A CATALYST FOR REGIONALIZATION OF RURAL WATER SYSTEMS1

ABSTRACT: The National Regulatory Research Institute has recommended the merger of small rural water districts in the United States. Success at bringing about merger of these districts, which contain fewer than 3,500 customers, has been highly limited. The subject of this paper is a demonstration project that may act as a catalyst to achieve the desired goal of regionalization. A computerized hydraulic data management program (CHDMP) was developed for a case study in Nelson County, Kentucky. University professors, graduate students, and two water utilities’ staffs cooperated in network analysis employing computer hardware and software. The utilities’ staffs were taught the science and technology of hydraulic model preparation, simulation, and analysis for the case study distribution systems. As an integrated system, the model contained 294 pipes, 234 nodes, six pumps, and 11 tanks. Each utility's problem areas were identified and some of the individual and mutual benefits of hydraulic planning were illustrated. A dialogue resulted between the managers. Each manager described his goals and agreed that, although political merger was not feasible at the present time, future economic factors could be a definite influence in reversing that decision.     

INTEGRATED PLANNING OF RURAL WATER SUPPLY AND SANITATION1

ABSTRACT: Development schemes to improve the health of the rural populace through prevention of the transmission of communicable diseases should be considered in the context of some kind of “Sanitation Package” to ensure effectiveness. The general practice of concentrating resources on limited objectives, like water quality improvement, is shown to be less effective than allocating the same resources to multi-objectives defined in the Sanitation package. Systems Dynamic Modeling based on the DYNAMO II language, is presented as a capable tool for sanitation systems planning.     

WATER SUPPLY AND WASTEWATER DISPOSAL IN RURAL AREAS OF INDIA1

ABSTRACT: Piped water supply and sewerage have been taken almost for granted in the developed countries. However, most people in the United States have little knowledge of the condition of public health amenities in the developing countries. The paper reviews the importance, background and current status of water and wastewater facilities in India. The relative situation in urban and rural areas, conventional practices in environmental hygiene, the programs for improvement and the problems involved with possible solutions are given. The case history of a town is also included for illustrative purposes.     

ASSESSMENT ANALYSIS FOR WATER SUPPLY ALTERNATIVES1

ABSTRACT Providing adequate water supplies of good quality is becoming a serious problem in many areas of the United States. Some of the alternatives proposed for meeting the growing shortage of clean-water or cheap-water are reallocation, reuse, and importation. This paper outlines a methodology to assess all of these water supply alternatives by examining the amount and time-staging for development of water sources. In conceptualizing the problem, sources of supply are classified in three categories: primary or base supplies, secondary or effluent supplies, and supplementary or imported supplies. A model of the water system is formulated as a “transportation problem” in linear programming depicting the possible sources of supply which can be used to satisfy the requirements of various water users. The optimizing objective in the model is to minimize the cost of water under various assumptions for operating the system. A case study of the Salt Lake Qty, Utah, area is used to illustrate the application of the model in obtaining optimal water supply allocations for projected future demands. Assessment of alternatives in the study include redistribution of supplies, time-staging of supplies and related treatment facilities, and sensitivity of allocations to changes in costs.     

PREDICTING INSTANTANEOUS PEAK DEMAND IN RURAL DOMESTIC WATER SUPPLY SYSTEMS1

ABSTRACT: Many rural areas of the United States still have no public domestic water systems. Typical land use patterns in these areas may require 1/2 mile or more of pipe per farm connection. Public systems serving these areas are economically feasible only if realistic short-term peak demand standards are available for their design. The lack of reliable data upon which to establish such criteria has resulted in a large variation in criteria among state and federal agencies involved in financing and in approving construction of these systems. During the summer of 1975 three distribution laterals of a rural system in Utah were master metered and instantaneous peak flows were recorded for 4 months. The metered lines served 4, 12, and 22 farm houses each. The frequency distribution of peak flows has been analyzed and compared with that developed during similar research in Mississippi and with the existing design standards of the Farmers Home Administration and the State of Utah.     

REGIONAL WATER SUPPLY PLANNING BY INTERACTIVE SYSTEMS ANALYSIS1

Abstract: This paper describes an interactive data and model generator that is intended to bridge the gap between the water resource enginner and planner and the mathematical progrmming systems approach to regional water supply planning. The optimization objective is to minimize total annual cost with respect to capital investment and operation and maintenance costs. The matrix generator formulates the necessary hydrologic, demographic and programming problem for system optimization. The interactive program guides the user through the input and optimization segments, totally eliminates the chore of manually structuring the model matrix aides in eliminating errors, and allows use by planners without skill in mathematical programming.     

COST EFFECTIVE OPERATION OF URBAN WATER SUPPLY SYSTEM USING DYNAMIC PROGRAMMING1

ABSTRACT: Efficient operation of a city water supply system is an important goal of all municipalities. Efficient operation should result in minimum operation cost through reduction in total energy use and/ or reduction in on-peak energy consumption. An optimization model was designed for operating the water supply systems of cities using groundwater. The Newton-Raphson pipe network was used for network analysis and a dynamic programming optimization algorithm was used for determining a schedule for pump operation in the pipe network system. The model is most suitable for use in small cities with up to 45,000 in population, but with large-scale disintegration techniques may also be used for larger cities. The savings in operation costs are a function of energy cost and energy use pattern and water use pattern in the area.     

