Impacts of supply duration on the design and performance of intermittent water distribution systems in the West Bank

This paper analyzes the intermittent water distribution system in the West Bank, Palestine. It quantifies the impacts of reduced supply duration on the hydraulics and costs of water distribution. It shows that designing systems based on intermittent supply criteria implies increasing the diameters of pipes significantly, which is expensive and infeasible. The paper recommends that studying the local conditions should precede the design of new systems to avoid reduced supply duration and related negative impacts. In addition, improving governance, revising tariffs, reducing leakage, saving water, involving the private sector, and improving water diplomacy should be considered in any water policy reform.     

Statutory Regulation of Water Quality in Modern Australia

Abstract

At the beginning of the 21st century, there has been recent development, in human historical terms, of substances that can cause serious harm to human health, and also development of remarkable new analytical technologies capable of detecting substances at the atomic level. Despite this, Australia, though an advanced country, has not implemented any mandatory water quality standards or developed a program similar to well established U.S. or European programs. Presented in this paper is an analysis of the statutory regulatory methods for domestic water in mainland Australia. First, the paper briefly reviews the need for mandatory regulations as opposed to voluntary guidelines. Second, the development of guidelines for drinking water by the National Health and Medical Research Council is reviewed, followed by the legislative requirements in each of the five mainland States of Australia. Drinking water guidelines have been used to assist planning and management and were not construed to be legally enforceable mandatory standards. Health Acts in each State remain the primary statutory defenders of water quality, and the variability between Acts is considerable. Third, other legislation that states the necessity of a high quality of water but does not guarantee its deliverance for all uses is referenced as miscellaneous provisions supporting the need for a comprehensive risk reduction water quality program. The main organizations that supply water in Australia are listed along with the nature of their obligations to supply a quality product. Each State has specific water sanctions that attempt to safeguard water quality, but the legal rights of customers have not advanced substantially. The major administrative scheme in Australia that can enforce quality is licensing, and is this limited to the urban regions of Victoria, New South Wales, and Western Australia.     

Influence of Intermittent and Continuous Modes of Water Supply on Domestic Water Consumption

In developing countries, water distribution systems are designed for continuous water supply (CWS) with peak factor between 2.0 and 3.0. While in practice, water is supplied for restricted hours in the morning and evening hours for various reasons. One of the assumption is that under intermittent water supply (IWS), water consumption in residential areas is less compared to CWS. A study was conducted in four Indian cities to evaluate influence of IWS and CWS on domestic water consumption. The selected water distribution system (WDS) represents specific situation in each city. Water consumption data was repeatedly collected through water meter readings in all the cities. The same WDS was switched over to CWS for few months with prior information to the residents. Water consumption was again measured under CWS mode of operation. Statistical analysis of water consumption was done for all the four cities under both modes of operation. The study indicates that domestic water consumption depends on adequacy of water supply, under IWS mode of operation. Water consumption do not change appreciably under CWS, if consumers water demand is satisfied under IWS.     

Contradictions and Challenges in China's Water Policy Development

Abstract

External assessment of China's water problems, and recommendations for policy solutions, often fail to recognize interrelated physical, institutional, historical-cultural, and ideologically-grounded contradictions in the water sphere, distinctive to China, that challenge Chinese policy makers in unique ways. As new market-based approaches to flood and drought prevention and control, water quality maintenance, adequate water supply, and ecological support are being discussed and implemented, problems of overcoming deep-seated contradictions in the water economy compel searching review of policy assumptions and strategies which force reconsideration and modification of longstanding strategies and procedures for managing water resources. This paper considers the implications of water policy contradictions and challenges in four key areas: (1) coordination of economic measures and legal constraints associated with a 1988 Water Law; (2) a major 1999 policy shift from emphasis on strutural engineering solutions in shuili (water management) enterprise to a broader resource-defined concept of “resource” water management (ziyuanshuili) in support of water sustainability; (3) continuing reference to traditional historical/cultural and Marxist theoretical perspectives despite increasing adoption of Western market-based instruments in water policy development; and (4) problems of modifying and adapting indigenous water science and engineering in the process of building a new water economy. The paper concludes that bilateral and multilateral efforts to ameliorate China's water problems may be successful in achieving limited technical objectives in the several water sectors but face difficulties in contributing to China's long-term water sustainability and hazard mitigation because they are insensitive to internal contradictions that are being addressed with ever greater intensity and urgency in the quest for solutions.     

