. The establishment of these three models could provide a basic framework for modeling the Mekong Delta, Cambodia.

Establishment of rating curves are often required by the hydrologists for flow estimates in the streams, rivers etc. Measurement of discharge in a river is a time-consuming, expensive, and difficult process. Furthermore, the conventional approach of regression analysis of the stage-discharge relation does not provide encouraging results especially during the floods. Therefore, present study is aimed at the application of support vector machines (SVM) based algorithm for modelling stage-discharge relation including the hysteresis effect. A data set of discharge-measuring station located on an Indian river has been used for analysis in the present study. A back propagation neural network model was also employed on the same data in order to compare the performance of the results based on support vector machines based modelling technique. The outcome of the study suggest that the support vector machines works quite well for both the data sets and produced promising results in comparison to the neural network technique. Finally, results also suggest the suitability of SVMs algorithm in predicting the looped rating curve having hysteresis effect as well.

Using the U.S. Environmental Protection Agency's (USEPA) Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) system, the Illinois State Water Survey developed a Soil Water Assessment Tool (SWAT) model for the Illinois River basin. The SWAT model was calibrated and verified using observed flows at Marseilles, Kingston Mines, and Valley City along the Illinois River. Over the 1993-2000 simulation period, Nash-Sutcliffe efficiencies for daily, monthly, and annual flows exceeded 0.7 at the three gaging stations, except daily flows at Kingston Mines. However, comparisons between the simulated and observed daily flows indicated that simulated and observed peak flows deviated in magnitude and timing. The SWAT model uses Muskingum and variable storage-flow routing schemes, which are less capable of routing flows in the complex Illinois River that has locks and dams, backwater lakes, and gentle hydraulic gradients with backwater effects from the Mississippi River. The goal of this study was to improve the hydrologic modeling accuracy for daily flow routing on the Illinois River. A one-dimensional unsteady state hydraulic model (UNET) developed for the Illinois River was coupled with the calibrated SWAT model. This paper compares modeling accuracies of the coupled SWAT-UNET models and SWAT model results.

The resolution of digital elevation model (DEM) used for watershed delineation and data extracted from the delineated watershed relevant to hydrography plays an important role in the calibration of hydrological models. The effect of DEM resolution on the drainage length, watershed area and average slope are studied in many earlier works. DEM resolution can have impact on hydrologic modeling parameters, water quality simulation results. The impacts of DEM resolution on results of the watershed response and water quality modeling are studied using HSPF (Hydrologic Simulation Program Fortran) model applied to a watershed in Kentucky in this study. Three major streams in this watershed are impaired due to pathogen pollution according to the current state of Kentucky water quality standard set for recreation. The effects of DEM resolution on water quality modeling and calibration for fecal coliform bacteria are studied using a HSPF model. Results from this study indicate that the DEM resolution affects hydrography parameters of the delineated watershed, influence the calibration process, and the non-point and point source loadings to the streams in the watershed.

Linking a land model to a water model at this interface is a major step in developing an integrated water quantity/quality modeling process. On the other hand, the quantification of variability and uncertainty of hydrology and water quality parameters is a great challenge facing water resources managers. The objective of this paper is to.report on the use of the Gridded Surface Sub-surface Hydrological Analysis (GSSHA) and CE-QUAL-W2 model interfaces in the Watershed Modeling System (WMS) as a framework for an integrated water resources approach that can stochastically model the land water interface. The conventional integrated water resources methods are primarily based on deterministic approaches. Whereas this research uses some statistical methods to address uncertainty and account for the randomness of model input variables. WMS is a comprehensive graphical modeling environment for various phases of watershed hydrology. It is a GIS-based pre/post processing software that supports many hydrologic/hydraulic and water quality models widely used by water resources managers/engineers. GSSHA is a 2d physical, distributed hydrologic model that simulates the hydrologic response of a watershed subject to given hydrometeorological inputs. CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic model capable of modeling watersheds with interconnected rivers, reservoirs and estuaries. The framework presents modeling the land portion of the watershed using GSSHA and taking the GSSHA output to use as input to CE-QUAL-W2. This process is repeatedly done using statistical simulation for GSSHA input parameters using probability density functions (PDFs) of selected parameters that are assumed to exhibit a probabilistic nature. Furthermore, the presented framework addresses uncertainty in both water quantity and quality. Statistical intervals are used to report results as opposed to single value. For example, a time series of a pollutant of choice is presented in a credible interval of, for instance, 95% confidence level would suggest there is a 95% probability that the pollutant lies between the interval limits. This is as opposed to reporting a single concentration value for each time step.

Isopleths are lines along which rainfalls have the same specified intensity. These isopleths form the basic information needed for the design of systems needed for roof drainage, urban drainage, water supply, irrigation and flood control. Hence they are very important for ‘water management'. For the design of roof drainage systems, rainfall data for short durations such as 2 minutes, 5 minutes, 10 minutes & 15 minutes are needed for return periods of 50 and 100 years. In Sabah State of Malaysia (Part of Borneo Island), from 1960 to 1984, only few stations were recording rainfall and that too only daily rainfalls. So, the minimum duration data available was only for 1 day. From 1985 onwards, the data for 5 minutes, 15 minutes, 30 minutes, 60 minutes & 120 minutes have been recorded along with daily rainfall. The available rainfall data is only for 19 years from 1985 to 2003. Based on these available data, rainfall data for longer return periods such as upto 100 years are predicted using multiple regression analysis of exponential type. The equation used is P = KT^at^bT₁^cP₁^d where P is the rainfall in mm, T is the return period of P in years, t is the duration of P in minutes, T₁ is the return period of P₁ in years, P₁ is the daily rainfall in mm and K, a, b, c, d are constants. After completing the Intensity — Duration — Frequency (IDF) curves for 52 stations & using these data, isopleths for storms of duration 5 minutes for return periods of 20 years, 50 years & 100 years are plotted. Using these isopleths, it would be possible to estimate the design rainfall for any location in Sabah.

