摘要:

In river basins where aquifers are intimately associated with streams, the unrestricted development of groundwater can reduce streamflows and hence jeopardize the rights to the flow of surface water. A simulation model to aid in the solution of such problems was developed. The model is composed of (1) a hydrologic model that represents the physical response of the stream‐aquifer system to changes in river flows, diversions, and pumping and treats streamflow as a stochastic input and (2) an economic model that represents the response of irrigation water users to variations in water supply and cost. These elements were incorporated into a decision framework so that the net income to the water resource system associated with alternative management schemes could be measured. The results of operating the model with parameters representing conditions in the South Platte Valley of eastern Colorado under alternative institutional and hydrologic conditions are reporte

ISSN:0043-1397    

DOI:10.1029/WR008i003p00533

年代:1972

数据来源: WILEY

摘要:

Optimal economic use of an aquifer over time is analyzed under conditions of economic growth, inequality of groundwater withdrawal and consumption, and availability of surface water and artificial recharge. The value of an aquifer as a natural water quality treatment facility is derived.

ISSN:0043-1397    

DOI:10.1029/WR008i003p00557

年代:1972

数据来源: WILEY

摘要:

The optimal control theory based on Pontryagin's minimum principle has been applied to the problem of specifying the best combination of minimum percent BOD waste treatment and effluent distribution policies for a single plant on a specified polluted river segment. The analysis features a new dual water quality stream standard consisting of a minimum allowable DO concentration at every point in the river segment combined with a maximum allowable BOD concentration at a specified downstream point. The optimal BOD effluent distribution policies are compared with choice suboptimal effluent discharge patterns associated with best single point, best uniform, and best bang‐bang injection policies. The inequality constraints, the nonlinearities in the system model, and the synthesis of the optimal controls were handled in a direct manner by using the Pontryagin control theory principle combined with gradient search and penalty function techniques. The results of the study very definitely established certain guidelines for increasing the assimilative capacity of a given river segment through judicious combinations of minimum percent BOD waste treatment and continuous BOD effluent distribution or dumping patterns associated with single plant effluents. The systems analysis was made tractable by incorporating a no short‐circuit constraint into the dumping polic

ISSN:0043-1397    

DOI:10.1029/WR008i003p00565

年代:1972

数据来源: WILEY

摘要:

A series of models has been developed in previous papers to estimate the best sized area to develop for irrigation from a given reservoir under conditions of variable supply and demand for irrigation water. The best operating policies for such a system were also derived. The approach of this paper extends the previous approach by recognizing the value of water carried over from one season to the next. A modified version of the previous approach is used to generate reservoir level transition probabilities and expected benefits. A dynamic programing model is then used to estimate the expected benefits from allocating water optimally between seasons. These expected benefits are a function of acreage developed for irrigation and beginning‐season reservoir levels. Such a function allows a decision maker at any decision point within an irrigation season to equate the expected net benefits from allocating water to the rest of the current season with the expected net benefits from saving such water for the following season. This decision‐making process is simulated for a number of seasons. The results of an application of the models indicate that such interseasonal transfer can considerably increase the present value of expected benefits from the proj

ISSN:0043-1397    

DOI:10.1029/WR008i003p00586

年代:1972

数据来源: WILEY

摘要:

A model is presented for predicting the local radiant flux and the net rate of gain or loss of radiant energy per unit volume on spectral and total bases for a layer of natural water by using exact radiative transfer theory. The model considers attenuation (absorption and scattering) and multiple scattering by water and accounts not only for the transmission and internal reflection of radiation at the air‐water interface but also for reflection at the bottom. Some numerical results are reported for pure water, multiple scattering being neglected. The results show that analyses that neglect the spectral nature of the incident flux and assume water to be gray lead to appreciable errors in total radiant flux computations and in the amount of internal absorption of solar radiation. For accurate predictions, the reflection from the bottom and the internal reflection from the air‐water interface must be properly accounted for in shallow wat