What is Public Participation in Water Resources Management and Why is it Important?

Abstract:

Australia has undergone comprehensive water policy reforms since the mid‐1990s. These reforms have imposed considerable uncertainties with respect to future supply and passed the risk management burden from water authorities to irrigators. There is, therefore, an increased need for risk management tools to assist irrigators in managing this increased uncertainty. Water markets are seen as important tools for managing this uncertainty and in assisting irrigation communities in the necessary adjustment process. Australia, therefore, provides an excellent case study in the extent to which irrigators have used markets as a risk management tool. It is concluded that allocation markets have been used by irrigators to manage uncertainty and risk within and between seasons while entitlement markets have been used to adjust irrigators’ risk position in the long term, resulting in subsequent use of the allocation market to manage this new risk position. However, there is clear evidence that the substantial uncertainty with respect to future supply has made irrigators reluctant to use the entitlement market and has therefore seen them rely heavily on the allocation market to manage their existing risk position. Also, existing water trading arrangements are impeding new investments in high value, efficient production systems. To address these two issues and to remove these impediments a new National Water Initiative is presently being implemented.     

Hydrology and Hydraulics in Planning and Operation of Water Resources Systems

ABSTRACT

A number of water supply schemes in developing countries have been observed to fail to yield water at the design capacity rates well before the elapse of the design period. Such failures frustrate the efforts of a nation in its water supply development programmes.

In this paper the causes of failures o f some typical components o f a water supply scheme have been discussed citing case studies from Tanzania in East Africa. It is observed that the elements o f design and maintenance are largely responsible for the failures o f water supply schemes.

Rehabilitation of failing water supply schemes in developing countries can substantially increase the number of people served with safe and adequate water supply. Clear national policies and adequate budgetary provision are required for successful implementation of water supply projects.     

Water Planning in Jordan

Abstract

This paper present a shift in water planning in Jordan from supply-side water management to more integrated and demand-driven water management. Assessment of existing water supply and demand is presented and strategies are outlined. Potential available water resources and uses are presented. Strategies to meet unsatisfied water demand are presented. These include use of nonconventional water resources, privatization, efficiency enhancement in distribution systems, and demand management. Scenarios for sustainable water management are developed. Each scenario was based on combinations of the role of government in the water sector and the national financial situation. Comparisons among these scenarios were performed for the case of Jordan and a set of recommendations are stated.     

Statistical Domestic Water Demand Model for the West Bank

Abstract

The water balance in the West Bank shows a severe deficit. Scenarios and strategies are formulated in order to overcome the deficit problem. These include options for better management of the existing water resources and the enhancement of new resources. This paper focuses on demand modeling as one of the key issues for effective water management. Although past literature about demand modeling is comparatively rich for different regions in the world, this research provides a unique study, due to the past political situation in the Middle East, for water demand modeling in the West Bank. The developed statistical domestic water demand model will assess the factors which influence domestic water use, and determine the parameters that may help in demand management. Rammallah City is used as a case study to illustrate the proposed framework of the analysis. The developed model indicates that water utility authorities can use price as a tool to ration water or encourage reduced water consumption in households.     

