Journal of Irrigation and Drainage Engineering

Simulation models have been used in a limited fashion to describe and characterize soil water flow in saturated conditions as an approach to optimize drainage design parameters. The dynamic hydraulic behavior of an ideal drain can be characterized by a drain intake resistance factor, solving a two-dimensional equation, including humidity retention functions, by a numerical method based on the finite-element analysis tool, describing time variations of streamline magnitudes and direction, water flow radial velocities, relative soil water content, and pressure head profiles throughout the drainage process. Two drainage pipe extraction areas of 7.85 and $39.47{\mathrm{cm}}^2{\mathrm{m}}^{-1}$ were simulated, with the drainage system embedded in a homogeneous and isotropic quartz sand under constant and variable discharge conditions. Simulation results indicate that the water entrance resistance factor must be considered in the design of a drainage network because the hydraulic behavior on the agricultural drain depends on its geometric characteristics.

Momentum transfer between a main channel and side floodplains tends to increase the floodplain shear and decrease the main channel shear. The increase and decrease in shear are greatly influenced when a compound channel has nonprismatic floodplains. In converging compound channels, water flow on the floodplain crosses over water flow in the main channel, resulting in increased interactions and momentum exchanges. An experimental analysis concerning the distribution of shear stress in the main channel and the floodplain for both prismatic and nonprismatic compound channels under different overbank flow conditions are performed. New equations are developed for predicting boundary shear stress distribution for a compound channel with the nonprismatic flood plain. Using these expressions the stage-discharge relationships for both prismatic and nonprismatic compound channels of lower width ratios are successfully estimated. The efficiency of the models is verified by applying natural river data sets.

Artificial groundwater recharge plans (AGRPs) have become central in surface water and groundwater management. This work proposes a two-stage approach for locating and prioritizing suitable sites for AGRP implementation. The two stages consist of (1) determining the effective criteria weights to develop thematic maps with geographic information system (GIS) with which to locate suitable sites for AGRP implementation, and (2) prioritizing the suitable identified sites for artificial groundwater recharge with the Nash conflict resolution method. This paper’s approach is applied in the Kerman Province, Iran, and the application results demonstrate that the most suitable sites for AGRPs are located in the western half of the province.

Superstorm Sandy and Hurricane Irene on the East Coast of the United States were wake-up calls that the floodplain delineation and flood damage estimation models need major overhaul. The first step in flood-related studies is frequency analysis. A great challenge has emerged on the validity of the data stationarity assumption. In hydrologic studies, data stationarity has been doubted due to climate change and variability, and sea-level rise. This paper presents an integrated scheme for floodplain delineation and flood damage estimation in coastal areas, considering the combined effect of inland and coastal flooding. For this purpose, time series of rainfall and water level and surge are tested for stationarity. Then, nonstationary frequency analysis is performed to determine the extreme flood events. Considering the coincidence of heavy rainfalls and storm surges as a serious concern in coastal regions, the joint probability distribution of rainfall and storm surge data is also investigated. Consequently, three flood scenarios are defined. A distributed hydrologic model is then utilized for floodplain delineation. A geographic information system (GIS)–based model, using depth-damage functions, land use data, digital elevation model (DEM), and raster maps, is used to estimate flood damage for Manhattan in New York City. Results showed that by incorporating nonstationarity in frequency analysis, design values of rainfall and extreme water levels could be significantly different than those obtained under the assumption of data stationarity. The results also indicated that floodplain extent and estimation of flood damage are increased when data nonstationarity is considered. However, these values are decreased when the joint probability of rainfall and water level is incorporated into defining flood scenarios.

Steady-state modeling of water distribution networks (WDNs) is the calculation of flow rates in pipes and nodal pressures for a given set of boundary conditions (i.e., water levels, pump curves, nodal demands, and so forth). The solution procedure is based on simultaneous solving of the energy and mass conservation equations in the network. There is a Newton-based method entitled the global gradient algorithm (GGA) for solving these equations and it is used for many commercial software programs. The GGA solves a positive definite symmetric linear system for finding head pressures and also updates the discharge of pipes at each iteration. After a predefined number of iterations, the GGA converges to the final solution quickly and it is the most efficient algorithm for WDN modeling. In this paper, for improving the convergence rate, a new method called the multilinear technique is presented that solves the nonlinear system of equations. In this method, nonlinear terms of energy equations are linearized based on maximum and minimum allowable discharge in pipes. Therefore, the set of continuity and energy equations is converted into a linear system and by solving this linear system a good initial solution is obtained. Then, this new solution is used for the linearization process in the next iteration. The process continues until convergence with the final solution with reasonable accuracy. To demonstrate the robustness and effectiveness of the multilinear algorithm, several real and hypothetical WDNs from a small to a large scale are tested. Results in benchmark and real networks show that after two iterations the multilinear algorithm converges with acceptable precision. The simulation of 1,000 hypothetical networks shows that the computational efficiency of the multilinear method in terms of time is almost half of those obtained by the GGA.

