Journal of Water Resources Planning and Management

Water management is multidimensional. It embraces planning, design, construction, operation, and maintenance. Its ingredients include technological capability, social attitudes, economic realities, political viewpoints, and environmental goals. Being able to effectively manage water resources often depends more on our ability to maneuver Within institutional constraints than to design technological fixes. Our engineering capability is more advanced than its application, yesterday's methods are being applied to tomorrow's problems, and regional problems are begging for solutions because we try to solve them on a local scale. The need for institutional reform is clear, but the key to accomplishing it is elusive. Both resource‐related and institutional factors must be considered. Accordingly, potential avenues for reform are presented in that context. The challenge is to face today's and tomorrow's problems with tools appropriate to the times and to the special features of the locality being served.

Water quality management programs that allow different waste discharge rates during different seasons of the year are an innovative approach for reducing the cost of waste treatment. This paper presents an approach for designing such seasonal waste discharge programs for river basins with several dischargers and illustrates it for the control of biochemical oxygen demand, BOD. By this approach, the risk of water quality violation is defined as the probability of incurring one or more water quality violations in any given year, and the seasonal waste effluent rates of the dischargers are designed to maintain a specified level of risk while minimizing the total waste treatment effort of the dischargers. Two seasonal waste discharge programs are proposed as surrogates for minimizing waste treatment effort, the minimum average uniform treatment program and the maximum total discharge program. Simulations of these programs suggest that either seasonal discharge program would significantly reduce waste treatment costs relative to a nonseasonal program. Furthermore, comparison of costs of seasonal waste discharge programs indicates that for the example river basin, a seasonal uniform treatment program may be implemented that is potentially more acceptable to the dischargers and is less costly than a seasonal maximum total discharge program.

The stormwater runoff quantity component of the U.S. Army Corps of Engineers storage, treatment, overflow, and runoff model (STORM) program has been successfully calibrated and verified for a residential community located in Dallas, Texas. Limited water quality data preclude application of typical statistical testing of model runoff quality predictive capabilities. A Monte Carlo simulation technique is therefore employed to ascertain probable ranges of STORM water quality predictions in light of both water quantity and quality input parameter uncertainties. The resulting 95% occurrence intervals of probable model runs are compared with a limited water quality data set to test model adequacy. An original modeling scenario, utilizing suggested areal accumulation rates derived from a study conducted in Seattle, Washington, is rejected because the measured total suspended solids concentrations are far above the upper bound of the computed 95% occurrence interval. A second modeling scenario using areal accumulation rates obtained from Tulsa, Oklahoma, cannot be rejected based upon the comparison of measured data and the computed 95% occurrence intervals.

A practical method for determining the road surface drainage system design with the theoretical lowest total economic cost (LTEC) is developed. The LTEC method determines the design rain which, when used in a rational‐based design context, will yield the most economic choices of gutters, inlets, and laterals considering both construction costs and risk costs. The method provides an alternative to the use of fixed return period design criteria. Daily rainfall serves as the random variable used in performing the risk analysis. The right‐hand tail of the probability density function for daily rainfall is approximated with a normal curve. A triangular hyetograph of average duration is assumed to be appropriate for representing an individual rainstorm. A nomograph and data selection guide are provided as design aids. Case studies are presented in an appendix. The method, based on minimizing traffic delay costs, applies to freeways, arterials, and major collectors; local streets with low traffic may be excluded.

Persistence is a phenomenon greatly influencing hydrologic time series. An explanation of its nature has been attempted in different ways, including transitory behavior or infinite memory of the process, and nonstationary process mean. An operational stochastic model for annual discharges is studied in this paper; its purpose is to reproduce the altemance of periods, sometimes called cycles, observed in hydrology. The model is of almost immediate application, being defined by parameters that can be estimated easily through the analysis of the autocorrelation function of the observed data. The model is expressed in two forms that are valid for the cases of normal and lognormal distributions of the variables, respectively. The dependence of the parameters of the variables distribution on the operating parameters of the process is graphically represented by curves interpolated from a large number of sampling points. The performance of the model is also evaluated with respect to its behavior in accordance to Hurst's phenomenon, by verifying the values assumed by Hurst's coefficient during the simulations.

The problem of optimal multiunit hydropower system configuration is analyzed considering long‐term operational aspects. The spatial distribution of individual system elements such as reservoirs and the vertical configurations representing heights of various dams, full supply levels, and minimum operating levels of the reservoirs are selected for optimum energy generation potential. The objective of maximizing the monthly firm energy has been successfully achieved first by applying the Incremental Dynamic Programming (IDP) technique, and then by the Stochastic Dynamic Programming (SDP) method which incorporates the streamflow stochasticity into the system. SDP maximizes the expected total annual energy generation subject to a prespecified monthly firm power output. Transitional probabilities are derived from the available historical streamflow records. The results obtained could be used in planning a reservoir system and in deriving a long‐term operational policy. In this study, they are used in deciding the optimum system configuration in a river basin development problem in Nepal.

EPA'S storm water management model (SWMM) simulates urban runoff quantity and quality. An interactive program has been developed by using expert‐system technology to automate the calibration of the water‐quality parameters of the runoff block of SWMM. It acts as a front end in the estimation of the parameters and the buildup of the input files. Production rules are employed for the interpretation of the simulation results in order to suggest some useral adjustments of the significant parameters. The goal of the expert system is to obtain a set of parameters for which the predicted pollutant loads are close to the measured loads. The expert system has been tested on several watersheds, proving that it could perform the calibration but that a shortcoming exists in the model itself that cannot be alleviated through calibration. The Denver experiment showed that the same set of parameters is not valid for low‐ and high‐intensity events.

This paper presents a watershed discharge hydrograph simulation model, based on the hydraulically based geomorphologic instantaneous unit hydrograph (IUH), developed by Kirshen and Bras (1983). This IUH was derived as a function of watershed geomorphology and the response of streams to lateral inflows, determined by solving one‐dimensional linearized equations of motion. The effective rainfall is calculated here to be equal to the gross rainfall minus the infiltration losses, presented with Philip's expression coupled with an empirical equation for soil moisture computation. Consideration is given to the role of mountainous terrain in runoff generation. For mountainous watersheds, the mountain runoff is regarded as a water depth on the alluvial channels. The effective rainfall depth is calculated to be equal to this water depth plus the rainfall depth minus the infiltration losses. The simulation model is verified through applications for three gauged watersheds in Saudi Arabia. A comparison is made between the observed and simulated hydrographs, and evaluation of the model results and limitations is provided.

The economic properties of three different permitting options for regulating ground‐water withdrawals are estimated by computer simulation of the economic return for irrigation of corn. The three regulatory options consist of withdrawal limitations in the form of ground‐water pumping permits allocated in proportion to overlaying land area with: (1) No trading of permits; (2) trading of long‐term (over years) permits; and (3) trading of both long‐ and short‐term (within year) permits. Seven scenarios representing different combinations of regulations and weather and crop‐yield predictability are simulated for farm plots in heavily irrigated areas of Kankakee and Mason counties, Illinois. Alternative assumptions regarding weather predictability are: (1) No knowledge at all; (2) complete knowledge of future weather and accurate crop‐yield modeling (i.e., response to weather conditions and quantity of applied irrigation water); and (3) knowledge of past weather and accurate crop‐yield modeling, but no knowledge of future weather. The results indicate that a considerable increase in economic efficiency may be realized from long‐term permit trading and improving the accuracy of weather and crop‐yield forecasting. The value of long‐term permit trading is found to diminish in the presence of accurate crop‐yield forecasting and is smaller yet if accurate weather prediction is available as well.