井库流量补偿式配水系统及其配水方式研究

分析城市多水源供水工程中配水系统不同组成方式存在的不足,通过改进“供水水库＋调节水 库”联合供水方式,创新地提出了一种井库流量补偿式配水系统。配水系统在调节水库库岸增设配水 井,上游供水水库输水管道接入配水井后再向下游水厂供水,配水井设连通闸与调节水库连通,配水井 与调节水库之间供水流量可相互补偿,在常规的供水水库单独供水、调节水库单独供水、供水水库和调 节水库联合供水配水方式基础上,还具有供水水库向调节水库和下游水厂同时供水的功能。配水井是 井库流量补偿调节的中枢,配水井的布置以及体型对系统调节的稳定性及效率影响巨大,结合千岛湖配 水工程水工模型试验成果,提出了一种岸坝组合碗式配水井结构。     

Women and Modern Domestic Water Supply Systems: Need for a Holistic Perspective

As domestic water managers, the strategic need of women has been identified as having access to domestic water sources that are convenient, reliable and located close to home. The need has been addressed through installation of low cost improved water supply systems in different parts of the developing world. While the need of women as domestic water managers has been globally articulated and addressed, perhaps adequate attention has not been drawn to the fact that this role is actually performed within the context of local communities where domestic water management activities are built upon the users' perceived needs to be fulfilled through culturally appropriate means. How do cultural intricacies in local communities influence the water fetching behaviour of women? What is the impact of such factors on the adoption and utilization of modern domestic water supply systems? The paper explores the implications of local cultural realities for the effectiveness of handpump as a modern domestic water supply systemarguing that the locally perceived water needs of women are holistic and fail to be adequately addressed through the new source. Consequently, it has been admitted only as an `add on' source, thereby hindering achievement of the basic objective of bringing women greater comfort, better health and socio-economic empowerment.

     

Validation and Examination of Existing Water Distribution Network for Continuous Supply of Water Using EPANET

Dire Dawa, the second largest city of Ethiopia, was facing about the distribution system adopted for supplying clean water. It was being observed that an intermittent type of supply with main and secondary distribution pipes. It was observed that, the current water demand has surpassed the present existing supply about 65%. Hence, in order to provide sufficient quantity and good potable water with continuous (24 X 7) water supply for various sectors of study area: Sabiyan region, Dire Dawa, Ethiopia, was selected. Also, Dire Dawa Water Supply & Sewerage Authority has taken a strong decision in order to validate and examine the existing water distribution network for improved water supply. On the other hand, the main important factor which effects the validation is that the age of pipes and other accessories in present existing network were longstanding. Therefore, to avoid the leakage losses and various problems encountered with the present system, a detailed is study is conducted and the analysis is carried out using EPANET tool to design for continuous water supply. After thorough analysis by considering future concerns, it was suggested that, two GLSRs of each with 2.7 Mm³ capacity may be provided in order to meet the future demands. The tanks are provided at required elevation to ensure that the water flows in all pipes of the network efficiently. Based on the output it was observed that the diameter of pipes from the existing system ought to be revised. Additionally, other parameters which effect the network like frictional losses, velocity of flow in the pipes, residual head and pressure at nodes were also examined thoroughly by the use of different tools like WaterGEMS and Auto CAD in addition to EPANET.     

Design Methodology of Free Water Surface Constructed Wetlands

Simple criteria, guidelines and models are established for free water surface (FWS) constructed wetland selection and preliminary sizing. The analysis employs models for FWS constructed wetland design, considering simultaneously the removal requirements and the hydraulics of the system. On the basis of these models, a step-by-step methodology is developed outlining the design procedure for new and performance evaluation for existing FWS constructed wetland systems. This methodology is combined with simple equations predicting the maximum wetland capacity in summer, so as to assist designers in sizing installations in tourist areas with increased summer populations. Furthermore, this methodology is further simplified, based on sensitivity analysis of the unit area requirements for wastewaters of various strengths, and various design conditions and performance criteria. In addition, comparison of the unit area requirements of FWS constructed wetland systems, subsurface flow (SF) constructed wetland systems and stabilization pond systems for wastewaters of various strengths and design conditions, provides designers with general guidelines concerning the preliminary selection between alternative natural treatment systems in areas where the use of natural systems is favored because of their low-cost, simple operation and high removal performance.     