ISSN:0043-1397    

DOI:10.1029/WR008i003p00595

年代:1972

数据来源: WILEY

摘要:

The importance of the subsurface response of watersheds has been vastly underrated in most studies of watershed behavior, both in a quantitative sense and in a generic sense. The mechanism of base flow generation and the nature of watershed response in base flow dominant streams are examined with a deterministic mathematical model that couples three‐dimensional, transient, saturated‐unsaturated subsurface flow and one‐dimensional, gradually varied, unsteady channel flow. The channel flow model uses the single step Lax‐Wendroff explicit technique to solve numerically the full shallow water equations. The subsurface flow model uses the line successive overrelaxation technique to solve numerically the Jacob‐Richards diffusion equation. The results of the simulations on a hypothetical basin suggest a wide variability in watershed response under the influence of variations in rainfall properties, antecedent moisture conditions, and saturated and unsaturated subsurface hydrogeologic properties. This evidence for a wide range of watershed response functions leads to the development of a healthy skepticism toward black box rainfall‐runoff correlations, the concept of basin linearity, and the rationality of hydrograph

ISSN:0043-1397    

DOI:10.1029/WR008i003p00609

年代:1972

数据来源: WILEY

摘要:

Factor analyses are carried out on five parameters measured in third order basins in five landscapes in eastern Australia: basin area, stream length, basin relief, basin perimeter, and stream number. A comparison of the factor solutions for the five landscapes suggests that departures from topological randomness are associated with the evolutionary decline of relief. Regressions between the geometric mean bifurcation ratio and relief indicate that very small headwater streams have been abstracted from the drainage networks in the two landscapes where relief has been erosionally reduced below 200 feet.

ISSN:0043-1397    

DOI:10.1029/WR008i003p00624

年代:1972

数据来源: WILEY

摘要:

The design capacity of a reservoir depends on the generating mechanism of the inflows. If one uses the sequent peak algorithm in a deterministic manner, the minimum capacity λmrequired to meet a specified level of demand α is shown to depend on α and the values of the lag 1 serial correlation coefficient ρ and the Hurst coefficienthof the inflows. Although these experimental results may not realistically describe the ranges of the values α, ρ, andhover which other objective functions can be expected to be sensitive to the flow generating model, they do indicate that such ranges exist and that one may have to consider carefully both the list of moments to preserve and the means for their unbiased preserv

ISSN:0043-1397    

DOI:10.1029/WR008i003p00634

年代:1972

数据来源: WILEY

摘要:

The effects on reservoir yield of the magnitude of the serial correlation of inflows are determined for a highly simplified situation in which inflows are normally distributed and do not exhibit seasonal variation. The results are obtained by simulation with large samples and are presented in the form of graphs showing the relationships between dimensionless variables.

ISSN:0043-1397    

DOI:10.1029/WR008i003p00642

年代:1972

数据来源: WILEY

摘要:

Nonuniform flow is defined as a flow in which the velocity at any given time changes from point to point along a streamline. Such a flow occurs in an estuary in which the cross‐sectional area increases in the longitudinal or downstream direction. A general solution to the one‐dimensional equation that describes the fate of a pollutant introduced into such an estuary has not been found; only certain special solutions have been given for various simple analytical expressions for the longitudinal variation of area and longitudinal dispersion coefficient. Furthermore solutions to this equation are given in terms of the longitudinal dispersion coefficient, the value of which is not determinable a priori. A peak concentration model is developed that is applicable to estuaries and rivers whose lengths are large in comparison to their widths and depths. This model permits the estimation of the longitudinal dispersion coefficientKefrom the geometry of the system and from measurements of the peak dye concentration determined by the release of a known quantity of a tracer material such as rhodamine WT. The geometry need not be specified analytically; it need be specified only numerically at the positions of the peak concentration. The tracer experiments and the manner in which the longitudinal dispersion coefficients are estimated are described. A method for estimating the applicability of the procedure is also presen

ISSN:0043-1397    

DOI:10.1029/WR008i003p00648

年代:1972

数据来源: WILEY