摘要:

ABSTRACT.Four commonly used models for predicting sediment yield are analyzed and compared using previously published data. Three of these models involve logarithmic transformations. Some of the problems involved in transforming data are discussed in the context of logarithmic transformations. These problems are illustrated using the results of standard regression analyses and economic loss function analyses. For the data analyzed, the linear model is preferable to each of the logarithmic models on the basis of each analysis, and the usual multiple objective nature of the model choice problem is thus modified. The extent to which these results can be generalized is discussed in the context of model choice.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02634.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.A multiple goal planning approach is proposed as a solution to the public water resources project selection problem. The goal programming technique enables a comprehensive water resources model. The model considers both economic and environmental objectives and may be implemented with data which are available to project planners.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02635.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02636.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.Fertilized eggs of perch (Perca fluviatilus L.) and roach (Rutilus rutilus L.) were reared at different pH values both in the field and in the laboratory. The results from the laboratory tests revealed that both species showed at least a 50% decrease in their hatching frequencies when reared at pH values below 5.6. At pH values below 4.6 both species studied show an almost complete lack of reproduction. The field studies with eggs from different lakes indicated that there might be an adaptation, manifesting itself as a higher frequency of hatching in water with a composition similar to that of the natural habitat. Field experiments also showed that the roach is more sensitive than perch to low pH values.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02637.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.The response of stream‐unconfined aquifer systems to localized recharge is investigated by means of a two‐dimensional finite element model. A variational approach is used in conjunction with the finite element method to solve the ground water flow equation. Linear approximated triangular elements are used to calculate the hydraulic head distribution in the flow region. The Crank‐Nicholson centered scheme of numerical integration is employed to approximate the time derivative in the flow equation. A computer program is developed to calculate the hydraulic head distribution in the flow region. Solutions provided by the finite element model should prove useful in the evaluation of quantitative and qualitative changes in aquifer systems due to natural or artificial recharge. In addition, they should prove useful in the study of irrigation and drainage pro

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02638.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02639.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.A relatively straightforward illustration of the potential uses of State Estimation techniques in water resources modeling is given. Background theory for Linear and Extended Kalman Filters is given; application of the filter techniques to modeling BOD and oxygen deficit in a stream illustrates the importance of model conceptualization, model completeness, uncertainty in model dynamics and incorporation of measurements and measurement errors. Potential applications of state estimation techniques to measurement system design; model building, assessment and calibration; and data extension are explored.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02640.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.In order to demonstrate the feasibility of a nonparametric statistical application in investigating the hydrologic impact of the rapid land use change accompanying intense urbanization, annual maximum peak flow data from an actual example (the Northeast Branch Basin, a recently urbanized Washington, D.C., suburban watershed) were analyzed. Annual peak flow data from the Patuxent Basin above Unity, Maryland, a rural watershed in close proximity to the study area, were compared to data from the Northeast Branch for the Same period utilizing the Wilcoxon matched‐pairs signed‐ranks test. A change in central tendency of each series was noted at the 0.01 significance level; however, the change was negative in the rural basin and positive in the urbanized Northeast Branch Basin. This central tendency change was considered indicative of an average decrease in the size of rainstorms producing annual maximum peak discharges. Rainstorm data from the Northeast Branch Basin were divided into two equal periods (before urbanization and after) and the Wilcoxon test was applied. It was found that rainstorms producing maximum annual peak discharges in the urbanized period were indeed smaller than those in the prior period (0.01 level of significance); however, larger annual peaks were produced. It was concluded that nonparametric statistical methods can be used readily with conventional methods to isolate and clearly analyze the various problems in an actual urban hydrologic st

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02641.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.An ever increasing number of communities throughout the nation are being forced by Federal legislation and local pressures to adopt land use and control measures related to drainage and flood protection. In many instances communities are hastily adopting ordinances and regulations which later prove difficult to administer and enforce. In addition, many of these ordinances and regulations are not producing the results originally anticipated. This paper discusses the basic elements of a drainage ordinance and evaluates the role of the ordinance in a comprehensive drainage program. This evaluation is based on the results of a two year study of drainage programs in five urban areas which produced a model urban drainage ordinance and recommendations on the administration of the ordinance. Personal interviews and local documents are used as the data base in formulating conclusions and recommendations.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02642.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

ABSTRACT.Increased public awareness of the environmental effects of large‐scale projects and concomittant public participation in the environmental impact assessment process demand that assessment methods and procedures fulfill a wide range of desirable characteristics. These are developed and offered as specific criteria against which currently proposed environmental assessment procedures should be judged. Such procedures as checklists, matrices, networks (stepped matrices), overlays, linear vector analyses, and nonlinear evaluation systems are presented and judged in light of the proposed criteria. It is concluded that the use of checklists, the most common assessment format used to date, does not constitute a viable assessment procedure. Use of the matrix or stepped matrix techniques in conjunction with the linear vector or nonlinear evaluation systems, with the latter modified slightly, is seen as an approach to environmental assessment that will achieve most of the established criteri

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1976.tb02643.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY