scispace - formally typeset
Search or ask a question

Showing papers on "Water supply published in 1991"


Journal ArticleDOI
TL;DR: In this article, an economic model to assess irrigation technology choice is developed, which takes into consideration aspects such as weather conditions and the dual effects of input quality (soil and water).

65 citations


Journal Article
R J Lee1
TL;DR: Routine microbiological monitoring of water supplies is primarily based on tests for coliforms, but these organisms may need supplementing with other organisms to further improve confidence in water supply hygiene.
Abstract: Standards for drinking water have been formalised in the United Kingdom by recent legislation. Routine microbiological monitoring of water supplies is primarily based on tests for coliforms. These organisms have been used successfully for indicating contamination and treatment failures, but may need supplementing with other organisms to further improve confidence in water supply hygiene. Novel techniques may greatly alter the water microbiology laboratory.

54 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examine the problem of extending access to potable water through conventionally controlled government services and describe the roles of non-governmental organizations and community management associations in improving service delivery and maintaining local water systems.
Abstract: This article examines the problem of extending access to potable water through conventionally controlled government services and describes the roles of non-governmental organizations and community management associations in improving service delivery and maintaining local water systems. Six sets of factors that are crucial to the success of community management are identified: adequate incentives, sufficient skills and resources, appropriate processes for water systems operations and maintenance, effective interorganizational relationships, appropriate technology, and effective systems of monitoring, evaluation and feedback. The components that must be taken into consideration in designing and implementing programmes for decentralizing water supply systems through community management are set out.

50 citations


01 Jan 1991
TL;DR: Researchers analyzed 1987 data on 2008 75% of children had access to a flush toilet) was basically the same for both urban and rural ares and the risk of stunting was the same in a high level of sanitation area whether or not they had individual access toA flush toilet.
Abstract: Researchers analyzed 1987 data on 2008 75% of children had access to a flush toilet) was basically the same for both urban and rural ares (31.5% and 33.3% respectively). Further the risk of stunting was the same in a high level of sanitation area whether or not they had individual access to a flush toilet. Thus sanitation should receive the same attention and resources as water supply in water and sanitation programs whose goal it is to improve health. The importance of sanitation is universal. The most important goal and evaluation indicator should be achieving a community level of sanitation in which at least 75% of the people have access to sanitary facilities and uses them properly.

44 citations


01 Jan 1991
TL;DR: Water level manipulations are one of the most effective tools in wetland management, provided fluctuations are well-timed and controlled as discussed by the authors, and the size and location of structures are important, but timing, speed, and duration of drawdowns and flooding also have important effects on plant composition, plant production, and avian use.
Abstract: Water level manipulations are one of the most effective tools in wetland management, provided fluctuations are well-timed and controlled. Manipulations are most effective on sites with (1) a dependable water supply, (2) an elevation gradient that permits complete water coverage at desired depths over a majority of the site, and (3) the proper type of water control structures that enable water to be supplied, distributed, and discharged effectively at desired rates. The size and location of structures are important, but timing, speed, and duration of drawdowns and flooding also have important effects on plant composition, plant production, and avian use. When optimum conditions are not present, effective moist-soil management is still possible, but limitations must be recognized. Such situations present special problems and require particularly astute and timely water level manipulations. For example, sometimes complete drainage is not possible, yet water is usually available for fall flooding. In such situations, management can capitalize on evapotranspiration during most growing seasons to promote the germination of valuable moist-soil plants. Timing of Drawdowns

39 citations


Journal ArticleDOI
TL;DR: The urban water problems in Southeast Asian cities are viewed as the consequences of rapid and uncontrolled urbanization and unsutainable development as discussed by the authors, which in turn has resulted in water problems of considerable magnitude.

