Simulation-Optimization Modeling for Sustainable Groundwater Development: A Moroccan Coastal Aquifer Case Study

A transient simulation model characterizing groundwater flow in the coastal aquifer of Rhis-Nekor was constructed and calibrated. The flow model was then used in conjunction with a genetic algorithm based optimization model to explore the optimal pumping schemes that meet current and future water demands while minimizing the risks for several adverse environmental impacts, such as saltwater intrusion prevention, avoiding excessive drawdown, as well as controlling waterlogging and salinity problems. Modeling results demonstrate the importance of this combined simulation-optimization methodology for solving groundwater management problems associated with the Rhis-Nekor plain.     

Development of a Management Model for a Surface Waterlogged and Drainage Congested Area

Inadequate drainage outlet causing surface waterlogging every year mainly during monsoon period (June through October) over a depressed land of 1062 km² in Mokama group of tals, India, led to a loss of one crop rotation. A management model aiming at minimization of the waterlogged area under constraints of control monsoon runoffs from tributaries discharge water to the depressed land has been developed. Magnitudes of regulated flows are guided by irrigation water requirement of crops grown in commands of different tributaries joined to the depressed land. A nonlinear optimization model has been envisaged and solved setting a total of 160 constraints satisfying conditions of water requirement for crops grown in two seasons and their time-dependent storage requirement. The optimization model has been solved using the Quantitative Systems for Business (QSB) software, which considers a line search methodology for unconstrained problems, and a sequential unconstrained minimization technique (SUMT) with penalty function methodology for constrained problems. The management model provides a solution for strategic water resources development and management in a basin having problems of scarcity, surplus and non-uniform distribution of surface water.     

Better Water and Land Allocation for Long-term Agricultural Sustainability

Water and land resources are limited and dwindling in quantity and quality due to pollution and the effects of climate change. The "world needs to produce over sixty percent more food to feed" its 9.9 billion population in 2050 using these dwindling resources. Increased food production is also necessary to achieve most of the "UN's SDGs such as SDG1 (No Poverty), SDG2 (Zero Hunger), SDG3 (Good Health and Well-Being), and SDG15 (Life on Land)", etc. The aforesaid "goal can be accomplished by optimizing the distribution of available water and land resources, which can be done through an optimization model". In this study, a water balance model was first developed "to assess the long-term groundwater recharge, which will help to understand the dynamics of the system". Then, after analyzing the results, an optimization model was formulated to maximize the net annual farm income in an irrigated region of India. The water balance model showed excellent results as indicated by "high R-squared (0.9728) and model efficiency (0.91)", and low RMSE (0.2516 m) and ME (-0.0526 m) values. The water balance analysis revealed "that the aquifer level has been rising at a steady rate" over the past two decades. The results of the water balance model were used to formulate various constraints of the optimization model. Under the optimal cropping system, the area of paddy decreases against an increase in the area of sorghum, pearl millet, and cotton during the monsoon. Whereas "during the winter, the area of wheat increases", and the area of mustard and barley decreases. Groundwater "abstraction has increased, eventually lowering the aquifer level and thus alleviating salinization and waterlogging problems in the region". Net yearly income in the region enhanced by more than twenty-two percent to ?821.24 million from the present ?671.33 million. The sensitivity analysis revealed that the crops' market price is the most sensitive factor in the optimization model. "It is recommended that government agencies and real-world agricultural farmers practice increased use of groundwater in conjunction with canal water to maximize farm income. The approach used is the first of its kind in the region under study, is easy to apply, and can be replicated in other regions of the world" dealing with comparative issues.

     

Effect of Substitute Water Projects on Tempo-Spatial Distribution of Groundwater Withdrawals in Chikugo-Saga Plain,Japan