The paper discusses an L-moments based regional rainfall frequency approach and its application in large areas with many regions and across a broad range of durations. Advantages of the technique in terms of robustness to outliers and stability of quantile estimates are demonstrated through real examples. This paper provides an overview of NOAA Atlas 14, the updates of the rainfall frequency atlases and technical papers published by the National Oceanic and Atmospheric Administration's National Weather Service for the Semiarid Southwest United States and the Ohio River Basin and surrounding states, focusing on technical/statistical aspects and developments and findings during the studies, such as (1) the criteria for identifying and verifying homogenous regions in a large area, (2) the goodness-of-fit for comparison and identification of distributions to best model the data in a region, (3) the concept of the real-data check and its use in regional frequency analysis, (4) consistency adjustments over a broad range of durations from 1-hour to 60-days, (5) identification of intersite dependence of the annual extreme precipitation and its impact on quantile estimates, (6) confidence limits as an uncertainty measure of the quantile estimates and, (7) the ratios of Partial Duration Series quantiles to Annual Maxima Series quantiles.

Urbanization is a growing trend world wide and presents many significant challenges in watershed planning. Distributed operational hydrology models can assist decision-makers in understanding the effects of land use and urban development policies on large watersheds, including runoff quantity and quality. The National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory (GLERL) has developed the Distributed Large Basin Runoff Model (DLBRM) as a large-scale model for the Great Lakes basin. This paper illustrates how the daily DLBRM may be used to model runoff impacts of urbanization. Urbanization trends within the Clinton watershed of Southeastern Michigan are discussed, including analysis of stationary stream flow trends of the watershed. Calibration issues regarding temporal parameter variability are also addressed followed by urbanization scenario simulations within the Clinton watershed.

After construction of dams, the hydrologic and hydraulic characteristics of rivers change drastically. Many researchers investigated these changes, affecting services and structures. The changes of river flow and sediment transport cause riverbed scour at downstream section. In this study, changes in the Lower Sakarya River are investigated after construction of Gokcekaya Dam in the Middle Sakarya Basin. Furthermore, gravels have been withdrawing from the Lower Sakarya River especially within 5 decades in order to meet construction materials for the surrounding large cities. Changes of expected probable floods are determined by using annual maximum discharges at both same stations. It is noticed that as the flood peak discharge decrease, the river flow regime is regulated. Sediment rating curves are determined and compared by using measured suspended load for before and after the dam. It is observed that the sediment transport was decreased at a rate 40–65 % after the Gokcekaya Dam.

Clustering is necessary for lack of data in a basin based on hydrometeorological homogeneity. Even principal characteristics of river basins, such as; climate, geology, and topography affecting water yields are different, some of them yield similar hydrologic outcome. In this study, 1410 stations of Turkey Rivers were classified by the cluster analysis on the basis of hydrological homogeneity. Monthly average yields (m³/s/km²) of 1410 river gauge stations on 26 river watersheds were used. It is aimed that the clusters to be homogeneous, the elements of the same cluster to be similar while they are not similar to those of a different cluster and the most meaningful groups to be made. The cluster number was found by using the agglomerative hierarchical cluster analysis method. Tests were conducted that stations from different geographic locations are considered in the same cluster independent of their geographic position. Turkey river basins were separated into 6 homogeneous regions and the yield distribution map of Turkey was obtained.

As a key part of an integrated floodwater management project, the Milwaukee County Grounds (MCG) Floodwater Facility has been designed in conjunction with downstream levee systems to sufficiently reduce water levels on the Menomonee River to provide a 100-year level of protection to previously flood-prone urban areas. The MCG facility functions by intercepting high flows from Underwood Creek, a major tributary of the Menomonee River, that would otherwise drive peak downstream water levels. Although the performance of the facility was designed and confirmed using a series of design events, each with different rainfall characteristics, the regulatory determination of flow reduction is based on continuous simulation hydrologic modeling using the Hydrologic Simulation Program — FORTRAN (HSPF). The urban setting of this project, the strategy required to reduce flood flows and the sophisticated modeling required to assess project performance all provided challenges to the MCG facility design. The project design has been completed and site regrading has been initiated. Project infrastructure will be constructed beginning in 2008 under a separate contract. Upon completion the MCG facility will reduce downstream flows sufficiently to remove 175 structures from the regulatory floodplain and likely save millions of dollars in flood damages.

Hedging rule for reservoir operation is used for rationing water supply. It accepts a small deficit in current supply so as to reduce the probability of a more severe water shortage. Recently, the community of water resources planning and management has started emphasizing the value of hedging rule because of growing water demand and increasing uncertainty in water sources. Although the concept is straightforward, the lack of the foresight of reservoir inflow makes it technically difficult to analyze. Uncertainty or imperfect information plays a very important role in hedging rule. However, few studies considers uncertainty in hedging rule analysis. This study develops a theoretical analysis of hedging rules for reservoir operations with consideration of uncertain reservoir inflow. Our approach is currently limited to a two-period optimization model (now and then) for a single reservoir, which is to maximize the utility over the two periods. General results have been derived for the following questions: (1) What is the timing for implementing hedging rules (when will it start and end)?, (2) When is a hedging rule trivial?, (3) What is the impact of the inflow uncertainty in the second period?, and (4) What is the impact of reservoir evaporation on the significance of a hedging rule? Moreover, a numerical model is developed to verify the conclusions from the theoretical analysis. The model specifies a certain type of utility function and represents the inflow uncertainty through a probability distribution function, and includes engineering constraints such as reservoir capacity and water withdrawal capacity. Therefore, the numerical model can be used to show more detailed analyses on price elasticity, uncertainty, and engineering capacities, which are difficult to include in the theoretical analysis.