36 citations


Journal ArticleDOI
TL;DR: In this paper, the sensitivity of some critical water management issues, such as reservoir storage and hydroelectric production, to climatic variability and change on a regional basis is analyzed and presented.
Abstract: The sensitivity of some critical water management issues, such as reservoir storage and hydroelectric production, to climatic variability and change on a regional basis is analysed and presented. This is the second of two papers presented in this issue dealing with the regional hydrological effects of climatic change. By using a set of plausible hypothetical climatic scenarios to represent both greenhouse warming and precipitation changes, the sensitivity of the guaranteed annual fresh water and energy supply levels has been evaluated under conditions of altered runoff for four connected multi-purpose reservoirs in central Greece. It is shown that reservoirs designed and operated under current climatic conditions are, in general, affected by the climatic changes examined. A dramatic increase of the risk associated with the annual guaranteed quantity of water supply and energy production would occur if greenhouse warming were accompanied by a reduction in annual precipitation. Significant increase...

30 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a multiple barrier approach in wastewater treatment, controlled storm water releases, and water supply enhancement, which can be accomplished through the application of a multiple-barrier approach.
Abstract: The greatest impact of water pollution on public health comes through drinking water, the source of which may be degraded by point and nonpoint pollution sources including municipal wastewater, storm water runoff, agricultural drainage, and food processing. While water treatment technology can successfully process poor quality source waters containing in excess of 2000 fecal coliforms/100 mL to produce potable water that meets the accepted drinking water standards, there is serious concern that the barriers to microbial breakthrough in the finished water may prove to be dangerously thin. Any momentary break in the treatment train could allow substantial levels of microorganisms to enter the final product—potable water. The burden of water quality enhancement should be a shared responsibility among all discharges and downstream users of these irreplaceable resources. Much can be accomplished through the application of a multiple barrier approach in wastewater treatment, controlled storm water releases, and water supply enhancement. Dischargers must seek to minimize pathogen releases, reduce particulate dispersion, and diminish organics in effluents. These factors impact heavily on the effectiveness of wastewater disinfection. Furthermore, with passage downstream to the water intake, these organic residuals may be the precursors of disinfection by-products created during drinking water treatment. Some water supply operations must revise their treatment practices to provide better protection from the passage of protozoan cysts and enhance the removal of organics before applying disinfection. Disinfection of water supply is critical and will only be consistently effective in a clean processed water.

28 citations


Posted Content
TL;DR: In a typical year, agriculture will irrigate about 9.6 million acres with 34 million acre-feet of water (DWR 2009, 4-10) or ….
Abstract: Agriculture plays an important part in California's economy and irrigation water is an essential factor in agriculture's success. However, California faces serious water supply issues, in which agricultural uses must compete with environmental uses and the demands of a growing population. Several options are open to policymakers regarding the state's supply, demand and transport of water. California's primary source for water is precipitation-rain and snowfall. In a normal precipitation year, the state will receive about 200 million-acre-feet (maf) in precipitation and imports from Colorado, Oregon and Mexico (DWR 2009, 1-4). Of the total supply, about 60 percent is used directly by vegetation or cropland or flows to salt sinks like saline aquifers or the Salton Sea. The remaining 40 percent, or about 80 maf, enters stream flows or wells and is distributed among agricultural, urban and environmental uses (DWR 2009, 1-4). About 30 maf is used for agricultural irrigation and about 9 maf enters urban and industrial uses. Most of the precipitation occurs in the north and east of the state. However, irrigation water demand is highest in the state's valleys and coastal plains so a storage and transport system was developed to capture this runoff and deliver it during the dry months. California has more than 1,200 surface water reservoirs, in addition to an extensive network of canals, levees, and treatment plants (see Figure 1). Since most of the urban demand lies in the south and along the coast, a series of pumps must transport water at great expense over mountain ranges. The irrigation provided by this system, together with the Mediterranean climate through much of the state, allows the cultivation of a great variety of crops. However, precipitation varies significantly from year to year and water supplies are therefore unpredictable. Moreover, current climate change models suggest that the Sierra Nevada snowpack is likely to decrease in the future (Kapnick and Hall 2009). Recently, increased efficiency in usage has also contributed to the state's ability to meet water needs. However, urban and industrial water demand has risen as the population has continued to grow. Urban water usage, including residential, commercial and industrial uses, is about 8.7 million acre feet annually and growing (DWR 2009, 4-10). Environmental and agricultural water usage vary significantly by year, depending on drought conditions. In a typical year, agriculture will irrigate about 9.6 million acres with 34 million acre-feet of water (DWR 2009, 4-10) or …