Due to large-scale agricultural irrigation and industrial production, groundwater had been excessively employed to benefit the economy development and life improvement in Chikugo-Saga plain since the middle of last century, which led to many environmental problems such as land subsidence, flooding inundation and water shortage. In order to mitigate the impact of environmental hazards, some water supply projects have been performed to substitute surface water for groundwater since 1970s. For the purpose of comprehending the influence of substitute water projects on groundwater withdrawals, a tempo-spatial groundwater withdrawals assessment model with the resolution of one month in time and one kilometer in space was initially established based on various data concerning meteorology, agriculture, land use, soils, surface water consumption and groundwater utilization by using GIS. According to the development of the substitute water projects, a 28-year study period 1979–2006 was then divided into four stages (i.e. 1979–1984, 1985–1995, 1996–2000 and 2001–2006) and the tempo-spatial distribution of groundwater withdrawals for each stage was represented by means of the proposed model. The tempo-spatial variation of groundwater withdrawals for various water use categories under the effect of substitute water projects was finally analyzed by comparing the distributions of groundwater withdrawals at different stages. The results show that with the advance of the substitute water projects studied, the groundwater pumpage for irrigation, industry or waterworks varies geographically and phasically in the plain. From the first stage to the last stage, there is a significant decrease by approximately 23 % in mean annual total groundwater withdrawals. During the study period, dramatic declines are found in agriculture-use groundwater pumpage in the downstream land of Chikugo river at the third stage, in industry-use pumpage in eastern Saga area at the second stage and found in waterworks-use pumpage in western Saga area at the last stage, while little change in agriculture-use pumpage in western Saga area and in industry-use pumpage in Chikugo area without the corresponding substitution projects. Moreover, it is indicated that the proposed assessment model of groundwater withdrawals is helpful to figure out the regional groundwater exploitation and its impact on the environment, particularly when there is the lack of groundwater pumpage data recorded. It is necessary to develop new substitute water supply plans to reduce the agriculture-use groundwater withdrawals in western Saga area and the industry-use withdrawals in Chikugo area, for more effective management of regional water resources in future.     

Management Strategy of Groundwater Resources and Recovery of Over-Extraction Drawdown Funnel in Huaibei City, China

Groundwater overexploitation is threatening our ecosystems and even the life of future generations. Once happens, elimination of the bad influence will be a long-term process. It should be a feasible approach to take the environmental recovery as a whole by the way of the groundwater management. A case study of water resources management in Huaibei city, within semiarid region of north Anhui province, China, was illustrated, especially on the issues of groundwater over-extraction drawdown funnel recovery. Taking into account the water demand for satisfying the urban development in the next 15 years, three target years of water resources planning were postulated as the present (2005), the short-term (2010) and the long-term (2020), respectively. Four hydrological years: wet year, mean year, dry year and extremely dry year, were also defined by the rainfall data for many years. A groundwater management model which could deal with twelve possible scenarios (3 target years of water resources planning ×4 hydrological years) was established based on simulation and optimization. The groundwater management model could optimize the strategies of water resources development, integrate various kinds of water sources, e.g. groundwater, surface water and additive water sources, and meet the water demand for the urban development within an area of Huaibei city. Importantly, in accordance with the groundwater management model solutions, the issues of groundwater over-extraction drawdown funnel, which has formed within the Huaibei downtown area for many years and lead to some environmental and social problems, would be solved over the whole planning period.     

Application of Neural Networks and Optimization Model in Conjunctive Use of Surface Water and Groundwater

This study develops an optimization model for the large-scale conjunctive use of surface water and groundwater resources. The aim is to maximize public and irrigation water supplies subject to groundwater-level drawdown constraints. Linear programming is used to create the optimization model, which is formulated as a linear constrained objective function. An artificial neural network is trained by a flow modeling program at specific observation wells, and the network is then incorporated into the optimization model. The proposed methodology is applied to the Chou-Shui alluvial fan system, located in central Taiwan. People living in this region rely on large quantities of pumped water for their public and irrigation demands. This considerable dependency on groundwater has resulted in severe land subsidence in many coastal regions of the alluvial fan. Consequently, an efficient means of implementing large-scale conjunctive use of surface water and groundwater is needed to prevent further overuse of groundwater. Two different optimization scenarios are considered. The results given by the proposed model show that water-usage can be balanced with a stable groundwater level. Our findings may assist officials and researchers in establishing plans to alleviate land subsidence problems.     

