Showing papers on "Water supply published in 1995"

The Contribution of People's Participation: Evidence from 121 Rural Water Supply Projects

Abstract: The study is based on systematic quantitative and qualitative analysis of 121 rural water supply funded by many different water supply agencies in countries throughout the developing world. The analysis consistently shows that beneficiary participation was more significant than any other factor in achieving functional water systems and in building local capacity. The results of this study have profound implications for the way the World Bank supports its partners in planning and implementing development programs. Among the lessons learned from the study are these : obtaining local participation in decision making about development is sound business practice, and special measures are needed to ensure that the marginalized are reached in the participatory process. Even is participation is assured in planning, agencies must listen and learn as project are implemented. These principles are clear, and their implications reach well beyond rural water supply projects. The challenge is to act on these principles and to place people at the center of development.

Sustaining water: an update. Revised data for the Population Action International report Sustaining Water: Population and the Future of Renewable Water Supplies.

Abstract: Data are presented on the annual per capita availability of renewable fresh water in 149 countries for the years 1955 and 1990 and on the annual per capita projected availability of renewable fresh water for UN low medium and high population projections in these countries for the years 2025 and 2050. Figures are given for total annual renewable fresh water by country in cubic kilometers population in thousands and per capita water availability in cubic meters. Renewable water is that which falls on a countrys territory or flows in from neighboring countries and is all the water a country can use sustainably. These updated figures reveal that if the UNs medium population projections become reality by the middle of the coming century 4.4 billion of the nearly 10 billion people on the planet will live in 58 countries experiencing either water scarcity or water stress. If the high projection occurs 7.7 billion people (65% of the worlds population) will live in 66 water-short nations. The low projection would see 3.5 billion people (44%) living in 51 water-short countries out of a total population of 7.9 billion.

Environmental Interventions in Developing Countries: Interactions and Their Implications

Abstract: This study assesses the effect of drinking water quality on diarrheal disease in good and poor sanitary conditions using a random sample of 2355 Filipino infants over the first year of life. The study provides powerful confirmation of the importance of environmental factors on diarrhea: The effects of water quality household sanitation and community sanitation are strong consistent and statistically significant. The positive impact of improved water quality is greatest for families living under good sanitary conditions with the effect statistically significant when sanitation is measured at the community level but not significant when sanitation is measured at the household level. Improving drinking water quality would have no effect in neighborhoods with very poor environmental sanitation; however in areas with better community sanitation reducing the concentration of fecal coliforms by two orders of magnitude would lead to a 40% reduction in diarrhea. Providing private excreta disposal would be expected to reduce diarrhea by 42% while eliminating excreta around the house would lead to a 30% reduction in diarrhea. The findings suggest that improvements in both water supply and sanitation are necessary if infant health in developing countries is to be improved. They also imply that it is not epidemiologic but behavioral institutional and economic factors that should correctly determine the priority of interventions. (authors)

Engineering in emergencies : a practical guide for relief workers

Abstract: Contents in detail Acknowledgements Introduction 1 Emergencies 2 The humanitarian relief system 3 Personal effectiveness 4 Personal security 5 Assessment and planning 6 Management 7 Logistics 8 Telecommunications 9 Environmental health 10 Environmental sanitation 11 Emergency water supply 12 Water source development 13 Water storage, treatment and distribution 14 Pumps 15 Mechanical plant 16 Electrical plant 17 Vehicles 18 Roads, crossings and airstrips 19 Shelter and built infrastructure 20 Temporary settlements Appendices Bibliography Index

Outbreak of cryptosporidiosis associated with a disinfected groundwater supply.

Abstract: In an outbreak of cryptosporidiosis in Warrington, a town in North-West England, 47 cases were recorded between November 1992 and February 1993, most within the first month. There was a strong statistical association between cases and residence in an area supplied from two groundwater sources. In a case-control study, a strong association between having drunk unboiled tap water from these sources, and a dose-response relationship were found. Oocysts were not detected in the water supply. During very heavy rainfall one source of water was found to drain surface water directly from a field containing livestock faeces, thereby bypassing natural sandstone filtration. Exceptionally heavy rainfall occurred at the probable time of infection. After withdrawal of the original water supply, the outbreak rapidly subsided. It was concluded that there was very strong evidence that this outbreak was waterborne. This, the second documented outbreak of cryptosporidiosis attributable to a groundwater supply, demonstrates that infection can be transmitted from a disinfected groundwater source despite apparently satisfactory treated water quality. We recommended that guidelines for protection of groundwater are implemented, raw groundwater should be routinely monitored for microbiological contamination, and the structure of all sources and waterworks should be assessed in risk surveys of water catchment areas.

