Mitigating Socio-Economic-Environmental Impacts During Drought Periods by Optimizing the Conjunctive Management of Water Resources

Multi-period optimization of conjunctive water management can utilize reservoirs and aquifer carry-over to alleviate drought impacts. Stakeholders’ socio-economic and environmental indices can be used to minimize the socio-economic and environmental costs associated with water shortages in drought periods. The knowledge gap here is the evaluation and inclusion of the socio-economic and environmental value of conjunctive water management in terms of its drought mitigation capability. In this paper, an integrated water quantity-quality optimization model that considers socio-economic and environmental indices is developed. The model considers and integrates reservoir and aquifer carry-over, river-aquifer interaction and water quality with stakeholders’ socio-economic indices of production, net income and labor force employment to evaluate the socio-economic and environmental value of conjunctive water management. Total dissolved solid (TDS) is used as the water quality index for environmental assessments. The model is formulated as a multi-period nonlinear optimization model, with analysis determining the optimal decisions for reservoir release and withdrawal from the river and aquifer in different months to maximize the socio-economic indices of stakeholders within the environmental constraints. The proposed model is used in Zayandehrood water resource system in Iran, which suffers from water supply and pollution problems. Model analysis results show that conjunctive water use in the Zayandehrood water basin reduces salinity by 50 % in the wetland and keeps water supply reduction during a drought under 10 % of irrigation demand.     

Optimal Long-term Operation of Reservoir-river Systems under Hydrologic Uncertainties: Application of Interval Programming

Long-term basin-wide reservoir-river operation optimization problems are usually complex and nonlinear especially when the water quality issues and hydrologic uncertainties are incorporated. It is due to non-convex functions in water quality modeling and a large number of computational iterations required by most of stochastic programming methods. The computational burden of uncertainty modeling can be reduced by a special combination of uncertainty modeling and interval programming, though the problem solution is still a challenge due to model nonlinearity. In this paper, an integrated water quantity-quality model is developed for optimal water allocation at river-basin scale. It considers water supply and quality targets as well as hydrologic, water quality and water demand uncertainties within the nonlinear interval programming (NIP) framework to minimize the slacks in water supply and quality targets during a long-term planning horizon. A fast iterative linear programming (ILP) method is developed to convert the NIP into a linear interval programming (LIP). The ILP resolves two challenges in NIP, first converting the large non-linear programming (NLP) into a linear programming (LP) with minimum approximation and second reducing the iterations needed in interval programming for NLP into just two iterations for the upper and lower limits of decision variables. This modeling approach is applied to the Zayandehrood river basin in Iran that has serious water supply and pollution problems. The results show that in this river basin at dry conditions when available surface water resources are below 85 % of normal hydrologic state and water demands are 115 % of current water demands, the total dissolved solids (TDS) concentration can be reduced by 50 % at the inlet of the Gavkhuni wetland located downstream of the river basin.     

流域水资源供需双侧调控模型及应用

针对水资源常规配置中供需分离、配置与调度结合不紧密,难以支撑流域水资源严格管理的问题,提出流域水资源供需双侧调控模型。在需水侧,通过建立供水量和效益函数关系,并考虑水土资源等约束条件,构建农业种植结构与灌溉制度优化模型;在供水侧,采用模拟与优化、配置与调度相结合的两阶段建模路径,构建多水源配置与水库群优化调度模型;通过来源于需水侧模型的"需水过程"与来源于供水侧模型的"可供水过程"的分解与耦合,实现供需双侧的联合调控,综合集成构建流域水资源供需双侧调控模型。将该模型应用于南四湖流域,提出了南四湖上级湖、下级湖等大型湖库工程的优化调度图与不同年型下农业种植结构和水资源配置方案,验证了模型的有效性。通过供需双侧协调优化,南四湖流域供需缺口缩小,农业种植效益增加,枯水年水分生产效益提高了0.70元/m³、平水年水分生产效益提高了0.63元/m³;生活和工业供水保证率稳定在95%,生态和农业供水保证率明显提升,分别由53%提高到71%、由67%提高到75%。     

