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Interbasin water transfer projects (IBWTPs) have become an important measure to alleviate regional water stresses by artificially regulating water resources between water-rich and water-scarce areas. However, there are many conflicting objectives and complex practical operational constraints that complicate the derivation of water allocation schemes for IBWTPs. Here, we propose a multiobjective optimization methodology for deriving water allocation schemes for IBWTPs, which includes three modules: (1) formulating a multiobjective optimal water allocation problem for IBWTPs based on practical operational constraints; (2) proposing a novel multiobjective cuckoo search (NMOCS) algorithm and combining it with a simulation-optimization approach to solve the water allocation problem; and (3) filtering the Pareto solutions using the analytic hierarchy process (AHP)-entropy method. Based on the multiobjective cuckoo search (MOCS) algorithm, the NMOCS employs four improvement strategies, including a population initialization strategy, flock search strategy, multistrategy external archive maintenance strategy, and adaptive parameters, to improve the convergence property and diversity of solutions. To test the performance of the NMOCS, we considered the MOCS and four widely used multiobjective evolutionary algorithms (MOEAs) as a comparison and employed these six MOEAs to solve 11 multiobjective mathematical benchmark problems as well as the water allocation problems of the Jiangsu Province, China, section of the South-to-North Water Diversion Project under normal, dry, and extremely dry hydrological conditions. The results show that the NMOCS outperformed other MOEAs in handling multiobjective mathematical benchmark problems, especially in ZDT1, ZDT2, ZDT6, DTLZ2, DTLZ4, and DTLZ7. Compared with other MOEAs, the NMOCS did not always capture the highest percentage of the reference water allocation schemes, but it provided more than 18% (greater than one-sixth) of effective water allocation schemes for all hydrologic conditions. Meanwhile, compared with optimal water allocation schemes derived from other MOEAs, the NMOCS effectively improved the operational performance under normal and drought hydrological conditions, especially in the total water pumping and the water withdrawn from the Yangtze River. This research can help to update our understanding of MOEAs, particularly the MOCS, and serve as a reference for better-allocating water resources in IBWTPs. [ABSTRACT FROM AUTHOR]

Accurate and well-categorized information on water supply, demand, consumption, and withdrawals is necessary for the assessment and management of water resources. In this context, the Water Accounting Plus (WA+) framework is a valuable platform for quantifying water flows. By utilizing remote sensing datasets, WA+ enables it to quantify water flows in a basin and compute hydrological processes while considering the impact of land use. To understand the water inflows, outflows, consumption, withdrawals, and storage variations of water resources, we applied the WA+ framework to a complex river basin, namely the Mahi River basin. Using blue and green water estimation, we segregated the irrigated and rainfed areas and computed the hydrological processes at the pixel level using the WaterPix model. We also calculated performance indicators to illustrate the state of water resources in the basin. Our analysis shows that the Mahi River basin is water-stressed and mainly relies on groundwater (GW) for irrigation. The average exploitable and available water flows from 2012 to 2020 were 34.07 Billion Cubic meter (BCM)/year and 30.38 BCM/year , respectively, and the average outflow was 20.65 BCM/year. The average vertical recharge and withdrawal of GW were 17.47 and 21 BCM/year , respectively, while surface water (SW) withdrawal was very low and concentrated in only a few areas. According to the results of the flow and GW sheets, 95% of the utilized flow came from GW, indicating a high dependency on GW. A 25% depletion of water storage was observed during the study period. These results indicate that overexploitation of GW for irrigation and depletion of water storage are the main problems in the Mahi River basin. Our study can help local and national authorities to identify areas with poor water management practices and develop appropriate water management plans and schemes [ABSTRACT FROM AUTHOR]