Simulation-Optimization Modeling for Conjunctive Use Management under Hydrological Uncertainty

The canal water supply, which is the only source of irrigation, in the rice-dominated cropping system of the Hirakud canal command (eastern India) is able to meet only 54 % of the irrigation demand at 90 % probability of exceedance. Hence, considering groundwater as the supplemental source of irrigation, conjunctive use management study by combined simulation-optimization modelling was undertaken in order to predict the maximum permissible groundwater pumpage from the command area. Further, optimal land and water resources allocation model was developed to determine the optimal cropping pattern for maximizing net annual return. The modelling results suggested that 2.0 and 2.3 million m³ of groundwater can be pumped from the bottom aquifer during monsoon and non-monsoon seasons, respectively, at 90 % probability of exceedance of rainfall and canal water availability (PERC). Optimal cropping patterns and pumping strategies can lead to about 51.3–12.5 % increase in net annual return from the area at 10–90 % PERC. The sensitivity analysis of the model indicates that the variation in the market price of crops has very high influence on the optimal solution followed by the cost of cultivation and cultivable area. Finally, different future scenarios of land and water use were formulated for the command area. The adoption of optimal cropping patterns and optimal pumping strategies is strongly recommended for sustainable management of available land and water resources of the canal command under hydrological uncertainties.     

Integrated Biophysical and Economic ModellingFramework to Assess Impacts of Alternative Groundwater Management Options

We developed an integrated biophysical and economic modeling framework to assess impact of various groundwater management options on seawater intrusion and waterlogging and ultimate impact on sugarcane profitability in a coastal region of North Queensland, Australia. The modelling framework used the output of a groundwater management flow model (waterlogged and seawater intruded areas) and a crop simulation model (simulated crop yield) and maximised the net revenue in a mathematical programming (optimisation) model. The framework determined the economically optimal level of water use on different soil types and in different management regimes and estimated impact of seawater intrusion and waterlogging on net revenue of growing sugarcane in two neighbouring water board areas (North Burdekin Water Board – NBWB and South Burdekin Water Board – SBWB). In NBWB, the predicted aggregate net revenue was highest ($19.95 million) when groundwater use was also highest (70%) while predicted aggregate net revenue was lowest when groundwater use was also lowest. In SBWB, the predicted aggregate net revenue was highest ($23 million) when groundwater use was relatively low (61%). The predicted aggregate net revenues of all the management options were higher in SBWB than NBWB.     

Simulation supported scenario analysis for water resources planning: a case study in northern Italy.

The work presents the results of a comprehensive modelling study of surface and groundwater resources in the Muzza-Bassa Lodigiana irrigation district, in Northern Italy. It assesses the impact of changes in land use and irrigation water availability on the distribution of crop water consumption in space and time, as well as on the groundwater resources. A distributed, integrated surface water-groundwater simulation system was implemented and applied to the study area. The system is based on the coupling of a conceptual vadose zone model with the groundwater model MODFLOW. To assess the impact of land use and irrigation water availability on water deficit for crops as well as on groundwater system in the area, a number of management scenarios were identified and compared with a base scenario, reflecting the present conditions. Changes in land use may alter significantly both total crop water requirement and aquifer recharge. Water supply is sufficient to meet demand under present conditions and, from the crop water use viewpoint, a reduction of water availability has a positive effect on the overall irrigation system efficiency; however, evapotranspiration deficit increases, concentrated in July and August, when it may be critical for maize crops.     

基于SWMM的高速公路服务区排水系统优化研究

高速公路服务区是为驾乘人员提供休息、加油和维修等服务的场所,对防洪排涝有较高的要求。为了快速分析和解决服务区地表积水问题,首先采用传统单排水系统SWMM模型对某服务区重现期为2,5,20 a的暴雨进行模拟,分析其地下管网排水状况;然后在传统模型基础上利用双排水系统理论完善模型,进而分析出其地表积水情况;最后针对服务区积水情况,采用低影响开发(LID)措施和管径修改对排水系统进行优化。模拟结果表明:对于重现期为5 a的暴雨,存在部分管道超载,无地表积水;对于重现期为20 a的暴雨,服务区多处地表积水,最大积水深度为30 cm;通过优化措施后,服务区可基本解决排水问题。研究结果可为服务区分析和解决积水问题提供技术参考。     

Planning of Groundwater Supply Systems Subject to Uncertainty Using Stochastic Flow Reduced Models and Multi-Objective Evolutionary Optimization