A Neural Networks Approach for Deriving Irrigation Reservoir Operating Rules

A neural networks approach is applied to the derivation of the operating rules of an irrigation supply reservoir. Operating rules are determined as a two step process: first, a dynamic programming technique, which determines the optimal releases byminimizing the sum of squared deficits, assumed as objective function, subject to various constraints is applied. Then, theresulting releases from the reservoir are expressed as a functionof significant variables by neural networks. Neural networks aretrained on a long period, including severe drought events, andthe operation rules so determined are validated on a differentshorter period. The behaviour of different operating rules is assessed by simulating reservoir operation and by computing several performance indices of the reservoir and crop yield through a soil water balance model. Results show that operating rules based on an optimization with constraints resembling real system operation criteria lead to a good performance both in normal and in drought periods, reducing maximum deficits and water spills.     

Examining Two Different Approaches to Modelling Management and Operation Rules in a Single River System Model

Different water agencies use different modeling tools for water resources planning and management. For example, different jurisdictions in Australia use a variety of river system models and these models vary considerably in approach and assumptions, including different time steps (monthly and daily), flow routing (different types of routing and no routing), ordering solution (optimization and heuristic) and representation of management and operational rules. These fundamental differences in approach make it difficult to integrate existing models of connected river systems at a basin scale. A collaborative joint venture (the eWater CRC) between research, industry and government partners has recently developed an integrated river system modelling tool called “eWater Source” to improve on the existing river system models in Australia. One of the major advances in Source is the implementation of two decision algorithms, heuristic and NetLP approaches, for water distribution modelling in the same modelling platform. This paper describes the implementation of heuristic and NetLP approaches for water delivery under management and operations rules in Source, and compares the performance of the two approaches through a case study in the Goulburn-Broken-Campaspe-Loddon (GBCL) river system in south-eastern Australia. The key performance measures used to compare the approaches include the efficiency and equity of water delivery to water users, impacts on the reliability of supply, agreement with storage operating targets, and model application run time. The results demonstrate that the heuristic approach implemented in Source can replicate the performance of the NetLP approach for a model of reasonable complexity. This is important because the run times of models with heuristic approaches are shorter than models with NetLP approaches, so this will allow more complexity to be represented than was previously practical in equivalent NetLP applications. Agreement between jurisdictions to move to the single river system modelling platform will contribute to overcoming the problems faced by river managers in Australia in transboundary river basins.     

Groundwater Vulnerability and the Reuse of Water,with Reference to Saudi Arabia

It is noted that an integrated water supply system incorporating surface water, groundwater and recycled water is essential and that in the definition of groundwater resources consideration should be given to the inclusion of some brackish and saline waters. The abstraction of groundwater in Saudi Arabia, irrespective of quality, is a mining operation so that increasing emphasis will need to be placed on desalinization and the recycling of sewage and industrial waste waters. Aspects of the reuse of such waters are discussed with respect to aquifer protection and aquifer value as a storage medium.     

Multiobjective management of a contaminated aquifer for agricultural use

Planned utilization of groundwater from a contaminated aquifer requires development of management strategies that determine the spatial distribution of withdrawal for allocation, as well as for control of water quality. Minimization of groundwater allocation for different purposes, and the control of contamination in the aquifer by a specified pumping strategy constitute a management problem with two conflicting objectives. In order to demonstrate possible tradeoffs between water quality control objective and minimum groundwater withdrawal objective, a multiobjective optimization model is formulated. The solution of the model specifies a strategy to control pollution distribution in the aquifer as per agricultural needs, and also evolve an optimal allocation policy to statisfy agricultural demands. Pareto-optimal solutions representing the tradeoff between the two noncommensurate objectives are established. The formulated model uses the embedding technique for simulating the flow and the transport processes in the aquifer. The constraint method is used to transform the multiobjective optimization model into a single objective optimization model. The resulting model is solved using the exterior penalty function method in conjunction with the Hooke-Jeeves method. The proposed model is easily adoptable for various agroclimatic regions and cropping patterns. For illustrative purposes, the model is applied to a specified study area. Although solutions of the model are presented and discussed as per agricultural requirements in terms of both quality and quantity, solutions for other kinds of water demands can be obtained using the same model with minor modifications. Results show that an optimal pumping strategy can be effectively utilized for controlling contamination in the aquifer.     

