Journal of Water Resources Planning and Management

Past drought experiences show that the failure of water supply systems to meet demands during droughts can be reasonably described in terms of the tangible monetary expenditures and economic losses related to emergency actions. A framework is presented that allows planners of water supply systems and utility managers to formulate least‐cost drought emergency plans, and to systematically examine the trade‐off between the expected value of the long‐term cost of coping with water supply deficits and the cost of the longterm water supply/conservation projects. The suitability of the framework as an analytical tool for water deficit planning is illustrated in a case study of the water supply system of Springfield, Illinois. The analysis shows that the optimal short‐term programs for the mitigation of potential shortages of water during droughts consist of a combination of moderate demand and loss reduction measures coupled with intensive utilization of emergency water supply systems. However, the choice of demand reduction measures should involve a certain degree of discrimination among various user sectors in order to avoid substantial losses to the local economy.

This paper reports on the development of a financial planning model for publicly‐owned water and sewer utilities. It was developed for and used by the Orange Water and Sewer Authority, which serves Chapel Hill and Carrboro, North Carolina. The model was formulated as a linear programming problem, whose solution generates a set of effective prices and bond issues over multiple time periods. Constraints include minimum annual balances, minimum annual net revenues, limits on arbitrage, controls on price variations, and limits on borrowing. Several possible objective functions are discussed. Projections of demands and a capital improvement program are required as exogenous inputs. However, as demonstrated in the application, the model can be used to evaluate effects of uncertainties in demand on prices and borrowing requirements. Estimating similar effects of changes in the mix and timing of capital projects are also possible. Results given in the paper were used in the formulation of a financial strategy for a utility of moderate size, but heavily impacted by rapid growth in the Research Triangle area of North Carolina.

This paper reviews the problem of model complexity in evaluating the tradeoffs between fish and power production on the Columbia River. Characterizations of model complexity are presented and appropriate levels of model complexity are discussed. Models currently used to investigate the conflict between fish and hydropower production in the Columbia River Basin are reviewed. It is concluded that the complexity of the models used to generate tradeoffs between conflicting uses of water in this setting hinder their successful application and, because of their reliance on historic streamflow records, do not adequately address the problem in a probabilistic framework. To demonstrate the value of a simplified model, the operation of an equivalent composite reservoir was simulated. After calibration of the simplified model (CRISP), a series of Monte Carlo simulations were run to indicate possible impacts of alternative operational strategies on firm and secondary power and average annual generation.

The impacts of drought upon electric power generation are reviewed, as well as factors influencing utility susceptibility to drought and the management challenges of water shortages. The paper summarizes current drought mitigation measures, characterizes operational objectives during drought, and presents planning and operational alternatives for long‐ and short‐term drought responses. A risk analysis approach is also developed for planning drought management strategies and applied to a case study.

The United States began structural flood control in the 1930s and added complementary nonstructural measures in the 1960s. Nevertheless, national flood damage totals continue to increase. Reversal of this trend will require better communication among regulatory agencies, experts assessing risk, and floodplain occupants. Modern technology provides tools to measure specific risks and communicate the hazards of property loss and personal danger to individuals able to act to reduce the losses. One problem with the existing communication based on a safety standard tied to the 100‐yr floodplain is that some locations in the 100‐yr floodplain are only subject to trivial damage by shallow flooding, while other locations outside that magic boundary are subject to major devastation and threats of drowning by floods that could be as common as the true 25‐yr event. Systematic estimation and dissemination of the risk of economic loss can reduce flood losses, vary community programs with the hazard to life and property, and help every floodplain occupant accommodate more effectively with his site‐specific problem.

A layout generation algorithm, called LGA, is developed for generation of sanitary sewer layouts, using a standard shortest path algorithm. For selection of the shortest path from each manhole to the final outlet, three sewer cost measures were formulated from the data on sewer lengths and surface elevations at the manholes. EX measure, which requires the definition of a hypothetical excavation volume for each sewer from the minimum cover depth and sewer slope, yielded the minimal excavations and invert depths when the generated layouts were hydraulically designed. The results were as good as, or better than, the layouts recommended for networks with up to 70 manholes. Due to computer memory restrictions, the larger networks must be subzoned for subsequent superposition. Guidelines are developed for subzoning as well as general implementation from testing of LGA with various‐sized networks.

A brief prospective of hydrologic analysis used for determination of spillway sizing is presented. The paepr describes the procedures for determining a reasonable upper limit of flood potential for a given drainage basin. In 1936, the National Weather Service and the Corps of Engineers reached a cooperative agreement whereby meteorologists of the Weather Service would use their professional capabilities to develop probable maximum precipitation estimates. In recent years the Bureau of Reclamation and the Soil Conservation Service have joined forces with the Weather Service and the Corps of Engineers in the preparation of hydrometeorological reports. The four agencies are presently engaged in a major study of probable maximum precipitation for the northwest United States. Information on major storms and floods is included that supports the hydrometeorological approach. The paper points out that the major federal dam construction agencies have been meeting regularly and are using the same basic hydrometeorological approach to size spillways.

Although technologically advanced methods have been used to manage large water resource systems, there is both a need and an opportunity for application of similar techniques at the level of the individual user. With a microcomputer as the computational tool, a decision support system (DSS) is developed for use by local water managers, where the appropriative water rights doctrine applies and irrigation is the primary water use. The DSS consists of data files describing the water rights, water use, and hydrologic systems integrated with simulation models for soil moisture and river routing in response to irrigation diversions and inflows. The model allows projection of irrigation demands and assessment of the effects of distribution strategies on flow in the river system. Operation of the DSS is demonstrated on a small, hypothetical river system. Even though the hardware and software appear to be suitable to the task, actual application may depend on cooperation among users and be limited to providing advice on amount and timing of irrigation.

The storage and handling of large quantities of petroleum products in a “sole source aquifer” area such as Nassau and Suffolk Counties of Long Island, New York, has resulted in numerous groundwater contamination problems. Recent legislative actions have provided for a means of minimizing future discharges but many previous and ongoing discharges of petroleum remain to be cleaned up. Recovery operations utilizing: (1) Positive and negative ventilating systems; (2) site well installation; (3) recovery well depression systems; and (4) treatment of discharge waters, have developed into effective and efficient cleanup techniques. The prevention of discharges of petroleum into our aquifers requires actions such as: (1) The replacement of steel tanks with cathodically protected steel, glass fiber reinforced plastic, steel clad with glass fiber reinforced plastic, double‐walled steel, etc.; (2) corrosion protection for piping; (3) inventory control; (4) leak detectors; and (5) testing programs. Vigorous programs concerning petroleum storage are needed immediately by federal, state, and local government, as well as by private industry.

The Aswan High Dam in Egypt has been the focus of considerable attention with respect to its impact upon the environment. Prior to its completion in 1971, critics of the project voiced concern about the potential problems of sedimentation in the reservoir, downstream scour, riverbed degradation and coastal erosion, proliferation of disease vectors, and decreased soil fertility in the Egyptian Delta. The extent and degree of these and other environmental changes directly associated with the Aswan High Dam have been examined. Deleterious effects from the project have been placed in perspective against its derived benefits. Remedial measures for environmental damage as implemented currently by Egypt are described. It is concluded that through careful water resource management, the Aswan High Dam will continue to provide Egypt with benefits for the long‐term future and the environmental problems can be effectively dealt with.