摘要:

A systematic evaluation was made of 165 village water supply and treatment systems in Northeast Thailand for studying problems involved in the design, construction, operation, administration, and financing of such systems. The evaluation included 1 year of field data collection covering system operation by village operators. This is believed to be the first such evaluation of the effectiveness of a rural water supply development program. Findings include quantification of strengths and weaknesses pertinent to management, and recommendations are developed for guiding governmental agencies operating such programs and international agencies participating in their planning and financing.

ISSN:0043-1397    

DOI:10.1029/WR011i003p00383

年代:1975

数据来源: WILEY

摘要:

Two different programs which attempted to improve water use and management were evaluated in eastern India. The improvement was through the installation of field channels in existing flood irrigation projects. The channels gave farmers better control over water on each field. The analysis highlights the importance of technically trained people and low‐cost project designs in making projects viable. Annual net returns of 300–350 rupees per acre were obtained in the Sambalpur villages with investment costs of only 34 rupees per acre. The contrasting pilot project in Raipur had a much lower profit potential due to high investment costs. The analysis adds support to the proposition that India should spend more public funds on modest improvements in existing flood irrigation systems and much less on large new irrigation proje

ISSN:0043-1397    

DOI:10.1029/WR011i003p00389

年代:1975

数据来源: WILEY

摘要:

This paper analyzes the impact of an improvement in pollution abatement technology on the costs of a firm producing under three alternative methods of pollution control: tax, subsidy, and emission standards. It is shown that the cost reduction to the firm will be greatest if the firm is operating under the pollutant tax method of pollution control, and therefore it is concluded that the incentive to improve pollution abatement technology will be greater if pollutant taxes are used to control pollution. In addition, it is shown that firms operating under emission standards or subsidy may have no economic inducement to produce some innovations in pollution abatement.

ISSN:0043-1397    

DOI:10.1029/WR011i003p00393

年代:1975

数据来源: WILEY

摘要:

The optimal release policy for a large and shallow lake subject to the double uncertainty of average monthly hydrologic input and instantaneous wind‐induced water rise is calculated. The case of Lake Balaton in Hungary is used to illustrate the methodology. Loss functions are obtained for each lakeshore section; losses due to unfavorable (high or low) water level are given on a monthly basis, and dynamic losses due to waves and wind tides are calculated by using an event‐based model. A stochastic dynamic programing formulation yields an optimum release policy whose sensitivity to loss functions and discount factor is exami

ISSN:0043-1397    

DOI:10.1029/WR011i003p00397

年代:1975

数据来源: WILEY

摘要:

Water resource designs are perfect examples of decision making under uncertainty. In fact, three types of uncertainties may exist in any design problem: natural, parameter, and model uncertainties. The last two may be considered as informational uncertainties that are due to the lack of perfect information about the streamflow processes. The use of regional information has been suggested as a technique for reducing parameter uncertainties. The use of Bayesian methodology provides a framework for combining regional information with at‐site historical records. Moreover, Bayesian methods allow the hydrologist to consider the parameter uncertainties as well as the natural uncertainties within the decision‐making process. Because of these two advantages the Bayesian approach is a more complete and realistic approach to problems of uncertainty in hydrology and water resource planning than presently used methodolog

ISSN:0043-1397    

DOI:10.1029/WR011i003p00405

年代:1975

数据来源: WILEY

摘要:

Gage catch from two standard weighing recording rain gages (Belfort model 5‐780), one with a modified Alter windshield and one with a rigid Alter type windshield, were compared for 89 storms with wind speeds ranging from 4 to 32 mph (6.4 to 51.5 km/h) and temperatures ranging from 14° to 69°F (−10° to 21°C). The differences between gage catches were statistically significant at the 1% level for wind speeds of 12 to 16 mph (19.3 to 25.7 km/h) and for temperatures of 23°F (−5°C) or less. Since on the average the windshields do not produce significantly different catches, either windshield can be used to compute actual precipitation by using the Hamon dual ga

ISSN:0043-1397    

DOI:10.1029/WR011i003p00415

年代:1975

数据来源: WILEY

摘要:

The recession of streamflow following storm periods has been studied for a long time. Flow during recessions is important as a dependable minimum supply of water. However, quantitative mathematical expressions are still lacking for accurately predicting flow during recession periods. A convolutional model of streamflow recession has been formulated and tested utilizing sequential values of mean daily discharge. Parameters of the model are determined by optimization with historical streamflow records. Preliminary relationships of parameters to rate of flow and size of drainage area are explored.

ISSN:0043-1397    

DOI:10.1029/WR011i003p00418

年代:1975

数据来源: WILEY

摘要:

The formulation of a mathematical model to predict transient flows in hydraulic networks is presented. The network formulation consists of breaking the network up into a series of connected reaches; reducing the finite difference equations for each reach into two ‘reach’ equations; forming an exterior matrix consisting of the reach equations, external boundary conditions, and interior compatibility conditions; solving the external matrix for the end values of discharge and water surface elevation for all reaches; and back‐substituting for all interior values. Examples presented include the James River, USA, estuary model (24 nodes and 26 reaches), the Cork Harbor, Ireland, estuary (13‐reach double‐looped network), and the Rio Bayamon basin, Puerto Rico. Results are very satisfactory when they are compared to k

ISSN:0043-1397    

DOI:10.1029/WR011i003p00423

年代:1975

数据来源: WILEY

摘要:

Studies have shown that the urbanization of a catchment can drastically change the flood characteristics of a river. Published results are synthesized to show the general relationship between the increase in flood flows following urbanization and both the percentage of the basin paved and the flood recurrence interval. In general, (1) floods with a return period of a year or longer are not affected by a 5% paving of their catchment, (2) small floods may be increased by 10 times by urbanization, (3) floods with a return period of 100 yr may be doubled in size by a 30% paving of the basin, and (4) the effect of urbanization declines, in relative terms, as flood recurrence intervals increase.

ISSN:0043-1397    

DOI:10.1029/WR011i003p00431

年代:1975

数据来源: WILEY

摘要:

Changes in storm hydrographs after road building, clear‐cutting, and burning were determined for six small watersheds in the Oregon Coast Range. Peak flows were increased significantly after road building, but only when roads occupied at least 12% of the watershed. Roads had no detectable effect on volumes of storm hydrographs. By reducing transpiration and interception, partial clear‐cutting increased peak flow, quick flow, delayed flow, and total storm hydrograph volume of some streams. Most increases were largest in the fall when maximum differences in soil water content existed between cut and uncut watersheds. Maximum increases in storm flow occurred after a 175‐acre watershed was 82% clear‐cut. Here peak flow increased 16 ft3/s/mi2, quick flow 1.5 in., and total storm hydrograph volume 2.6 in. during the fall. The average increase in winter peak flows was smaller. The effect of roads on peak flows has significance for design of culverts and bridges in headwater areas, but probably does not influence downstream flooding. Increases in streamflow after clear‐cutting should have no appreciable effect on either damage to bridges and culverts in headwater areas or downstream flooding. Caution must be used in extending results of this study to storm runoff events of low frequency and large

ISSN:0043-1397    

DOI:10.1029/WR011i003p00436

年代:1975

数据来源: WILEY