Water Transfers in Water Resource Systems

Abstract: Water transfers are a common component of many regional water systems, and are increasingly being considered for meeting growing water demands and for managing the impacts of drought. Water transfers can take many forms and can serve a number of different purposes in the planning and operation of water resource systems. However, to be successful, water transfers must be carefully integrated with traditional water supply augmentation and demand management measures. This integration requires increased cooperation among different water-use sectors and resolution of numerous technical and institutional issues, including impacts to third parties. This paper identifies the many forms that water transfers can take, some of the benefits they can generate, and the difficulties and constraints that must be overcome in their implementation.

An outbreak of waterborne cryptosporidiosis associated with a public water supply in the UK.

Abstract: In November and December 1992, an outbreak of waterborne cryptosporidiosis occurred in Bradford, a city in the North of England. In all 125 cases were involved, the majority of whom lived in part of the city which received its drinking water supply from a single water treatment works. A case control study demonstrated an association between illness and the consumption of tapwater from this source; those drinking large volumes being more likely to have been ill. Treated water from the defined source yielded cryptosporidial oocysts. Heavy rainfall was recorded in the catchment area of the reservoir supplying raw water to the treatment works, immediately prior to the probable time of infection, based on dates of onset of illness.

Private Sector Participation in Water Supply and Sanitation in Latin America

Abstract: The publication consists of two chapters. In the first, Options for Private Sector Participation - the main problems of the public sector are analyzed, the rationale for private sector participation (PSP) is explained, and the array of options for PSP is reviewed. In the second chapter - Case Study: The Buenos Aires water supply and sewerage services awarded by the government of Argentina to a private consortium of foreign operators and local investors is presented and analyzed, because it provides an excellent example of the planning and implementation stages that are needed to ensure a successful transition from public to private management. The three primary objectives of the pubic sector with respect to private sector participation are to expand the water supply and sewerage systems in order to increase population coverage, to expand sewage treatment in order to reduce water pollution and public health hazards, and to provide better quality of service. The secondary objectives are to ensure higher operating efficiency and to finance the system without public subsidies or guarantees.

Optimization of Transfers in Urban Water Supply Planning

Abstract: A number of water supply agencies in the western United States have begun to integrate water transfers into their overall water supply planning, including the use of transferred water as an additional water source with particular cost and availability characteristics. This paper presents applications of two-stage and multistage linear programming for preliminary estimation of the least-cost integration of several water marketing opportunities with water conservation and traditional water supplies. Water marketing opportunities here can include dry-year options and spot-market water transfers.

Risk Assessment of a Water Supply System during Drought

Abstract: In this paper the feasibility of using risk an alysis for the planning and operation of a water supply system is evaluated through a case study where limited water resources have to be shared by Fukuoka city and the small neighbouring comm unities when drought occurs. Actual data of water demand and water supply together with actual reservoir inflow data are used. An application of the method which analyses two existing water supply subsystems is presented. The possible situations, in which drought occurs or the water demand target increases, are simulated and the risk is calculated and analysed .

The basin of Mexico.

Abstract: This chapter in a book on environmentally threatened regions of the world which presents a case study of the Basin of Mexico illustrates that the conditions of open space water availability water and air quality and sewage treatment are pushing the region beyond the ability to sustain the present quality of life. Mexico Citys urban expansion is expected to cover 2700 sq. km by the year 2000. 30 million people will live in the Basin. The region will need a sustained source of water. This would require expensive water pumping from other regions. At the present rate of change 92% of the Basin will soon be covered by houses and roads. During the past 100 years the region has shifted from high self-sufficiency in natural resources to dependence on imports. The Basin passed its ability to supply sufficient water for its population in the 1960s. Mexico City has not solved the problems of solid waste disposal and recycling. Air quality is very low in some areas at certain times of the year due to thermal inversions that trap pollutants. Automobile emissions account for 85% of all atmospheric pollutants and the number of cars continues to increase at a rate of 7% annually. Vulnerability is dependent on reducing the number of cars on the road and on sustained emission controls. Environmental awareness occurred during the 1970s. During the 1980s environmental policy became a higher government priority. In mid-1980 the government began to act to prevent pollution. Several laws were passed during 1989-94 to prevent pollution. However the programs and laws have had minimal impact on the critical levels of pollution. Economic interests are still strong and the control measures are too small in scope to have an impact. Four major types of environmental groups are active and aim to change public opinion. The history of this region is one of growth collapse and rebirth. The government and society must find new ways to solve old problems of centralism resource dependence and pollution.