The typical modeling approach to groundwater management relies on the combination of optimization algorithms and subsurface simulation models. In the case of groundwater supply systems, the management problem may be structured into an optimization problem to identify the pumping scheme that minimizes the total cost of the system while complying with a series of technical, economical, and hydrological constraints. Since lack of data on the subsurface system most often reflects upon the development of groundwater flow models that are inherently uncertain, the solution to the groundwater management problem should explicitly consider the tradeoff between cost optimality and the risk of not meeting the management constraints. This work addresses parameter uncertainty following a stochastic simulation (or Monte Carlo) approach, in which a sufficiently large ensemble of parameter scenarios is used to determine representative values selected from the statistical distribution of the management objectives, that is, minimizing cost while minimizing risk. In particular, the cost of the system is estimated as the expected value of the cost distribution sampled through stochastic simulation, while the risk of not meeting the management constraints is quantified as the expected value of the intensity of constraint violation. The solution to the multi-objective optimization problem is addressed by combining a multi-objective evolutionary algorithm with a stochastic model simulating groundwater flow in confined aquifers. Evolutionary algorithms are particularly appropriate in optimization problems characterized by non-linear and discontinuous objective functions and constraints, although they are also computationally demanding and require intensive analyses to tune input parameters that guarantee optimality to the solutions. In order to drastically reduce the otherwise overwhelming computational cost, a novel stochastic flow reduced model is thus developed, which practically allows for averting the direct inclusion of the full simulation model in the optimization loop. The computational efficiency of the proposed framework is such that it can be applied to problems characterized by large numbers of decision variables.     

Total Urban Water Cycle Models in Semiarid Environments��Quantitative Scenario Analysis at the Area of San Luis Potosi, Mexico

Systems view thinking and holistic urban water cycle concepts are increasingly called upon for integrated analysis of urban water systems to mitigate water stress in large urban agglomerations. However, integrated analysis is frequently not applied due to the inherent complexity, limitations in data availability and especially the lack of guidelines and suitable software tools. The paper presents the application of the total urban water balance model UVQ to the City of San Luis Potosi (1.2 Mio inhabitants) under the arid conditions of Northern Mexico. UVQ is a lumped parameter model which describes water and contaminant flows from source to sink in urban areas and includes all water types such as rainwater, imported water, surface runoff, wastewater and groundwater. The results were especially useful for spatially explicit groundwater recharge calculation in urban areas. A range of urban water scenarios, including different supply strategies and the effect of externalities such as demand change, were simulated and compared to a calibrated baseline scenario. The analysis demonstrated that shallow urban groundwater resources can substantially mitigate problems of water scarcity and overexploitation of deep aquifers if appropriate water quality protection or fit-for-use paradigms are put into place. The modelling exercise delivers relevant information for the decision making process and identifies the most relevant shortcomings in current monitoring systems. This represents a key step on the path to water sensitive and sustainable urban development, including the urban aquifers which have been neglected in the management policy of most cities of the Mexican arid zone.     

基于 SWMM 的平原区小城镇排涝体系评估与优化

针对我国平原区小城镇面临严重内涝灾害威胁的问题,结合平原区小城镇的排涝体系特点,探索一种简便 的平原区小城镇排涝体系评估和优化方法。基于暴雨洪水管理模型（storm?water?management?model,?SWMM) 建立 平原区典型小城镇排涝模拟模型,并采用历史洪涝数据对模型进行率定和验证。在此基础上,通过对典型重现期 暴雨下的内涝模拟,评估典型城镇排涝能力。根据管渠超载时间、节点积水时间和积水量,找出排涝体系薄弱环 节,提出有针对性的排涝体系优化方案,并对优化效果进行评估。结果表明：建立的排涝模拟模型基本可靠,模拟 结果与实际情况基本相符;典型小城镇排涝体系薄弱点主要为主干管渠排涝压力大,蓄水池未得到有效利用;据 此提出的优化方案效果明显,在 20 年一遇暴雨情况下,可以减少典型小城镇 90% 的积水时间和 67% 的积水量, 显著提高城镇排涝能力。     

Conjunctive Use of Surface Water and Groundwater: Application of Support Vector Machines (SVMs) and Genetic Algorithms

