摘要:

A river basin authority seeking to maximize the economic value of a river's pollutant disposal and water quality services may limit pollutant discharges and/or increase the river's waste assimilative capacity. Pricing pollutant disposal induces disposers to recognize the opportunity cost of this service, or the value of downstream water quality foregone at the margin. The income from pollution charges can also reimburse the authority for the cost of capacity augmentation. There is some evidence that optimal pollutant charges would yield less than the cost of an optimal level of artificial aeration because of mild scale economics. Low flow augmentation, similarly optimized, should earn a surplus because of both diminishing marginal product and eventual increasing cost of reservoir storage.

ISSN:0043-1397    

DOI:10.1029/WR007i004p00759

年代:1971

数据来源: WILEY

摘要:

Determining the optimal timing of irrigations over a season in an uncertain environment is a significant problem in operating and planning irrigation schemes. In the absence of suitable experimental results, a plant growth‐soil moisture simulation model is incorporated into a two state variable stochastic dynamic programing model to determine the optimal intraseasonal allocation pattern for irrigation water in a variable environment. Historical traces of climatic data are used, although these data could be synthesized. Given the initial assumptions within the model, the results suggest that an irrigator should maintain available soil moisture in the root zone at a high level, even if it means exhausting the water supply early in the season. However, optimal irrigation strategies are sensitive to changes in the biologic assumptions within the model and thus indicate the importance of good experimental data on which to base these assumption

ISSN:0043-1397    

DOI:10.1029/WR007i004p00770

年代:1971

数据来源: WILEY

摘要:

The study investigates the usefulness of land values to measure the capitalized damages to agricultural land resulting from flooding by using a multiple linear regression technique to control for nonflood factors affecting land values. The model is applied to a study area on the Missouri River by using appraisal data on the value of land and improvements. Significant differentials in land values between two flood‐free areas and a flood‐prone area attributable to flood risk are individually established. Comparison of the results with other measures of flood risk shows the results to be relia

ISSN:0043-1397    

DOI:10.1029/WR007i004p00789

年代:1971

数据来源: WILEY

摘要:

This paper develops a model designed to distribute spatially recreation use estimates forthcoming from ‘structural demand’ equations of a recreation market. To illustrate the model's operation, a description of its empirical implementation for a regional case study area is given. Data needs and sources are specified, empirical results are set forth, and policy implications are drawn. The ability to use the model to simulate policy actions is pointed

ISSN:0043-1397    

DOI:10.1029/WR007i004p00798

年代:1971

数据来源: WILEY

摘要:

Timber and water research conducted at the Fernow Experimental Forest provides a 10‐year record of timber growth and streamflow increases. An approach for evaluating streamflow increases in terms of timber growth forgone is modeled. Light cutting (up to one‐fourth of the timber volume) slightly increased the value of timber growth as well as the amount of streamflow. Cutting one‐third to one‐half of the merchantable volume sacrificed timber regrowth for streamflow gain. Cutting one‐half to three‐fourths of the timber volume resulted in small streamflow increases for large sacrifices of timber regrowth. Cutting three‐fourths or more of the forest vegetation provided major increases in streamflow but no return from timber during the 10‐year period of regrowth. Average annual water costs ranged from 0 to $1.30 per thousand gallons. Although these water costs may be invalid outside the Fernow Experimental Forest, they nevertheless suggest a magnitude for water costs under similar fo

ISSN:0043-1397    

DOI:10.1029/WR007i004p00812

年代:1971

数据来源: WILEY

摘要:

The output from most analytical procedures used to set firm output levels for water projects is not associated with any given probability of failure to meet those output objectives. As a result, such output cannot always be used with confidence in the design and operation of water resource systems. A simple procedure is proposed that uses Monte Carlo techniques in deriving the optimum contract levels for a multipurpose system subject to constraints imposed by stated maximum permissible probabilities of failure to meet firm contract deliveries. The procedure is tested by analyzing a particular reservoir system. Similar procedures can be designed to handle multireservoir, multipurpose systems with a large number of such constraints and can be used to choose between alternative designs and fix optimum contract levels and release rules. Probability tables derived from such analyses can be used to improve the operational efficiency of water resource systems.

ISSN:0043-1397    

DOI:10.1029/WR007i004p00819

年代:1971

数据来源: WILEY

摘要:

A hydraulic structure such as a reservoir built on the basis of sample information is, in general, overdesigned or underdesigned in relation to perfect information. The resulting loss in net benefits is called the expected opportunity loss (EOL) due to imperfect information and is a function of sample size. Computation of the EOL requires perfect information. The EOL can, however, be found in one of two ways. One procedure estimates the EOL by sampling from a synthetic sequence of a stochastic input, such as streamflow, generated on the basis of estimates of the population moments. The other procedure involves a design decision within the framework of subjectivist (or Bayesian) statistics.

ISSN:0043-1397    

DOI:10.1029/WR007i004p00827

年代:1971

数据来源: WILEY

摘要:

Secondary flow plays an important role in a number of areas in hydraulics, such as sediment transport, distribution of primary flow velocity and boundary shear, flow resistance, and stream meandering. In this study, secondary currents generated in a straight, triangular open channel are investigated and used to develop a method of calculating secondary flow in an entire transverse cross section of a straight channel. The method developed involves the use in different regions of a cross section of different sets of curvilinear coordinate systems consisting of isovels of primary flow and their orthogonal trajectories. Descriptions of the method as well as calculated results are presented.

ISSN:0043-1397    

DOI:10.1029/WR007i004p00834

年代:1971

数据来源: WILEY

摘要:

Analysis of flow duration curves showed that reforestation of a 44‐acre watershed near Coshocton, Ohio, reduced flow in the low flow tail of the curve but did not significantly reduce flows above 0.25 inch per day. Other analyses showed that reductions also occurred in the maximum annual flow volumes for all periods of flow durations of 1 day or longer. The onset of dormant season flow was significantly delaye

ISSN:0043-1397    

DOI:10.1029/WR007i004p00845

年代:1971

数据来源: WILEY

摘要:

The numerical values of parameters in the mathematical model describing the dissolved oxygen (DO) and biochemical oxygen demand (BOD) concentrations (e.g., the reaeratio.n coefficient and the BOD removal coefficient) are determined in a systematic manner so that a best fit to the noise corrupted DO data is obtained asymptotically. The goodness of the estimates is evaluated by the squared difference between measured DO concentrations and concentrations calculated from the mathematical model. A stochastic approximation algorithm of the Robbins‐Monro type is applied for computing the parameter values in a sequential manner. The algorithm converges in the mean square sense to the parameter value that furnishes a local minimum for the average of the error criterion. The procedure is illustrated by several numerical examples. Because of the sequential nature of the algorithm, savings in computer time as well as in the required memory capacity are obtaine

ISSN:0043-1397    

DOI:10.1029/WR007i004p00853

年代:1971

数据来源: WILEY