Showing papers on "Water supply published in 2000"

Global Water Resources: Vulnerability from Climate Change and Population Growth

Abstract: The future adequacy of freshwater resources is difficult to assess, owing to a complex and rapidly changing geography of water supply and use. Numerical experiments combining climate model outputs, water budgets, and socioeconomic information along digitized river networks demonstrate that (i) a large proportion of the world's population is currently experiencing water stress and (ii) rising water demands greatly outweigh greenhouse warming in defining the state of global water systems to 2025. Consideration of direct human impacts on global water supply remains a poorly articulated but potentially important facet of the larger global change question.

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 20th 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 elim...

The changing water paradigm. A look at twenty-first century water resources development.

Abstract: Water resources management approaches around the world are changing dramatically. This ichanging water paradigmi has many components, including a shift away from sole, or even pri- mary, reliance on finding new sources of supply to address perceived new demands, a growing emphasis on incorporating ecological values into water policy, a re-emphasis on meeting basic human needs for water services, and a conscious breaking of the ties between economic growth and water use. A reliance on physical solutions continues to dominate traditional planning approaches, but these solutions are facing increasing opposition. At the same time, new methods are being developed to meet the demands of growing populations without requiring major new construction or new large-scale water transfers from one region to another. More and more water suppliers and planning agencies are beginning to explore efficiency improvements, implement options for managing demand, and reallocating water among users to reduce projected gaps and meet future needs. The connections between water and food are receiving increasing attention as the concerns of food experts begin to encompass the realities of water availabil- ity. These shifts have not come easily; they have met strong internal opposition. They are still not univer- sally accepted, and they may not be permanent. Nevertheless, these changes represent a real shift in the way humans think about water use. This paper summarizes the components of this ongoing shift and looks at the new paths being explored. It evaluates the major reasons for the change in approach and discusses the applicability of these new concepts in different parts of the world.

Water scarcity in the twenty-first century.

Abstract: As we approach the next century, more than a quarter of the world's population or a third of the population in developing countries live in regions that will experience severe water scarcity. This paper reports on a study to project water supply and demand for 118 countries over the 1990-2025 period. The nature and geographic focus of growing water scarcity are identified. In the semi-arid regions of Asia and the Middle East, which include some of the major breadbaskets of the world, the ground water table is falling at an alarming rate. There is an urgent need to focus the attention of both professionals and policy makers on the problems of ground water depletion, which must be seen as the major threat to food security in the coming century.

Sustainable water resources management

Abstract: Defining and measuring sustainability is a major challenge. This article argues these limitations need not stop us from trying to identify and value the possible impacts of what we are doing, or are thinking about doing, over time periods much longer than the lives of our investments, or even of the lives of those of us living today. Sustainability is a relative concept that must be applied in an environment undergoing multiple changes, changes that are occurring over different temporal and spatial scales. We depend on our water resource systems for our survival and welfare. Yet no one expects them to be restored to, or survive in, their most productive pristine states in the face of increasing development pressures for land in their watersheds and for water in their streams, rivers, lakes, and aquifers. A continuing task of water resource planners and managers is to identify the multiple impacts and tradeoffs resulting from what we who are living today may wish to do for ourselves and our immedi...

Peer Reviewed: MTBE-To What Extent Will Past Releases Contaminate Community Water Supply Wells?