In order to discover the resistance characteristics of overland flow with vegetation cover, indoor drainage experiments with six slopes, seven flow discharges, and five degrees of vegetation cover are systematically studied based on the basic theories of hydrodynamics and hydraulics. The experimental results show that the overland flow index of nonsubmerged vegetation gradually increased from 0.333 to 0.845 as the degree of vegetation cover increased. Moreover, the relationship between the flow resistance, water depth, and Reynolds number did not present a monotonic increasing or decreasing tendency, but depended on the vegetation cover. When the degree of vegetation cover was lower than the critical value, the flow resistance coefficient decreased with increasing water depth and Reynolds number, whereas the opposite tendency was found when the degree of vegetation cover was greater than the critical value. The resistance coefficient gradually increased with increasing vegetation cover when the flow discharge was constant. Moreover, the increasing rate became steeper as flow discharge increased. The prediction formulae of average velocity and the resistance coefficient are proposed, and predicted results agree with corresponding experimental data. This conclusion is of scientific significance both in understanding the mechanisms of flow retardation and sand fixation by vegetation as well as in guiding the implementation of ecological restoration projects.

Irrigation networks use a warped transition to connect a narrow rectangular channel section with a relatively wide trapezoidal earth-channel section. The flow through the transition often separates from its sidewalls. This can cause significant head losses and increase the risk of eroding the downstream channel, which is undesirable. This paper experimentally investigates the use of a single vane and three vanes located in the warped transition to reduce flow separation. Laser Doppler anemometry measurements of flow velocity were obtained and used for the determination of three-dimensional flow parameters, including the longitudinal flow profile, energy loss in the transition, and maximum velocity in the transition exit flow. The details of flow separation, turbulence intensity, and secondary flow characteristics were studied. The experimental results indicated that the three-vane system was the most efficient transition case, producing such desirable characteristics as flow uniformity, the reduction of secondary flow intensity, and the reduction of maximum velocity in a short reach of the downstream channel. The improvements of the flow characteristics in vane systems are attributed to the effective reduction of flow separation and hence the energy loss. The findings from this experimental study have a direct application to the design of efficient irrigation channels.

Laterals constitute the basic element of a field-scale pressurized irrigation hydraulic network. The availability of accurate and robust computational methods applicable to lateral hydraulics is, therefore, essential for the development of pressurized-irrigation system management models. Existing water-distribution network analysis models with provisions for computing pressure-dependent outflows along pipelines can be used to simulate flows in irrigation laterals. However, such models cannot be readily customized into an efficient hydraulic module of a coupled field-scale pressurized-irrigation system management model, because of their level of complexity and other practical difficulties related to program development and maintenance. This suggests that hydraulic simulation modules, specifically designed for irrigation laterals, need to be developed for applications in pressurized-irrigation system modeling. Simulation models were developed for irrigation laterals based on computational methods used in hydraulic manifolds. Alternatively, a lateral can be conceived as a branched hydraulic network and the hydraulic simulation problem of an irrigation lateral can then be formulated based on standard network analysis techniques. There is some ground to presume that, among applicable pipe network analysis techniques, the gradient method produces a more general and robust formulation of the hydraulic simulation problem. Thus, the objective of the study, presented here, is to develop a hydraulic simulation model for irrigation laterals, based on a standard network analysis technique (specifically the gradient method), and to evaluate the model. Accordingly, for computational purposes an irrigation lateral is described as a branched hydraulic network with links and nodes. Lateral pipe segments and emitters or riser-emitter assemblies, as the case may be, are treated as links. The network nodes are comprised of junction nodes with unknown heads and fixed-head nodes with given heads. The link energy balance and the nodal continuity equations describing flow over the entire lateral are coupled to form a nonlinear system, which is solved iteratively for the variables: link discharges and nodal heads. The hydraulic simulation model is evaluated through comparisons of model outputs with field data and outputs of an existing model.