Combined simulation-optimization models have been widely used to address the management of water resources issues. This paper presents a simulation-optimization model for conjunctive use of surface water and groundwater at a basin-wide scale, the Zayandehrood river basin in west central Iran. In the Zayandehrood basin, in the past 10 years, a historical low rainfall in the head of the basin, combined with growing demand for water, has triggered great changes in water management at basin and irrigation system level. The conjunctive use model that coupled numerical simulation with nonlinear optimization is used to minimize shortages of water in meeting irrigation demands for four irrigation systems. Constraints guarantee the maximum/minimum cumulative groundwater drawdown and maximum capacity of irrigation systems. A support vector machines (SVMs) model is developed as a simulator of surface water and groundwater interaction model while a genetic algorithm (GA) is used as the optimization model. Conjunctive use model runs for three scenarios. Results show that the accuracy of SVMs as a simulator for surface water and groundwater interaction model is good and that it is possible to decrease the water shortage for irrigation systems with application of proposed SVMs-GA model.     

GRACE, GLDAS and measured groundwater data products show water storage loss in Western Jilin, China

Water storage depletion is a worsening hydrological problem that limits agricultural production in especially arid/semi-arid regions across the globe. Quantifying water storage dynamics is critical for developing water resources management strategies that are sustainable and protective of the environment. This study uses GRACE (Gravity Recovery and Climate Experiment), GLDAS (Global Land Data Assimilation System) and measured groundwater data products to quantify water storage in Western Jilin (a proxy for semi-arid wetland ecosystems) for the period from January 2002 to December 2009. Uncertainty/bias analysis shows that the data products have an average error <10% (p < 0.05). Comparisons of the storage variables show favorable agreements at various temporal cycles, with R(2) = 0.92 and RMSE = 7.43 mm at the average seasonal cycle. There is a narrowing soil moisture storage change, a widening groundwater storage loss, and an overall storage depletion of 0.85 mm/month in the region. There is possible soil-pore collapse, and land subsidence due to storage depletion in the study area. Invariably, storage depletion in this semi-arid region could have negative implications for agriculture, valuable/fragile wetland ecosystems and people's livelihoods. For sustainable restoration and preservation of wetland ecosystems in the region, it is critical to develop water resources management strategies that limit groundwater extraction rate to that of recharge rate.     

A Framework for Ground Water Management Based on Bayesian Network and MCDM Techniques

Groundwater resources are steadily subjected to increasing water demands. The aquifers are considered as the most accessible source of fresh water. In recent years, they have been faced with severe water withdrawal in arid and semi-arid countries like Iran and thus some aquifers was considered as forbidden aquifers that it means the water withdrawal from these aquifers is unauthorized. Given a critical situation, groundwater resources management in the form of tools such as monitoring the level of the aquifers and developing the restoring scenarios is essential. Therefore, for this purpose, a framework has been developed based on prediction of groundwater level using Bayesian Networks (BNs) model. Furthermore, Multi Criteria Decision Making methods (MCDM) techniques proposed and employed for ranking of proposed groundwater management scenarios. This framework was evaluated for restoring the Birjand aquifer in Iran in different hydrological conditions. A probabilistic Dynamic BN was proposed for groundwater level prediction under uncertainties. After analyzing the obtained results, the applicable short term scenarios for groundwater management as well as appropriate economic, social and technical criteria were defined for decision making procedure. Then, using elicitation of decision makers’ opinions on the relative importance and performance of criteria, SAW, TOPSIS and PROMETHEE-II techniques were applied to rank the scenarios and the obtained results were aggregated by Borda method for final ranking of the scenarios. Lastly, the final results demonstrates the capability of the proposed framework for groundwater resources planning and management which can be employed for reducing the risk of aquifer level declining.     