This paper interprets the characteristic of rubber dam, introduces the rubber dam development and application in China, and discusses the expectation of rubber dam.

The ecological environment which human existence depends on is more and more under threat due to our own over consumption of water resources. Desertification of land and shrinkage of oases are ubiquitous in droughty area. Various structural and non-structural measures have been taken to hold back such environment deterioration, such as peremptory water transfer. In this paper the downstream region of the Tarim River has been.chosen as the test area. In the 7^th decade of the last century, many reservoirs were built on the upstream of the river for irrigation purposes. Due to the increased water diversion on the upstream, river flow disappeared on the downstream and the downstream natural conditions became worse since then. The river basin authority then decided to send water downstream through compulsory means to protect the downstream eco-environment. Water from upstream reservoirs and lakes has been diverted to downstream several times since 2000. In order to evaluate changes of the downstream eco-environment before and after the water transfer, especially changes in the size and vegetation cover density of the downstream oasis, analysis was conducted in this study. Remote sensing is found to be an efficient tool in such investigation due to its multi-resource and multi-temporal characteristics. Image data collected from MSS, TM, CBERS-2 and MODIS are used to study the land cover changes. Through overlaying and buffering analysis in the GIS platform, a relationship between vegetation and water resource has been established. The result will be of significance to more efficient natural environment protection and more reasonable water resource allocation for this river basin in the future.

In this paper, the Qingtongxia irrigated area of Ningxia Hui Autonomous Region of China will be used as the study area. The local agriculture depends absolutely on irrigation because of rare rainfall and very dry climate conditions. It is located in the upstream of the Yellow River. In the last few decades, the irrigation area has enlarged a lot under the encouraged land reclamation policy. Serious land salinization problem has been resulted due to the local custom of wasting irrigation. A lot of water was diverted for agriculture. The situation has changed since 2000, however, because the permitted water volume to be diverted from the Yellow River for this district was reduced to about 60% of the former actual water diversion due to the implementation of the water resources reallocation program along the whole Yellow River basin. Under such situation, this irrigated area was forced to adjust their crop planting patterns for water saving purposes. In this study, the evolution process will be monitored using remote sensing technology. Result shows that three aspects of the water resources related problems can be reflected clearly. It is found that new cultivated land has increased a lot in nearly twenty years time. Land salinization problem is also serious due to long time high groundwater level and strong evaporation. Results also show that the irrigated area has adjusted a lot to reduce its irrigation water diversion. It is clearly shown that area of the high water consumption crop such as paddy has reduced, while that of low water consumption crop such as wheat and corn increased more since 1999. It is hoped that the result can help the irrigation manager to make more reasonable irrigation plan in the future. The result will also be of positive meanings to the whole Yellow River basin that will face with long-term water-saving requirement.

The Ejina natural oasis, located on the downstream delta area of the inland Heihe river basin, is surrounded by gobi and desert and featured by poplar forest. It has been under serious threat of water shortage and eco-environmental deterioration starting from the late 1950's, especially from 1980's, due to over agricultural water diversion at the middle reach. Water into the oasis became less and less since then. A whole basin trans-provincial water allocation program, as the first step, has been implemented since 2000 to hold back the rapid withering trend of the oasis as quick as possible. A three year emergent water saving and environment protection project, as the second step, was also carried out during 2001 to 2003. This has directly resulted in a step by step increase of water volume into the oasis during the last five years. In this paper, two questions regarding the evolution of the oasis eco-environment during the past two decades will be answered using multi-temporal satellite images. The first question is how fast the oasis had withered from the middle 1980's. The second question is to what extent the oasis has recovered from 2000 to present. Based on the results from remote sensing analysis, the relation between water reallocation and eco-environment evolution will be assessed.

Middle Route Project of South-to-North Water Transfer is the backbone project for sustainable development of North China. This paper put forwards the necessity and the main features of the project. It is emphasized that the basic law of the project planning and designing is benefit to both the water supply area and water diverted area. How to put into practice this law is the main line of this article. China features large in territory and great different natural climate condition. The spatial distribution of water resources is uneven and non-coordinated with the national economic layout of China. Since 1980s, water resources shortage has became more and more serious in a larger scope with economic development. Along with the concept setting up of water being as a kind of resources, great progress has been achieved in water saving area. According to the statistical data, from 1980 to 1997, GDP of China increased by 7.4 times, reached to 11000 billion RMB, but water use increased by 25%, the water saving potential capacity has been greatly developed. Chinese economy is being in high-speed development, water resources demand will still increase. This requires us in one hand to develop water saving potential capacity and more in another hand to transfer water in a long distance by means of market and government macro regulation and control, for solving fundamentally water resources shortage problem.