A Simplified Methodology for Optimal Location and Setting of Valves to Improve Equity in Intermittent Water Distribution Systems

In this paper, a simplified methodology to increase the water distribution equity in existing intermittent water distribution systems (WDSs) is presented. The methodology assumes to install valves in the water distribution network with the objective to re-arrange the flow circulation, thus allowing an improved water distribution among the network users. Valve installation in the WDS is based on the use of algorithms of sequential addition (SA). Two optimization schemes based on SA were developed and tested. The first one allows identifying locations of gate valves in order to maximize the global distribution equity of the network, irrespectively of the local impact of the valves on the supply level of the single nodes. Conversely, the second scheme aims to maximize the global equity of the network by optimizing both location and setting (opening degree) of control valves, to include the impact of the new flow circulation on the supply level of each node. The two optimization schemes were applied to a case study network subject to water shortage conditions. The software EPA Storm Water Management Model (SWMM) was used for the simulations in the wake of previous successful applications for the analysis of intermittent water distribution systems. Results of the application of the SA algorithms were also compared with those from the literature and obtained by the use of the multi-objective Non-Dominated Sorted Genetic Algorithm II (NSGA II). The results show the high performance of SA algorithms in identifying optimal position and settings of the valves in the WDS. The comparison pointed out that SA algorithms are able to perform similarly to NSGA II and, at the same time, to reduce significantly the computational effort associated to the optimization process.

     

Appraisal and Assessment of World Water Resources

Abstract

A critical analysis of the present situation on the global water resources assessment is made. Basic data and methodological approaches used by the author for the assessment and prediction of water resources, water use and water availability on the global scale are briefly described. On the basis of data generalization of the world hydrological network new data are given on the dynamics of renewable water resources of the continents, physiographic and economic regions, selected countries as well as on the river water inflow to the world ocean. The results of the assessments for the 20^th century and for the future before 2010–2025 on the water supply for municipal, industrial and agricultural needs as well as an additional evaporation from reservoirs are presented. Loads on water resources and water availability depending on socio-economic and phisiographic factors are analyzed; regions of water scarcity and water resources deficit are discovered. Possible ways of water supply improvement and elimination of water resources deficit in different regions and countries are discussed     

A Large Scale Study of Drinking Water Requirements in the Po Basin (Italy)

Abstract

A newprocess that consists of showing the dependence of drinking water consumption on the economic, productive, and physical characteristics of municipalities was proposed. Statistical procedures were used in a survey of the territorial distribution of drinking water consumption in the Po Valley (Italy) carried out using the results of the 1987 National census and Ministry of Public Works investigations. The factor analysis proved to be particularly useful, allowing the expression of two components describing the water supply of the municipalities included in the survey, respectively defined as water availability and anthropic activity. The former is explained through variables such as precipitation, air temperature, and the geographical location of the municipality, according to specific climatic peculiarities. The latter is adequately represented by the type ofprevalent activity of the population (i.e., rural or urban), the level of urbanisation of the municipalities, and then the level of public services itprovides and the overall municipal income. The methodology described could prove useful in planning and managing the resources allocated for drinking purposes. Adjustment coefficients for the average per capita consumption of each demographic class are then calculated using suitable multiple regression models based on results of the factor analysis. An estimation of the water losses in the supply systems of some Italian towns is also presented.     