Abstract: RICHARD JOHNSON, JAMES PANKOW, DAVID BENDER, CURTIS PRICE, AND JOHN ZOGORSKI T he increasing frequency of detection of the widely used gasoline additive methyl tertbutyl ether (MTBE) in both groundand surface waters is receiving much attention from the media, environmental scientists, state environmental agencies, and federal agencies. At the national level, the September 15,1999, Report of the Blue Ribbon Panel on Oxygenates in Gasoline (i) )tates that between 5 and 10% of community drinking water supplies in high MTBE use areas show at least detectable concentrations of MTBE, and about 1% of those systems are characterized by levels of this compound that are above 20 pg/L. In Maine, a desire to determine the extent of MTBE contamination led to a 1998 study (2) that revealed that this compound is found at levels above 0.1 pg/L in 16% of 951 randomly selected household wells and in 16% of the 793 community water systems tested in that state (37 wells were not tested). The study also suggested that between 1400 and 5200 household wells may have levels above 35 pg/L, although no community water supplies were found to be above that concentration. For comparison, Maryland, New Hampshire, New York, and California have set MTBE remediation \"action levels\" at or below 20 pg/L, and EPA has set its advisory level for taste and odor at 20-40 pg/L (3). In California, concern regarding MTBE reached statewide levels in 1996 when seven wells supplying 50% of the water for the city of Santa Monica were removed from service because of MTBE at concentrations as high as 600 pg/L. For the city's Charnock well field, an initial review of known and suspected petroleum spill sites identified about 10 potential sources that lay within 1 km of the well field, lay above the hydrologic unit accessed by the well field, and were created after MTBE use began in the state (4). At the time that contamination of die wells was discovered, pumping of the Charnock well field was at 5 million gallons/day (mgd). This aggressive pumping was approximately twice the total natural flow of water moving into the aquifer. Despite the presence of a protective aquitard in the system, the pumping had dewatered a significant portion of the upper aquifer, caused water to flow toward the well field from all directions, and had greatly increased the likelihood that the community water supply (CWS) wells in Santa Monica would in fact become contaminated by one or more persistent organic pollutants such as MTBE. Besides leaking underground fuel tanks (LUFTs) and leaking pipelines, other sources of MTBE in groundwater include tank overfilling and faulty construction at gas stations, spillage from vehicle accidents, and homeowner releases. In Maine, it is pos-

Water resources management in smallholder farms in eastern and southern africa : an overview

Abstract: Livelihood security in Eastern and Southern Africa is strongly dependent on rainfall distribution and land management practices among smallholder farmers. Over 95 % of the food producing sector is based on rainfed agriculture. The major challenge for the rural communities, representing up to 80 % of the population in certain countries, is to improve the productivity of the arable land and the available water resources. This paper gives an outline of the hydrological challenges facing smallholder farmers with focus on water scarce areas. The importance of rainfall partitioning rather than rainfall totals is discussed. The main focus is on the management of rural water using low-tech practices, both for domestic purposes and for crop production. Case studies from Eastern and Southern Africa are presented, showing the potential of stabilising the water supply over time both for livestock, household use, and for crop production. The challenges facing research and extension of introducing water management on different scales (household, community, catchment) is discussed.

Surveillance for waterborne-disease outbreaks--United States, 1997-1998.

Abstract: Problem/condition Since 1971, CDC and the U.S. Environmental Protection Agency (EPA) have maintained a collaborative surveillance system for collecting and periodically reporting data relating to occurrences and causes of waterborne-disease outbreaks (WBDOs). Reporting period covered This summary includes data from January 1997 through December 1998 and a previously unreported outbreak in 1996. Description of the system The surveillance system includes data regarding outbreaks associated with drinking water and recreational water. State, territorial, and local public health departments are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC on a standard form. Results During 1997-1998, a total of 13 states reported 17 outbreaks associated with drinking water. These outbreaks caused an estimated 2,038 persons to become ill. No deaths were reported. The microbe or chemical that caused the outbreak was identified for 12 (70.6%) of the 17 outbreaks; 15 (88.2%) were linked to groundwater sources. Thirty-two outbreaks from 18 states were attributed to recreational water exposure and affected an estimated 2,128 persons. Eighteen (56.3%) of the 32 were outbreaks of gastroenteritis, and 4 (12.5%) were single cases of primary amebic meningoencephalitis caused by Naegleria fowleri, all of which were fatal. The etiologic agent was identified for 29 (90.6%) of the 32 outbreaks, with one death associated with an Escherichia coli O157:H7 outbreak. Ten (55.6%) of the 18 gastroenteritis outbreaks were associated with treated pools or ornamental fountains. Of the eight outbreaks of dermatitis, seven (87.5%) were associated with hot tubs, pools, or springs. Interpretation Drinking water outbreaks associated with surface water decreased from 31.8% during 1995-1996 to 11.8% during 1997-1998. This reduction could be caused by efforts by the drinking water industry (e.g., Partnership for Safe Water), efforts by public health officials to improve drinking water quality, and improved water treatment after the implementation of EPA's Surface Water Treatment Rule. In contrast, the proportion of outbreaks associated with systems supplied by a groundwater source increased from 59.1% (i.e., 13) during 1995-1996 to 88.2% (i.e., 15) during 1997-1998. Outbreaks caused by parasites increased for both drinking and recreational water. All outbreaks of gastroenteritis attributed to parasites in recreational water were caused by Cryptosporidium, 90% occurred in treated water venues (e.g., swimming pools and decorative fountains), and fecal accidents were usually suspected. The data in this surveillance summary probably underestimate the true incidence of WBDOs because not all WBDOs are recognized, investigated, and reported to CDC or EPA. Actions taken To estimate the national prevalence of waterborne disease associated with drinking water, CDC and EPA are conducting a series of epidemiologic studies to better quantify the level of waterborne disease associated with drinking water in nonoutbreak conditions. The Information Collection Rule implemented by EPA in collaboration with the drinking water industry helped quantifythe level of pathogens in surface water. Efforts by CDC to address recreational water outbreaks have included meetings with the recreational water industry, focus groups to educate parents on prevention of waterborne disease transmission in recreational water settings, and publications with guidelines for parents and pool operators.

Hydrologically sensitive areas: Variable source area hydrology implications for water quality risk assessment

Abstract: A conceptual approach to assessing water quality risk in the context of variable source area hydrology was developed and applied to the New York City (NYC) water supply watersheds. The term hydrologically sensitive area (HSA) was used to refer to areas in a watershed especially prone to generating runoff that are, therefore, potentially susceptible to transporting contaminants to perennial surface water bodies. As an example, a cost benefit method for quantifying HSAs was developed and applied such that water quality protection was balanced with agricultural needs for NYC watersheds. In accordance with the variable source area concept, the spatial extent of HSAs vary throughout the year. On an annual average, approximately 10% of the watershed is designated HSA and about 20% of the total annual runoff originates on these HSAs. This study is meant to illustrate an approach to dealing with water quality risk assessment.

The vulnerability of wetlands to climate change: A hydrologic landscape perspective

Abstract: The vulnerability of wetlands to changes in climate depends on their position within hydrologic landscapes. Hydrologic landscapes are defined by the flow characteristics of ground water and surface water and by the interaction of atmospheric water, surface water, and ground water for any given locality or region. Six general hydrologic landscapes are defined; mountainous, plateau and high plain, broad basins of interior drainage, riverine, flat coastal, and hummocky glacial and dune. Assessment of these landscapes indicate that the vulnerability of all wetlands to climate change fall between two extremes: those dependent primarily on precipitation for their water supply are highly vulnerable, and those dependent primarily on discharge from regional ground water flow systems are the least vulnerable, because of the great buffering capacity of large ground water flow systems to climate change.

Privatizing Water, Producing Scarcity: The Yorkshire Drought of 1995*

Abstract: The Yorkshire drought of 1995 was the most extreme climate event faced by the English and Welsh water industry since its privatization in 1989. As an emblem of crisis in privatized water management, and as a potential signal of climate change, the 1995 drought has motivated change in water regulation and management. In this paper I challenge conventional interpretations of the 1995 water supply crisis as a natural hazard or as a result of managerial ineptitude. Drought is conceptualized as the production of scarcity, an outcome of three interrelated practices: meteorological modeling, demand forecasting, and corporate restructuring and the regulatory “game.” These practices are situated within an analysis of the context of the regulatory implications of the privatization of the water industry in 1989. I explore the simultaneously natural, social, and discursive elements of water scarcity and situate them within an analysis of privatization as reregulation, rather than deregulation. This analysis brings insights developed in debates over “real” regulation and regulation theory to bear on nature-society analysis, while extending this debate through theorizing regulation as, in part, a discursive practice. The ensuing rereading of drought challenges conventional interpretations of environmental crisis, raises questions about the implications of water industry privatization, and emphasizes the need to account for the role of the state and the intricacies of “real” regulation in analyses of resource management.