In the US federal system, state governments play important roles between the federal and local levels in water resources planning, coordination, and regulation. How they coordinate these functions can indicate the degree of integration of their agencies and programs. A database of state programs was used to compile indicators of integration among water quality and quantity and drinking water source quality, as well as the status of comprehensive water planning. In most prior appropriation states and in some states in riparian areas, the management of water withdrawals and water quality remains in separate agencies. Some 35 of 50 states have a version of a "state water plan." A scattered pattern of institutional arrangements shows that titles and functional coordination evolve in response to contextual situations, although state water management agencies have matured, and many have stable organizational forms. Water rights and regulatory controls for clean water and safe drinking water are firmly in place. Organizational structures are not likely to change much, but integration can be improved through management mechanisms and appropriate uses of planning, particularly at the watershed scale. State governments are pressed to be active in water resources management because they have authority in a geographic sphere closest to the scales of watersheds, river basins, and regional aquifers. This authority is important for states to respond to new threats like climate change, worsening floods, long-term drought, and public health challenges. Like in other levels of government, the workforce in state water management agencies is mobile and requires constant capacity building. Institutional memory is especially important, and state government executives require a rapid but comprehensive view of past experiences in organizational management in regulation, planning, and interactions with the federal and state governments. The paper provides a review of these experiences, along with suggested priorities for water management enhancements that may help in the future. [ABSTRACT FROM AUTHOR]

This study investigates annual river basin-level water criticality (ratio of available water to withdrawals) considering effects of climate change on supply and of future population change on demand. A steady-state water balance model was developed to estimate the water mass budget and disaggregate the internal and external water supply sources at a river basin level. Future precipitation and evapotranspiration were dynamically downscaled under a moderate greenhouse gas emission scenario to 4-km horizontal resolution using a regional climate model for a decade centered on 2090. The climate data were also statistically downscaled via the bias correction spatial disaggregation (BCSD) method applied to the CMIP5 (the fifth phase of the Coupled Model Intercomparison Project) archives for four emission scenarios for decades centered on 2040 and 2090. Bootstrapping and k-nearest-neighbor (k-NN) algorithms were applied to simulate futurewater demand and external basin supply with uncertainty. Water stress is classified into four levels: (i) "very high-water stress" when the water criticality ratio <1.25, (ii) "high water stress" when criticality ranges from 1.25 to 2.5, (iii) "moderate water stress" when criticality ranges from 2.5 to 10, and (iii) "no water stress" when criticality >10. A basin with a criticality ratio of 1 indicates that the basin demand has been exactly met by the available supply sources. Most river basins have current water criticality less than 2 and are dependent on inflow from other basins (i.e., are not self sustaining). Future projections indicate modest increases in net available water for Utah through the end of the current century from climate change, with increasing vulnerability largely driven by population growth. Out of 11 basins, 4 achieve a high and 3 achieve a very high water stress status by the 2040s. Four basins achieve a very high water stress status by the 2090s compared to only two in a very high water stress status in the 2010s. [ABSTRACT FROM AUTHOR]

This work presents a methodology for extracting optimal operational rules for selective reservoir water withdrawal by considering fixed levels of reservoir water outlets for thermal control. The outlet water temperature of the Karkheh reservoir, Iran, is simulated with the CE-QUAL-W2 model. A data-mining model (the LIBSVM model) is applied as a surrogate model of the CE-QUAL-W2 model and coupled with a genetic algorithm (GA), resulting in the LIBSVM-GA algorithm. The selective withdrawal approach considered four fixed reservoir outlets, located at 120, 140, 163, and 181 m above sea level, to account for reservoir thermal stratification. This paper’s methods are evaluated with nonselective and selective withdrawal operations through different scenarios in which single outlet, fixed withdrawal proportions, fixed monthly variable proportions, continually variable (10-day) proportions using total monthly LIBSVM input data, and continually variable (10-day) proportions using separated monthly LIBSVM input data are considered. The highest outlet (at 181 m) was found to be the best level for the nonselective withdrawal scenario. The best selective withdrawal operations scenario was the continually variable (10-day) proportions using separated monthly LIBSVM input data, which minimize the root-mean-square deviation (RMSD) between upstream and downstream temperatures during the operating period. [ABSTRACT FROM AUTHOR]

