The water supply is fine: decision‐maker perceptions of water quantity and supply‐side management

Years of research have called for more science to be integrated into water management decisions and for a shift from supply‐side to demand‐side management; yet, there remains a strong emphasis on supply‐side approaches and in many areas limited attention to hydrological data. A survey and interviews with decision‐makers in western North Carolina reveal that there is only low‐level concern about water quantity, and this drives a continued emphasis on supply‐side management and no perceived need for hydrological data. The historical realities of low demand and abundant water have generated a perception of ‘water supply’ as disconnected from physical, hydrological systems and allowed for ad hoc decision‐making processes to prevail. The lack of well‐established processes may, ironically, provide significant opportunities for employing collaboration among researchers and decision‐makers to develop policies and processes that integrate data into making water management decisions and thus prompt increased attention to water demand.     

Water resources management in the Jordan River Basin

The Jordan River Basin is under great hydric stress. Increases in population and agricultural demand are contributing to the closure of the basin. This paper analyses the results of integrated water resources planning model (WEAP) by studying the vulnerability of water resources in the lower Jordan River under a changing climate pattern and growing water demands. Water balance models show that all aquifers supplying the city of Amman will be depleted within the next few decades. Mitigation measures should include the introduction of additional water into the basin through the Red Sea–Dead Sea canal, in addition to demand management measures such as water conservation and increase in irrigation efficiency. The findings of this study would provide a useful guide to the co‐riparians for policy formulation, decision making and dispute resolution. Cooperation among the five riparian countries may be improved by building a Geographic Information System (GIS) database that provides access to accurate data for hydrological analysis.     

THE WATER EFFICIENCY OF RETROFIT DUAL-FLUSH TOILETS: EXPERIENCE FROM SOUTHERN ENGLAND

In Water Resources Plan submissions to the Environment Agency in 1999, water companies predicted increases in demand over the next twenty-five years. With significant environmental and economic constraints on new resource developments, attention has focused upon the potential savings that water-efficiency measures can achieve.
The use of water for toilet flushing accounts for about 30% of household consumption, thereby offering considerable potential for water saving. The conversion of existing single-flush siphonic cisterns to dual-flush operation could be one method of achieving a desired reduction in water use, in accordance with the 'twin-track' approach to balancing supply and demand.
This small study, which was jointly funded by Southern Water and the Environment Agency, sought to measure the effectiveness of dual-flush toilets in reducing water consumption through an eight-month study of five retrofit devices which were installed in thirty-three unmetered domestic properties in West Sussex.     

Economic implications of water efficiency measures I: assessment methodology and cost-effectiveness of micro-components

Economic efficiency has recently become one of the primary objectives of water management decisions. In particular, as vulnerability of freshwater systems has become evident and there is a trend for water supply managers to look towards water demand management, identifying the cost of such measures is becoming increasingly important. In England and Wales, Part G of the Building Regulations requires that water consumption of a new dwelling should not be more than 125 litres/capita.day. However, while compliance with this is determined by the water use characteristics of the installed micro-components (WCs, showers, basin taps, kitchen taps, baths, dishwashers and washing machines), the cost to consumers resulting from installing water efficient micro-components is not clear. This paper evaluates the potential economic implications of water saving micro-components, assessed from the consumers’ perspective. A methodology has been developed and implemented to assess the cost-effectiveness of several types of water efficient micro-components. A range of cost assessment methods was applied, and critically reviewed comparing their outcomes. It was found that conventional cost assessment methods are unsuitable for identifying the least cost options to consumers. Of the applied methods, the modified annualised assessment method appears to be a relatively better option.     

Water conservation potential in educational institutions in developing countries: case study of a university campus in Ghana

This paper presents evidence of the potential for institutional water conservation in a developing country using a university campus in Kumasi, Ghana, as a case study and suggests measures for reducing water demand in institutions. A water end-use survey was conducted using a sample of 144 students from six halls of residence to determine lavatory faucet (tap), showerhead and water closet water-use. The average per capita water use was 115.12 ± 5.33 litres per day at 95% confidence level. Results of the water end-use analysis showed that students use high quantities of water for bathing (61.90 ± 4.06 litres per capita per day at 95% confidence level). There is a potential for reducing the annual water demand by 30.85% through water conservation measures such as retrofitting with water-efficient showerheads and water closets. The payback period for the cost of retrofitting in the current study was found to be 6.5 years.     