Microbiological standards for water and their relationship to health risk

Abstract: Summary: Maintenance of the microbiological quality of water has been used as an important means of preventing waterborne disease throughout the twentieth century. The commonest microbiological tests done on water are for coliforms and Escherichia coli (or faecal coliform). This paper reviews the legislative and other guidance for microbial standards in drinking and bathing waters and considers evidence for the relationship between the microbiological quality of water and risk to human health. In the past measures of the microbiological quality of water correlated well with risks of acquiring gastrointestinal disease. More recent work suggests that gastrointestinal disease is more strongly associated with the presence of enterococci than of E. coli. New diseases such as cryptosporidiosis have been shown to cause outbreaks of waterborne disease when levels of conventional microbiological parameters are satisfactory. In response to this, and because of failure of prosecution in one outbreak, the United Kingdon (UK) Government has introduced new legislation that requires water providers to perform a risk assessment on their water treatment facilities and to implement continuous monitoring for cryptosporidium. A new European directive on drinking water has been introduced and legislation on cryptosporidium in drinking water has been proposed in the UK.

Occurrence of pathogenic microorganisms in the Saint Lawrence River (Canada) and comparison of health risks for populations using it as their source of drinking water.

Abstract: A 300-km portion of the Saint Lawrence hydrological basin in the province of Quebec (Canada) and 45 water treatment plants were studied. River water used by drinking water treatment plants was anal...

Infrastructure Risk Analysis Model

Abstract: One key element of our nation's infrastructure is our communities' drinking water supplies. Growing consumption by expanding populations, industrial and public pollution, the tragedies of both nature and human accidents, and the emergence of threats by domestic terrorists, disgruntled employees, and computer hackers continue to torment the nation. Add to these concerns the anxiety over Y2K failures of the utilities that control these systems; they all pose potential perils to freshwater reserves that local municipalities, state, and federal governments are obligated to protect. This paper serves to introduce the probabilistic infrastructure risk analysis model developed for a small community's water supply and treatment systems. The paper adopts a holistic approach to model a water infrastructure system's interconnectedness and interdependencies. This approach can also be used for other interconnected infrastructure elements such as physical facilities, electric power generation and distribution, and tele...

Public Infrastructure and Private Costs: Water Supply and Time Allocation of Women in Rural Pakistan*

Abstract: The role of infrastructure in promoting development has been established. It is noted that improvements in infrastructure increase the efficiency of production. In this case study the authors investigated how the quality and quantity of infrastructure affect the time women in Pakistan allocate to their various activities. The focus is on the relationship between access to water--at both the household and the community levels--and the time allocation of rural women who have the primary responsibility for water collection. Findings indicate that changes in the availability of infrastructure affect time use both at the household and individual levels. At the household level it is shown that poor infrastructure induces women to reduce their market-oriented work and thus their contribution to household income. Moreover poor infrastructure also causes an increase in the total work burden of women and a decrease in leisure. However with improved public water-supply infrastructure the total time women spend in all activities would be lowered with a substitution of water collection and income-generating activities. In addition a public water-supply system may also reduce the pathogen content of water thereby improving its quality. This increase in quality will most likely to bring health and sanitary benefits.

Climate change impacts and human settlements in Africa: prospects for adaptation.