Minimizing environmental impact whilst securing drinking water quantity and quality demands from a reservoir

Complying with the demands of drinking water supply whilst minimizing environmental impact poses a great challenge in water management. This study investigates the potential of withdrawal management of drinking water reservoirs to alleviate the disruption of the river continuum by a reservoir dam with respect to temperature and discharge. The aim is the identification of an optimal withdrawal strategy to provide a near‐natural discharge temperature and flow for the downstream river without jeopardizing drinking water production. First, we identify the applicability of new withdrawal regimes for raw water security and downstream river demands. Second, we search for an ideal withdrawal regime in scenario simulations using a numerical reservoir model (“General Lake Model”). The scenarios on a drinking water reservoir in Germany demonstrate that we are able to derive an optimized reservoir management. The numerical model is provided for operators as a simple and efficient tool for optimizing the withdrawal strategy within reservoir management.     

A Suitable Tool for Sustainable Groundwater Management

Artificial recharge is used to increase the availability of groundwater storage and reduce saltwater intrusion in coastal aquifers, where pumping and droughts have severely impaired groundwater quality. The implementation of optimal recharge methods requires knowledge of physical, chemical, and biological phenomena involving water and wastewater filtration in the subsoil, together with engineering aspects related to plant design and maintenance operations. This study uses a novel Decision Support System (DSS), which includes soil aquifer treatment (SAT) evaluation, to design an artificial recharge plant. The DSS helps users make strategic decisions on selecting the most appropriate recharge methods and water treatment technologies at specific sites. This will enable the recovery of safe water using managed aquifer recharge (MAR) practices, and result in reduced recharge costs. The DSS was built using an artificial intelligence technique and knowledge-based technology, related to both quantitative and qualitative aspects of water supply for artificial recharge. The DSS software was implemented using rules based on the cumulative experience of wastewater treatment plant engineers and groundwater modeling. Appropriate model flow simulations were performed in porous and fractured coastal aquifers to evaluate the suitability of this technique for enhancing the integrated water resources management approach. Results obtained from the AQUASTRESS integrated project and DRINKADRIA IPA CBC suggest the most effective strategies for wastewater treatments prior to recharge at specific sites.     

Urban Water Management Using Fuzzy-Probabilistic Multi-Objective Programming with Dynamic Efficiency

This paper introduces a new multi-objective optimization model for integrated urban water management. The model, based on compromise programming, is applied for the case of Tabriz city in Iran. The water demand of this city is rapidly growing and because of the limited resources, water supply is now more vulnerable to any mismanagement. Therefore the model attempts to optimize the water supply plan of city concerning three main objectives of maximizing the water supply, minimizing the cost and minimizing the environmental hazards. Due to the vagueness in defining the first objective, it is modeled by using the fuzzy set theory. Further, the uncertainty in satisfying some constraints is tackled by using the chance constraint approach. The decision variables are the extent of water withdrawal from the city aquifer, three different water transfer schemes and also the extent of demand management by leaks detection and pipes rehabilitation. Then the fuzzy-probabilistic multi-objective model is solved by considering the new idea of dynamic efficiency in the utility of decision maker and the results provide the optimum water supply in the planning horizon. The model results in robust solutions in which the demand management option dominates the new water transfer. Implementing the results of this model supports the environmental conservation and sustainable development.     

Identification of River Sections for Domestic Water Supply along the Yangtze River in Jiangsu Province, China

This paper presents major findings from a recent study aiming to systematically determine suitable river sections for local domestic water supply along the Yangtze River in Jiangsu Province, China. On the basis of analysis on the current riverbank utilization and bank stability, accessible and stable river sections in the region were selected. The water quality in these river sections was then studied using a two-dimensional unsteady flow and pollutant transport/transformation model, RBFVM-2D. The model was calibrated and verified against the hydrodynamic data, water quality data and remote sensing data collected from the river. The investigation on the pollution sources along the river identified 56 main pollution point sources. The pollution zones downstream of these point sources are the main threat for the water quality in the river. The model was used to compute the pollution zones. In particular, simulations were conducted to establish the relationship between the extent of the pollution zone and the wastewater discharge rate of the associated point source. These water quality simulation results were combined with the riverbank stability analysis to determine suitable river sections for local domestic water supply.     

基于贝叶斯理论的武烈河水质综合评价

选取2010年武烈河6个监测断面的水质监测数据作为研究对象,采用贝叶斯公式对其水质进行综合分析评价,结果表明:各监测断面水质评价均在Ⅲ类以上,总体水质结果较好,符合水功能区划要求;66.7%的断面达到Ⅰ类,包括高寺台上游、双峰寺水库坝址、雹神庙和污水处理厂出水口下游4个断面;高寺台下游断面只达到Ⅲ级,主要是由于高寺台镇及其矿区生活污水和农业退水未经处理直接排入河道造成的。为保障双峰寺水库运行后的流域水环境质量和供水安全,需从水源地建设、点源治理和面源治理3个方面采取水环境保护措施。     

Distributed Simulation‐optimization Model for Conjunctive Use of Groundwater and Surface Water Under Environmental and Sustainability Restrictions

Evolving optimal management strategies are essential for the sustainable development of water resources. A coupled simulation-optimization model that links the simulation and optimization models internally through a response matrix approach is developed for the conjunctive use of groundwater and surface water in meeting irrigation water demand and municipal water supply, while ensuring groundwater sustainability and maintaining environmental flow in river. It incorporates the stream-aquifer interactions, and the aquifer response matrix is generated from a numerical groundwater model. The optimization model is solved by using MATLAB. The developed model has been applied to the Hormat-Golina valley alluvial stream-aquifer system, Ethiopia, and the optimal pumping schedules were obtained for the existing 43 wells under two different scenarios representing with and without restrictions on stream flow depletion, and satisfying the physical, operational and managerial constraints arising due to hydrological configuration, sustainability and ecological services. The study reveals that the total annual optimal pumping is reduced by 19.75?% due to restrictions on stream flow depletion. It is observed that the groundwater pumping from the aquifer has a significant effect on the stream flow depletion and the optimal conjunctive water use plays a great role in preventing groundwater depletion caused by the extensive pumping for various purposes. The groundwater contribution in optimal conjunctive water use is very high having a value of 92?% because of limited capacity of canal. The findings would be useful to the planners and decision makers for ensuring long-term water sustainability.

     

Developing a Multi-Objective Conflict-Resolution Model for Optimal Groundwater Management Based on Fallback Bargaining Models and Social Choice Rules: a Case Study

Conflict-resolution models can be used as practical approaches to consider the contradictions and trade-offs between the involved stakeholders in integrated water resource management. These models are utilized to reach an optimal solution considering agents interactions. In this paper, a new methodology is developed based on multi-objective optimization model (NSGA-II), groundwater simulation model, M5P model tree, fallback bargaining procedures and social choice rules to determine the optimal groundwater management policies with an emphasis on resolving conflicts between stakeholders. By incorporating the multi-objective simulation-optimization model and bargaining methods, the optimal groundwater allocation policies are determined and the preferences of the stakeholders as well as social criteria such as justice are also considered. The obtained data set, based on Monte Carlo analysis of calibrated MODFLOW model, is used for training and validating the M5P meta-models. The validated M5P meta-models are linked with NSGA-II to determine the trade-off curve (Pareto front) for the objectives. Social choice rule and fallback bargaining methods, as conflict-resolution models, are applied to determine the best socio-optimal solution among stakeholders, and their results are compared. The effectiveness of the proposed methodology is verified in a case study of Darian aquifer, Fars province, Iran. Results indicated that the solutions obtained by the proposed conflict-resolution approaches have an appropriate applicability. Total groundwater withdrawal, after applying the optimal groundwater allocations, reduced to 20.85 MCM, resulting in a 4.62 m increase in the mean groundwater level throughout the aquifer.     

