Hybrid Leakage Management for Water Network Using PSF Algorithm and Soft Computing Techniques

Reduction of leakages in water distribution system (WDS) is one of the major concerns for water industries. This paper presents a hybrid leakage reduction model using pressure management technique, performed by optimizing water storage level in the tank, along with optimized control and localization of pressure reducing valve (PRV) in water distribution system. Pattern Sequence-based Forecasting (PSF) algorithm is used for prediction of flow rate (demand) from the tank for next 48 h, to calibrate the future desire water storage level in the tank. A mathematical tank and pump simulation algorithm is proposed for optimization of water storage level in the tank. A modified reference pressure algorithm is proposed for efficient localization of pressure reducing valve. Multiobjective genetic algorithm (NSGA-II) is used for finding out the optimized operational control setting of the pressure reducing valve for leakage minimization. The proposed algorithm leads to better leakage reduction of 20.81% in modified benchmark WDS, with a reduced number of the pressure reducing valves. Constraints such as maintaining lower hydraulic failure index (<0.01), emergency water storage, etc. is also considered. It can be concluded that the proposed hybrid leakage reduction technique provides efficient as well as cost-effective solution for leakage control.     

Development of Multiple Leakage Detection Method for a Reservoir Pipeline Valve System

The detection of multiple leakages in pipeline systems has been one of the challenging issues for the control of water loss in water distribution systems. Inverse transient analysis can be a useful principle for predicting leakage through the calibration of location and leakage quantity, based on the pressure reflection that originates from an abnormal boundary condition. In this study, an innovative leakage detection method is proposed to address unknown conditions on multiple leakage dimensions through introduction of revised leakage expressions based on a frequency domain approximation. A multiple leakage function was modified for an efficient representation of multiple abnormalities at a reservoir pipeline valve system. An iterative metaheuristic scheme (IMS) was designed to handle an optimization scheme for multiple leakages using a pressure response for a discharge impulse introduced through value manipulation. In order to address unsteady friction in hydraulic transients combined with multiple leakages, both one-dimensional and two-dimensional models were used to derive leakage expressions for turbulent and laminar flow conditions. An isolated multiple leakage function (IMLF) was proposed to exclusively encapsulate the impact of leakages and unsteady fiction. Considering uncertainties in the hydraulic transient propagation, data noise, and multiple local optima issues in large parameter calibrations, three advanced schemes were modularized to improve detectability of IMS. Several hypothetical examples were presented to show the potential of IMS, validity of three advanced schemes, and robustness in multiple leakage prediction compared to existing approaches.     

Pressure Zoning Approach for Leak Detection in Water Distribution Systems Based on a Multi Objective Ant Colony Optimization

Leakages result in considerable loss of water in water pipe networks. Therefore it is an important issue to detect leakage amount and its approximate location. Leakages in water distribution system are directly related to the operating pressure. In the current study, a new model is proposed for leakage amount and location detection and it is applied into two benchmark water distribution networks. In the proposed method, the water distribution networks are divided into three pressure zones in order to consider the leakage differences in different operating pressures. Then, nodal pressures and demands are calibrated using a new multi objective ant colony based optimization model. In this method, leaks are simulated as extra nodal demands. For determining the nodes where leakage happens, a probability based scheme is used. The leakage occurrence probability varies depending on the pressure zone that each node is located. The results illustrate the applicability of the proposed model for detecting the leakages in water distribution systems.     

Leakage Identification in Water Distribution Networks with Error Tolerance Capability

Leakages in water distribution networks have caused considerable waste of water resources. Thus, this study proposes a novel method for hydraulically monitoring and identifying regions where leakages occur in near-real time. A large network is first divided into several identification regions. To exploit a strong constructive and discriminative power, sparse coding is used, thereby adaptively coding the information embedded in observed pressures efficiently and succinctly. And a linear classifier is trained to determine the most likely leakage regions. A benchmark case is presented in this study to demonstrate the effectiveness of the proposed method. Results indicate that the proposed method can identify leakage events with enhanced tolerance capability for measurement errors. The method is also partially effective for identifying two simultaneous leakages. Certain practical advice in balancing the number of sensors and regions is also discussed to enhance the application potential of this method.