This paper deduces a new flow-resistance equation for open-channel flow applying dimensional analysis and self-similarity theory. The incomplete self-similarity hypothesis is used to establish the flow velocity distribution whose integration gives the theoretical expression of the Darcy-Weisbach friction factor. The theoretical resistance equation then is tested by the available field measurements of flow velocity, water depth, river width and bed slope carried out in 653 reaches of several Canadian mountain streams. A relationship between the $\mathrm{\Gamma }$ function of the velocity profile and the channel slope and the flow Froude number is also established. The analysis shows that the Darcy–Weisbach friction factor can be accurately estimated by the proposed theoretical approach based on a power-velocity profile. Finally, the Darcy–Weisbach friction factor values obtained by the proposed theoretical resistance law are compared with those estimated by the approach of Rickenmann and Recking.

Infiltration trench is one of the best stormwater management practices to control excessive runoff volume in urban areas. Most of the methods or models employed for designing an infiltration trench are either very simplified which leads to unreliable results or suffer from inconsistency of using one equation in variably saturated soil. Therefore, in this paper, the authors have developed a new one-dimensional infiltration trench model based on Richards’ equation for modeling flow movement in variably saturated soil, coupled with a surface water balance equation as the upper boundary condition, using implicit finite-volume method. The proposed model allows for periodical ponding in the storage, interaction between storage and subsoil, and flow movement in variably saturated soil beneath the storage. The model was run under different scenarios and tested against several experimental and analytical test cases. The obtained numerical results were mass balanced and exhibited accurate simulation of the flow movement in unsaturated soil as well as ponded infiltration in a saturated controlled experimental trench.

This work proposes data-mining algorithms for runoff projection under climate change conditions. Specifically, genetic programming (GP), artificial neural network (ANN), and support vector machine (SVM) data-mining tools are applied for runoff projection and their predictive skills are compared by means of several standard indicators of models’ performance. The approach herein implemented predicts future regional precipitation and temperature with the Hadley Centre Coupled Atmosphere-Ocean General Circulation Model version 3 (HadCM3) atmosphere-ocean general circulation model (AOGCM) followed by runoff prediction with GP, ANN, and SVM in the Aidoghmoush Basin, Iran. This paper’s results demonstrate that SVM outperforms GP and ANN by 7 and 5%, respectively.

Performance of porous asphalt (PA) was evaluated on a parking lot of the Washington State University Puyallup campus that included three pavement treatments in triplicate: maintained impervious asphalt (MIA), maintained porous asphalt (MPA), and unmaintained porous asphalt (UPA). Maintained treatments were annually swept with a regenerative air street sweeper. Infiltration rates measured annually using an infiltration ring declined over the course of the study (2011–2015) from 118 to $39\mathrm{mm}/\min$ for the MPA, and from 134 to $54\mathrm{mm}/\min$ for UPA, respectively. Lower infiltration rates on maintained cells relative to unmaintained cells are ascribed to the air-blast and suction cycle that characterizes the type of street sweeper used. The authors hypothesize that particulate matter was forced deeper into the porous structure of the pavement wearing course, reducing infiltration rates in the maintained cells. Annual maintenance was shown to be too infrequent and did not prevent infiltration rates from declining, with parts of the pavement cells becoming clogged. However, performance of the pavement as a whole, measured by relating total storm inflow to storm outflow, did not decline over the study period with 99.5% of storm inflow infiltrating into the porous asphalt pavement surface. Time-series analysis showed that peak flow mitigation of stormwater was considerably superior with permeable pavements in comparison with impervious pavement surfaces.

With the limited availability of meteorological variables in many remote areas, estimation of evapotranspiration (ET) at different spatiotemporal scales for efficient irrigation water management and hydrometeorological studies is becoming a challenging task. Hence, in this study, indirect ET estimation methods, such as moderate resolution imaging spectroradiometer (MODIS) satellite-based remote-sensing techniques and the water-budget approach built into the semidistributed variable infiltration capacity (VIC-3L) land-surface model are evaluated using the Penman-Monteith (PM) equation approach suggested in the literature together with a crop coefficient approach. To answer the research question of whether regional or local controls of a river basin with tropical monsoon-type climatology affect the accuracy of the VIC and MODIS-based ET estimates, these methodologies are applied in the Kangsabati River Basin in eastern India at $25\times 25\mathrm{km}$ resolutions attributed with dominant paddy land uses. The results reveal that the VIC-estimated ET values are reasonably matched with the PM-based ET estimates with the Nash-Sutcliffe efficiency (NSE) of 54.14–71.94%; however, the corresponding MODIS-ET values are highly underestimated with a periodic shift that may be attributed to the cloud cover and leaf shadowing effects. To enhance the field applicability of the satellite-based MODIS-ET products, these estimates are standardized by using a genetic-algorithm-based transformation that improves the NSE from $-390.83$ to 99.57%. Hence, this study reveals that there is the need of a regional-scale standardization of the MODIS-ET products using the PM or lysimeter data or possible modification of the MOD16A2 algorithm built-into the MODIS for generalization. Conversely, the satisfactory grid-scale ET estimates by the VIC model show that this model could be reliably used for the world’s river basins; however, at smaller temporal scales, the estimates could be slightly inconsistent.