Abstract: Climate change impacts on African human settlements arise from a number of climate change-related causes, notably sea level changes, impacts on water resources, extreme weather events, food security, increased health risks from vector home diseases, and temperature-related morbidity in urban environments. Some coastlines and river deltas of Africa have densely populated low-lying areas, which would be affected by a rise in sea level. Other coastal settlements will be subjected to increased coastal erosion. Recent flooding in East Africa highlighted the vulnerability of flood plain settlements and the need to develop adaptive strategies for extreme weather events management and mitigation. In the semi arid and arid zones many settlements are associated with inland drainage water sources. Increases in drought will enhance water supply related vulnerabilities. Inter-basin and international water transfers raise the need for adequate legal frameworks that ensure equity among participating nations. Similarly, water supply and irrigation reservoirs in seasonal river catchments might fail, leading to poor sanitation in urban areas as well as food shortage. Hydroelectric power generation could be restricted in drought periods, and where it is a major contributor to the energy budget, reduced power generation could lead to a multiplicity of other impacts. States are advised to develop other sources of renewable energy. Temperature changes will lead to altered distribution of disease vectors such as mosquitoes, making settlements currently free of vector borne diseases vulnerable. Rapid breeding of the housefly could create a menace associated with enteric disorders, especially in conditions of poor sanitation. The dry savannahs of Africa are projected as possible future food deficit areas. Recurrent crop failures would lead to transmigration into urban areas. Pastoralists are likely to undertake more trans-boundary migrations and probably come into conflict with settled communities. Adaptive measures will involve methods of coastal defences (where applicable), a critical review of the energy sector, both regionally and nationally, a rigorous adherence to city hygiene procedures, an informed agricultural industry that is capable of adapting to changing climate in terms of cropping strategies, and innovations in environment design to maximise human comfort at minimum energy expenditure. In the savannah and arid areas water resource management systems will be needed to optimise water resource use and interstate co-operation where such resources are shared. Climate change issues discussed here raise the need for state support for more research and education in impacts of climate change on human settlements in Africa.

Water scarcity and the role of storage in development

Abstract: Of the four major ways of storing water -in the soil profile, in underground aquifers, in small reservoirs, and in large reservoirs behind dams-the first is possible only for relatively short periods of time. In this paper, the authors concentrate on the three kinds of long-term technologies, and compare the hydrological, operational, economic and environmental aspects of each.

Reducing Vulnerability of Water Resources of Canadian Prairies to Potential Droughts and Possible Climatic Warming

Abstract: Past and the present studies show that the Canadian Prairies havebecome warmer and may have been drier in the last four to five decadesbut the drying trends are scattered and inconclusive.Statistical analysis shows that only the Winter and Fall (insome instances) precipitation is marginally related to ENSO andthe PNA (Pacific North Americ) Index, and streamflow is highlyvariable. With uncertainties on the potential impact of climaticchange and other uncertainties, several strategies are proposedto reduce the vulnerability of the Prairies to future droughts,where surface water is the primary water supply and agricultureis the major water user: (1) Continue implementing small-scalewater resources projects and increase water storage through snowmanagement, (2) increase integration between existing waterresources systems, and (3) promote water conservation measuresin agriculture practice, water pricing and water metering.

Microbiological Aspects of Biofilms and Drinking Water

Abstract: Water Supply, Treatment, and Distribution Epidemiology Waterborne Diseases Risk Assessment Legislation and Water Quality Biofilm Development in General Biofilm Development in Drinking Water Microbes and Public Health Significance Methods of Sampling Biofilms in Drinking Water Materials Used in the Transport of Drinking Water Disinfection and Control of Biofilms in Drinking Water

Valuing Water Supply Reliability

Abstract: Instead of creating water supply systems that fully insulate mankind from climate-imposed water deficiencies, it is possible that for municipal water systems a nonzero probability of water supply shortfall is efficient. Perfect water supply reliability, meaning no chance of future shortfall, is not optimal when water development costs are high. Designing an efficient strategy requires an assessment of consumer preferences pertaining to the reliability of water supply. Contingent valuations of both current and future shortfalls are reported. The consistency of these measures is gauged using an expected utility model. Copyright 2000, Oxford University Press.