The south of China has more water while north has less. In order to solve water shortage in Huang-Huai-Hai River Basin, the South-to-North Water Transfer Project will be built to deliver water separately from the upper, middle, lower reaches of the Yangtze River. The South-to-North Water Transfer Project is composed with the three routes, East Route, Middle Route and West Route, which can be connected to from a huge network with "four transverse and three longitudinal waterways" with such four rivers as the Yangtze River, Yellow River, Huai River and Hai River. The implement of the first stages project of East Route and Middle Route can promote carrying capacity of water resources and environment in water receiving areas, promote the efficiency of resources dispatching, the strategic adjustment of economy structure and reserves for economic development, inhibit and gradually improve the deteriorating ecological environment and ensure the sustainable development of economy, society and environment. China is a country short of water resources. Although the total amount of water resources reaches 2812.4 billion m³, per capita is only about 2100 m³, one-fourth of the world average, due to the large population. Moreover water resources are unevenly distributed in both space and time, and water resources are incompatible with combination of other resources. Therefore, appropriate allocation of limited water resources for raising water use efficiency is a very important issue for China's social and economic sustainable development. According the layout character of water resource in our country, Chairman Mao Zedong put forward a great idea on October 30, 1952, that since there is more water in the south than in the north, it is desirable to transfer some water if possible. Since then, under the lead and care of the Party Central Committee and State Council a large number of scientific and technical people have made preparation for the South-to-North Water Transfer Project during the past 50 years, during which lots of investigation and survey have been done. Based on comparison of so many alternatives, a fundamental scheme composed of the east, middle and west routes has been developed and lots of valuable results have been obtained. In Dec, 2002, The General Program of the South-to-North Water Transfer Project was approved by the State Council. Now some of the works of the first stage of East Route and Middle Route have been under construction.

North China faces severe water scarcity — more than 40% of the annual renewable water resources are abstracted for human use. Nevertheless nearly ten percent of the water used in agriculture is applied for producing food exported to South China. To compensate for this ‘virtual water flow' and to reduce water scarcity in the North, the huge South-North Water Transfer Project is currently being implemented. This paradox, transfer of huge volumes of water from the water-rich South to the water-poor North versus transfer of substantial volumes of food from the food-sufficient North to the food-deficit South, is receiving increased attention, but the research in this field stagnates at the stage of rough estimation and qualitative description. The aim of this paper is to review and quantify the volumes of virtual water flows between the regions in China and to put them in the context of water availability per region. The analysis shows that North China annually exports about 52 billion m³ of water in virtual form to South China, which is more than the maximum proposed water transfer volume along the three routes of the Water Transfer Project from South to North.

Huang-Huai-Hai River Basin, the recipient area of Water Transfer Project, is one of the most water-scarce territories in the world. Water resources already became the key factor to tie up the socioeconomic development. Therefore, to quantitatively analyze its contribution to national economy will be an important reference for the huge water diverting project evaluation. This paper calculates the output elasticity and marginal benefit of water by establishing Cobb-Dauglas production function for Huang-Huang-Hai and whole nation. The result shows the marginal benefit of Huang-Huai-Hai including agriculture is around 2.9yuan/m³, excluding agriculture is around 13.2 yuan/m³, which is higher than national average value. It can be predicted that the water marginal benefit will increases as scarcity of water, correspondently the GDP losses by water shortage will be intensified. Thus, implementing the diverting project will be a wise way to diminish the loss.

This paper is concerned about the following problems: (1) Flood simulation for urban areas based on compound models of 1-D and 2-D hydraulic models, (2) Flood losses estimation and assessment by applying hydrological and hydraulic approaches, and (3) Application of advanced information technologies in flood simulation, information visualization and system integration, such as GIS, WEB, Database and Flash, etc. Case studies have been done for some Chinese cities, such as Shanghai, Hangzhou, Beijing etc.

In the northwest of China, the Qinghai province intends to construct a main tunnel to divert water from the upper Datong River to the Huangshui River. In order to determine the feasible diversion of the main tunnel, a diversion dam operation model is established employing varying design diversion as one of its inputs and the Range of Variability Approach (RVA) is used. Results shows that the diversion in the upper Datong River must not exceed 377 million cubic meters that is about 23.86% of 1.58 billion cubic meters, mean annual runoff of the upper Datong River under the case not diverting water in December, January and February, which is much less than 1422 million cubic meters suggested in 1997. The mean annual diversion of the main tunnel can reach 284 million cubic meters that is about 17.97% of annual runoff of the upper Datong River.

Since reform and opening, especially since entering the new century, economy in China has maintained a rapid and healthy development and more and more key hydraulic projects and hydropower stations have present the characteristics of rapid speed, short period and good benefits, but at the same time, they also have bought new challenges for soil and water conservation and ecological environment protection. In the late 1990s, China has instituted a set of laws and regulations on soil and water conservation and ecological environment protection to reinforce environment management in development and construction projects. We were implementing ecological environment construction engineering of soil and water conservation at the same time when the Three Gorges Hydraulic Project on the Yangtze River, Xiaolangdi and Wanjiazhai Hydraulic Projects on the Yellow River, Dachaoshan Hydraulic Project on Lancang River and other key hydraulic projects and hydropower stations were being constructed, and have achieved notable effects. The common characteristics of the soil and water conservation and ecological environment construction of the main key hydraulic projects are: First, making water and soil conservation plans and its special designs at the beginning of major project design. Second, implementing prevention-control measures of water and soil loss when the project was under construction. Third, accepting major project consisted of special acceptance of water and soil conservation engineering, performing the national requirements of the "three-simultaneity" system between the construction and development projects and the water and soil conservation very well.

Preferential flow indicates that an ordinary phenomenon of rapid and non-equilibrium transport of water and solutes happens in most of soil. It causes a latent pollution of ground and surface waters and affects runoff yield and concentration. This paper studies the preferential flow movement of the dark coniferous ecosystem of Gongga Mountain, sets up the classification of the preferential flow and discusses the types of preferential flow in the reached area. Results show that the perceptible type of the preferential flow in the young, mid-aged and over-mature is macroporous flow; it is finger flow or funnel flow in the mature forest soil and will gradually transform to macroporous flow as the soil layer is deeper. The purpose of this research is to analyze systemically the law of soil water movement of dark coniferous forest ecosystem of Gongga Mountain and to provide theoretical basis for the effective watershed management.