Perimeter controls [i.e., sediment barriers (SBs) or sediment retention devices] are typically used on construction sites to retain sediment and prevent polluted stormwater runoff from adversely affecting aquatic habitats and clogging storm sewers. Often, parameters based on rule-of-thumb are applied to the design of SBs without knowing their expected performance capabilities. This issue is further complicated by the difficulty in devising a scientifically sound, repeatable testing methodology, replicating field conditions to assess performance. To resolve this issue, a test apparatus was designed and constructed at the Auburn University—Erosion and Sediment Control Test Facility to replicate in-field rainfall runoff rates for purposes of conducting full-scale experiments on various SBs. This apparatus allows for performance testing and direct comparisons between various SB products, practices, and installations. The overall intent of conducting full-scale testing is to improve design criteria and enhance the in-field performance of SB practices. Initial test results for a woven polypropylene silt fence reinforced with a polypropylene grid and supported by wooden posts performed well structurally with an average sediment retention rate of 90.5% by volume.

In the present study, the electrical conductivity of the soil solution (${\sigma }_p$) was predicted using a linear model in which the bulk soil electrical conductivity (${\sigma }_b$) effect on the apparent dielectric permittivity (${ϵ}_s$) was considered. The performance of the proposed model was evaluated by measurements with a dielectric sensor (the WET sensor) in four porous media at four different levels of electrical conductivity of the moistening KCl solution (${\sigma }_w$). It was found that the relationship between the square root of the permittivity (${ϵ}_s$) and soil volumetric water content ($\theta$) was dependent on soil type, which is consistent with the low operating frequency of the sensor. Establishing a soil specific ${\theta }_m–{\sqrt{ϵ}}_s$ relationship substantially increased the $\theta$ measurement accuracy compared to the factory calibration. It was shown that the new approach for the ${\sigma }_p$ prediction gave reasonably accurate results in sands irrespective of the ${\sigma }_p$ values. For the finer porous media, it improved the prediction of ${\sigma }_p$ only for the higher salinity levels, but the ${\sigma }_p$ values appear to be underestimated. The relationship between the corrected dielectric permittivity ${ϵ}_R$ and ${\sigma }_b$ is strongly linear for ${\sigma }_w$ and ${\sigma }_b$ values up to 6 and $1.7\mathrm{dS}·{\mathrm{m}}^{-1}$, respectively.

A 4.2-ha sugarcane field in Guyana was instrumented to measure hydrometeorological variables and water table depths in order to calibrate DRAINMOD. The model performs favorably, with a Nash–Sutcliffe model efficiency (NSE) of 0.72, index of agreement (IoA) of 0.92, mean absolute error (MAE) of 16.5 cm and percentage bias (PBIAS) of 1.0%. DRAINMOD is then used for long-term simulations of the field hydrology using historical climate data. The simulated field discharges are used to compute average drainage rates (DR) for five durations ($1\text{-}\text{day},2\text{-}\text{day},\dots ,5\text{-}\text{day}$). The annual maximum drainage rates for each of the five durations are then fitted to the Gumbel distribution (EV1) for frequency analysis. The return period for an average 3-day (DR3) duration drainage event is estimated, and it is shown that the historical design drainage coefficients ($35–50\mathrm{mm}{\mathrm{day}}^{-1}$) used for surface drainage systems in sugarcane fields along Guyana’s coastland have return periods ranging from 1 in 2 years to 1 in 5 years. These return periods are within recommended values commonly used for agricultural drainage systems.