27 citations


Journal ArticleDOI
TL;DR: The trend is for less crop restriction and wider crop rotation and thus higher effluent quality requirements as mentioned in this paper, and the economical considerations are favourable even with the need for seasonal storage and extra treatment.

27 citations


Journal ArticleDOI
TL;DR: In this paper, a study of 24 successful watershed management programs yielded a number of techniques utilities can use to protect drinking water supplies, which utilities can then use to improve drinking water quality.
Abstract: Studies of 24 successful watershed management programs yielded a number of techniques utilities can use to protect drinking water supplies

Journal ArticleDOI
TL;DR: The place of sanitary education programmes as a priority among the objectives of health policies is highlighted, with recommendations for technical improvement of water improvement programmes in developing countries.

Journal ArticleDOI
Shamim Ahmad1
TL;DR: In this article, the authors presented the results of a survey regarding public perception and attitude towards water and water reuse in Doha located in the arabian gulf, and found that people seemed to be prejudiced against water reuse.

Journal ArticleDOI
TL;DR: In this article, an ex ante cost benefit analysis of the proposed expansion of the Comprehensive Water Supply Scheme is undertaken, in which the independent variables are the characteristics of a property, including whether or not the property is connected to the Scheme.
Abstract: During the 1950s and 1960s pipelines were built to provide water to many farms in the central wheatbelt of Western Australia using public funds. The resulting network has become known as the Comprehensive Water Supply Scheme. The expansion of the Scheme is currently under consideration. An ex ante cost benefit analysis of the proposed expansion is undertaken. An earlier analysis which focused on the benefits of the reduced necessity to cart water was rejected by farmer groups because of the inability of the analysis to properly account for domestic benefits and risk reduction. To overcome these criticisms a hedonic model of farm land values is formulated in which the independent variables are the characteristics of a property, including whether or not the property is connected to the Scheme. The implicit marginal price (or value) of Scheme connection is then derived. An advantage of this technique is that it estimates the value that the farmers allocate to Scheme water in the market place. The conclusion is that the benefits of Scheme water are considerably less than the costs.

Journal ArticleDOI
TL;DR: In this article, the authors describe some steps that are being taken across the United States to restrict demand, including the setting up of water conservation offices, committees, coordinators, and conferences; the planning of conservation programs by utilities and water districts; and the implementation of conservation measures by the residential, commercial, industrial, and agricultural sectors.
Abstract: Decreasing sources of supply are resulting in a trend toward demand-side alternatives in water management and toward striking a balance between new source development and conservation. This article describes some steps that are being taken across the United States to restrict demand, including the setting up of water conservation offices, committees, coordinators, and conferences; the planning of conservation programs by utilities and water districts; and the implementation of conservation measures by the residential, commercial, industrial, and agricultural sectors. Surely the vast cycles by which water is drawn up into the clouds to return to the earth could never be touched wrong