Guanting reservoir (GR) is the second biggest reservoir in the Huabei district, north area of the China, it waters is the upper Yingdinghe river, composed of the sub-waters of Sangganhe river, Yanghe river and Guishuihe river. The watershed of GR is 43402 square kilometers (sq km), includes the area of Inner Mongolia, Shanxi province, Hebei province and Beijing city. Its storage capacity is 4.16 billion cubic meters, and the flood control volume is 2.99 billion cubic meters. Based on the investigating and monitoring of the sediment distribution in the watershed of GR, its results show that the total sediment yielding due to the soil and water loss in the GR watershed is 4.565 billion tons for the last five decades, among of them, soil and water conservation kept about 0.771 billion tons, it occupies 16.89% of total's amount. The water conservancy project retained about 0.765 billion tons, it occupies 16.76% of total's amount. The irrigation land deposited about 0.965 billion tons, it occupies 21.14% of the total's amount. The water course riverbed deposited about 0.816 billion tons, it occupies 17.88% of total's amount. The GR intercepted about 0.75 billion tons, it occupies 18.02% of total's amount. And the GR discharged about 0.425 billion tons, it occupies 9.31% of total's amount, respectively. According the statistics, to compare the sediment retention ratio of the soil and water conservation of the last twenty years, from 1981 to 2000, and the early thirty years, from 1950–1980, it increased about 26.27%.

The rainfall-triggered flashflood, landslide and mudflow disasters are regarded as a part of flood disasters in China, and usually called "hilly disasters". Flood disasters are severe in China, not only cause heavy damages but also bring about many human casualties each year. However, the average human death caused by hilly disasters takes about 2/3 of the total human losses due to floods in recent years, and this has become an evident problem in flood disaster mitigation in the country. After analyzed the flood disasters, the hilly disasters, the present weakness in hilly disaster prevention, the author proposed 6 countermeasures, which are in urgent need to implement recently for reducing human losses caused by hilly disasters.

Beijing is located in the north end of north china plain, its coordinates is 115°25'~117°30' E and 39°28'~41°05'N, its total area is 16800 km², in which the mountain area is 10400 km², covers 62% of the total area. The highest mountain is Donglingshan mountain in Mentougou region, its elevation is 2303 m. The slope area of hill below 200m covers 23.1% of the total mountain area. The slope are above 25°covers 46.4% of the total mountain area. The area of the plain is 6400 km², coves 38% of the total area. The lowest elevation is small than 10 m. In history, the Debris-flow in Beijing mountain area happened frequently, latest years, with the implementation of the control measures, the hazards were prevented effectively.

Based on a (K-epsilon) model and using a finite volume, method, a model was developed to simulate the 2-dimensional velocity profile under ice cover. The comparison of the simulated results from this model with the measured data from experiments indicated that the data matched well with each other. The simulation indicated that the velocity profile varied with the roughness ratio between the ice cover and the river bed. The maximum velocity was larger for unequal roughnesses between the ice cover and the river bed than that for equal roughnesses between the ice cover and the river bed (symmetrical shape for velocity profile). However, the maximum velocity location only shifted within a limited depth range. The trend and value for the velocity profile simulated by this model matched well with those measured in the experiments.

In this paper, using one-dimensional mathematic model of suspended load, joint computation is carried out on the scour-deposit variations of the mainstream of the middle and lower Yangtze and the regions of the Dongting Lake. On the basis of the achieved results, the effects of establishing and controlling the sluices on the sour-deposit of the river and lake as well as the three exits' flow dividing and sediment dividing are investigated. The investigated results indicate that after establishing and controlling the sluices, the flow-dividing and sediment-dividing amount through the three exits will decrease, of which the Songzikou will have the most decrease; the effect on the scour-deposit variation of the mainstream's channel will be little; the deposit amount of the Songzikou flow-dividing channel will increase largely, but that in the regions of the Dongting Lake will decrease obviously.

This paper develops a methodology for estimating water resources availability (that is, the total amount of usable water) under various levels of reliability. Water resources availability in each of the 12 sub-regions in Taiwan is then calculated by using the developed methodology. The annual water resources availability is finally determined for the four major regions in Taiwan. The results show that the annual water resources availability is 4,423 million m³ in the Northern region, 7,738 million m³ in the Central region, 4,125 million m³ in the Southern region and 3,522 million m³ in the Eastern region. The total annual water resources availability is 19,808 million m³ in Taiwan.

Water resource consumption is certainly one of the most complicated and delicate issues in planning and developing an urban area. Supply and demand on a single line is very easy to handle. However, with growing population and expanding city parameters, intertwined water pipes get ever so complicated and subsequently water management becomes an enormous task. Fortunately, with the help of system dynamics analysis, this enormous task can be broken down into easy-to-manage and understand steps not only to water managers but also to the general public. Hence, we adopt System Dynamics to build a water consumption model of Hsinchu region to give different strategies of industry and water management, and to illustrate variations of the water supply versus consumption. Based on the structure of Hsinchu water resource system, we used VENSIM to build a system dynamics model, which enables to build a virtual laboratory to test the manager's strategies and to communicate with the interested groups who are not experts of water management.