Handbook of ancient water technology

Abstract: A magisterial handbook on water use and water technology in an area from Mesopotamia to the Atlantic Ocean, from the beginning of the Neolithic period up to ca. A.D. 600. Based on the archaeological and written evidence, it discusses the socio-economic background, irrigation and drainage, water supply, water in recreation (fountains, baths, etc.), larger hydraulic works (canals and sluices, dams, drainage), water-power, water legislation and the administration of water resources.

The Design of "Smart" Water Market Institutions Using Laboratory Experiments*

Abstract: One of the problems with proposals for substantialinstitutional change in water systems is thatmodification and irreversibility make the processslow, cautious and costly to society. In this paper,we discuss the role that experimental economics canplay in evaluating proposed institutional changes tohelp facilitate a more rapid and smooth adoption ofchanges in the water system. Experimental economicsyields a formal and replicable system for analyzingalternative market structures before they are actuallyimplemented. For example, a water market can bedeveloped and tested in the laboratory under supplyand demand constraints that reflect drought conditionsthat might occur in California, or other arid regionsin the world. We present a prototype of a Californiawater transfer model and the results from a series ofwater market experiments. Results include realizedmarket efficiency and surplus distribution, as well asan analysis of market price volatility. Theimplications of this research extend well beyondCalifornia water markets, not only to water markets inother arid regions, but also to the design of marketsfor other environmental goods, including tradablepollution permits and fishery ITQs.

Contractual choice and performance: the case of water supply in France: the case of water supply in France

Abstract: [fre] Il existe une litterature abondante en economie des couts de transaction sur le choix d'une entreprise entre faire ou faire faire. A notre connaissance, il n'y a pas de test econometrique de ce type portant sur l'arbitrage que fait un gouvernement entre offrir directement un service ou le confier a un operateur. Nous presentons un tel test, utilisant une base de donnees qui porte sur l'ensemble des Unites Distributrices d'Eau pour les villes francaises de plus de 5000 habitants. Nos resultats suggerent fortement : 1) qu'il y a une logique economique dans les choix contractuels effectues ; 2) qu'il n'y pas d'avantage absolu pour un mode de gouvernance, les performances dependant de l'adequation d'un mode aux attributs des transactions. [eng] There is a vast literature in transaction cost economics on the choice made by firms to integrate or not. To our knowledge, there have been no previous tests for understanding decisions made by governments to provide a service or to outsource. Our paper presents such a test, using a data base on all units supplying water for towns of more than 5000 inhabitants in France. Our results strongly support that : 1) There is an economic rationale to contractual choices in public utilities ; 2) There is no absolute advantage for one specific mode of governance, performance depending on the fitness of the mode of governance to the attributes of the transaction.

Can China feed itself? An analysis of China's food prospects with special reference to water resources.

Abstract: SUMMARY Water is certainly an important factor in China's food security. Some authors have argued that up to 70% of the country's grain production depends on irrigation. Since the water resources for agriculture in northern China are getting increasingly exhausted and diverted to urban and industrial consumption, they have published grim predictions of food shortages. The following analysis uses a detailed agro-climatic model to estimate China's maximum grain production potential under rain-fed and irrigated conditions. It shows that far less than 70% of China's grain production critically depends on irrigation. Large areas in the south and some areas in the northeast can produce substantial amounts of grain using only natural precipitation. According to our model, some 492 million tons of grain can be produced at current technology without additional irrigation. However, depending on diet, this may still not be enough for China's grain demand in 2025, which was estimated at up to 650 million tons. Only w...