Optimal Groundwater Management Using Genetic Algorithm in El-Farafra Oasis,Western Desert,Egypt

Groundwater is the unique source of fresh water in El-Farafra Oasis, western desert, Egypt. The increasing demand of groundwater in El-Farafra Oasis has resulted in an indiscriminate exploitation of this source causing environmental hazards such as decline of groundwater levels and well interference. In this paper, the study of these problems is conducted. The methodology introduced in this paper includes application of mathematical and Genetic Algorithm (GA) techniques. This situation has led to a growing realization that through good management, use of groundwater can be made more productive and sustainable. The proposed model of optimization is based on the combination of the MODFLOW with GA. The performance of the proposed model is tested on groundwater management problem (maximization of total pumping rate from an aquifer at steady-state). The results show that the GA solutions nearly agree with the solutions of other methods of previous works. Thus, it can be used to solve the management problems in groundwater. This model is used to develop the optimal pumping rate and number of wells in El-Farafra Oasis under different scenarios. The results show that under the current situation, the optimal pumping rate is 183023 m³/day. The second scenario assumes an increase of number of wells by 20%, the optimal rate reaches 220016 m³/day. The third scenario proposes pumping rate 254484 m³/day which equalizes an increase in the cultivated area by 4000 acres, the optimal rate reaches 258007 m³/day.     

Comprehensive Assessment of Water Resources in the United Arab Emirates (UAE)

Lack of sufficient quantities of water in the UAE is one of the major problems facing sustainable development. The arid climate of the country plays a significant role in the water resources availability. Rainfall, which is a main source of recharge for different water resources, such as surface water and groundwater, is scanty and extremely irregular in time and space. Evaporation, which reduces the amount of surface water, is high. Heavy pumping of groundwater has deteriorated groundwater levels. Desalination plants have been launched in different parts of the country to meet increasing water demands due to increasing population and economical development in the country. The continued reduction of water storage will hinder the development in the country. To avoid this problem, integrated water resources management (IWRM) strategy should be implemented. Searching for new non-conventional resources is also essential. This paper aims to assess the conventional and non-conventional water resources in the UAE and estimates the past and future water demands. In addition, this article focuses on future water strategy scenarios and plans.     

石家庄市暴雨内涝精细化水动力模型应用

近年来石家庄市极端天气逐渐增多,局部短历时强降雨的发生愈加频繁,造成城区大范围积水,损失严重。基于高精度DEM数据,采用小尺寸结构化网格建立石家庄市暴雨内涝精细化水动力模型。模型精确反映了房屋建筑、城市道路、立交系统和排水渠系等典型城市地物;采用分区径流系数和糙率体现不同下垫面的影响;通过将排水分区精细划分至各雨水干管实际控制街区模拟管网实际排水过程,并设置点源模拟城市立交泵站。模型高精度地模拟了该市主城区房屋阻水、庭院雨水出流、地道桥等低洼处汇水积涝、路面行涝、管网排水以及泵站抽排水等具有典型城市特征的水流现象,计算统计了城区积涝面积、积水点及积水路段。将该市内涝危险性等级划分为高、中、低三级,结合模拟结果进行风险分析及等级划分,分析结果为石家庄市防涝减灾工作和内涝风险管理提供信息支持,具有重要实用价值。     

Assessing Impacts of Conservation Measures on Watershed Hydrology Using MIKE SHE Model in the Face of Climate Change

Climate change triggers changes in temperature, precipitation, evapotranspiration, etc. and has a significant impact on water resources in many regions. Considering the increasing scarcity of water as a result of climate change, conservation of water and groundwater recharge have become crucial factors for water resources planning and management. In this paper, an attempt is made to study the detailed hydrological behaviour of a treated watershed using physically based distributed hydrological modelling system MIKE SHE to assess the impact of conservation measures on watershed hydrology considering future climate change. Three hypothetical management scenarios are simulated for the period 2010–2040. RegCM4 regional climate model is used in the study for RCP 4.5 and RCP 8.5 scenarios. Detailed hydrological water balance is extracted for individual years from 1979 to 2009 to compare relevant components. The evaluation for base period shows 10.06% reduction in surface runoff and 11.33% enhancement in groundwater recharge. Further simulation with RCP 4.5 and RCP 8.5 scenarios show notable reduction in surface runoff and increase in groundwater recharge. The structures in the micro-watershed influence the surface runoff and increase infiltration into the soil, resulting in higher groundwater recharge. MIKE SHE simulations for various structures management scenarios establish the role of conservation measures in reducing surface runoff and enhancing groundwater recharge under substantial effect of climate change. The results will assist in decision-making on watershed development plans in quantitative terms, including planning for water conservation measures in the face of climate change.