Optimal Use of Irrigation Water in the Jordan Valley: A Case Study

Water shortage is a serious problem in most countries in theMiddle East. Irrigation water consumes about three-fourths of theavailable fresh water resources in Jordam and many othercountries in the region. This article presents a practical approachto manage and optimize the irrigation water use in the region.The ultimate objective is to minimize the outside water and tomanage the irrigation water use under geographic,socio-economic, and demographic constraints. This approach usesthe added value (net revenue) of one cubic meter of waterconcept in evaluating different irrigation water use management.This concept has been demonstrated, based on a case study in theJordan Valley.This case study shows that water scarcity can be incorporated inirrigation water management by proper choice of crops andfarming patters. The objective function is to maximize the netrevenue from the agricultural production process subjected tolimitation on water and other production and marketing factors.Results of analysis showed that a net water saving of about9%occurred if the objective function is to minimize water useunder the same level of profitability. This example shall beuseful for water and agricultural planners. Sometimes virtualwater is widely exported in form of crops that consumes largeamounts of water without full economic consideration to theadded value of water. In some cases, food imports may be afeasible option in water-poor countries instead of water import.     

A Branch-and-Bound Algorithm for Optimal Pump Scheduling in Water Distribution Networks

Nowadays water distribution operation systems are accomplished with the aid of qualified professionals who use their experience in order to achieve a satisfactory performance of the several hydromechanical devices, which are part of the system, such as boosters and valves. In general, these operational rules are empirical and the main goal is to assure the availability of water for the population, with no special concerns about saving energy used in pumping systems. Besides, these empirical rules often disregard hours of lower energy rates. There are several research works concerning the developments of operational rules optimization applied to specific water distribution systems. However, in this work, a general optimization routine integrated with EPANET is presented, which allows the determination of strategic optimal rules of operation for any type of water distribution system. Moreover, a Branch-and-Bound algorithm is also used, where finding the global optimal solution is guaranteed, in admissible computational times. The water distribution system used in this work corresponds to a hypothetical network proposed in the specialized literature.     

Pressure Management Through Optimal Location and Setting of Valves in Water Distribution Networks Using a Music-Inspired Approach

Pressure management through Pressure Reducing Valves (PRVs) is probably the most used approach related to the leakage management in Water Distribution Networks (WDNs). Its effectiveness in reducing the amount of water losses in existing networks has been highlighted in many papers. In this study, the topic is addressed with particular reference to meta-heuristic optimization techniques, that have proved to be very effective in producing good results with reduced use of computational resources. In particular, the application of the Harmony-Search (HS) method to the location and setting of a pre-fixed number of PRVs is proposed and discussed. A single objective optimization problem is defined which aims at the leakage reduction through the minimization of the water pressures. A double harmonic component is adopted for taking into account both the location and the setting of each PRV. The hydraulic constraints handled by a simulation software are considered as well. The approach is applied to a couple of WDNs: one is the Jowitt and Xu well-known literature test case and the other is a real WDN in Naples, called Napoli Est. The methodology has showed very good results compared to those obtained by using classical Genetic Algorithm techniques both in terms of leakage reduction and computation time.     

Rational Pricing of Water as an Instrument of Improving Water Use Efficiency in the Agricultural Sector: A Case Study in Gujarat,India

The agricultural sector in India accounts for over 85% of the total water used for various purposes in the country. However, the efficiency of water use in agriculture is very low, approximately 40% for surface irrigation and 60% for groundwater irrigation. Part of the reason for the low efficiency is the highly subsidized price of irrigation water that encourages the excessive application of water to crops. This paper is based on a case study conducted in the command area of a public irrigation canal in the state of Gujarat, India. It attempts to explore the role of the rational pricing of canal irrigation water in motivating farmers to use water judiciously and thereby enhance the water use efficiency in irrigated agriculture. The paper contends that farmers are sensitive to an increase in irrigation water charges, but unless the administered price is increased to the level that would prevail in a free market, it will not have its intended effect on irrigators.     