Inventory of water management practices in Harare, Zimbabwe

Lake Chivero, in Zimbabwe, is the major water supply source for the greater Harare area. This paper looks at the sustainability of current practices of the urban water cycle in relation to water quantity and quality management in the Chivero catchment. Data on population, water supply, water and wastewater treatment and river flows were obtained from urban councils and government departments. The data were used to assess water consumption, wastewater generation, treatment and disposal practices, river flow trends, raw water abstractions and water demand patterns. The results showed that the current situation is not sustainable as water quantity in the catchment will soon be a problem at current levels of consumption while water quality is already a problem, especially with regard to nutrient levels. Water and nutrient management strategies, which include water use efficiency, treatment and water recycling and nutrient reuse in controlled urban agriculture, are recommended as matters of urgency.     

Risk‐based water resources planning in practice: a blueprint for the water industry in England

Resilient water supplies in England need to be secured in the face of challenges of population growth, climate change and environmental sustainability. We propose a blueprint for water resources planning that uses system simulation modelling to estimate the frequency, duration and severity of water shortages at present and in the context of future plans and scenarios. We use multiobjective optimisation tools to explore trade‐offs between these risk metrics and cost of alternative plans, and we use sensitivity analysis to identify plans that robustly achieve targets for tolerable risk, alongside other performance objectives. The results of a case study in the Thames basin demonstrate that the proposed methodology is feasible given commonly available data sets and models. The proposed method provides evidence with which to develop water resource management plans that demonstrably balance the risks of water shortages, costs to water users and environmental constraints in an uncertain future.     

Comparing the utility of LiDAR data vs. multi-spectral imagery for parcel scale water demand modeling

In this paper we examine whether land-cover measures derived from multi-spectral (MS) imagery in combination with light detection and ranging (LiDAR) data sources better predict parcel scale urban water consumption than measures derived solely from MS imagery. Land-cover measures such as the percentage of impervious surface and vegetative cover are important predictors of household level water use. This study found that the additional effort required to obtain LiDAR data does not appear to add predictive power for water demand modeling. We suggest that MS imagery is just as useful estimating household level water demand.     

分质供水在缺水型中小城镇供水系统中的应用

根据水资源特点和饮用水水源布局,对沂水县中心城区供水系统提出分质供水的方案。以优先利用地表水、积极引用客水、合理开采地下水、严格限制自备井为原则,对分质供水水源地进行了规划,并介绍了饮用水水厂和工业水厂的建设规划。分质供水的实施,能够满足中心城区的用水需求,改善供水水质,节约制水能耗,确保供水安全。     

Combined space cooling and water heating system for Hong Kong residences

The combined space cooling and hot water preheating system that utilizes the rejected condenser heat is considered one of the most cost effective energy conservation measures. However, simultaneous consumption characteristics are absent in public domain. Questionnaire surveys have been conducted to obtain the relevant information from 126 households residing in high-rise public rental residential buildings in Hong Kong, achieving a confidence level of 95%. The candidate households were selected by a convenience sampling approach, and the questionnaire was constructed using either forced-choice format or in numeric response format. The data obtained were verified by correlation analysis. Data collected includes the occupancy pattern, the installed air-conditioner and water heater characteristics, and the utilization pattern of air-conditioning and hot water. Based upon the collected data and site measurements, hourly, daily and monthly heat recovery and hot water heating demand profiles were established, as well as the correlation between tap water and outdoor air temperatures. The combined profiles enable the evaluation of the feasible use of the combined system, and for future sizing of hot water storage tanks. The potential energy and fuel cost saving associated with the use of the proposed combined system for typical public rental housing in Hong Kong was estimated to be 50%.     

Financial sustainability of rural water supply: An analysis of cost recovery,revenue collection,and efficiency

Maintaining a financial sustainable pipe water supply (PWS) is one of the serious challenges in sustainable provision of water supply in rural areas. Poor revenue collection and willingness to pay for the service is adding severity to the problem. This study analyses the factors affecting revenue collection in rural water utilities and measures its efficiency in maximizing revenue and average hour of water supply per day. The findings convey that cost recovery is a failure in rural water supply even they are not able to generate revenue. Inactive community participation, the notion of free water supply, unaccountable payment is main reason for poor revenue collection. Therefore, active community participations, educating the household on water supply, adoption of accountable payment mode will be a step towards revenue generation. To attain efficiency, the utilities can expand their output revenue and hours of water supply by 22% without altering their input. This study is an empirical contribution in the field of sustainable provision of water supplies, which address the problem of poor revenue generation in rural water supply and find out the reason for it.     