ECONOMIC DESIGN OF CENTRAL WATER SUPPLY SYSTEMS FOR MEDIUM SIZED TOWNS1

ABSTRACT. Adequate and good-quality water supply for medium sized towns is costly when there are insufficient quantity and low quality of groundwater or surface water. In a central water supply system serving a number of towns, the economies of scale may permit a sufficient and good-quality supply at lesser rates. Such a system has the flexibility of supplying rural population through small service lines. The system may be an interbasin or intrabasin conveyance depending on the location of a suitable water source and the economics of the supply network. Seven cost elements are pertinent to the optimum or least-cost design of network consisting of pipelines and pumping stations. The relevant cost functions are based on the available data gathered from various sources. Water conveyance costs are calculated for various flow rates, pipeline diameters, flow variabilities, static heads, and interest rates, thus providing a measure of sensitivity of the conveyance cost to such variations. The economies of scale, the sensitivity of optimum unit conveyance costs, and variations in unit costs with change in cost functions are useful in making a feasibility study for a proposed conveyance system.     

A LINEAR ANALYSIS OF AN URBAN WATER SUPPLY SYSTEM1

The use of linear programming as a planning tool for determining the optimal long-range development of an urban water supply system was explored. A stochastic trace of water demand was synthesized and used as an input to the model. This permitted evaluating the feasibility of imposing demand restrictions as an effective cost reduction mechanism. The City of Lincoln, Nebraska, was used as the urban model. The fundamental problem was to allocate limited water supplies from several sources to an urban load center to minimize costs and comply with system constraints. The study period covered twenty years, and findings indicate the planning direction for stage development during this period. Sensitivity analyses were performed on cost coefficients and demands. Thirteen sources were included in the initial computations. Conclusions were that linear programming and generated demand traces are useful tools for both short- and long-term urban water supply planning. Lowering peak demands results in long-range development of fewer sources of supply and more economic and efficient use of the supplies developed.     

CAPITAL COST OF RURAL WATER DISTRIBUTION SYSTEMS1

ABSTRACT: The cost of water service to rural residents is very high compared to urban areas. This is true even after subsidization by Farmers Home Administration (FmHA) loans and grants. Capital cost data on 44 projects financed by the Ohio office of the FmHA during the period August 1968 to January 1977 are used to derive cost equations for 26 components of rural water distribution systems. These components represent 92 percent of the capital cost of the pipeline distribution systems studied. The data can be used to economically design rural water supply systems from a capital cost viewpoint. More data are needed on operation and maintenance costs as well as central and cluster well costs before totally economic system designs can be undertaken.     

TEMPORARY WATER TRANSFERS FOR DRY-YEAR WATER SUPPLY1

ABSTRACT: Temporary transfers of water for dry year water supply are analyzed for cost and operational feasibility. The temporary transfer is implemented as part of a water rights option agreement (WROA) between a lesson and a lessee. First, engineering analysis determines the technical feasibility and operations plan under the Colorado doctrine of prior appropriation. The cost of the WROA to a water utility is estimated. Other considerations in the agreement are discussed. The WROA is compared to other dry-year supply alternatives using a water system simulation model to obtain expected cost and operational performance characteristics.     

CONSERVATIONAL WATER PRICING FOR INCREASED WATER SUPPLY BENEFITS1

ABSTRACT: A study was undertaken to see if benefits from water supply could be increased by utilizing price-usage information in reservoir design studies. Three pricing policies were examined. The first policy assumed no price-use relationship, and quantity demanded was based on existing community usage with a low water rate. The price of water was set to recover system costs. A price-use relationship was assumed in the second policy and the water rate was constant. The price of water was determined from the associated system which provided maximum expected net benefits. The third policy assumed the price-use relationship and the price charged for water during each billing period was a non-linear function of storage which increased as the amount of water in storage at the beginning of the period decreased. It was found that the use of the conservation pricing policies substantially reduced storage requirements while providing demonstrable net benefits to the community and a large average supply. The conservation pricing policies substantially lowered the average price paid for water. The effect of uncertainty in consumer response to changes in price was studied by using a probabilistic price-use relationship. This uncertainty did not significantly reduce the effectiveness of the conservation policy. It was concluded that demand management by the use of a proper pricing policy could significantly increase net water supply benefits to a community.     

WATER SUPPLY COSTS FOR SMALL PRIVATE UTILITIES1

ABSTRACT: This paper examines the cost of water supply for small and mid-sized private water utilities. An econometric approach was employed in which data on utility costs and characteristics were used to estimate a total water supply cost function from which average and marginal costs were derived. The results suggest that although average and marginal costs decline with output, the rate of decline rapidly approaches zero, and unit costs therefore appear to remain relatively constant over a wide range of output. Implications of the results for pricing policy are examined.     

