摘要:

Three problems involved in planning and operating an irrigation system are (1) the short‐run problem of allocating a quantity of water in time over an irrigation season, (2) the intermediate‐run problem of deciding what area of crop to plant at the beginning of an irrigation season, and (3) the long‐run problem of deciding what area of land to develop for irrigation. This paper concerns the intermediate‐run problem. Crop growth is simulated with a simple crop growth model over a number of years on a large acreage supplied with water from a reservoir subject to stochastic inflows; the demand for water by the crop also being stochastic. Irrigation decision rules at each of a number of decision points in time are taken from the output of a simulation‐dynamic programing model used to solve the short‐run problem. The approach used allows for the abandonment for the rest of the season of portions of the area initially irrigated but does not allow for temporary abandonment, and reinstatement during the season, which is a limitation. The results show the best irrigated acreage to plant to be an approximately linear function of the reservoir contents at the beginning of the season. The function is found to be highly sensitive to changes in the profitability of the best dryland alternative enterprise. The cost of planting suboptimal acreages is found

ISSN:0043-1397    

DOI:10.1029/WR007i005p01051

年代:1971

数据来源: WILEY

摘要:

Whether a water treatment plant is installed as an independent facility or as an addition to an existing system of such plants, the determination of its capacity depends to a great extent on its total cost, which is composed of the amortization of capital investment and the fixed and variable operating costs. This total cost is formulated as a function of capacity and use rate on the basis of data reported by Koenig on surface water treatment.

ISSN:0043-1397    

DOI:10.1029/WR007i005p01064

年代:1971

数据来源: WILEY

摘要:

An input‐output model was adapted to estimate the environmental repercussions of changes in the economic structure of the Charleston, South Carolina, metropolitan area. The model contains two basic elements: (1) the Leontief inverse of a regional input‐output matrix, and (2) an environmental matrix containing data on resource use or residuals emission per dollar of gross output for each sector of the input‐output matrix. Implementation of the model is achieved by postmultiplying the environmental matrix by the Leontief inverse. The results show the cumulative effects on the local environment of both the direct and indirect changes resulting from changes in the economy structure of the area, and these results provide a basis for estimating the environmental repercussions of alternative changes in the local ec

ISSN:0043-1397    

DOI:10.1029/WR007i005p01070

年代:1971

数据来源: WILEY

摘要:

Water quality management based on water quality standards and required waste treatment levels has serious informational and administrative problems. An alternative management system of marketable rights to change water quality is analyzed to stimulate a search for improved management tools. Such a system of rights can (1) simplify the problems in existing management systems of new discharger entry into a region, (2) incorporate the economic efficiency of the ‘effluent charge’ system and the regional management approach, and (3) provide a mechanism for government or the private sector to adjust the quality of water without creating serious economic penalties for other parties discharging waste or requiring high water quality. A marketable right to discharge waste into a specified area of water subject to the observance of a water quality standard at the boundaries of that area is proposed. Utilities would compete for major rights, whereas individuals would purchase minor rights from a utility. The utility would provide control of waste discharges that impact only segments of a body of water and an institution that could shift water quality above the stand

ISSN:0043-1397    

DOI:10.1029/WR007i005p01079

年代:1971

数据来源: WILEY

摘要:

The operation of some hydrologie systems can be represented by a functional series expansion involving higher order nonlinear generalizations of the convolution integral, which underlies the unit hydrograph concept. A method was developed to determine the linear and nonlinear response functions of such systems on the basis of concurrent records of the input and output. This procedure was successfully tested in a special laboratory catchment and in a natural watershed to establish rainfall‐runoff relation

ISSN:0043-1397    

DOI:10.1029/WR007i005p01087

年代:1971

数据来源: WILEY

摘要:

The rainfall‐runoff relation was expressed by the convolution integral. The kernel function was evaluated by the Fourier and Laplace gamma transforms and by the direct method. Three analytical examples (known kernels) were analyzed and used to compare the effectiveness of these methods. The Fourier transform method was used for field data. The results indicated that for a third of the storms oscillatory kernels were obtained. Oscillations were not necessarily due to nonlinearities but could arise from random noise in the data. Low‐pass digital filtering of input (excess rainfall) and output (direct runoff) eliminated the kernel oscillations in most cases. The cutoff frequency was approximately the sampling frequency. Accurate output reproduction was obtained by convolution of the original kernel, the smoothed kernel, or the kernel resulting from the filtered d

ISSN:0043-1397    

DOI:10.1029/WR007i005p01102

年代:1971

数据来源: WILEY

摘要:

The catchment is considered as a nonlinear system with rainfall input and streamflow output. The system is analyzed by using a discrete form of the nonlinear convolution integrals in conjunction with stepwise multiple regression to obtain a prediction equation from the available rainfall and streamflow records. Experimental results for two rural catchments show that the analytical techniques employed have practical application in the continuous simulation of complex catchment behavior.

ISSN:0043-1397    

DOI:10.1029/WR007i005p01118

年代:1971

数据来源: WILEY

摘要:

The concept of deterministic hydrologic cycles is questioned from physical and statistical points of view. The spectra of streamflow series are shown to vary with time, and this variation suggests the nonstationary character of the data. Demodulation techniques are used to study the statistical character of the amplitude and phase of the annual streamflow cycle, and the use of the results in models for simulation is suggested. A case study performed with several Markovian type models shows that the seasonal variation in the standard deviation should be incorporated in any model used for design. It is also shown that the type of distribution used for the random component does not have a great influence on streamflows generated for storage design. Great care should be taken when using logarithmic models because they may produce very distorted synthetic traces when improperly used.

ISSN:0043-1397    

DOI:10.1029/WR007i005p01127

年代:1971

数据来源: WILEY

摘要:

This paper is a continuation of a previous one in which a stochastic model for analyzing excessive streamflows was presented. The model was based on the assumption that flood peak exceedances are independent, identically distributed random variables and that their occurrence is subject to the Poisson law. In the present paper a model is developed for nonidentically distributed exceedances on the assumption that only those exceedances during a particular season may be considered identically distributed. From this hypothesis the distribution function of the maximum flood peak exceedance in an arbitrary interval of time (0,t] is determined. The results are then applied to the 72‐year record of the Greenbrier River at Alderson, West Virginia. The theoretical and observed results agree reasonably wel

ISSN:0043-1397    

DOI:10.1029/WR007i005p01144

年代:1971

数据来源: WILEY

摘要:

Recent research studies have investigated an airborne gamma radiation detection system to determine the water equivalent of snowpacks in nonmountainous areas. Snow attenuates natural gamma emissions from the soil, and the magnitude of attenuation is related to the mass of the water blanket between the soil and the detector. Gamma spectral and total counting rates are collected and recorded by an airborne system using 14 4‐ by 4‐inch sodium iodide (NaI (Tl)) crystals. These data are corrected for soil moisture, background radiation, and effects of air density. Extensive snow depth and density measurements were taken to determine ‘ground truth’ water equivalent under the flight path. Results of the first year of research indicate that gamma spectral data may be expected to give areal measurement of snow water equivalent within at least 0.2–0.5 inch over favorable terrain. The use of total count data is even more promising but requires methodology still under development for eliminating background int

ISSN:0043-1397    

DOI:10.1029/WR007i005p01151

年代:1971

数据来源: WILEY