二层结构的流域生态调度研究Ⅱ：松花江流域生态调度实践与应用

随着生态文明建设、人水和谐理念的深入,生态调度也从理论方法研究进入实践应用阶段,但从工程生态调度到流域生态调度仍有诸多技术问题。本文以流域生态调度需求迫切的松花江流域为例,在梳理流域经济发展与生态保护需求的基础上,构建松花江流域二层结构流域生态调度模型,在流域层面水量总体配置的基础上针对重点生态断面、水库进行生态优化调度。通过从流域水量调控到断面生态流量调度的耦合分析,给出不同方案流域水量供需平衡和水源配置基础上的重点断面生态调度结果,提出重点水库的调度规则优化方案,验证了二层结构流域生态调度模型的实际应用效果,可为流域生态调度实践和相关研究提供依据和参考。     

浙江省水乡区域水资源可持续利用机制初探

浙江省水资源总量丰富 ,但存在人均占有量不足、年内分配不均、地下水超采、水污染日益严重等问题 ,而传统水资源管理体制存在的管理不顺的弊端无法有效控制水污染 ,难以统筹管理城乡水资源。参照欧美发达国家和深圳、上海对水资源进行综合开发和统一管理的先进管理模式 ,指出为实现江南水乡区域水资源可持续利用 ,建议理顺水资源管理体制 ,建立水务局 ,对城乡水资源进行一体化管理 ,建立节水型社会 ,防治水污染 ,维护和改善水环境。     

长江中游黄州河段采砂影响分析

河道采砂等人类活动对河道演变的影响是河流动力学研究的一个重要课题。以长江黄州河段为例,在实测水沙系列的基础上,采用平面二维水沙数学模型研究了不同流量级下工程河段采砂后水位、流速和汊道分流比等变化规律,并模拟了不同典型年水沙条件下洲滩河段演变过程和采砂区冲淤特性。研究结果表明,在不同流量条件下,随着流量的增加,水位和流速变化幅度有所减小、影响程度降低;分流比对平滩流量反应更加敏感,平滩流量条件下分流比有明显增加;三峡水库蓄水运行后,在不同典型水文年条件下,随着洲滩的冲刷后退加剧,布置在洲尾的采砂区泥沙回淤明显。     

Reservoir System Reliability Constrained by Salinity

A generalized reservoir/river system sim ulation model, which incorporates salin ity considerations, was developed and applied in an evaluation of the water supply capabilities of a reservoir system in the Brazos River Basin. W ater resources management and utilization in this river basin is severely constrained by natural salt pollution. The paper outlines a general approach for developing the required input data and applying the simulation m odel in evaluating water supply reliabilities subject to specified maximum allowable salt concentration s. Key issues are identified and discussed from the perspective of the illustrative case study. The m odelling and analysis m ethodology is pertinent to other river basins as well.     

Multi-objective stochastic groundwater management of nonuniform,homogeneous aquifers

Like any other resources planning and management, groundwater management is performed in a stochastic environment in which the system itself involves a number of random elements. Consequences as a result of decisions made based on analyses are not certain. This paper presents a management model using the chance-constrained framework which explicitly considers the random nature of aquifer properties. The model enables the derivation of an optimal groundwater management policy that would satisfy required operation performance reliability. Furthermore, the chance-constrained model is extended to the multi-objective optimization framework in which a tradeoff between total water supply pumpage and system performance reliability is explicitly considered. The models are applied to a hypothetical example of a steady, nonuniform, homogeneous confined aquifer.     

Multiobjective water resources systems analysis using genetic algorithms--application to Chou-Shui River Basin, Taiwan.

Multipurpose operation is adopted by most reservoirs in Taiwan in order to maximize the benefits of power generation, water supply, irrigation and recreational purposes. A multiobjective approach can be used to obtain trade-off curves among these multipurpose targets. The weighting method, in which different weighting factors are used for different purposes, was used in this research work. In Taiwan, most major reservoirs are operated by rule curves. Genetic algorithms with characteristics of artificial intelligence were applied to obtain the optimal rule curves of the multireservoir system under multipurpose operation in Chou-Shui River Basin in central Taiwan. The model results reveal that different shapes of rule curves under different weighting factors on targets can be efficiently obtained by genetic algorithms. Pareto optimal solutions for a trade-off between water supply and hydropower were obtained and analyzed.