The impact of small farm reservoirs on urban water supplies in Botswana

Abstract: In eastern Botswana there are many small farm reservoirs within the catchments of the major water supply reservoirs, and there is increasing demand for more small reservoirs. The increasing development of farm reservoirs has an impact on the availability of water from the major reservoirs, which supply urban and industrial users, and this creates a conflict between the needs of the rural water users and the urban and industrial users. This paper describes a model which has been developed to allow the effects of the existing small reservoirs and the possible impacts of future proposed ones on the water resources of the major reservoirs to be quantified. The model provides a planning tool, enabling guidelines for future small reservoir development to be determined. The model is a general one which could also be calibrated and applied in other areas with a broadly similar climate. The results of a series of model runs indicate the rate of decline of runoff and yield from the major reservoirs as the total capacity of small reservoirs within the catchment increases. It also shows how this decline is affected by secondary factors such as the relative location of the small reservoirs within the catchment, the typical size of small reservoirs and the type of use to which they are put. The results clearly indicate the adverse effect which uncontrolled development of farm reservoirs would have on the water supplies from the major reservoirs. By quantifying these effects, planners have some of the necessary information to determine the optimum balance between development of small-scale rural water supplies and large-scale urban supplies.

Drought Water Rationing and Transferable Rations

Abstract: Water rationing is a common, but little studied, technique for managing urban water supplies during drought. This paper reviews a wide range of approaches for implementing water rationing for urban drought management. These rationing approaches are assessed in terms of practical and theoretical performance. The paper then examines the potential benefits of allowing drought water rations to be transferable or marketable. Transferable rights have become a common suggestion for allocating scarce resources for a wide range of water-quantity and water-quality problems. Although attractive in terms of economic theories of resource allocation, transferable drought water rations often will be uneconomical for small transactions, due to likely high costs of completing transactions. However, transferable drought water rations might be useful for allocating scarce water among large industrial, commercial, and institutional users and among residential users with very different water demands. The equity effects of tra...

Divided Waters: Bridging the U.S.-Mexico Border

Abstract: Among all natural resource and environmental problems between the United States and Mexico, water has been the most troublesome, with ongoing historic contests over water supply becoming superseded by new controversies over water quality. Divided Waters analyzes the politics of water management along the U.S.-Mexico border, using the case of Nogales, Arizona and Nogales, Sonora as a window on the problems and possibilities involved. The authors explore the water problems that Ambos Nogales shares with larger border communities surface and groundwater contamination, inadequate and insecure supplies, inequitable distribution of resources, flooding, and endangered riparian habitats considering both the physical characteristics of the water supply and the coping mechanisms of the people who make use of it. They review the prevailing confusion of laws, administrative practices, and political incentives, then recommend the design elements they believe must be included before successful improvements can occur at both the institutional and the resource management levels.

Multiple criteria for evaluation of reliability aspects of water resource systems

Abstract: The problem of multiple criteria for evaluation of water resource systems is addressed. Alternative criteria for quantifying various reliability aspects like recurrence, duration, severity and conse­ quences of the non-satisfactory system performance are reviewed. The notions of uncertainty and non-stationarity are also discussed. They pertain to both the demand and supply sides of the problem. Therefore, joint analysis must be carried out. Applications of the concepts and methodology to case studies of expansion of water supply systems in Poland are presented. The analysis was based on the assumption of stationary hydrology (historical flows) with no account of possible climate change impacts on water resources and with different projections of demographic growth and economic development. Several variants of modification of the supply were considered, including the cases with hypothetical new reservoirs. Now, only a few years after the studies were conducted, it is known that future water demands will be very different from the scenarios considered.

