摘要:

ABSTRACT:A model was developed of the periodic‐stochastic structure of daily precipitation over an area. The model is based ona multivariate normal distribution. The square roots of daily precipitation at a point were found to approximate a sample from a univariate normal distribution that had been truncated at zero. The zero daily precipitation amounts were considered negative amounts of unknown quantity. The multivariate normal distribution was used to describe the variation of daily precipitation over an area. The periodic fluctuations of the model parameters were described with Fourier series. The model was tested using data from two areas of different precipitation characteristics. Data generated with the model contained many of the statistical characteristics observed in the historical dat

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02244.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:The optimization of real‐time operations for a single reservoir system is studied. The objective is to maximize the sum of hourly power generation over a period of one day subject to constraints of hourly power schedules, daily flow requirement for water supply and other purposes, and the limitations of the facilities. The problem has a nonlinear concave objective function with nonlinear concave and linear constraints. Nonlinear Duality Theorems and Lagrangian Procedures are applied to solve the problem where the minimization of the Lagrangian is carried out by a modified gradient projection technique along with an optimal stepsize determination routine. The dimension of the problem in terms of the number of variables and constraints is reduced by eliminating the 24 continuity equations with a special implicit routine. A numerical example is presented using data provided by the Bureau of Reclamation, Sacramento, Californi

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02245.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:A method is reported for estimating the height of wind waves in any lake for a given wind condition. Maximum wind speeds from five climatological stations in and around Ilinois for the period of 1950–1972 were analyzed and the maximum wind speed for various durations and return periods were presented. Statistical analysis of wind wave data collected from Carlyle Lake indicated the Rayleigh distribution fitted the wave height distribution reasonably well and that the nondimensional energy spectra followed the (f/fm)‐5rule in the equilibrium range of frequencies. From a consideration of various forces and physical properties of riprap particles and water, a relationship was developed to estimate the stable weight of riprap particles. A practical design criteria is proposed to stabilize lake shores against wind wa

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02246.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:The municipal water conservation options available to meet the goals of a national water conservation policy are evaluated. Water conservation with water conservation devices is shown to offer many significant advantages over education and pricing and metering as a method of accomplishing water conservation goals. Current constraints on the use of water conservation devices are outlined, and their elimination is suggested if the nation's water conservation goals are to be met.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02247.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:Iron, added as (Fe‐EDTA)‐, was found stimulatory toV. spiralisat a concentration of 0.05 ppm. (Fe‐EDTA)‐had no effect upon growth ofV. neotropicalisas measured by changes in dissolved oxygen and dry weight. Results are compared with those derived from similar studies withHydrilla verticillataandEgeria densa. The implications of lake drawdown and aeration are di

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02248.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:The hypothesis of this paper is that the frequently used regulatory practice which employs point estimates in water pollution control objectives, in combination with monitoring at infrequent intervals, is an inadequate scientific procedure for the measurement and control of pollution. The first part of this paper outlines the relevant sampling theory which applies to the measurement of effluent from industrial plants and describes the possible errors in sampling practice which currently affect the interpretation and enforcement of environmental standards. In the second part of the paper, the authors describe briefly the environmental significance of biological damage functions. In the final part of the paper, the authors recommend that existing pollution control regulations be restructured to be more efficient and effective in the protection of both corporate and social interests. By adopting two different approaches to regulation depending upon the nature of the appropriate damage functions and critical fish species, it is possible to reduce significantly the waste of resources.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02249.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:A monthly model and two daily models (I and II) are presented for the purpose of generating monthly and daily rainfall sequences in the Quae Yai river basin in Thailand. Performance of the models are evaluated by comparing the statistical parameters of the generated sequences with those from historical data. For monthly generation, Thomas‐Fiering model worked satisfactorily in spite of the monthly correlations being weak, if any. Daily Model I, which assumes no persistence between daily rainfall amounts within the wet spells, could not preserve some important parameters regardless of the simplicity in model construction. Application of multi‐state transition probability matrix model gave good results, although the user has to modify some parameters looking at the performance of the model for each historical rec

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02250.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:As of 1976 over 225,000 acres were being irrigated by center pivot units in a five‐county area of the Columbia Basin in Oregon and Washington. Most of the development took place since 1970. Dynamic application of center pivot technology altered the concept of irrigability in the study area, converting lands that were often rolling, sandy, and plagued by wind erosion from low grade grazing to productive irrigated units. This development was entirely by private enterprise, with large corporate farms accounting for much of the effort. Little prior comprehensive planning or coordination took place. When the circulation of water is altered on such a massive scale, however, unplanned impacts may be far reaching. In this case they include:1) acceleration of the shift to high cost thermoelectric generation, 2) alteration of state institutions designed to allocate water, and 3) possible significant alterations of the socioeconomic fabric of small rural service center

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02251.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:The outflows of Lake Superior through the St. Marys River have been modified from natural conditions, initially by the construction of engineering works, such as bridges, and later by the construction of control works and the regulation of the lake. For all practical purposes, the period from 1860 to 1887 represents the natural river conditions. During the period 1888‐1900 the regimen was modified by the construction of the International Railroad Bridge and the Chandler‐Dunbar Power Canal. In 1901 construction began on the compensating works. Following the completion of the compensating works in August 1921, the Lake Superior outflows were regulated in accordance with the Orders of Approval, 26 and 27 May 1914. A hydrologic response model was developed to simulate the natural Lake Superior regime. The model was run for the 1860–1975 period to simulate natural Lake Superior levels and outflows. The simulated levels were compared with the recorded levels to determine the effect of regulation. It was found that regulation has resulted in a rise in Lake Superior water levels. The simulated natural outflows for the period from 1937 to 1975 were run through the Great Lakes hydrologic response model to analyze the regulation effects on Lakes Michigan‐Huron, St. Clair, and Erie. The results show no long‐term bias due to r

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02252.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACT:Significant errors in estimating surface runoff and erosion rates are possible if a watershed is assumed to contribute runoff uniformly over the entire area, when actually only a portion of the entire area may be contributing. Generation of overland flow on portions of small semiarid watersheds was analyzed by three methods: an average loss rate procedure, a lumped‐linear model, and a distributed‐nonlinear model. These methods suggested that, on the average, 45, 60, and 50% of the drainage area was contributing runoff at the watershed outlet. Infiltrometer data support the partial area concept and indicate that the low infiltration zones are the runoff source areas as simulated with the distributed‐nonlinear

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1978.tb02253.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY