Showing papers on "Water supply published in 1981"

Effect of investments in water supply and sanitation on health status: a threshold-saturation theory.

Abstract: A general theory on the relationship between water supply and sanitation investments and health, the threshold-saturation theory, is proposed. The theory takes into consideration three variables: health status, socioeconomic status, and sanitation level, and attempts to encompass, for the first time in one general theoretical framework, numerous conflicting empirical findings. The two-tiered S-shaped logistic form of the relationship that is proposed assumes that at the lower end of the socioeconomic spectrum there is a threshold below which investments in community water supplies and/or excreta disposal facilities alone result in little detectable improvement in health status. Similarly, at the higher end of the socioeconomic scale, it is suggested that a point of saturation is reached beyond which further significant health benefits cannot be obtained by investments in conventional community sanitation facilities. A preliminary attempt to validate this model using published data on sanitation level (defined as access to water supply), life expectancy, and adult literacy rates, for 65 developing countries, appears to provide preliminary support for the threshold saturation theory but further empirical validation is required before a quantitative predictive model can be developed.

Residential Water Conservation

Abstract: Severe pressures on many urban water utilities are the result of water shortages, high treatment costs, scarce supplies and rapid growth. Various water-conservation techniques can be used to reduce the demand for water by urban customers. These include restrictions on use, installation of water-saving devices, metering, horticultural changes, pressure reduction, reuse, and public education. The effects of metering, water-saving devices and price increases on residential water demand are explored for some typical communities. Secondary effects of conservation on revenue production and return flow are also discussed.

A Water Supply Cost Model Incorporating Spatial Variables

Abstract: This paper presents new evidence on scale economies in multi-product firms. Previous studies are limited in view of recent advances in the theory of the multi-product firm. The water utility is chosen here as a multi-product firm providing multiple ...

A model for water reuse planning

Abstract: A water reuse planning model has been developed for use in determining the optimum reuse of waste-water on a regional basis that minimizes the overall cost of water supply for single period planning. Wastewater from all use sectors, along with fresh water, are considered as candidate sources or origins of water for other elements within the use sector and also for elements of other use sectors. Quality parameters of various sources of flows are explicitly considered. The model allows for economies of scale in treatment and transportation through the use of a nonlinear objective function and consists of both linear and nonlinear constraints. The model is solved using a large-scale generalized reduced gradient technique. The analysis of hypothetical examples shows how the model can evaluate various planning scenarios, allowing the planner a broad spectrum of solutions to choose from.

The occurrence of trihalomethanes in public water supply systems of New York state

Abstract: ished water systems as well as indicating contamination from other sources Each of the samples collected was analyzed for the eight organic chemicals In addition, several water treatment and water quality parameters were noted at the time of sample collection The parameters recorded when available included water temperature, raw water color, prechlorination and postchlorination doses, raw water pH, finished water turbidity, chlorine contact time, chlorine residual, and chemicals added during treatment The possible associations drawn between the THM levels encountered and the water treatment parameters are discussed in the conclusions

Demand Forecasting in Water Supply Networks

Abstract: The problem of forecasting consumer water demands over a 24 hour period is formulated within the framework of an on-line computer based pump scheduling scheme for optimum operational control of a water supply network. Two well known forecasting techniques are considered and compared, in terms of accuracy and computational feasibility, using real data from a network in the United Kingdom.

The Relationship of Cholera to Water Source and Use in Rural Bangladesh

Abstract: The cholera experience of a sample of families in a rural area of Bangladesh is reported in relation to water supply and use. Tanks were the primary source for 65% of families, canals for 20% and the river for 14%. The highest attack rate was associated with access to canal water (13%). Attack rates did not vary markedly according to the purpose for which a source was used. The importance of cultural patterns in water use is identified.