Optimal Location of Pump as Turbines (PATs) in Water Distribution Networks to Recover Energy and Reduce Leakage

Water distribution networks are high energy and low efficiency systems, where water pressure is frequently reduced by dissipation valves to limit leakage. The dissipation produced by the valves can be converted to energy production to increase the efficiency and reduce the energy impact of networks. If valves are replaced by turbines or pumps as turbines (PATs), they can both reduce pressure and produce energy. This study focuses on the optimal location of PATs within a water distribution network in order to both produce energy and reduce leakage. A new optimization model is developed consisting of several linear and non-linear constraints and a newly proposed objective function, where the turbine installation costs as well as the energy production and the economic saving due to the reduction of leakage can be accounted all together. The case study shows that the application of the mathematical model to a synthetic network ensures better results, in terms of both energy production and water saving, in comparison to other procedures.     

A Superposed Model for the Pipe Failure Assessment of Water Distribution Networks and Uncertainty Analysis: A Case Study

Pipe failure often occurs in water distribution networks (WDNs) and results in high levels of water loss and socio-economic damage. Physical-based, statistical and data-driven models have been developed to estimate pipe failure rates (failures per km of pipe per year) to efficiently manage water losses from WDNs and to ensure safe operations. Due to the complexities of pipe failure patterns, we develop a superposed statistical model to depict the relationship between pipe failure rate and pipe age. The model’s level of uncertainty was then quantified by simulating pipe failures as Poisson numbers. Part of Beijing’s WDN is taken as a study case, and pipe failure data for a 4-year period, as well as pipe properties, are collected to develop the pipe failure model. The case study results show that the pipe failure rates vary with time in a non-monotonic manner and that the proposed model captures pipe failure behaviour with an R² value of 0.95. A 95% confidence interval of modelled pipe failures for each pipe age group is used to describe the uncertainty level of the model. We find that 88% of the observations fall under the 95% confidence interval. The established model could be applied to prioritize pipes with higher failure rates to optimize pipe replacement/rehabilitation strategies. Our uncertainty analysis of this model can help utility managers understand the model’s reliability and formulate reasonable WDN management plans.     

Application of Parameter-Less Rao Algorithm in Optimization of Water Distribution Networks Through Pressure-Driven Analysis

Water Resources Management - Water distribution networks (WDNs) connect consumers to the source of water. The primary goal of optimizing WDNs is to minimize the network costs as WDNs entail high...     

基于DEA模型的用水效率研究——以云南省为例

自2009年开始连续3年的云南大旱凸现了云南省水资源利用效率的问题.通过基础表格调查法,收集了云南省12个州市2009年水资源与社会经济的指标,在此基础上,利用数据包络分析法(DEA)计算并分析了云南省各州市的水资源利用相对效率.研究结果表明:玉溪、楚雄、大理、曲靖以及保山的水资源利用效率相对较高,其他州市应参考这5个...     

Optimal water allocation at different levels of climate change to minimize water shortage in arid regions (Case Study: Zayandeh-Rud River Basin,Iran)

Climate change is one of the most important factors influencing the future of the world's environment. The most important impacts of climate change are changes in water supply and demand in different regions of the world. In this study, different climate change patterns in two RCP4.5 and RCP8.5 emission scenarios (RCP: Representative Concentration Pathway), were adopted for the Zayandeh-Rud River Basin, Iran, through weighting of GCMs (General Circulation Models). These climate change patterns are including ideal, medium, and critical patterns. Using the LARS-WG model (Long Ashton Research Station Weather Generator), the outputs of the GCMs were downscaled statistically and the daily temperature and precipitation time series were generated from 2020 to 2044. Then, based on this information, the inflow volume into the Zayandeh-Rud Reservoir was predicted by the IHACRES model (Identification of unit Hydrograph and Component flows from Rainfall, Evaporation and Streamflow) and the agricultural water demand was also estimated based on future evapotranspiration. Finally, using GAMS (General Algebraic Modeling System) software, water resources in this basin were allocated based on the basic management scenario (B) and the water demand management scenario (D). The results showed that the average monthly temperature will increase by 0.6 to 1.3 °C under different climate change patterns. On the other hand, on the annual basis, precipitation will decrease by 6.5 to 31% and inflow volume to the Zayandeh-Rud Reservoir will decrease by 21 to 38%. The results also showed that the water shortages based on the baseline management scenario (B) will be between 334 and 805 MCM (Million Cubic Meters). These range of values varies between 252 and 787 MCM in the water demand management scenario (D). In general, the water shortage can be reduced in the Zayandeh-Rud River Basin with water demand control, but complete resolution of this problem in this region requires more integrated strategies based on a sustainable development, such as a fundamental change in the cropping pattern, prevention of population growth and industrial development.     

