Journal of Water Resources Planning and Management

Accumulation of sediment from upstream agricultural land may shorten the lifetime of a reservoir and reduce its long-term benefits. This paper presents a framework for assessment of management strategies that simultaneously considers upstream soil conservation and downstream reservoir-level sediment control. A dynamic model that utilizes optimal control theory is developed for this purpose. Simulation results from the model are expected to provide practical information for policy makers, such as determination of the best sediment removal technology, the optimal timing to install this technology, and the optimal pattern of soil conservation efforts. An illustrative application to Lake Aswan, which is located between the Sudan and Egypt, indicates that the highest permissible level of soil conservation and the unconstrained dredging installed at 22 years are the best management practices, giving a sustainable life of the reservoir and net benefits of $117.8 billion. The cooperative strategy compared to the noncooperative and baseline strategies increases social net benefits by $6.5 billion and $7.8 billion, respectively. To test the robustness of this study’s results, sensitive analysis for key parameters, such as interest rate, water price, agricultural sediment contribution, and soil conservation effectiveness was performed. The results are very sensitive to selected parameters. As suspected, interest rate and water price shift the net present value of watershed on both sides. However, the rank of alternatives does not change.

In contrast to most common methods used in optimal control of reservoir systems requiring a large number of decision variables, parametric rule can make a radical reduction in the number of decision variables without yielding inferior solutions. However, parametric rule employs the standard operating policy to determine releases of reservoirs as much as demand only if there is enough water in the system, which may result in single periods of severe short supply during droughts. The purpose of this paper is to devise an operating rule for multireservoir system by combining parametric rule with the hedging rule to avoid catastrophic water shortage during droughts. In this way, decision variables to be optimized not only make a significant reduction compared with traditional operating rules, but also severe short supply during droughts can be controlled effectively. This paper employs a water supply multireservoir system in northern China to explore the changes of shortage characteristics produced by the proposed rule over a long horizon. In the case study, particle swarm optimization algorithms with a simulation model are used to optimize the decision variables. The results indicate that the extended parametric rule has a significant advantage over the classic parametric rule in dealing with the multireservoir operation problem during droughts.

The development and management of irrigation facilities has been recognized as the key to national development in India. Despite their high priority and massive investments, the performance of major irrigation projects has been disappointing. Substantial benefits can be achieved from relatively small increases in operating efficiencies. The main objective of this study is to develop a short-term, real-time reservoir operating policy in a multicrop, multiseason environment integrating reservoir release decisions with field irrigation requirements. A real-time reservoir operation model defines the set of releases to be made into each offtake on the main canals of a reservoir for a known set of release targets, reservoir storage state, and forecasted inflow in the current period, minimizing the deficit function. An intercrop allocation model allocates reservoir releases of the current period among competing crops. On implementing the irrigation decisions of the intercrop allocation model for the current period, soil moisture is updated with the rainfall that actually occurred and irrigation that was applied in the current period. A new set of irrigation targets for the remaining periods is determined by running the single-crop intraseasonal allocation model for each crop constraining the allocations of the previous periods to the actual irrigation performed. With the revised targets and updated reservoir storage, reservoir operation and intercrop allocation models are run sequentially for all time periods in real time. The models developed are demonstrated through a case study of the Nagarjuna Sagar Reservoir Project. The real-time reservoir operation model is run for data from the years 2004–2005 with and without updating irrigation targets, and the results are discussed. The crop production measure is found to be high in the case of updated targets, underscoring the importance of updating irrigation targets.

Available water resources are decreasing in river basins around the world. Some reseachers have suggested various indicators and methods that should be used to allocate water resources. This paper attempts an integrated approach to water allocation that accounts for a wide range of factors at the river basin level. Using the Hai, Huai, and Yellow River Basins of Shandong Province in China, 19 indicators were assimilated into a water scarcity index and weighted based on surveys collected from 82 multidisciplinary experts. Fuzzy set probability was then used to quantify water scarcity for each river basin. A water allocation method was also calculated using 13 indicators and objectively weighted using the analytical hierarchy process. Results show that all river basins in Shandong Province have severe water scarcity and highlight that economic factors play the most critical role in water scarcity, followed by water supply factors then water demand. Water allocation indicators were prioritized according to water resource pressure and utilization proportionality among districts in the Huai River Basin. The results should provide direction for future research.

The water industry worldwide is facing challenges of water and revenue losses. To reduce these losses and improve efficiency of water distribution systems, tools and methods have been developed over the years. This paper reviews the current tools and methodologies applied to assess, monitor, and control losses in water distribution systems. The aim is to identify the tools and methods that have been applied, knowledge gaps, and future research needs. The review findings indicate that a number of water loss management tools and methods have been developed and applied. They vary from simple managerial tools such as performance indicators to highly sophisticated optimization methods such as evolutionary algorithms. However, their application to real-world water distribution systems has been found to be generally limited. Future research opportunities exist through close collaboration of research institutions and water service providers to close the gap between theory and applications. Although not exhaustive, this review could be a valuable reference resource for practitioners and researchers dealing with water loss management in water distribution systems.

The cost of electricity used for pumping in water-distribution systems typically represents the largest part of the total operational costs. Therefore, optimization of pump operations is a major concern for water utilities around the world, especially in recent years with significantly increasing energy prices. Recently, to maximize cost and energy savings, pump scheduling is frequently done in real time by integrating the relevant optimization software into the water company’s supervisory control and data acquisition (SCADA) system. This, however, requires solving a complex, large, nonlinear optimization problem in a computationally efficient manner, typically in less than 1 h. To achieve this, the pump-scheduling problem is solved in this paper by a novel hybrid optimization method that uses linear programming (LP) and a greedy algorithm: LPG. The new methodology is applied to two case studies: the artificial, benchmark case study of Anytown network and the real-life pump-scheduling problem of the Richmond water-distribution network (WDN) in the UK. The results obtained clearly demonstrate that the LPG hybrid method is capable of solving real-life pump-scheduling problems in an extremely computationally efficient manner while preserving the accuracy (i.e., the near optimality) of the obtained solution. This makes the method particularly appealing for use in real-time pump-scheduling applications.

Accounting for water in a distribution system can be improved by dividing systems into smaller, metered zones. This paper proposes an approach that could create boundaries for district metered areas (DMA) automatically on the basis of the community structure of water distribution systems. Community structure—the gathering of vertices into communities such that there is a higher density of edges within communities than between them—is a common property of many complex systems. For verification, the method was tested on a real-world distribution system, and the result was compared with a manually designed DMA layout. Although further improvements are necessary, because the achieved community structure is in excellent agreement with the zoning plan in reality, this approach is a new addition to the number of automated methods aimed at complementing and eventually substituting the empirical trial-and-error approach.

Characterization of critical water distribution system (WDS) contamination scenarios—defined by a set of attributes, a probability of occurrence, and a specific level of consequences—is a prerequisite for preparation of reliable and cost-effective mitigation, preparedness, and emergency response plans. This study develops Monte Carlo and risk-based optimization schemes to evaluate contamination risk of WDSs for generation of this important class of scenarios, which are representative of the most vulnerable aspects of the system. Defining attributes of contamination scenarios are identified as contaminant type and amount, contamination location, start time, duration, and time of year scenario occurs. Well-documented waterborne outbreaks reported in developed nations are analyzed to empirically estimate statistical characteristics of defining attributes in accidental events. Monte Carlo simulation is conducted to determine the probability distribution of public-health consequences, aggregate conditional risk, and significance of different scenario attributes. A multiobjective optimization methodology is proposed to capture the attributes of critical accidental contamination scenarios. The principal risk components of likelihood and health consequences are treated as optimization objectives and are maximized simultaneously to identify an ensemble of nondominated critical scenarios. The multiobjective approach provides insight into system risk and potential mitigation options not available under maximum-risk or maximum-consequences analyses. Performance and applicability of developed models is demonstrated on the WDS of a virtual midsize city that possesses characteristics of complex real-world distribution networks.

Optimal design of tunnels and surge tanks is a major concern in the implementation and operation of large hydropower plants, particularly those in which tunnels are long and water hammer is likely. In this paper, flow simulation and an optimization process have been linked in an iterative manner to develop a general model for the optimal design of hydropower tunnels and surge tanks for the emergency condition of operation (maximum surge pressure). The governing equations for the analysis of transient flow in conduits are solved using a finite difference scheme. Furthermore, a genetic algorithm (GA) optimization technique is utilized to select the optimal diameter for the headrace tunnel, penstocks, and surge tanks. The benefit-cost ratio is considered as the objective function in the optimization analysis. The proposed method was used to design diameters for Marun hydropower tunnels (an in-operation large hydropower dam located in southwest Iran). The results were compared with results from a nonlinear optimization technique. They revealed considerable savings in construction cost, attributable to the application of GA. The calculated pressures across the tunnels with and without surge tank agree with valve closure theory and previous studies. The model is able to optimize diameters for a branching system of tunnels and penstocks with surge tanks.

Loss of water caused by leakage is a common phenomenon observed in all water distribution systems (WDSs). The volume of leakage around the world is considerably high, and its control is crucial to meet the increasing water demand caused by rapid population growth and urbanization. The most important component of a leakage-control strategy is target setting in terms of economic level of leakage (ELL). The ELL is an economic indication depending on individual network conditions, operating system pressures, demands and their patterns, marginal cost of water, and operating practices. This paper discusses the economic aspects of leakage for a pilot district metered area (DMA) of the WDS of the Metropolitan Waterworks Authority (MWA) in Bangkok, Thailand. The study developed two nomographs for the quick estimation of ELL and active leakage-control cost (ALC) with minimal data analysis. The first nomograph shows the relationship between cost of leakage control, average operating pressure, and level of leakage in the WDS. The second nomograph shows the relationship between ELL, operating-system pressure, and marginal cost of water. The nomographs have been developed based on leakage volume, cost of water, and hydraulic and operational conditions of the WDS. To model different hydraulic and leakage scenarios, the U.S. EPA’s EPANET simulation engine has been used. The research will help utility managers understand different aspects of leakage economics and will lead to better management of their WDSs.

Management plans for natural resources can be viewed as policy instruments that deliver multiattribute goods held in the public domain, requiring input from experts, stakeholders, and citizens. This research adds a key dimension to the state of New Hampshire’s Lamprey River Instream Flow Study. Using a series of quantitative and qualitative research methods, the values and objectives of stakeholders and the general public were analyzed regarding management of the river. Findings show that respondents are most concerned with the ecological integrity of the river above all other attributes elicited from the stakeholders (e.g., water-withdrawal amount, recreation days, and number of community business users).