In a complex aquifer system, groundwater levels are highly dynamic in nature and measurement of groundwater levels requires systematic networks of observation wells (OWs) considering hydrological variations. The existing previously developed groundwater monitoring networks make use of limited hydrological input parameters, mainly groundwater level (GWL). In addition to GWL, other factors that influence groundwater availability are required to finalize the number and location of the OWs in a groundwater monitoring network. An understanding of the control of different hydrological factors is essential prior to designing groundwater monitoring networks. The purpose of this study is to evaluate the impact of hydrological factors on the selection and location of OWs using a geospatial approach. This paper presents a case study of the Wainganga basin located in central India, where irrigation takes place both through ground and surface water. Factors examined in the present study are changing seasons, cropping pattern, the normalized difference vegetation index (NDVI), type of aquifer, and GWLs in command and noncommand areas. From the NDVI analysis using moderate-resolution imaging spectroradiometer data, it may be concluded that, in the absence of GWL data, NDVI can also be an indicator of groundwater utilization in irrigated areas. Results from the study identify preferable zones where OWs may be added (west, southeast, and some central parts of the study area) based on hydrological factors in the complex aquifer system. Parameters described in the study can also be useful in designing, modifying, and periodically reexamining existing groundwater monitoring networks and in facilitating more reasonable monitoring network design.

The unavailability of some meteorological variables, especially solar radiation and wind speed, is the main constraint for reference evapotranspiration (ETo) estimation using the standard United Nations Food and Agriculture Organization (FAO) Penman–Monteith (FAO-PM) equation in most developing countries. The application of ETo methods with fewer input requirements is necessary under limited climatic data conditions. The FAO-PM method under limited data conditions and nine of Valiantzas’ equations were evaluated for daily ETo estimation in a humid climate in Uganda. The FAO-PM method with missing relative humidity data performed very well across Uganda, whereas using the long-term local wind speed average values in place of missing wind speed data resulted in inaccurate ETo estimates. Under missing solar radiation measurements, the FAO-PM method showed different performances relative to the locations. When more than one climatic variable is missing, the FAO-PM method yielded poor ETo estimates compared to the FAO-PM method with full climatic data. The performance of Valiantzas’ equations depends on data requirements: the more meteorological inputs, the higher the ETo accuracy.

Vertically mounted circular orifices have been extensively used for flow measurements. The operation of a side orifice is not always under a high headwater above the crown of the orifice, as a result, the prediction of partially submerged flow is characterized as a mixing flow between weir and orifice flows. The general equations of weir and orifice need to be tailored to predict partially submerged orifice flows. The purpose of this study is to derive a new method for calculating the discharge flow rate through partially submerged circular orifice. The method applies a weighting factor to construct a reliable rating curve for the transitional flow from a weir flow when the flow depth is shallow to an orifice flow when the flow depth becomes deep. The proposed method is further normalized in form of the Froude Number using the diameter of the orifice as the characteristic length and gravitational acceleration as the characteristic time. For engineering practices, the best-fitted orifice discharge coefficient was determined to be 0.53 using the least squared error method.

In this paper, the dimensionless stage-discharge relation for a sharp-crested triangular labyrinth weir, determined in a previous study, is initially tested by some experimental runs carried out in a laboratory flume. According to this relationship, the flow magnification is affected by the length-magnification ratio and the head to one cycle width ratio. The measurements allowed to test the applicability of this dimensionless relation for different values of both the angle of the sidewall to the main flow direction and the weir height. Finally, the proposed dimensionless equation was also tested by using experimental measurements carried out for broad-crested triangular labyrinth weir.

Laboratory tests were carried out to investigate the hydraulics of submerged flow over triangular weirs and weirs of finite-crest length with upstream and/or downstream ramp(s). Water surface profiles were recorded as the weir submergence set and for various stages of submergence. Variations in modular limit and discharge reduction factors for the present weirs were studied. It was found that the modular limit varied with the ratio of the free-flow head to the total streamwise length of the weir. Characteristic length scales such as horizontal and vertical distances from the toe of the surface jump and the first wave trough to the downstream crest edge of the weir were measured to generalize different wave patterns. It was found that the toe of the surface jump moved toward the weir as the weir submerged and varied linearly with the submergence level, which is the ratio of tailwater to headwater depths. For weirs of finite-crest length with upstream and downstream ramps (i.e., embankment weirs), the toe of the surface jump moved toward the weir as the submergence level increased up to 0.7. For higher submergence levels, the trough of the surface wave moved toward the downstream and eventually washed away. Efficiency and performance of the present weirs were evaluated with their own free-flow conditions. Empirical formulations were developed to predict the discharge reduction factor with submergence level. The performance of triangular weirs in submerged-flow conditions was found to be better than that of corresponding sharp-crested weirs; weirs became more efficient as the ratio of the free-flow head and the total length of the weir increased.