Water and sanitation: health and nutrition benefits to children.

Abstract: This document is the ninth chapter in a book that identifies priorities for action to enhance child growth and nutrition in developing countries This chapter concentrates on poor sanitation and contaminated water as causes of infectious disease The first part of the chapter examines evidence that improved water and sanitation reduce exposure to pathogens and disease In these studies the presence of a flush toilet was associated with bottle-fed infants being less likely to die and with significantly higher height-for-age among low-income preschoolers Child growth was enhanced in households with both a latrine and increased water usage Similarly the presence of piped water reduced mortality among bottle-fed infants and among low-income preschool children in general Data from different parts of the world show a greater effect of sanitation and water supply improvements on children of less-educated mothers and in contrast of better-educated mothers Water quantity may be more important than quality in reducing exposure to pathogens in contaminated environments The second part of the chapter considers how improved water supplies save women time formerly spent collecting water and lead to improvements in child health because more time may be spent on child care on learning and on income generation It is concluded that water and sanitation improvements improve child health and nutrition and that water and sanitation interventions can complement other interventions or compensate for undesirable conditions The design of such interventions would benefit from research into 1) the conditions in which such improvements could be maximized 2) direct measurements of the mechanisms in which increases in water quantity quality and maternal time reduce pathogen transmission 3) the use of time saved 4) the interaction between disease transmission and behavior and 5) the relationship between improved water and sanitation and acceptance of other interventions

Rural-to-urban water transfers: measuring direct foregone benefits of irrigation water under uncertain water supplies

Abstract: Irrigation water from a southeastern Colorado county has been sold to distant municipalities. The county's junior water right delivered limited and uncertain water supplies which were used on relatively poor soils. The ability of water markets to allocate water to the highest-valued use was addressed by assessing the direct foregone benefits of the transfer using deterministic and discrete stochastic sequential (DSSP) programming models. Crop mix predicted by the DSSP followed observed regional patterns. The DSSP was thus used to derive regional water demand from which foregone value was estimated. Direct regional foregone agricultural benefits were relatively low-due to uncertain water supplies and unproductive soils-indicating the market selected a low-valued supply for transfer.

Public service deficiencies and Aedes aegypti breeding sites in Venezuela.

Abstract: The 1992 study reported here assessed relationships between potable water supply and trash collection practices and the prevalence of dengue vector mosquito (Aedes aegypti) breeding sites in 30 towns located along the north coast of Venezuela. Within each study town, 100 homes were chosen. At each of these homes the number of water-bearing containers and containers harboring A. aegypti were determined and interviews were conducted to obtain information about the local water supply, trash collection services, and excreta disposal. In general, A. aegypti breeding indexes were high: 55% of the residences were found to harbor A. aegypti immature forms; there was an average of 118 breeding sites per 100 residences; and 24% of the water-bearing receptacles were observed to contain the mosquito. The statistical method of principal component analysis was employed to rank the 30 towns in terms of variables describing public service deficiencies, and correlations existing between the variables studied were determined. Direct correlations were found between two water supply variables (frequency and duration of water supply interruptions), between the excreta disposal and trash collection variables, between the duration of water supply interruptions and the Aedes breeding indexes, and between the duration of water supply interruptions and the mean number of A. aegypti breeding sites found in water storage containers. Overall, the towns with the poorest services were found to have the highest breeding indexes and the greatest numbers of water storage containers harboring the mosquito. It is concluded that public service (water supply and waste disposal) deficiencies were largely responsible for A. aegypti propagation in the study towns. Accordingly, it is recommended that local programs be implemented for recycling containers, constructing water storage tanks that cannot harbor Aedes larvae, and conducting health education and community participation campaigns directed against the mosquito.