Water reuse planning models: Extensions and applications

Abstract: A water reuse planning model has been developed for determining the optimum allocation of water and reuse of wastewater on a regional basis for multiperiod planning that minimizes the overall cost of water supply. Both water quantity and water quality parameters of various sources of flows are considered. Wastewater from all use sectors, along with freshwater, can be considered as candidate sources or origins of water. The model considers the capacity expansion of treatment facilities and allows for economies of scale in treatment and transportation through the use of nonlinear objective functions. Either the large-scale generalized reduced gradient or the successive linear programing methods can be used to obtain solutions to the models. Both single-period and multiperiod models are applied to a region including San Antonio, Texas. The single-period model was applied to planning scenarios for the years 1980, 2000, and 2030. The multiperiod model was applied using a planning horizon consisting of three periods, 1980–2000, 2000–2030, and 2030–2060. Comparisons were made of the single-period model applications and the multiperiod applications. The solution of a sequence of single-period problems does not correctly represent the dynamic nature of the systems.

Water, Sanitation, Health: For All: Prospects for the International Drinking Water Supply and Sanitation Decade, 1981-90

Abstract: The International Institute for Environment and Development published a book reviewing the possibility of everyone having access to potable water and adequate sanitation and thus improved health. The book is dedicated it to a late lobbyist to the UN (Barbara Ward) for the establishment of the 1980s as the International Drinking Water Supply and Sanitation Decade. The book begins with a discontinuation of the reason for this theme including who did not have clean water an adequate sanitation and projected targets and costs. The authors also looked at water and sanitations links with disease especially during rainy seasons and the economic and social costs of transporting water. Some of the problems with water supply and sanitation programs including maintenance repair and construction are addressed. The authors also emphasized the importance of health education which can be integrated in to existing public health programs. They stressed that clean water without concomitant sanitation efforts are fruitless thus they provided lessons learned and obstacles to avoid to reach decade goals. The authors presented 3 case studies from Colombia India and Kenya. In Colombia in 1980 936 towns had a water supply but only 217 had water treatment plants. Water pollution came from sewage industry and coffee wastes. The President of Colombia planned to invest US $190 million in water and sanitation projects but the government invested only US $24 million in 1980. 33% of the worlds people without clean water and sanitation lived in India in 1980. 53% of the Indian urban population had no sanitation facilities in all. India was able to produce its own water supply systems however (e.g. in India Mark II pump). Arid Kenya continued having considerable with providing an accessible water supply and adequate sanitation to residents. The authors concluded the book with a chapter on the expectations and prospects for the Decade.

Deterministic Models for Predicting Residential Water Consumption

Abstract: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.

Designation of Principal Water-Supply Aquifers in Minnesota

Abstract: From introduction: The purpose of this report is to describe the general quality and quantity of water in the principal water-supply aquifers in Minnesota.

Analysis of Firm Water Supply Under Complex Institutional Constraints

Abstract: River basin computer simulation studies often do not properly include the complex legal and institutional factors governing water allocation. These factors include formal water rights and informal borrowing agreements among the basin water users. An attempt has been made in this study to show that such factors can be included. We also show that an optimal, integrated approach to reservoir operations in a river basin can do much to alleviate the burden of new demands placed on available water resources. The procurement of a firm water supply for a proposed coal fired power plant is analyzed as a case study. An efficient river basin simulation model is used to determine the viability of a scheme for providing an annual firm water supply to the plant, with consideration of the existing water storage and demands within the basin. Given the hydrologic sequence considered, the model results show that the proposed strategy is viable in that the required firm water supply can be realized without causing harm to decreed water users in the basin. However, integrated diversion and reservoir operations are required to assure a desirable uniform rate of delivery of reusable effluent to the power plant.

Wetlands' Use for Water Management in Florida

Abstract: The 2,300 square mile (6,000 km²) Kissimmee River Basin in Central Florida is under pressure for rapid expansion due to urban encroachment and agricultural activities The river contributes the major portion of surface inflow and a substantial portion of the nutrient loads to Lake Okeechobee, the primary water supply source for South Florida A basin-wide water management scheme has been proposed based on detention of runoff, restrictions of surface water discharge rates, and routing flow through natural or manmade marshes The ability of these marshes to serve as quantity and quality control areas is evaluated, and specific questions are addressed concerning trade-offs among drainage, flood control, water supply, and water quality enhancement