01 Nov 1991
TL;DR: In this article, a meso-scale hydrological model based on the stochastic storage theory is presented for the sensitivity analysis of the water balance components to changing climatic forcings.
Abstract: The IIASA Water Resources Project addresses the development and application of methods and procedures needed to identify policy strategies for water resources planning and operation. Due to population growth, industrial and agricultural development, increased pollution and the impact of global climatic change, the reliability of water supply may substantially decrease in various parts of the world, causing serious social and economic problems. There is a need for studies on possible policy actions, aimed at the development of more resilient and more robust water systems, based on a sound understanding of geophysical processes which regulate the hydrological cycle in a changing environment. This paper concerns methodological tools for the sensitivity analysis of the water balance components to changing climatic forcings. It presents a new meso-scale hydrological model based on the stochastic storage theory, and its application to the sensitivity analysis and to water balance impact studies. The model allows to calculate runoff characteristics, evaporation and catchment storage on the basis of standard climatological data, and eventually on the basis of alternative climate scenarios. It was tested for a number of river catchments in Europe and Africa. The possible effects of the expected changes in air temperature and precipitation will give rise to various problems in many fields of water resource management. For this reason, the paper may be of interest not only to hydrologists, but also to decision makers in water industry.

Journal ArticleDOI
TL;DR: The improved water supply showed no contamination with coliforms even after storage, and the prevalence of infectious skin diseases and diarrhoea among pre-schoolchildren showed no correlation with the quality of drinking water or the use of water per caput.
Abstract: The impact of the installation of a system to supply chlorinated drinking water in Venda, South Africa, on water quality, water use and health status was evaluated by means of questionnaires, examination for skin infections, and microbiological analysis of water samples. Although the water collection journey became shorter in comparison with use of traditional water supplies such as boreholes and unprotected springs, water use per caput showed no increase. The improved water supply showed no contamination with coliforms even after storage. Borehole water exhibited low coliform counts at the source, but after storage a 10- to 15-fold increase took place. Water samples from unprotected springs exhibited high coliform counts, which declined during storage. The prevalence of infectious skin diseases (27·5%) and diarrhoea (3·7%) among pre-schoolchildren showed no correlation with the quality of drinking water or the use of water per caput . Although the prevalence of infectious skin diseases did exhibit a negative correlation with the frequency of washing, no significant health benefit of the improved water supply could be demonstrated in this limited study.

01 Jan 1991
TL;DR: In this article, the authors present a discussion of surface water drainage in urban areas of low-income countries drainage options maintenance and drainage failures and the need for community participation and the participation of the entire community and coordination between agencies must take place in order to maintain the system.
Abstract: This report presents a discussion of surface water drainage in urban areas of low-income countries drainage options maintenance and drainage failures and the need for community participation. The annexes include a glossary of terms; design calculations for calculating stormwater flow and drain size and monitoring the speed of flow; terms of reference for consultants; and recommended information resources for orienting a drainage committee. Many low-income countries find that stormwater drainage is one of the most urgent infrastructure needs in urban areas. Many urban areas are situated in coastal areas that have the highest average rainfall and that are subject to flooding. Tropical rainfall is more intense than in temperate climates. Lack of drainage is exacerbated by steep slopes such as in Rio de Janeiro or very flat land such as in Bangkok Calcutta Jakarta Manila or Dar es Salaam. The consequences of a lack of drainage can be death from flooding and landslides; fecal-oral infections from contaminated water on hands utensils or drinking water; and transmission of disease from mosquitos swarming in standing water. Town planning impacts on drainage problems. Removal of vegetation decreases water retention and resistance to soil erosion. Roads must be built above the flood level. Natural drainage channels should not be obstructed by roads buildings or domestic refuse. Solid waste must be collected regularly. Drains must be cleaned regularly to remove accumulated silt vegetation and refuse. The participation of the entire community and coordination between agencies must take place in order to maintain the system.

Journal ArticleDOI
TL;DR: In this paper, the results obtained during the first 18 months have provided useful criteria for ensuring a satisfactory public health protection and adequate aesthetics of the golf course facilities, and the established disinfection strategy together with the natural microbial inactivation taking place at the two landscape impoundments can provide an irrigation water with consistently less than 10 cfu/100 mL of faecal conforms and faecals streptococci.