     

Multi-criteria Decision Making for Integrated Urban Water Management

The city of Zahedan, in South-eastern Iran, has high population growth, limited local freshwater resources and inadequate water distribution system resulting in water supply failures in recent years. This paper will investigate integration of several demand management measures such as leakage detection on water distribution network, water metering and low volume water fixtures as well as the conjunctive use of surface and groundwater resources of this city. For integration of water management criteria, compromise programming will be used as a multi-objective decision making method. The criteria include minimizing the cost, maximizing water supply and minimizing the social hazards due to the water supply operations. This model will derive optimum long-term plans for implementation of water resources. The results will show that demand management can delay a water transfer project for Zahedan city up to 10 years. Compromise programming is as an efficient tool for integrated water resources management in urban areas and the method is capable to being used by decision-makers in other cases.     

Groundwater Rise Problem and Risk Evaluation in Major Cities of Arid Lands – Jedddah Case in Kingdom of Saudi Arabia

Arid lands are in the need of additional water supply but water transportation from outside of the natural hydrological cycle causes the groundwater to rise within the urban areas. Additional water supply from surrounding areas or through the desalination plants provides comfort in domestic activities but after the usage, its disposition is necessary in an efficient manner. Unfortunately, arid region cities have neither sufficient nor efficient sewage system. Consequently, the water returned to surface cesspools and leakages from insufficient sewage system makes internal groundwater recharge within the urban area. Additionally, water supply system leakages further raise the groundwater level. Deterioration in water quality becomes a potential danger for the infrastructure and foundations. Surface depressions in the city may be flooded due to groundwater level rise and at times bed smells occur at various parts of the city. In this paper, a quantitative method is followed to assess groundwater level rise risks in addition to the few chemical risks associated with sulfate and chloride solids. It is observed that each one of these variables has different probability distribution function and expose risk maps with different features.     

Managing Adaptation of Urban Water Systems in a Changing Climate

Current evidence is that climate change is occurring, it is largely manmade and it will have significant implications for human civilisation. Australia is particularly vulnerable to the anticipated effects of climate change, creating major challenges for water resource management and water supply security. Climate change adaptation offers a means by which we can reduce our exposure to future climate change risks, whilst at the same time exploiting any potential benefits that may arise from climatic changes. This review outlines the current major climate change adaptation challenges facing the water supply industry at large, with a particular focus on these challenges in an Australian context. It also aims to highlight the critical knowledge gaps and strategies required to assist in the formulation of adaptation responses to the range of potential impacts on water infrastructure and future water security. A diverse range of management and assessment techniques are used by relevant professions in industry. Here, an adaptive management approach is presented highlighting the important information required for robust assessment.     

调水工程水力控制综述

调水工程水力控制是一门新的交叉性学科,是一门研究采用工程措施和运行方法对系统内水流的运动实施控制的学科。本文介绍了该学科的理论体系、主要研究内容。论述了相关理论的国内外研究现状、进展,存在的问题,包括管道水击、明渠非恒定流、冰水力学、系统故障和泄漏检测技术、以及大系统的优化设计和运行最优化、地理信息系统、现代计算机数字三维仿真等。介绍了调水工程水力控制形成发展的历史,提出了几个值得关注的发展新方向和建议。     

Pressure Management Model for Urban Water Distribution Networks

A technique for leakage reduction is pressure management, which considers the direct relationship between leakage and pressure. To control the hydraulic pressure in a water distribution system, water levels in the storage tanks should be maintained as much as the variations in the water demand allows. The problem is bounded by minimum and maximum allowable pressure at the demand nodes. In this study, a Genetic Algorithm (GA) based optimization model is used to develop the optimal hourly water level variations in a storage tank in different seasons in order to minimize the leakage level. Resiliency and failure indices of the system have been considered as constraints in the optimization model to achieve the minimum required performance. In the proposed model, the results of a water distribution simulation model are used to train an Artificial Neural Network (ANN) model. Outputs of the ANN model as a hydraulic pressure function is then linked to a GA based optimization model to simulate hydraulic pressure and leakage at each node of the water distribution network based on the water level in the storage tank, water consumption and elevation of each node. The proposed model is applied for pressure management of a major pressure zone with an integrated storage facility in the northwest part of Tehran Metropolitan area. The results show that network leakage can be reduced more than 30% during a year when tank water level is optimized by the proposed model.     