从管网供水漏失率分析乡镇供水现状

分析了目前乡镇供水回收率普遍偏低的主要原因：供水主管线老化，深井水硬度较大造成管道严重结垢、渗漏，年久失修；规范中乡镇供水标准制定偏高，与实际使用情况不符，造成供水量与用水量的不平衡；乡镇水厂管理水平低，出现以小带大的管线设置，增加了水头损失，降低了供水压力。提出了加强乡镇技术管理水平和对老管线进行测漏排查的建议，以期为合理规划乡镇用水量标准提供参考依据。     

节能改造变频供水系统

简单介绍了变频供水系统的配置及能耗情况,分析了变频供水系统在节能方面的优势,并阐述了变频供水系统配置与节能的关系及优化措施,结合具体实例对采用变频供水系统产生的节能效益作了具体说明,以促进其推广应用。     

从供水成本现状看合理水价的形成机制

为了解供水企业的实际成本状况,促进合理水价机制的形成,对某省辖市（含县级市）的供水成本进行了调查和审核.在此基础上提出了水价改革的设想.     

福州市水资源供需平衡的对策

水资源规划的核心是水资源平衡,水资源平衡是需求和供给的平衡,需水量预测包括工业、农业、城镇生活和河道生态需水量四个部分。通过分析用水统计数据,研究用水结构特点,进行需水量预测,提出水资源供需平衡规划及对策。     

Public engagement with water conservation in London

Understanding water demand and consumers' capacity for change is essential in underpinning water demand management and water efficiency programmes. This paper presents the outcomes of a qualitative study, which used discussion groups relating to water infrastructure with environmentally aware citizens in five London boroughs in the Lower Lea River Basin. The results showed a subtle interaction between users, water and technology. Users are generally unaware of their own water consumption. Individual perceptions of changes in water behaviour are constrained by habit and lack of knowledge about what changes can be made and how. Knowledge of environmental information was described as the inspiration behind making any changes. The paper concludes that access to information about water resources, infrastructure and conservation measures should be enhanced because although information sources are abundant, participants claimed they were inaccessible without considerable effort. Finally, an emphasis should also be put on helping the public form a more substantial part in environmental decisions.     

Quantitative microbial risk assessment with respect to Campylobacter spp. in toilets flushed with harvested rainwater

In light of increasing pressures on water supplies in some areas, water demand management and water conservation techniques are likely to become increasingly prevalent. In‐house systems using alternatives to mains supplies for nonpotable uses present one such option for reducing potable water demand. This paper, through a formal desk‐based health impact assessment (HIA) and quantitative microbial risk assessment (QMRA), examines one of the possible health implications (Campylobacter infection from toilet flushing) resulting from the use of rainwater harvesting in the home in the United Kingdom. This is investigated using data from the literature and a hypothetical case study population of over 4000 people (based on data for the ‘average’ population in England), with the results being expressed as disability‐adjusted life years (DALYs) (on an annual basis) and placed in context of the ‘tolerable’ risk from drinking‐water supplies.     

Development of small district adjustment based on public water demand to decrease the municipal water supply load

This research microscopically estimates the spatial distribution of water demand and aims to use this to improve the existing zone system. So, this study used geographic information system (GIS) to predict the spatial distribution of water demand according to building unit by applying the basic unit of water use by purpose. Based on the results, the buildings were then grouped into blocks to produce a methodology for controlling small districts using a microscopic approach to decrease the water supply load based on water demand per block. Finally, verification was conducted by quantitatively evaluating the load-decreasing effect through the application of the above methodology. We evaluated efficiency and verified the study's methodology by analysing urban areas that had been Manhattanized and densificated, finding a reduction of approximately 16.7%. The possibility of expanding the study's scope to medium and large districts was suggested.     

一种衡量供水系统能耗合理性的新指标

在努力降低供水系统能耗的同时,提出一个能有效衡量能耗合理性的指标是很重要的。我国现有的单位耗电量指标及综合单位耗电量指标在考核供水系统整体能耗合理性方面缺乏横向可比性。针对这一情况,在分析供水系统输水所需最小能量的基础上提出功效性指标,并通过对该指标的分析,证明该指标具有对不同供水系统整体能耗情况进行对比的功能。     

变频供水与水泵-水箱联合供水的节能比较

供水方式的选择是高层建筑生活给水系统设计的关键,它直接关系到生活给水系统的使用效果和工程造价;选择合适的给水方式,可以极大的节约用水量和耗电量。通过对水泵-水箱联合给水方式和变频给水方式的能耗比较,发现水泵-水箱联合给水方式更加节能。