The purpose of this study is to evaluate the applicability of man-made ponds on assisting regional water resources management. The domain of interest is the water supply district of the Shihmen Reservoir, especially the water straitened Taoyuan area in northern Taiwan. To overcome the shortage of irrigation water in the past, numerous man-made ponds were excavated in the Taoyuan area to storage water in wet days. Due to the development of industry and economics in recent years, some farmlands were replaced by buildings and plants and the agricultural purposes of these man-made ponds have no longer existed. However, flooding and drought are still two natural hazards frequently invading this area. The possibility of given new functions to past man-made ponds will be explored in this study. Field investigation will be conducted to identify the drainage area, connecting canals, and the associated farmland sizes for selecting target ponds for further analyses. Hydrological analyses will be conducted to evaluate the capability of using man-made ponds for flood retention. System dynamic simulations will be performed to evaluate the feasibility of man-made ponds on assisting water resources during drought, as well as the possibility of applying natural purification mechanisms to improve the water quality of man-made ponds.

Sustainable river basin management is a wide concern currently. However, some quantitative indicators are still needed to make the principle of sustainability more accessible for decision making. One particular question regarding sustainable river basin management is: How much water in a river is needed for sustaining both human activities (including the current ones and projected new developments in the future) and ecosystem integrity? This study assesses water availability with consideration of climatic and hydrologic conditions, water supply infrastructure and water management institutions in the context of river basins. A management model at the river basin scale is applied to assess not only human water demand and supply for domestic, industrial, and agricultural sectors, but also natural demands. Four different indicators: "Criticality Ratio" (CR), "Depletion Ratio" (DR), "Human Impact Ratio" (HR) and "Outflow Ratio" (OR) are used to assess the impact of human interferences on the environment of a river basin. The model and indicators are applied to the major river basins in the U.S., and the result shows that CR is close or greater than 1.0 (withdrawal is more than the renewable water) in the basins of western U.S.; the average value of these indicators will not change significantly during the next 20 years in most of the basins in the U.S.; the variation of CR will become larger in some basins such as California (water region) and Columbia. For the basins with large average CR or large variation, water saving actions should be undertaken; for other basins, there still remains some capacity for additional human uses, but the new development should be assessed very carefully.

Mathematical modeling has been assisting water resources engineers for many years. Throughout the last few decades, it has proven to be an indispensable tool to manage water resources in a sustainable context. The objective of this paper is to review some recent modeling and research efforts as knowledge transfer and capacity building in Iraq, Nile Basin countries and the Middle East. The United Nations Education, Science, and Cultural Organization (UNESCO) in collaboration with the Environmental Modeling Research Laboratory (EMRL) of Brigham Young University (BYU) is conducting a knowledge transfer and capacity building for water resources engineers in the Middle East, Iraq and the Nile basin countries. These efforts include training on integrated water resources management and the use of Watershed Modeling System (WMS), developed at EMRL. Ongoing research collaborations include providing scientific and technical guidance to water resources professionals in the aforementioned countries/regions through training workshops, joint research papers and software technical assistance.

Estimation of non-point source (NPS) pollution from cropland runoff is an important feature of regional water quality planning. In the present work, influx of non-point source pollutant loads in terms of the nitrate (NO₃) and ortho-phosphate (o-PO₄) loads from agricultural areas at different locations of Kali River in western Uttar Pradesh, India, were monitored. Different mathematical techniques, based on mass balance and reaction kinetics, were used to estimate the influx of these loads between different reaches of Kali River. A total of 576 field data sets were obtained from sixteen sampling stations during the period from March 1999 to February 2000 for analysis. Remote sensing IRS-LISS III and PAN digital data were utilized to obtain land use and land cover. A Geographical Information System (GIS) was used to develop a digital elevation model in order to delineate flow paths and agricultural areas contributing non-point pollution to different sampling points. The NPS loads estimated from different existing equations were compared with the corresponding observed values and the suitability of these equations was assessed for Kali River. Certain basin characteristics were critical for assessing the impact of non-point source pollutant loads in the river. The length of the river reach showed the highest correlation with the corresponding non-point source loads.

The water problems of the Middle East and other similarly arid regions are not isolated within any given segment of the water cycle, nor is it efficient to consider the challenges of water supply, demand, disposal and reuse independently. This paper presents an integrated linear, deterministic optimization model developed to determine the minimum cost configuration of future water supply, wastewater disposal, and reuse options for Beirut, Lebanon. To the best of our knowledge, this is the first study to demonstrate an optimization model of the entire anthropogenic water cycle. The model includes interconnections between supply, demand, disposal and reuse, thereby minimizing the cost of both water supply and wastewater disposal simultaneously. By distinguishing between potable and nonpotable demands and permitting the supply of a lower grade of water to some demands, our results reveal new opportunities for cost-reductions in Beirut's water system. After use of inexpensive conventional sources, reclamation and reuse are shown to be more cost-effective than desalination to provide nonpotable water for toilet flushing, lawn watering and irrigation. Furthermore, if nonpotable aquifer recharge were permitted, reclaimed water from the centralized wastewater treatment plant could be used to augment Greater Beirut's coastal aquifer, which in turn could supply increased quantities of both potable and nonpotable water to the urban sectors.

Bangladesh is the lowest riparian country of the Ganges-Brahmaputra-Meghna (GBM) basin which constitutes one of the largest river systems in the world. More than ninety percent of the freshwater resources of the country originate outside the political boundary. Currently, Bangladesh faces extreme uncertainty in water management due to increased interventions of the rivers in the upstream reaches in India. Water sharing between the two countries has become a contentious issue since the commencement of the diversion of the Ganges flow at the Farakka Barrage in 1975. Recently disclosed unilateral plan of a mega-project for inter-basin transfer of water by India poses greater threat to the entire water resources, ecology and livelihood of several tens of million of poor people. In this paper, the authors analyze the effect of the apparent basin-wide development on the water resources and pro-poor water management of Bangladesh. The previous experience of the Ganges set a baseline for that analysis. This shows that the entire Southwestern region of the country has been severely affected including agricultural, ecological and socioeconomic sectors. The adverse effects would multiply extending major part of the country if the proposed transfer of water from Brahmaputra basin is realized. Consequently, Bangladesh is in a dilemma for managing its vital water resources and fragile ecology which has profound implication in medium and long term planning for integrated water resources management. This study examines the sensitivity of the water resources system to the anticipated upstream development. Finally, the shortcomings of the recently approved National Water Management Plan in addressing the potential risk have been scrutinized to indicate probable actions to cope with this crucial issue.

Drawing upon the experience of century, nations have constructed a customary international law for transboundary fresh water resources built around the principle of equitable utilization. The earliest complete formulation of this body of law was the Helsinki Rules on the Uses of International Rivers of the International Law Association of 1966. Like all customary law, this body of international law retains flexibility by being vague while allowing only for relatively primitive enforcement mechanisms. In an effort to improve things, the United Nations drafted a convention to codify the customary law. Even before that the UN Convention enters into force, it has been taken as a cogent summary of the relevant customary international law. The UN Convention, however, fails to integrate the environmental or ecological concerns and relevant human rights that have emerged in international law into the older body of international water law. Beginning in 1996, the International Law Association undertook to reformulate the Helsinki Rules in order to incorporate international environmental law and international human rights law. The project, for which I served as Rapporteur, concluded in August 2004 with the Association's approval of the Berlin Rules on Water Resources. The Berlin Rules speak in terms of a new paradigm of international water law that focuses on ecological integrity, sustainability, public participation, and minimization of environmental harm—principles not reflected in the Helsinki Rules and only developed in rudimentary form and then only for transboundary waters in the UN Convention. This paper will serve to introduce the Berlin Rules.

Staff at the LBJ School of Public Affairs evaluated the impacts of water and wastewater (W/WW) projects along the Texas/Mexico border to determine whether these recently financed projects by the U.S. and Mexican governments achieved two of the Border 2012 goals: reduce water contamination and improve environmental health. The study included: interviews with government officials; compilation of available data and information; and visits to local utilities. The study addressed whether the sources of pollution and other health risks related to water along the Rio Grande/Rio Bravo have been identified, evaluated, and mitigated. It assessed short and long term consequences of W/WW infrastructure in the region. Mexico and the United States have been taking steps to meet the challenge of providing W/WW services to communities along both sides of the border. High growth rates, immigration, and financial conditions in low-income communities have been barriers to utility service provision. Some of the large Mexican cities along the border offer incomplete utility coverage, have unreliable service during the day, and have inadequate treatment of W/WW. This study has documented how the investment in W/WW has improved human health and the environment, and indirectly facilitated economic prosperity and other social improvements. Wastewater service has been extended in many cities and colonias. Overflow of septic tanks prior to the installation of the wastewater collection system that once endangered children's health has been reduced because of centralized wastewater collection as have problems with sewer runoff during storm events. The WW plants reduced health problems and diseases related to untreated wastewater in the Rio Grande/Rio Bravo and its tributaries. The pipe systems have reduced wastewater leaks into underground water sources. Field observations during the study revealed numerous national commercial stores opening, substantial residential home construction, and a shift from an agricultural to an industrial/commercial economic base. The boost to the economy has generated tax revenue and given utilities a resource base to justify private sector investment. While the projects in the area have moved along with considerable progress, there remains much to be done. Roughly half of the infrastructure projects still need to be completed. Certain colonias still have people hauling water tanks on the back of trucks, which poses a health risk. Some Mexican border cities are now completing what have been emergency and catch-up projects. Although the W/WW program is addressing the rapid growth with every project completed, a watchful eye must be kept on the region to assure sustainability and avoidance of the root causes that led to the problems in the beginning. The projects evaluated met objectives of increasing access to clean water supply, decreasing reliance on septic tanks, and reducing sewage overflow during storm events.

Hydrologic modeling in combination with field measurements is used to understand subsurface drainage patterns and how drainage water management may impact subsurface drainage in the upper Midwest, particularly in Iowa. Long-term measured subsurface drainage data from an on-going drainage study in north-central Iowa was used to calibrate and validate DRAINMOD, a deterministic hydrologic model to simulate a soil-water regime of surface and subsurface water management systems. The model was then used with long-term (1945-2004) weather records with the objective of understanding the timing, duration, and volume of subsurface drainage flow patterns. Controlled drainage, a drainage management practice, was considered in the modeling simulations to assess its potential to reduce subsurface drainage in the upper Midwest. In the north-central Iowa, approximately 45% of the annual subsurface drainage occurs in the months of April and May, and approximately 80% of the annual subsurface drainage has occurred by the end of June. When simulating controlled drainage practices, there was approximately a 16% reduction in the volume of annual subsurface drainage but most of this reduction was reflected in increased surface runoff. The timing of subsurface drainage in these landscapes specifically during the spring coincides with the time of planting, crop germination, and early crop development. This coincident may limit the effectiveness of drainage management practices such as controlled drainage to reduce subsurface drainage and thereby nitrate-nitrogen export in the north-central Iowa.