Irrigation and water resources in latin america and the caribbean: challenges and strategies

Abstract: Latin America and the Caribbean are relatively well endowed with water resources However, population growth and rapid urbanization are putting considerable pressure on water available for irrigation Local and regional water scarcity problems are exacerbated by severe water quality problems; and wastewater is frequently used for irrigation Moreover, prospects for new investments into irrigation development appear limited This paper examines the factors underlying irrigation development in Latin America and the Caribbean, reviews the water supply situation, and describes trends in water demand and irrigated agriculture The overall water management in the region is assessed, and recent trends in investments in the water sector, with a focus on large-scale irrigation systems, are analyzed The paper concludes that in this context of accelerating demand and declining irrigation investments, new water development is not the primary solution to water resource challenges in the region Much greater attention is needed on water policy and management reform to improve the efficiency and equity of irrigation and water supply systems

Pricing Irrigation Water : A Literature Survey

Abstract: Getting prices right and allocating water efficiently will become increasingly important as demand for food and water increases and as water scarcity becomes more of a problem. Pricing water efficiently will help meet the increasing demand, but what is the best way to make pricing more efficient? As water scarcity and population pressures increase, more countries are adopting water pricing mechanisms as their primary means of regulating the consumption of irrigation water. The way to allocate water efficiently is to get the prices right, but how to accomplish this is open to debate. Water pricing methods are sensitive to the social, physical, institutional, and political setting. To assess the costs and benefits of a particular irrigation project, the pricing method must be tailored to local circumstances. Johansson's survey of the resource economics literature on irrigation services and pricing will be useful for developing comprehensive guidelines for water policy practitioners. He synthesizes accumulated knowledge about the implementation and performance of various water pricing methods used over the past two decades: volumetric pricing (marginal cost pricing), output and input pricing, per area pricing, tiered pricing, two-part tariffs, and water markets. Theoretical and practical issues will become increasingly important as demand for food and water increases. Pricing water efficiently will help meet that demand, but what is the best way to make pricing more efficient? Many argue that water markets offer a solution, but under what circumstances are water markets viable? What effect will decentralization have on farm production and the rest of the economy? What forces are moving toward decentralization or (re)centralization? The answers to these questions are complex and often site-specific. To help compare them, Johansson lists case studies, data sources, and relevant methodologies in the appendixes. This paper - a product of the Rural Development Department - is part of a larger effort in the Bank to improve the efficiency of water use. The study was funded by Rural Development, Development Research Group, and the Bank's Research Support Budget under the research project Guidelines for Pricing Irrigation Water Based on Efficiency, Implementation, and Equity Concerns.

More Reservoirs or Transfers? A Computable General Equilibrium Analysis of Projected Water Shortages in the Arkansas River Basin

Abstract: A computable general equilibrium model of the southeastern Colorado economy is used to compare the economic impacts of a proposed increase in reservoir storage to an alternative: temporary water transfers. While both provide municipalities with reliable water supply during droughts and are shown to benefit both rural and urban communities, temporary transfers are accomplished at a much lower economic and environmental cost. This analysis illustrates how computable general equilibrium models provide a more realistic portrayal of the impact of policy changes than inputoutput analysis by allowing substitution in response to economic conditions.

Analysis of 20th century rainfall and streamflow to characterize drought and water resources in puerto rico

Abstract: During the period from 1990 to 1997, annual rainfall accumulation averaged 87% of normal at the 12 stations with the longest period of record in Puerto Rico, a Caribbean island with a 1999 population of 3.8 million. Streamflow in rivers supplying the La Plata and Loiza reservoirs, the principal water supply of the San Juan metropolitan area, was at or below the 10th flow percentile for 27% to 50% of the time between December 1993 and May 1996. Diminished reservoir levels in 1994 and 1995 affected more than 1 million people in the San Juan metropolitan area. Water rationing was implemented during this period and significant agricultural losses, valued at $165 million, were recorded in 1994. The public endured a year of mandatory water rationing in which sections of the city had their water-distribution networks shut off for 24 to 36 hours on alternate days. During the winter and spring of 1997–1998, water was rationed to more than 200,000 people in northwestern Puerto Rico because water level in the Guajat...