Journal of Water Resources Planning and Management

The South Australian government has recently formed a committee to investigate conflicts over the use of resources in the Mt. Lofty Ranges, including improvements to the quality of water supplied to the city of Adelaide. The committee is examining potential land‐use and land‐management policies. The writers have developed a prototype of a decision support system (DSS) that will estimate the effects of these policies on water quality and the costs of implementing the policies. The DSS consists of three modules. The policy module allows the user to build up a suite of policies in a formal syntax. The second module, the catchment model, will estimate the effects of these policies on total phosphorus, total nitrogen, and turbidity levels. The user can query the DSS about these estimates in the third module. The prototype has been evaluated by the South Australian Engineering and Water Supply Department, and a second version of the DSS is now being designed.

In the past, the effects of pollution abatement were measured in terms of the size of reductions achieved. This paper demonstrates a method that can be used to measure effects in relation to the practical significance of the reductions for the people living in the area concerned. The approach used in the project on locally adapted regulatory impact analysis (LARIA) aims to overcome the problem of finding a correct balance between the size and cost of the effort required in relation to the benefit to society for conservation projects. The proposed methodology consists of four parts. First, the user interests in the Lake Mjøsa basin are determined, and relative weights expressing the importance is given to the uses. Then, a water‐quality‐effect model is developed. Focus is placed on developing a phosphorus effect model taking into account the biological availability of phosphorus. The third step is a model to express the benefit to society from improvement in water quality. The fourth step is to identify and rank all available abatement measures using information from the effect model and the cost of implementation of each measure.

A methodology is developed that estimates the parameters and the past pumping or recharge history of an aquifer simultaneously. A maximum likelihood procedure is used to estimate the aquifer's parameters in conjunction with a filtered stochastic description of the hyraulic‐head distribution in an aquifer to back‐calculate the well‐pumpage or recharge rates at known locations in the aquifer using a linear regression technique. The procedure is iterative so that updated well‐pumpage rates can be used to improve parameter estimates until the solution has converged. The methodology is tested using a hypothetical aquifer and two different cases. The first case involves the estimation of an aquifer's parameters and the pumping history of one well that was unknown; the second involves the estimation of an aquifer's parameters and the pumping history of two wells that were unknown. Results of these tests demonstrate the validity and usefulness of the proposed estimation technique.

Nassau County, New York is presently developing a water management plan. In addressing the fundamental question of the ability of the aquifer to yield sufficient quantities of water for public supply, two approaches have been used. The first is hydrograph analysis of water levels over a 45‐year period. The second approach involves using a three‐dimensional, finite element ground‐water model. Results include an analysis of the aquifer response to the stress of increased consumption and severe drought. Water balances are developed for each aquifer under predevelopment and present conditions. The technical analysis concludes that the aquifer can yield sufficient quantities of water, but present consumption also means diminished streamflow and potential salt‐water intrusion. The paper also highlights how various planning perespectives affect the interpretation of the technical analysis. Purely technical information is not sufficient to reach a consensus on water issues. Education of the public and other participating agencies, as well as consensus‐building techniques and public relations, are needed to develop an effective plan.

Findings of a survey about experiences managing public water supplies during the drought of 1988 are reported. Responses were obtained from 408 of the 501 large utilities in the United States to whom the questionnaire was sent. Although the news media correctly portrayed the drought of 1988 as being serious in some regions of the country, the fact that one‐half of all urban water utilities called for conservation revealed very widespread impacts. About one‐half of the utilities had ordinances or other written drought policies. Only 28% of the reporting utilities had a technicaal report, computer program, or some other form of technical support for triggering conservation. Managers were generally pleased with their decisions, but the existence of technical support increased their level of satisfaction.

A stochastic dynamic programming model for the optimization of hydropower prroduction of a multiple storage‐reservoir system with correlated inflows has been developed. Application was made to a subsystem of the Brazilian hydroelectric system. The model consists of two parts. An off‐line, one‐time‐only, deterministic dynamic program computes the value of the stored water in all of the reservoirs as a function of the several reservoir storages and the month of the year. The calculated values represent potential energy generation and are based on historical flow data. The on‐line program is formulated in terms of a stochastic dynamic program and conducted in real time for operational use. Each month a multidimensional search is made for the optimal set of reservoir releases that maximize system benefits. The search uses the probability transition matrices and the tables of stored‐water benefits for the particular month determined by the off‐line program. The optimization requires knowledge of the previous month's inflows and the starting storages for the current month; but these, of course, are observables and are readily determined. The following month, the on‐line search procedure is repeated to find the optimal releases for that month. The off‐line program also can be used to obtain trade‐offs between expected energy‐generation benefits and water‐management benefits consequent to some other objective, such as flood control. Model performance was checked against actual operational data for a Brazilian subsystem, and there are indications of superior performance by the model.

The idea of levels of service for resource allocation is explored in managing troublesome urban collector streams in Charlotte, N.C. Results suggest that a classification system based on levels of service would be of significant use to public officials in analyzing problems of remediation. Assigning levels of service provides a basis for quantitative communication between laypersons and technical staff. The level‐of‐service concept is adapted from those in use in transportation applications. Five levels of service are suggested to describe the functional quality of urban streams. The proposed level of service measures represent a reasonable approach to assessing the performance quality of an urban stream. A major benefit of using the measures is the opportunity to view the stream system as a whole instead of as a series of citizen complaints. The downstream effects of various alternatives can be more easily assessed when the downstream conditions are already known. The prioritization of projects based on level‐of‐service measures would allow public funds to be spent more equitably.