Water Quantity/Quality Management and Conflict Resolution: Institutions, Processes, and Economic Analyses

Abstract: Illustrations Acknowledgments Introduction Institutions and Processes Concepts and Case Studies Management of Water Problems through Laws and Government Organizations Evaluation of Two Institutional Arrangements for Resolving Interstate Water Disputes by William B. Lord and Douglas S. Kenney The Role of the U.S. Government in Water Quality and Quantity Issues by Cynthia Dyballa The Federal Clean Water Act and Its Application to the San Francisco Bay Estuary by Gregory A. Thomas Institutional Development and Performance in Managing Southern California Groundwater Basins by William Blomquist Water Use and Transfer in Taiwan by Ching-Kai Hsiao Water Dispute Resolution Mechanisms in India by Shashikant Raghunath Sahasrabudhe, Ved Prakesh Vohra, and Mukesh Kumar Conflict Resolution in Ontario Water Resources Policy by Isobel W. Heathcote Interstate Water Management: The Case of the Murray-Darling Basin in Australia by Warren Musgrave Design of Markets and Other Institutions The Design of Institutional Arrangements for Water Allocation by K. William Easter and Yacov Tsur Resolving Water Transfer Conflicts Through Changes in the Water Market Process by Charles W. Howe and David J. Goodman Alienable Privatization Policies: The Choice between Inefficiency and Injustice by Norman Frohlich and Joe Oppenheimer Integrating Equity, Efficiency, and Orderly Development in Western U.S. Groundwater Allocation by Arthur H. Chan Integration of Quantity and Quality in a Water Market by Asghar Sabbaghi and Nicolas Spulber Conflict Resolution Through Bargaining, Negotiation, and Mediation Toward a New Nile Waters Agreement by Dale Whittington, John Waterbury, and Elizabeth McClelland Resolving Conflicts Over Water Disputes in the Jordan River Basin by Aaron Wolf and Stephen Lonergan Conflict Over Eastern U.S. Water Transfers: Toward a New Era of Negotiation? by Leonard A. Shabman and William E. Cox Western U.S. Indian Water Conflicts: A Discussion of Economic Issues by Bonnie G. Colby Resolving Intergovernmental Water Disputes through Negotiation by Jeffrey L. Jordan Lessons in Conflict Resolution: The Case of the Denver Water Department by Kathleen Anderson and Tim Holeman Resolving Environmental Conflicts through Mediation by An Painter Bargaining and Water Disputes: A Perspective on the Coming Decade by Leonard A. Shabman Coalitions, Collective Action, and Cooperation Competing Demands for California's Scarce Water by Richard E. Howitt and Henry Vaux Collective Action in Irrigation by Raouf F. Khouzam Cooperative Solutions for Problems of Water Supply by Edna Tusak Loehman Cooperative and Noncooperative Water Diversion in the Great Lakes Basin by Nir Becker and K. William Easter Innovations in Cooperation: North American Waterfowl Management Plan by Luther P. Gerlach Methods of Economic Analysis Designing Institutional Rules Protecting the Quality of Water Resources: Designing an Emission Charge System in New Zealand by Frank Scrimgeour Political Economy of the Transition from Water Rights to Water Markets by Farhed A. Shah and David Zilberman Minimizing Potential Distortions in a Spot Water Market: A Multilateral Bargaining Approach by R. Maria Saleth and John B. Braden A Bargaining Model for Water Transfers Including Water Quality by George B. Frisvold and Margriet F. Caswell Common Pool Resources: The Relevance of Laboratory Experimental Research by Steven C. Hackett and James M. Walker Evaluation of Alternatives and Interest Group Analysis Positional Analysis Applied to Water Pollution Problems in Developing Countries by Dugushilu Mafunda and Stale Navrud Political Power Measures for Water Management Interest Groups by C. Robert Stark, Jr., David S. Bullock, and Wesley D. Seitz Analyzing Interest Group Preferences for Groundwater Management: An Application of the Analytic Hierarchy Process by Keith Willett and Ramesh Sharda Contingent Valuation in Resolving Local Public Water Problems by Wesley N. Musser, Lynn M. Musser, Andrew S. Laughland, and James S. Shortle Economic and Political Analysis of Dredging Ohio's State Park Lakes by Fred J. Hitzhusen, Somskaow Bejranonda, Timothy Lehman, and Robert Macgregor Index