Optimal Land-Use Management for Surface Source Water Protection Under Uncertainty: A Case Study of Songhuaba Watershed (Southwestern China)

The water supply to Chinese cities is increasingly degrading from pollution due to watershed activities. Consequently, water source protection requires urgent action using optimal land-use management efforts. An inexact linear programming model for optimal land-use management of surface water source area was developed. The model was proposed to balance the economic benefits of land-use development and water source protection. The maximum net economic benefit (NEB) was chosen as the objective of land-use management. The total environmental capacity (TEC) of rivers and the minimum water supply (MWS) were considered key constraints. Other constraints included forest coverage, government requirements concerning the proportions of various land-use types, soil loss, slope lands, and technical constraints. A case study was conducted for the Songhuaba Watershed, a reservoir supplying water to Kunming City, the third largest city in southwestern China. A 15-year (2006 to 2020) optimal model for land-use management was developed to better protect this water source and to gain maximum benefits from development. Ten constraints were involved in the optimal model, and results indicated that NEB ranged between 893 and 1,459 million US$. The proposed model will allow local authorities to better understand and address complex land-use systems and to develop optimal land-use management strategies for balancing source water protection and local economic development.     

Comparison Among Resilience and Entropy Index in the Optimal Rehabilitation of Water Distribution Networks Under Limited-Budgets

The replacement of existing pipes is a strategy for the rehabilitation of water distribution networks that is frequently adopted by water companies. Usually, the optimal choice of the pipes diameter is a difficult optimization task, because limited budgets are available. In order to support the selection of a rehabilitation strategy, surrogate reliability measures are often used as an indirect measure of the water distribution system hydraulic performance. Among others, the resilience and entropy indices have attracted considerable interest because they both represent a measure of the network robustness. In the present work, a comparison between these indices is provided in the framework of the optimal rehabilitation of an existing network under limited budget constraint. The resilience and entropy indices are applied to the case of a realistic water distribution network in an extended period simulation framework. Several values of the maximum budget allocable for rehabilitation are considered, and hydraulic calculations are undertaken by means of a pressure driven approach within a modified EPANET 2 environment. The effectiveness of the two surrogate reliability measures is demonstrated by an a-posteriori reliability assessment.     

Water Management of Irrigation Dams Considering Climate Variation: Case Study of Zayandeh-rud Reservoir, Iran

Dependency of reservoir operation on the climate variation occurs especially in regions, where agricultural demand has a significant share of the total water demands. The variability between demands that are based on annual climate conditions may be larger than the uncertainty associated with other explanatory variables in long-term operation of an irrigation dam. This paper proposed a rule curves to the water managers of the Zayandeh-rud reservoir in Iran in long-lead reservoir operation. A regional optimal allocation of water among different crops and irrigation units is developed. The optimal allocation model is coupled with a reservoir operating model, which is developed based on the certain hedging that deals with the available water and the water demands mutually. This coupled model is able to activate restrictions on allocating water to agricultural demands considering variation of inflow to the reservoir, variation of demands and the economic value of allocating water among different crops and irrigation units. The resulted rule curve is presented with a number of tables for more details and accuracy and a simple curve, which is more useful for operational purpose.     