Egypt: after the Aswan Dam

Abstract: Ten years after its completion, the controversial Aswan High Dam's hydrologic and human consequences are clearer because of a joint US-Egyptian interdisciplinary study. Water supply and distribution is emerging as a major world resource problem with the recognition that unsafe drinking water and inadequate sanitation contribute to health problems. Dams provide water supplies, but they also create conditions favorable to the spread of water-borne diseases. The Aswan Dam solved problems of flooding and drought by opening 2.5 million acres to year-round irrigation, although some of the reclaimed land has been lost to urban expansion and shoreline erosion, and provides hydroelectric power. The negative effects include increasing soil salinity, changes in the water table, excessive downstream water plant growth, and diseases such as schistosomiasis and other intestinal parasites, and the social impact on the Nubians, whose homeland was flooded. Planners must use the information gathered in this study to see that the benefits outweigh the human costs. 22 references, 7 figures.

Cost of Small Water Supply Treatment Systems

Abstract: Many of the major problems associated with implementing the Safe Drinking Water Act are related to small water systems. These problems include, but are not limited to, inadequate facilities, inadequate operation and maintenance, inadequate water quality monitoring, and contaminant level violations. Many of these problems can be traced to a lack of appropriate technology for treating water sources. Various treatment techniques, including package plants, are explored, and their costs are evaluated.

Water resource optimisation in small dams in the dry zone of Sri Lanka : a time series analysis and stochastic simulation approach

Abstract: Small dams constitute the centres of traditional settlements and a predominant source of water supply in the Dry Zone of Sri Lanka. Many of the dams do not have connections with perennial supplies and hence are solely dependent upon their own catchments' rainfall for replenishment. Typically, the water resource provides for in situ domestic uses and for the irrigation of crops, mainly rice, particularly during the dry season. With these two uses somewhat in conflict, a definition of community welfare is proposed. Taking the case of early maturing rice crops, it is seen that welfare can be maximised by matching the cropping calendar of the wet and dry season with the rainfall distribution. In this framework withdrawal is minimised. A major consideration in the formulation of this water resource optimisation problem involves the justification of a 'level of water applicationyield' production function for rice. Direct solution of the optimisation problem is complicated by the temporal nature of allocation and the stochastic dynamic nature of water supply in the dam. The approach adopted is to first build a simple transfer function model of water storage using rainfall and other major causal variables as inputs and allowing for the effects of uncertainty and measurement noise. Then by applying the recursive instrumental variable approximate maximum likelihood method for identification of the appropriate model structure and identification of the parameters and their distributions therein, a statistically based time series model is made available for performing Monte Carlo simulations. Thus, the effects on storage can be observed by separately entering various supplementary irrigation policies and

Browning of America

Abstract: The overuse of ancient underground aquifers combines with an uneven distribution of water resource, drought, waste, and pollution to present serious policy choices which could follow the same ineffective path as our oil policies. Irrigating arid and semi-arid lands is an energy-intensive and expensive undertaking that needs to be reexamined. Water shortages due to shifts in weather patterns can lead to heavier-than-normal reliance on the major aquifers, while contamination of surface and ground waters further depletes US water supplies. Policy decisions must be made that will alter wasteful consumption habits, introducing metering and conservation to convince Americans that cheap water, like cheap oil, is no longer available. (DCK)

Optimization of Water Resources for Irrigation in East Jordan

Abstract: The paper describes an approach towards optimal allocation of surface and ground water resources to three agricultural areas in the Jordan Valley under conditions of scarce water supply. The optimizing model allocates water from three main rivers, each with reservoir storage, and from two ground water sources to three irrigation regions. Productivity of irrigation water, expressed as the net present value of the regional agricultural output, but allowing for crop water deficits, is first maximized using nonlinear programming. The allocation process then adopts techniques of linear programming to determine the least cost alternative based on the unit cost of water from each resource at each destination, as it varies with time.