COMPARATIVE EVALUATION OF STATISTICAL METHODS FOR WATER SUPPLY FORECASTING1

ABSTRACT: While the correlation coefficient and standard error of estimate are frequently used when comparing models of seasonal water yield, the following criteria may be more important in selecting one model from among several alternatives: rationality of the regression coefficients, the distribution of the residual errors, and the correctness of indicators of the relative importance of the predictor variables. These criteria were used to compare seasonal water yield models that were calibrated using multiple regression, stepwise regression, principal components regression, polynomial regression using a principal components rotation, and constrained pattern search. Hydrologic data from the Upper Sevier River basin in southern Utah were used to illustrate the comparative analysis process. The prediction equations used the April-July streamflow volume as the criterion variable.     

PEAK PERIOD DESIGN STANDARDS FOR SMALL WESTERN U.S. WATER SUPPLY SYSTEMS1

ABSTRACT: In order to determine design capacities for various components of municipal and rural domestic water supply systems, engineers must estimate water requirements for an entire year (water rights), for the peak season (reservoir storage), for the peak day (pump or treatment plant size), and for peak hour (pipeline sizes). Historically, per capita water use rates have varied greatly between systems, particularly in semiarid regions where outdoor demands are large. The resulting uncertainty in design capacity estimates can cause either inadequate capacities or premature investment. In order to minimize that uncertainty multiple regression and frequency analyses were made of the various water demand parameters mentioned above for 14 systems in Utah and Colorado. Specifically, demand functions are reported for average month, peak month, and peak day. Peak hour demands were also studied but are reported in a different paper. The independent variables which were significant for monthly and daily demands were price of water and an outdoor use index which includes the effect of variation in landscaped area and accounts for use of supplementary ditch or pressure irrigation systems. The demand functions were developed with data from systems varying in size from very small low density rural systems to Salt Lake City's water system. The correlation coefficients (R²) vary from 0.80 to 0.95.     

SIMULATION OF INTEGRATED SURFACE WATER AND GROUND WATER SYSTEMS - MODEL FORMULATION1

ABSTRACT: The unique characteristics of the hydrogeologic system of south Florida (flat topography, sandy soils, high water table, and highly developed canal system) cause significant interactions between ground water and surface water systems. Interaction processes involve infiltration, evapotranspiration (ET), runoff, and exchange of flow (seepage) between streams and aquifers. These interaction processes cannot be accurately simulated by either a surface water model or a ground water model alone because surface water models generally oversimplify ground water movement and ground water models generally oversimplify surface water movement. Estimates of the many components of flow between surface water and ground water (such as recharge and ET) made by the two types of models are often inconsistent. The inconsistencies are the result of differences in the calibration components and the model structures, and can affect the confidence level of the model application. In order to improve model results, a framework for developing a model which integrates a surface water model and a ground water model is presented. Dade County, Florida, is used as an example in developing the concepts of the integrated model. The conceptual model is based on the need to evaluate water supply management options involving the conjunctive use of surface water and groundwater, as well as the evaluation of the impacts of proposed wellfields. The mathematical structure of the integrated model is based on the South Florida Water Management Model (SFWMM) (MacVicar et al., 1984) and A Modular Three-Dimensional Finite-Difference Groundwater Flow Model (MODFLOW) (McDonald and Harbaugh, 1988).     

LINEAR PROGRAMMING APPLICATIONS IN WATER RESOURCES1

Applications of linear programming to water quality and water quantity problems are discussed, and a fairly comprehensive sample of recent literature in these areas is reviewed. Basic elements of linear programming are also discussed. Emphasis is placed on the elements of linear programming that make it a useful tool for analyzing water resource problems and the basic features of various water resource problems that render them amenable to meaningful analysis by linear programming.     

DEVELOPMENT OF A WATER SUPPLY PROTECTION MODEL IN A GIS1

ABSTRACT: As part of a larger model to identify lands suitable for acquisition, a water supply protection model was developed using the Southwest Florida Water Management District's GIS. Several hydrologic and hydrogeologic data layers were overlaid to develop maps showing ground-water supply suitability, protection areas for surface-water supply, protection areas for major public supply wells, susceptibility to ground-water contamination, and recharge to the Floridan aquifer. These intermediate layers were combined into a final map to prioritize protection areas for water supply.     

MAPS - A PLANNING TOOL FOR CORPS OF ENGINEERS REGIONAL WATER SUPPLY STUDIES1

ABSTRACT: A computer program (MAPS - Methodology for Areawide Planning Studies) has been developed by the U.S. Army Corps of Engineers, Waterways Experiment Station to assist planners in producing a comprehensive array of alternatives without sacrificing the detail and accuracy of the analyses. MAPS is a set of computer based models which can be used to simulate the water resource alternatives and to develop planning level design and cost estimates. Two application examples are discussed. The Salinas-Monterey (California) Urban Study sought to identify and determine cost of combinations of water source, transmission, and treatment to meet an array of water needs in future years. The Nashville (Tennessee) Urban Study had similar objectives but the output was prepared on a service area basis for more than 40 such units. Using MAPS it was possible to prepare planning level design and cost estimates for a very large number of alternatives.