Even in relatively water-rich regions, withdrawal and consumption of water has the potential to create instream freshwater ecosystem water scarcity, especially at seasonal and local scales. Water resource policy must balance consumptive uses of water against corresponding ecosystem impacts of flow depletion. In this study, the concept of an adverse resource impact threshold, as established by the Michigan Water Withdrawal Assessment Process, is applied in conjunction with a water use database to identify the cause, location, and scale in space and time of instream freshwater ecosystem water scarcity caused by consumptive uses of water. The study results show that there is a strong multiscalar linear relationship between freshwater consumption, adverse resource impact ecological flow thresholds, and spatial scale. On average and at the whole-watershed scale, water scarcity does not exist in this watershed, but water scarcity does occur on a localized basis, especially in the summer and at small watershed scales of less than , because of a combination of irrigation withdrawals, concentrated urban withdrawals, and low ecological flow thresholds. The aggregated effects of localized flow depletion also affect scale catchments. Management of water scarcity in water-rich areas should therefore focus on the spatio-temporal locations where the impacts occur and where an average pattern of water abundance yields to localized scarcity, in this case during late summer months in subwatersheds smaller than . This analysis informs integrated water resources management approaches, contributes to a better understanding of the relationship between scale and environmental impact as water is shared among competing uses, and sheds light on the use of adverse resource impact ecological flow thresholds to define water scarcity in relatively water-rich regions. These results may be generalized to inform the implementation of the Michigan Water Withdrawal Assessment Process and similar processes throughout the Great Lakes region and in water-rich locations around the world where water is generally abundant but localized water scarcity is becoming an increasingly important issue. [ABSTRACT FROM AUTHOR]

A predictive framework is developed and applied to evaluate benefits of multilevel intake configurations in managing temperature (TW) and turbidity (CT,W) in water withdrawn from a water supply reservoir, Schoharie Reservoir, New York, that presently, has a single level intake. High values of TW occur in late summer for the reservoir in major drawdown years, and high CT,W levels occur irregularly following runoff events. The framework, composed of a tested two-dimensional water quality model for temperature and turbidity linked to a heuristic optimization algorithm, supports automated selection of intake levels to meet user-specified operational goals. Multilevel intake configurations are demonstrated to avoid exceedences of a State discharge standard (21.1°C) for TW for the conditions of a critical historic year, through a strategy of withdrawal of warmer upper layers through early summer and subsequent blending with cooler lower layers as necessary, at both the existing intake site and a deeper down-reservoir location. The adequacy of the existing intake site is challenged for this critical year if a conservative lower TW standard is set to accommodate the effects of model uncertainty. Amelioration of high CT,W values is demonstrated for multilevel intake configurations. The operation of a multilevel intake facility in the reservoir would result in a shallower epilimnion and metalimnion in many years, and summer surface temperatures would be lower in major drawdown years. The modeling approaches used in this analysis are generally applicable to support evaluations of multilevel intake configurations for other water supply lakes and reservoirs. [ABSTRACT FROM AUTHOR]

The frequency of water conflicts in riparian areas has increased in recent years, forcing water agencies to consider regulating water withdrawals from streams. In this paper, we evaluate permitting programs that would be part of such regulations. The research focuses on fixed- and fractional-flow-based permit systems, the former of which allows a constant volume of withdrawal similar to the practice in appropriative areas; the latter of which allows water abstractions proportional to streamflow. The evaluation is undertaken with respect to three performance criteria: Low flow frequency, users’ net benefit, and withdrawal interruption frequency. It is concluded that the fixed-flow-based permit program is able to provide a high net benefit but causes frequent minimum streamflow violations and withdrawal interruption due to its relatively simple withdrawal formula. The fractional-flow-based permit program is found to achieve a better tradeoff in preserving the natural flow regime, the net economic benefit, and convenience to water users and administrators. [ABSTRACT FROM AUTHOR]

Contaminant intrusion into water distribution networks can have disastrous consequences. This event poses a threat to public health and could result in political instability and social problems. After the contaminant and its source are detected, the main issues are consequences management and contaminant withdrawal from the water distribution network. To do this, several actions are required, including containing contaminant spread by closing valves and opening hydrants to flush out the polluted water. These actions may lead the network to a critical state in which the pressure of some nodes falls below the standard measure. In these network conditions, a pressure driven analysis of the water distribution network would be necessary. In this study, a combination of hydraulic simulation based on pressure driven analysis and particle swarm optimization is used to minimize the negative effects of contaminated water on public health as an immediate response after the contaminant entrance into water is detected. Based on the type of contaminant, two different emergency response strategies are introduced. Multiobjective optimization is performed when a nonharmful contaminant has entered the network. In this case, the main objectives are to minimize the impacts of contaminated water on consumers and the cost of operations. In another response strategy, reducing the time the network requires to return to a normal state is the objective of single-objective optimization when the contaminant is harmful. The proposed model was applied on the water distribution network of Sabzevar in northeastern Iran. The results proved the model's credibility and its applicability in real water distribution networks, even in cases of contaminant intrusion. [ABSTRACT FROM AUTHOR]