Conventional surface and subsurface drainage practices and common crop fertilization methods have resulted in increased nitrate losses from agricultural fields to surface waters. However, research results from several humid region locations over the past 20 years have documented that controlled subsurface drainage can significantly reduce (40–50%) nitrate-N losses carried in drainage discharge from cropland. Other research has shown the benefit of post-harvest cover cropping as a nitrogen sink, which also reduces nitrate loss. Research has also shown that nitrate carried in stream flow can be significantly reduced by diverting the stream flow through wetland resource areas before routing it back into the main stream. This paper discusses the combination of these into a suite of BMPs to reduce nitrate losses from cropland for improved stream water quality. Application of this suite of practices throughout the Mississippi River Basin could significantly reduce the amount of nitrate carried to the hypoxic zone in the Northern Gulf of Mexico. A cooperative action group, Drainage Water Management Systems Task Force (ADMS-TF) was formed in 2002 by employees of USDA's Agricultural Research Service (ARS), Natural Resources Conservation Service (NRCS), Cooperative State Research, Education, and Extension Service (CSREES), and University research and extension partners to promote and implement drainage management (controlled drainage) on cropland to reduce nitrate losses in drainage discharge. The initial efforts of the Task Force, conducted cooperatively with drainage industry representatives, were in eight humid region Midwestern States of IA, IL, IN, OH, MI, MN, MO, & WI. Best management practices (BMPs) of cover cropping and wetland diversion are also recommended as complementary practices to further reduce nitrate load in receiving waters and improve surface water quality. Retrofitting existing subsurface drainage systems for managed (controlled) operation is a major goal of the Task Force. The vast majority of all subsurface drains installed to date in the United States are conventional subsurface drains with gravity flow outlets to the full depth of the drain. An outlet control structure (e.g., overflow weir, valve, or pumped sump) can be used to convert it to a drainage water management system. For new installations, the Task Force has recommended shallower drains, for example no deeper than 3.0 ft., thus reducing the potential for nitrate-N loss in discharge if an outlet control is not installed. These same principals also apply to deep drainage ditches, and the potential benefits of managing (controlling) ditch drainage systems are also being explored by Task Force members.

Controlled drainage, nutrient management planning, and a combination of both were implemented and evaluated throughout the upper Core Creek watershed to reduce nutrient loading to the Neuse River. Hydrology and drainage water quality were monitored at fifteen locations within the watershed for a period of five years. DRAINMOD-N was calibrated on a field-by-field basis to predict long-term hydrology and nitrate losses based on BMPs implemented and crops grown throughout the watershed. Predicted NO₃-N reduction was most effectively accomplished when controlled drainage and a nitrogen management plan were used in conjunction with one another. If implemented separately, a nitrogen management plan was predicted to be more effective than controlled drainage alone. The cropping system also impacted the drainage rate and nitrate loss from the fields. Potentially, a 30% and 75% nitrate reduction can be achieved growing cotton or soybeans, respectively, as compared to corn. Controlled drainage reduced the drainage outflow by 6.8 centimeters (21.3%) annually, compared to conventional drainage. This flow reduction accounted for 11.5% of the NO₃-N reduction leaving the watershed.

Plastic mulch and drip irrigation are commonly used in high intensity vegetable production regions such as Florida. Drip irrigation can be much more efficient than sprinkler irrigation since only the root zone of the cropped area is irrigated. However, improper irrigation management can lead to wasted water and leaching of soluble chemicals such as nitrate. In this project, several irrigation treatments were established that allowed up to five watering events per day depending on a soil water threshold controller (SMS) for tomato and green bell pepper. As a comparison time based treatments (TIME) of once daily irrigation were established to mimic typical producer practices. In addition, zero tension drainage lysimeters were buried 0.6 m below the beds in several treatments to monitor leaching of water and nitrate nitrogen. SMS control of irrigation resulted in 29%–44% less irrigation water used on tomato and 37%–66% less water used on pepper when compared to TIME treatments. Tomato yield was significantly higher on SMS treatments compared to TIME treatments, but yield was similar across all pepper treatments. SMS treatments increased irrigation water use efficiency 2–3 times compared to TIME treatments on both tomato and pepper. Both the amount of water captured in drainage lysimeters and the mass on NO₃-N were significantly lower on soil water based irrigation control compared to once daily time based irrigation commonly used by producers.

The procedures used by the public agricultural weather networks to estimate reference evapotranspiration (ETref) in the western United States were assessed to determine how many networks have adopted the ASCE Standardized Reference Evapotranspiration Equation ETszEQ. Five states now use the ETszEQ to generate ETref values. Several additional procedures are used to estimate ETref in the region. The most widely used procedures are 1982 Kimberly Penman Equation and the Nebraska Penman Equation. ETref values computed using these two Penman Equations were found to be similar to ETref values computed using the ETszEQ, suggesting a switch to the ETszEQ would not cause serious problems with existing irrigation management/crop water use programs in states using these two Penman Equations.

Bahiagrass (Paspalum notatum) crop coefficients (K_c) were determined in central Florida in 2004 and 2005. Crop evapotranspiration (ET_c) rates were measured simultaneously using weighing lysimeters and an eddy correlation system. Reference evapotranspiration (ET_o) values were calculated by the standardized ET_o equation by the Environmental and Water Resources Institute of American Society of Civil Engineering using weather data from a nearby reference ET station. The K_c values were developed from the measured ET_c and calculated ET_o values. Relevant soil moisture results indicated that the soil at the experimental sites was not water stressed and had a full canopy cover. A 12 cm grass height was closely maintained during the two year study period. Lysimeters were considered as the standard to directly measure ET_c. In this research, three relative large weighing lysimeters, each equipped with four commercial load cells, provided an accuracy of 0.29 mm. The lysimeters were double steel tanks with an inner surface area of 2.32 m² and a soil depth of 1.37 m. An eddy correlation system was used to directly measure the turbulent fluxes of water vapor (LE) and sensible heat (H) above the crop canopy. The distance between the lysimeters and the eddy stations was 80 m. Daily crop coefficient values were estimated using ET_c measured by the lysimeters and the eddy correlation system. The K_c values determined by the eddy correlation method were similar to that by the lysimeters during the summer season. The largest K_c difference was found in winter time when the grass growth was minimal and irrigation requirement was negligible.