Managing Water Resources Under Conditions of Scarcity: On Consumers’ Willingness to Pay for Improving Water Supply Infrastructure

Conservation and efficient management of water resources is an essential ingredient for achieving sustainable development. River basins in Southern Europe are suffering from high water stress, while leakages in some areas far surpass recommended levels. This study uses the contingent valuation method in order to assess willingness to pay (WTP) by consumers in the Guadalquivir River basin in Spain for improving urban water supply infrastructure and reducing leakages. On average, individuals would be willing to pay an extra charge on their water bill ranging from €8.23 to €9.65. In addition to the expected positive effect of income on WTP, respondents with negative perceptions of their drinking water quality as well as those most affected by the economic crisis have a lower WTP. Conversely, WTP is higher for men and respondents showing greater commitment to the environment. These results provide policymakers with information that might help them to improve water-pricing policies in a context of severe water scarcity, especially considering the principle of cost recovery introduced by the EU Water Framework Directive in pricing water services.     

Introducing a Novel Flexible Conjunction System to Pressure Control in Water Distribution Networks

Pressure management is one of the most significant water demand management methods to reduce leakage in water distribution networks. Leak as an adverse event is directly related to the pressure. Therefore, reducing extra network pressure decreases leakage in water distribution networks. The pressure reducing valves have some disadvantage. For example, they break down quickly. Therefore, in this study, a novel system named Pressure Reducing Flexible Storage (PRFS) was introduced that hasn’t these disadvantages and it could consider a good alternative for pressure reducing valves in water distribution networks. In this system, a spherical tank containing a flexible rubber cover was installed at the network node. By increasing the pressure in the conjunction, the foam was compressed and reduced the pressure. In this study, the presented system was simultaneously modeled by using Flow-3D and ABAQUS softwares, and pressure decrement was estimated in the conjunction. The results show that the proposed system can decrease the pressure in the conjunctions of water distribution network by about 18%. Therefore, it could be considered as a good alternative for pressure reducing valves in water distribution networks.     

基于输水损失动态变化特性的渠系优化配水模型研究

渠系优化配水是灌区减少渠道渗漏损失、提高渠系水利用效率的重要节水管理措施,但当前渠系优化配水模型的渗漏损失计算方法难以真实反映渠床土壤透水性随时间动态变化的特征,导致人为的配水偏多或者偏少.鉴于此,本文探索性引入渠床土壤前期影响含水量的概念来描述渠床土壤湿润程度在渠道输配水过程中的动态变化,提出了一种新的渠道输水渗漏损...     

土工膜和GCL防渗结构缺陷渗漏量试验研究

为评估土工膜和GCL防渗结构的缺陷渗漏量,给防渗结构设计提供有益参考,本文依据施工、特殊部位和偶然条件等对缺陷的影响程度,开展了土工膜防渗层和土工膜+GCL防渗结构在不同缺陷条件、不同GCL水化条件和不同水头条件下的室内渗漏试验,并对比分析了两种防渗结构的渗漏量及其影响规律.结果 表明,土工膜+GCL防渗结构不仅可以降...     

Groundwater management and development by integrated remote sensing and geographic information systems: prospects and constraints

Groundwater is one of the most valuable natural resources, which supports human health, economic development and ecological diversity. Overexploitation and unabated pollution of this vital resource is threatening our ecosystems and even the life of future generations. With the advent of powerful personal computers and the advances in space technology, efficient techniques for land and water management have evolved of which RS (remote sensing) and GIS (geographic information system) are of great significance. These techniques have fundamentally changed our thoughts and ways to manage natural resources in general and water resources in particular. The main intent of the present paper is to highlight RS and GIS technologies and to present a comprehensive review on their applications to groundwater hydrology. A detailed survey of literature revealed six major areas of RS and GIS applications in groundwater hydrology: (i) exploration and assessment of groundwater resources, (ii) selection of artificial recharge sites, (iii) GIS-based subsurface flow and pollution modeling, (iv) groundwater-pollution hazard assessment and protection planning, (v) estimation of natural recharge distribution, and (vi) hydrogeologic data analysis and process monitoring. Although the use of these techniques in groundwater studies has rapidly increased since early nineties, the success rate is very limited and most applications are still in their infancy. Based on this review, salient areas in need of further research and development are discussed, together with the constraints for RS and GIS applications in developing nations. More and more RS- and GIS-based groundwater studies are recommended to be carried out in conjunction with field investigations to effectively exploit the expanding potential of RS and GIS technologies, which will perfect and standardize current applications as well as evolve new approaches and applications. It is concluded that both the RS and GIS technologies have great potential to revolutionize the monitoring and management of vital groundwater resources in the future, though some challenges are daunting before hydrogeologists/hydrologists.     