Journal ArticleDOI
TL;DR: Researchers identified the points of contamination responsible for the cholera outbreak in Piura and Trujillo Peru to be wells distribution systems and house.
Abstract: Epidemic cholera reached South America in January 1991 and later spread to Central America and the United States. It afflicted 312000 people and claimed 3200 lives. Since cholera had not been in Latin America for almost 70 years health authorities allowed environmental health barriers to cholera collapse. For example the Governments of the Region agreed in 1961 to abide by the Charter of Punta del Este to provide water and sewerage to 70% of the urban population and 50% f the rural population by 1971. They did not achieve their goals for the rural population. In fact at the end of 1988 water was piped to 79% of the urban households and an additional 11% of the urban population had access to a public water source. Sewerage services served 49% of the urban population and with other methods of excreta disposal 80% of the population had adequate excreta disposal. On the other hand only 55% of rural inhabitants had access to either piped water or public standpipes. Further sanitary excreta disposal services only covered 32%. Besides the water quality of existing water supply systems was poor. Since feces of infected people have as many as 1 billion Vibrio cholerae and in some of Vibrio up to 80% of carriers exhibit only mild symptoms or no symptoms at all it is easy to understand how cholera took hold in Latin America. Researchers identified the points of contamination responsible for the cholera outbreak in Piura and Trujillo Peru to be wells distribution systems and house. Annual population growth in Latin America at 2.6% poses specific problems to providing enough water and sanitation services to all in need especially those in marginal areas around the cities (who will make up 40% of the population by 2000).

Journal ArticleDOI
TL;DR: For the first time in the history of the water sector, experts from developing countries were invited to join "as equal partners" in a previously Donor-dominated Water Supply and Sanitation Collaborative Council as mentioned in this paper.
Abstract: For the first time in the history of the water sector, experts from developing countries were invited to join 'as equal partners' in a previously Donor-dominated Water Supply and Sanitation Collaborative Council.

Patent
22 Apr 1991
TL;DR: In this paper, a filtration unit is used to remove large particles for the waste water and the filtered water passes into a storage tank which holds the water until needed, and then the water is drawn by a pump and delivered to a device which will scent and colour the water prior to entry into a conventional toilet cistern.
Abstract: A toilet water supply system which replaces the existing mains water supply to the toilet cistern with domestic recoverable waste water resulting in overall reduction of domestic consumption and more efficient use of pure water. This is achieved by collecting waste water from recoverable sources through pipework (1) to a filtration unit (2), which removes large particles for the waste water. A facility is provided with the filtration unit (2) to enable the filter to be cleaned. The filtered water passes into a storage tank (3) which holds the water until needed. From the tank (2) the water is drawn by a pump (5) controlled by pressure switch (6) assisted by an accumulator (7) and delivered to a device (8) which will scent and colour the water prior to entry into a conventional toilet cistern.

Journal ArticleDOI
TL;DR: A hydrological model of a dambo is described and empirical results presented which suggest that, with certain limitations, irrigated dambo cultivation has a relatively small impact on water resources.

Journal ArticleDOI
TL;DR: In the Near East Region, wastewater reuse in agriculture is an accomplished and accepted fact, with a high degree of social and political commitment as mentioned in this paper, however, given the health and environmental hazards associated with reuse of wastewater, the formalization of wastewater treatment and reuse in all countries is urgent.

Journal ArticleDOI
TL;DR: In this article, the authors reviewed the progress made during the International Drinking Water Supply and Sanitation Decade (IBWSD) in terms of percent receiving water services, the urban areas made good progress: 77% in 1980 to 82% in 1990.
Abstract: In global terms this paper reviews the progress made during the International Drinking Water Supply and Sanitation Decade. There has been considerable progress. In terms of percent receiving water services, the urban areas made good progress: 77% in 1980 to 82% in 1990. In the rural areas progress was even greater, 30% had water services in 1980 versus 63% in 1990. There was also considerable progress in institutional terms. A positive trend towards better linkage betweeen authorities dealing with water supply and sanitation and those dealing with economic development, was one. Another was the awareness of the need for community involvement. In some cases progress was hampered by fragmentation of governmental authorities dealing with water and sanitation at the rural and/or urban level. In the 1990s an important issue will be financing the infrastructure needed to bring water and sanitation services to those not already covered and to an increasing population. Institutional issues will continue to be important as well.