Modelling Determinants of Health

Abstract: McKeown (1976) suggested that a large part of the historical improvements in the health of populations of the now developed nations took place in conjunction with socioeconomic improvements. The relevance of this to developing countries and its economic implications was explored with an analysis of infant mortality rates (IMR) in the 22 districts of Sri Lanka in relation to housing and basic utilities. The percentage of households in each district of Sri Lanka with basic utilities in the year of the National Census (1971) were correlated and regressed against the IMR/1000 live births for the same year. The utilities were tap water well water river water latrines cement floors asbestos or tile roofs brick or cabook walls and electricity. A sequential regression analysis with stepwise elimination was used. The only variables significantly associated with the IMR appeared to be those concerning the nature of the water supply used by the households. Latrines were significantly associated with IMR once allowance was made for qualitative differences between districts. The cost of effecting changes in IMR by extending subsidies to water supply improvements is estimated.

Blaney-Criddle Coefficients for Western Turf Grasses

Abstract: Evapotranspiration rates were measured for several turf grasses in Arizona, California, Colorado, and Wyoming. These data were used to calibrate the Blaney-Criddle method for estimating evapotranspiration rates. Warm-season grasses used less water than did cool-season grasses when grown in warm climates. However, Kentucky bluegrass did exhibit heat stress that reduced its evapotranspiration rates below what would be expected when soil temperatures exceed 25/DEG C. The data were collected in urban areas and should be representative of city-wide water requirements for turfed areas.

Reduction of water solids contributions to apparent cotton dust levels through use of special water in atomizers

Abstract: A method of treating the water supplied for humidification of the textile processing room environment (e.g. weaving room) results in reduced apparent cotton dust concentrations, while maintaining or increasing processing efficiency. The water supplied to the humidification system for the processing environment is pure water, such as reverse osmosis water, distilled water, deionized water, demineralized water, etc. Humidification is primarily achieved utilizing atomizers, and a pure water supply can be generated on-site by treating tap water with conventional deionizers or demineralizers.

Risk Avoidance Objective in Water Resources

Abstract: In the past, risk has been considered implicitly in the planning and management of water resources systems analysis. A method is developed through which risk indices are explicitly defined for the operation of a water supply system that provides water mainly to meet regional irrigation and energy requirements. The risk indices obtained can be included in the system objective function to be optimized.

Controlling method for water heater

Abstract: PURPOSE:To prevent flactuation of the total amount of hot water supply despite flactuation in the amount of water supply, by terminating water supply when calculated value of supply water flow signal reaches a certain amount in a water heater that sets the temperature of water by regulating water supply. CONSTITUTION:In a water boiler 7 that burns fuel F while water W is supplied, the supply water W is detected by a flow amount sensor 1 and counted by a counter 2. The counted signal is compared with a preset value A by a comparator 3 and when the counted signal reaches the preset value, the output signal is sent to a controller 6 and a water supply amount controller 5 terminates water supply. When there is no output signal from the comparator 3, the controller 6 supplies the predetermined amount by the water supply controller 5, based on the supply water temperature signal from the supply water temperature sensor 4.

Rural water supply and the problem of health in village India, case of the Varanasi District.

Abstract: The present paper presents an existential analysis of the condition of rural India in reference to water supply and pollution and the resulting health hazard mainly due to high content of chloride, nitrate, sulphate and the hardness. From the view-point of public health, the prevailing sources of water supply i.e. wells, streams and reservoirs, are the subject of contamination as they are exposed to pollution from surface drainage, household and animal refuse, as well as from the uncleaned buckets used for carrying water. In reference to bacterial checkup of athe well water awareness among villagers is necessary, so that the government authorities may provide good quality drinking/potable water through their schemes.

Water Supply as a Limiting Factor in Western Energy Development

Abstract: This paper discusses the consumptive water needs of the various energy conversion processes including oil shale retorting, coal gasification and liquefaction, electric power generation, and slurry pipelines. Projected energy development water needs in the upper Colorado River and Upper Missouri River basins are compared with projected agricultural needs and water available. The comparative cost and values of water to energy and agricultural development are discussed to emphasize this as well as the political and social factors entering into the picture.