Issues and Implications of Carbon-Abatement Discounting and Pricing for Drinking Water System Design in Canada

Water utilities generate greenhouse gas (GHG) emissions when they construct, retrofit, and operate their water distribution systems. The prospect of introducing carbon-abatement strategies such as carbon pricing and using low discount rates for project planning could potentially change the manner in which water utilities plan and design their drinking water systems. The objectives of this paper are to: (i) Review the current issues and controversies surrounding the choice of discounting rate and carbon prices in Canada to reduce the GHG emissions linked to operating water systems in Canada; (ii) Review previous research that has examined the impact of discounting and carbon pricing on design decisions in water supply and distribution systems, and; (iii) Illustrate the possible implications of carbon-abatement strategies (discounting and carbon pricing) on the design of Canadian water systems by way of a real-world case study. The implications of discount rate and carbon price uncertainty on water distribution system design are illustrated with the Amherstview-Odessa water transmission system in Ontario, Canada. The results of the Amherstview study indicated that lowering discount rate led to significant increases in electricity costs. The study results also suggested that for a sufficiently low discount rate of 1.4%, increasing carbon price led to a larger pipe size and pipe cost to offset carbon costs levied on fossil-fuel based electricity to operated the pumps for the life of the system. Additional studies are needed on large-scale water systems to inform decisions on system upgrades taken by water utility managers.     

Building New Water Resources Projects or Managing Existing Systems?

Abstract

The planning of regional water resources systems and their subsequent management has to rest firmly on three foundations: availability of water of adequate quality, demand for water expressed quantitatively for specific periods of time, and direct, indirect, and externality costs. Mathematical models of hydrosystems represent only a segment of the real world. The basic science of hydrology is an empirical discipline, and its basic law is the continuity equation. Optimization of operating rules based on this law of conservation of matter may face difficulties when the objective function is expressed in economic terms. Overcoming this obstacle requires the use of targets (for water releases and stored volumes) expressible in physical units. The optimization objective can then be expressed as the sum of the squares of the differences between the results of the analysis and the targets. An additional complexity is created by parties who are interested in regional hydrosystems for purposes other than the traditional water supply and flood control. They may require certain elevations of water levels in streams and reservoirs for wildlife or recreational purposes or minimal flows needed for fishing and fisheries. All these complexities lead to an expansion of regional water resources models so as to enable the manager to investigate factors and decision alternatives not included in the model. A regional water resources system is relevant only in so far as it advances the solution of socio-economic and political issues and promotes development rather than growth. Management of existing systems should take precedence over building new water resources projects     

Water and Sustainable Development in Ghana

Abstract

Water is vital for the survival and development of every community or society. The health of a given community is reflected to a large extent in the water quality of the community's available water resources. In Ghana, efforts have been made since colonial days to supply both the urban and the rural communities with potable water to enhance the rapid socio-economic development of the country. It is economically viable due to the remoteness of most of the rural communities to supply them with potable water from local sources such as groundwater. The urban water supply systems are mainly based on surface water sources. With the ever-expanding population, there is a need to improve freshwater resources conservation and management in order to avoid impending shortages. To ensure the total coverage of all rural and urban communities by the year 2020, a huge capital outlay of $1 billion and 51.5 billion, respectively, is needed. Most of these funds are expected to come from the private sector, both local and foreign, with the Government making some substantial contribution.     

青海省水中长期供需平衡模型建立与应用

依据水资源系统分析原理,建立了一个多层次、多水源、多用户的水资源长系列供需平衡动态调算模型。模型主要由数据管理、供需平衡计算、规划调整、结果统计分析四部分组成。模型主要控制方程包括水量平衡方程、行业水供需平衡方程、边界条件类方程、初始条件以及特殊类方程。模型的调度规则包括了供水调度规则和用水调度规则。与传统供需分析模型相比,该模型具有针对缺水区域进行新增工程能力布设的规划能力。该模型应用于青海省水中长期供求规划中。应用结果表明,该模型实现了青海省水资源供需平衡分析中可供水量、供水保证率、水资源开发程度、供水能力、余缺水量以及新增工程能力规划等一系列指标的计算,为水资源管理部门提供了一个科学的、有效的决策工具。     

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.