Quality Evaluation of Groundwater Resources using Geostatistical Methods (Case Study: Central Lorestan Plain,Iran)

In this research, based on the qualitative data of 40 wells, variations of water quality parameters of the Central Plain Aquifer were evaluated using kriging and IDW (Inverse Distance Weighting) methods. Owing to the normal distribution of the studied parameters (except Na⁺, SO₄^2?, and TH: total hardness), ordinary kriging was used for modeling. The analysis of the data trends indicated that all the variables were influenced by in two general trends, i.e., NW–SE and NE–SW. In fact, these trends were a result of the effect of the structural conditions on aquifer properties such as transmissivity and flow direction. Variogram analysis (based on C₀ near zero and C₀/σ² ratio between 0.0–0.5) showed that the Na⁺, TDS (total dissolved solids), Ca²⁺, and TH variables have a good spatial structure and the BOD (biochemical oxygen demand), COD (chemical oxygen demand), NO₃^?, and EC variables have poor spatial structure. The BOD, COD, NO₃^?, and EC (electrical conductivity) variables have the smallest range and isotropic distribution. On the other hand, the Ca²⁺, Mg²⁺, Na⁺, SO₄^2?, Cl^?, HCO₃^?, pH, TDS, TH and Alk (alkalinity) parameters are characterized by anisotropic distributions. The Na⁺, TDS, Ca²⁺, and TH variables have the largest range. The results showed that both the IDW and kriging methods have close estimates to one another. The pH variable decreases toward the outlet whereas the EC and TDS variables increase along the direction of water flow and toward the outlet. The distributions of the BOD and COD variables do not perfectly match with the aggregation of industrial activities in the central part as well as the agricultural activities in the southeastern and central parts of the aquifer. The distributions of the Ca²⁺, Mg²⁺, and Alk variables completely follow the geology condition and regional spread of carbonate formations. The Na⁺ concentration increases from the center toward the outlet. The concentration of the Cl^? variable is the highest in the central part of the plain due to the concentration of agricultural and industrial activities. The distribution of the SO₄^2? variable is influenced by a natural factor (lithology), especially in the southeastern parts and the outlet as well as artificial factors (agricultural and industrial activities) in the central and southeastern parts of the aquifer. The NO₃^? variable, which is directly influenced by agricultural and livestock-farming activities, has its maximum concentration in the southeastern areas.     

Water,Wastewater, and Environmental Security Problems: A Case Study of Mexico City and the Mezquital Valley

ABSTRACT

Increasing social tensions and conflicts can now be observed due to growing water scarcities and higher wastewater discharges in many parts of the world. These conflicts can be analyzed in two ways. First, a social conflict can be responsible for creating water scarcity by reducing accessibility, destroying water systems, and reducing water availability. Second, water resources scarcity, both in terms of quantity and quality, can often be the cause of conflicts in a society. The article focuses on the second type of conflict by analyzing several examples from Mexico: especially conflicts that have been generated by the use of the wastewaters of Mexico City for irrigation in the Mezquital Valley since 1912.     

农民饮用水工程建后管理现状及对策分析——以丽水市莲都区为例

农民饮用水工程是一项民心工程,针对莲都区饮用水工程建设情况及建后管理工作存在的问题,介绍了当地政府关于强化饮用水建后管理采取的有效措施,并对解决饮用水建后管理提出了自己的思路。     

铁岭市水库群联合供水优化调度方案研究

本研究基于水库群聚合虚拟法、利用逐步优化算法,制定了铁岭地区聚合虚拟水库的联合供水调度方案,并采用分水比例法确定了各成员水库共同供水任务的分配比例。结果表明:该方案可满足全市各类型的用水需求,利用该优化调度模型可制定科学合理的水库联合供水优化调度方案,从而为该地区的水资源配置提供参考。     

Application of Water Poverty Index (WPI) in Nepalese Context: A Case Study of Kali Gandaki River Basin (KGRB)