A Compromise Programming Model to Integrated Urban Water Management

Integrated urban water management is an important and critical matter in every city and country. Many objectives and criteria such as satisfaction of the urban water consumers, the national benefits and social hazards must be considered in the integrated urban water management. So the integrated urban water management can be considered as a multi-objective problem. In this paper, a mathematical model which uses the compromise programming model is presented to optimize this multi-objective problem. Three famous objectives involving water distribution cost, leakage water and social satisfaction level are considered. To evaluate the performance and efficiency of the proposed model, Hamedan potable water network is chosen as a case study. Results show that the proposed model is capable to present effective solutions for the considered problem. So the proposed mathematical model can be used as an efficient tool for the integrated urban water management in every urban area.     

Diagnosis of Pipe Systems by means of a Stochastic Successive Linear Estimator

Environmental concerns and legislation of the water industry have recently drawn the attention of many researchers to the management, calibration and power cost reduction of water pipeline systems. Effective water system management rests upon the knowledge of the current state of a water pipeline system. For example, leakages, unknown status of in-line valves, and partial blockages are often a source of management costs. These anomalies must be detected and corrected as early as possible. In this paper a diagnosis tool is presented able to detect leaks, partially closed in-line valves and partial blockages by means of transient head measurements. The algorithm introduced is a Stochastic successive Linear Estimator [SLE] (Yeh et al. Water Resour Res 32: 2757–2766, 1996a) which provides statistically best unbiased estimate of these anomalies and quantifies the uncertainty associated with these estimates via assimilation of available information. Therefore, the information from common diagnosis techniques e.g., inspection methods, and head measurements available at different locations of the system, obtained by different transient tests are fused to provide the most accurate and reliable diagnosis.     

基于县级河长制的内陆地区饮用水源地管理体系构建

我国欠发达地区面临着饮用水源地管理模式落后、管护效率较低的困境。本文以新疆皮山县为例,在梳理该县饮用水源地概况、水源地管理存在的问题、河长制推行情况及遇到挑战的基础上,构建了基于县级河长制的集中式饮用水源地管理体系。其核心是整合相关部门事权,设立专职的饮用水源地管理机构,并将其纳入河长制联席会议,对其实施日常授权和临时授权的清单化权限管理,充分开发利用河长制信息平台,以实现饮用水源地高效管理的常态化。     

确保粮食安全和环境可持续发展的水土资源利用

主要讨论灌溉农业所面临的挑战.随着人均可用水量的不断下降,灌溉农业必须提高水资源利用效率,同时进一步采用有利于环境的经营和管理方式.灌溉界面临的压力是如何通过提高作物产量和用水效率来实现生产率的最大化.今后的发展方向是以更加高效率、有成效的方式利用水资源,而实现从"提高每滴水的粮食产量"向"少用水,多产粮"的转变,则有助于该目标的实现.为了尽可能减小外在因素的影响,将来的努力方向是在全面性和整体性上下工夫.     

管道系统漏损控制技术进展

为了提高供水效率和运行管理水平,针对国内外关于供水管道系统漏损控制方面的现状,从管网故障监测技术及设备、泄漏定位模型方法、信号辨识与算法寻优、健康维护和智能管理等视角梳理了管道系统泄漏监测与漏损控制技术的进展及存在的主要问题,分析了各检测方法用于管网泄漏问题的适用性。在此基础上,从实用角度提出了管网漏损控制值得解决的关键问题和方向如下:(1)针对漏损的监测和预警,应研究面向漏损监控的管网网络组建优化布置及快速预警技术;(2)针对小泄漏的定位模型,应研究管网漏损区域辨识与基于水力反问题分析的主动检测理论和方法;(3)针对检测设备研制,应重点研发基于探地雷达、光纤传感和内窥机器人等新技术的关键设备;(4)针对管网健康维护和智能管理,应研究复杂管网独立计量区域划分方法及管网健康评价和优化维护技术。     

Policy options for promoting urban–rural cooperation in water management: a review

As most cities share their water basins with rural areas, an efficient and environmentally sensible urban water management system needs to consider the interplay between urban and rural water uses. This article analyses the three main challenges at this interface: increased competition for water resources (scarcity); flood management (abundance); and freshwater quality conservation (pollution). The merit of potential policy options is discussed from an economics perspective, taking examples from successful experiences in cities around the world. The benefits and challenges arising from enhanced coordination and integration between urban and rural water management are highlighted.