Private Sector Participation in Water Supply and Sanitation in Latin America

Abstract: The water and sanitation sector in Latin America and the Caribbean is facing a crisis of confidence. The return of cholera to the region in 1991 was a symptom of deep seated problems and exposed the fragility and inadequacy of publicly operated water supplies and sanitation systems. Despite substantial efforts to improve the quality and coverage of service, one quarter of the urban population is not connected to a public water system, half lacks public sewerage, and the sewage is virtually untreated. The results are a constant threat to the health of the entire population, a perpetuation of unmet basic needs of the poor, and a steady deterioration of the environment. In recent years, private sector participation in water and sanitation has been a topic of discussion among various countries in Latin America, as evidenced by the large attendance at a number of regional seminars organized by the Technical Department of the World Bank's Latin America and the Caribbean Regional Office. These seminars have shown that virtually all public water companies are interested in cooperating with the private sector. Some have advanced further and have already involved the private sector in their operations in one way or another. The seminars have catalyzed the pursuit of greater private sector participation and the evolution of privatization models adapted to the institutional realities of Latin America and the Caribbean. This publication incorporates some of the insights gained at these seminars and is aimed at assisting the decisionmaking process that many countries face. The publication consists of two chapters. In the first¾Options for Private Sector Participation¾the main problems of the public sector are analyzed, the rationale for private sector participation (PSP) is explained, and the array of options for PSP is reviewed. In the second chapter Case Study: The Buenos Aires Concession the large concession for the Greater Buenos Aires water supply and sewerage services awarded by the government of Argentina to a private consortium of foreign operators and local investors is presented and analyzed, because it provides an excellent example of the planning and implementation stages that are needed to ensure a successful transition from public to private management.

Technical efficiency of rural water utilities

Abstract: Technical efficiency of rural water utilities is determined using frontier production functions An indirect production function is developed to model the two-step production process of a local government-controlled firm Data from 26 rural Nevada water utilities are used to estimate inefficiency in terms of firm-specific variables A multistep estimation procedure is used instead of single-step maximum likelihood estimation Model selection tests are used to choose the best model Privately owned utilities are most efficient; self-governing water districts are the least efficient Municipal governments operate the most and least efficient utilities

Water and Land as Quantity-Rationed Inputs in California Agriculture: Empirical Tests and Water Policy Implications

Abstract: This paper evaluates competing models of input use for two inputs, surface water and land, in central California agriculture. Applying a model of the multiproduct firm, a variable input model is compared to a fixed input model using model specification tests. Test results support the fixed input model for both surface water and land. The finding that surface water is a quantity-rationed input addresses an important water policy issue, implementation of the Central Valley Project Improvement Act. Water rationing has implications for three key provisions of the act involving water price increases, water marketing, and water supply restrictions.

Financing water supply and sanitation under Agenda 21

Abstract: This paper assesses the financing challenges which have to be met by developing countries if water resources are to be managed efficiently, if the quality of the aquatic environment is to be improved and if water related services are to be delivered in a responsive, efficient and equitable way. This paper takes the view that attaching ‘price tags’ to water supply and sanitation, as was tentatively done in Agenda 21, is a misguided approach and that what is needed is articulation of clear principles which should underpin the financing of water supply and sanitation investments. To illustrate the approach the paper focuses heavily on experiences from World Bank water supply, sanitation and urban development projects over the past 30 years. The challenge is to develop appropriate institutional and financial arrangements. The essence of such arrangements is that they ensure that societies mobilize appropriate levels of resources for providing water related environmental services and that these resources are used in the most efficient and effective way possible.

Environment and Health in Central and Eastern Europe: A Report for the Environmental Action Programme for Central and Eastern Europe

Abstract: This volume is divided into three discussions. The first is the examination of the determinants of health in central and eastern Europe and contributions from history the physical environment the economy life styles and the social and political environment. The second part evaluates health exposure to harmful environmental conditions from mining poor town planning lead air pollution arsenic in drinking water microbiologically contaminated water food contaminants unique problems and concerns where data is lacking. The final discussion addresses environmental actions investments and the need for remediation-oriented health data. The evidence suggests that environmental pollution is one of a number of competing determinants of health including shortcomings in medical care and life style factors such as smoking diet and exercise. Data from 12 countries in central and eastern Europe are used to identify specific locations and the nature of the environmental problem. The countries include Bulgaria the Czech Republic Slovakia Hungary Poland Romania Estonia Latvia Lithuania Belarus western Russia and the Ukraine. The most common health problems pertain to lead in the air and soil and neurobehavioral dysfunction air-born dust and respiratory conditions sulfur dioxide and other gases nitrates in drinking water contaminants in food and contaminants in water. Drinking water is contaminated by inappropriate fertilizer application improperly located rural septic tanks feed lots and agricultural businesses. Contamination also occurs from inappropriate disposal of water contaminated with arsenic viruses or bacteria pesticides radionuclides and chlorinated organic compounds. Inappropriate handling or disposal of lead dust heavy metals pesticides polycyclic aromatic hydrocarbons and chlorinated organics such as PCBs affect the toxicity of foods. Public investment will be required to speed up the process of environmental improvement and to address persistent environmental problems. Priorities are investment in dust collection systems emission reduction replacement of coal as fuel and proper disposal of manures and domestic septic waste.