This article details an application of Water Poverty Index (WPI) to evaluate state of water resources in the context of Nepalese river basins with a case study of Kali Gandaki River Basin (KGRB) located in western Nepal. Considering that water poverty issues and indicators to represent them are location-specific, selecting suitable indicators with due care of local context and data availability is essential to apply the WPI, a holistic tool for water resources planning and management. In this study, it suggests and describes a set of ten WPI indicators and twelve variables suitable in the Nepalese context. The selected set of indicators and variables is used to discuss water poverty situation in the study basin as a whole, spatial variation within the basin and variation at different spatial scales in the basin, that is, basin, sub-unit of the basin (district) and sub-unit of the district (Village Development Committee (VDC)). The study result shows that WPI varies widely (from 37.1 to 56.5) within the study basin suggesting the need of location-specific policy interventions. At different spatial scales, there is no clear trend; however, analysis of the WPI components shows higher resources and access at basin level; higher use, environment and capacity at sub-sub-unit of the basin level. Such variations suggest the need of scale-specific policy interventions and management plans to improve overall water poverty situation in the study basin. Overall, the WPI helped to examine the water poverty situation and recommend priority areas of policy interventions for the improvement of water-poverty situation in the basin.     

Combining Population Growth Model and Generalized Additive Model to Determine Optimal Water Level FOR Waterbird Conservation: A Case Study of Siberian Crane (Leucogeranus Leucogeranus) in Lake Poyang,China

Siberian crane (Leucogeranus leucogeranus) is one of the most endangered species in the world. The ecological integrity of its main wintering ground at Poyang Lake in China is crucial for the future of the species because Poyang Lake accommodates 99% of its global population. With the Three Gorges Dam fully operational, science‐based adaptive strategies are urgently needed to avoid catastrophic ecological consequences. This study quantified the link between water level variation and population growth rate of the Siberian crane in Poyang Lake using a suite of advanced statistical techniques. We first used the stochastic Gompert growth model within the state space modelling (SSM) framework to infer population growth rate, density dependence, and process variability and observation errors. We then applied generalized additive models (GAMs) to the population growth rate to quantify the effects of environmental stochasticity. Our SSM results indicated that there was little support for density dependence, and environmental stochasticity was the main forcing for Siberian crane population variations in Poyang Lake. Although the SSM suggested that water levels in both high‐ and low‐water seasons were important factors for Siberian crane population, inference on their effects were elusive because of large confidence intervals of the estimated coefficients. Using GAM, we confirmed the non‐linear effects of water level on population growth rate. Based on the modelled response curves, we proposed the optimal water level for Siberian crane conservation: (a) maximum summer water season level should be less than 19.5 m and (b) minimum winter water level should be between 8.7–10.2 m. Our methods of integrating population dynamic model and GAM have wide relevance for regional biological conversation efforts that seek to maintain a resilient population of threatened species. Copyright © 2014 John Wiley & Sons, Ltd.     

Identifying Prominent Explanatory Variables for Water Demand Prediction Using Artificial Neural Networks: A Case Study of Bangkok

The water demand of a city is a complex and non linear function of climatic, socioeconomic, institutional and management variables. Identifying the prominent variables among these is essential in order to adequately predict water demand, and to plan and manage water resources and the supply systems. Further, the need for such identification becomes more pronounced when data constraints arise. The objective of this study was to establish, using correlation and sensitivity analyses, a minimum set of variables required to predict water demand with significant accuracy. Artificial Neural Networks (ANN) models were developed to predict short-term (daily) and medium-term (monthly) demands for Bangkok. Using meteorological and water utility variables for short-term prediction, and different ANN architecture, 16 sets of models with a 1-, 2- and 3-day lead period were developed. Although the best fit models for the three lead periods used different input variables, prediction accuracies over 98% were achieved by using only the historic daily demand (HDD) as the explanatory variable. Similarly, for medium-term prediction, 11 sets of models with lead periods of 1-, 2- and 6-months were developed, using meteorological, water utility and socioeconomic variables. The best fit models for the three lead periods used all explanatory variables but prediction accuracies of more than 98% were obtained by downsizing the variable set. The meteorological variables have a greater influence on medium-term prediction as compared to short-term prediction, suggesting that future water demand in Bangkok could be significantly affected by climate change.