Journal Article
TL;DR: In this article, the authors examined the problem of water supply-demand balance from the viewpoint of supply demand balance, and showed that unless there is a change in the current water use practices, groundwater, the major water resource of the Kingdom, will be mined in few decades and the extent that its usefulness may be severely diminished as a resource.
Abstract: Water demand in the Kingdom of Saudi Arabia has increased from 1750 million cubic meters (Mm3) in 1975to more than 9,600 Mm3 in 1985, a five-fold increase in ten years. At the same time increase on the supply side through water recycling and seawater desalination has been from around 18 Mm3 to 605 Mm3 during the same period. The development of these additional water supplies have been, however, far short of the increase in water demand, with groundwater making up the difference. This paper examines the above problem from the viewpoint of supply-demand balance. First, the paper assesses the surface and groundwater resources of the Kingdom, and the present as well as the future conditions of sea water desalination and water cycling. The water demands of the various use sectors are given followed by projections of future water demands. The third phase compares the water supply-demand situation under present and future conditions. From this comparison it was evident that unless there is a change in the current water use practices, groundwater, the major water resource of the Kingdom, will be mined in few decades and the extent that its usefulness may be severely diminished as a resource. When this develops, a severe water crisis will occur. The crisis can be reduced in severity, or averted, by taking the needed steps to bring into balance the annual water use with annual water supply.

Journal ArticleDOI
TL;DR: It was concluded that although treatment facilities will reduce the health burden in the region, a number of behavioural and sanitation factors may be more important and could act to minimize the potential impacts of improved water quality.

Journal Article
TL;DR: In this article, the authors present the procedures and techniques employed as part of the Bay-Delta proceedings to evaluate the water supply impacts of various proposed flow and water quality objectives for the Delta.
Abstract: This paper presents the procedures and techniques employed as part of the Bay-Delta proceedings to evaluate the water supply impacts of various proposed flow and water quality objectives for the Delta. The primary tool selected for analyzing the impacts was DWR's Planning Simulation Model. A number of alternative objectives to protect various beneficial water uses were proposed by the Board in their plan. Simulation studies were formulated and conducted to analyze the proposed objectives individually and in combination. Impacts were examined by comparing study results with a base study using current Delta flow and salinity requirements. The CVP-SWP system was used as a surrogate to the whole system to evaluate overall water supply impacts. These impacts could then be used to evaluate the relative benefits or trade-offs of proposed changes in Delta flow or water quality objectives. This process brought various water interests together so that agreement on technical methodology could be used as a basis for reaching a clearer understanding of statewide impacts of proposed Delta water quality plans.

Book ChapterDOI
14 Nov 1991
TL;DR: In this article, a better strategy is suggested for dealing with the "disposal" of saline agricultural drainage waters which provides greater practical benefit to be derived from the total water supply than blending does.
Abstract: This chapter provides conceptual arguments and empirical evidence to show that the blending approach typically used for water quality protection can result in economic losses to the agricultural community as a whole. A better strategy is suggested for dealing with the “disposal” of saline agricultural drainage waters which provides greater practical benefit to be derived from the total water supply than blending does. In this strategy the drainage water is intercepted, isolated from the good-quality water, and reused for the irrigation of suitably salt-tolerant crops in the same project. Ultimately, a greatly reduced volume of secondary drainage water is disposed of or treated in some manner other than blending.

Journal ArticleDOI
TL;DR: In this paper, a deterministic optimization model is presented for analyzing groundwater development and use options in an urban setting for a multi-year planning period, where water quality management issues are considered through aquifer flow control.