Impact of chlorination of water in domestic storage tanks on childhood diarrhoea: a community trial in the rural areas of Saudi Arabia

Abstract: During the period September 1991 to February 1992 standard chlorination packages of calcium hypochloride were provided for the first time to 171 families residing in the catchment area of the Sabt-Bany Bishr Primary Health Care Centre in the rural areas of the Asir region, south-western Saudi Arabia. The villagers added the packages to their home storage water tanks each time they added water from the 220 nearby wells. Analysis of the water samples taken from these wells showed that all of them were bacteriologically unfit for human use. By the end of the study period there were no bacteriologically unfit water samples taken from the tanks of the participating families. Children under 5 years of age whose families were not using chlorinated water had twice the risk of diarrhoea compared to children from the participating families (odds ratio = 1.98, P = 0.047). The use of chlorinated water was associated with a 48% reduction in diarrhoea. These results indicate that the chlorination of water can be successfully carried out locally in rural areas to improve the health of the population.

Global water crisis: the major issue of the 21st century, a growing and explosive problem.

Abstract: The authors explore what is considered to be the emerging issue of the 21st century shortages of water. It is expected that the Netherlands which is entirely dependent on water from other countries will be in an extremely vulnerable position. The quantity of fresh water is limited. Contamination of water reduces water quality and availability. Many World Bank projects focus on management of the water supply for sanitation irrigation hydroelectric power and construction of dikes in order to prevent flooding. The World Bank concludes that everyone worldwide must acknowledge that fresh water is a scarce natural resource. The Action Plan Agenda 21 of the UN Rio Conference emphasized the importance of the widespread shortage gradual destruction and increased pollution of fresh water reserves. The four major world problems with fresh water are 1) shortages of renewable supplies 2) unequal distribution of supplies 3) problems of water quality and health and 4) disastrous effects of unrestrained construction of dams and reservoirs. Only 2.5% of the total amount of water on earth is fresh water of which 69.4% is in the form of ice snow or permafrost and most of the remainder is ground water. Fresh water in lakes and rivers is only about 1% of fresh water available on earth. Most of the precipitation that falls on land every year is lost through evaporation. 45000 sq. km is the absolute maximum available annually. Distribution of water among industry agriculture and households varies by country. Arid regions constitute about 33% of Europe 60% of Asia 85% of Africa and most of Australia and western North America. 14% of countries are at or under the poverty line of water availability 37% have dangerously dry conditions 14% have average levels and 35% have ample supplies. Examples of water management are given for the Amazon River the Euphrates and Tigris the Aral Sea and the Rhine River Basin. It is estimated that the world supply of fresh water would meet the needs of 4.5-9.0 billion people.

Spatial modelling of snow water equivalent using airborne and ground- based snow data

Abstract: As the population and industrial infrastructure of the United States continue to grow, the demand for water and the need to forecast water resources accurately are intensifying. Hence, the National Weather Service maintains a set of conceptual, continuous, hydrologic simulation models used to generate extended streamflow predictions, water supply outlooks and flood forecasts that are the basis for major water management and disaster emergency services decisions for the United States. A vital component of the hydrologic simulation models is a snow accumulation and ablation model that uses observed temperature and precipitation data to simulate snow cover conditions. The simulated model states are updated throughout the snow season using snow water equivalent estimates obtained from airborne and ground-based snow water equivalent data. The National Weather Service has developed a spatial model to obtain integrated snow water equivalent estimates for updating the snow model; however, it is designed to incorporate only ground-based data. In this research, we describe the spatial model and show how to modify it to include data of two different supports (the airborne and ground-based data) so that more precise integrated snow water equivalent estimates can be obtained. The results are illustrated on snow data collected in the Upper Colorado River basin.