摘要:

The Galerkin‐finite element method can be used to simulate the two‐dimensional movement of the saltwater front in the Cutler area of the Biscayne aquifer near Miami, Florida. The concentration distributions for steady state and transient conditions can be obtained by using pressure head data measured in the field for formulating boundary conditi

ISSN:0043-1397    

DOI:10.1029/WR012i001p00065

年代:1976

数据来源: WILEY

摘要:

Well response tests, often referred to as slug tests, provide a relatively simple and inexpensive method for estimating aquifer transmissivity. An approximate theory is developed for the problem of underdamped well response where the inertia of the water in the well column results in force‐free oscillation of the water level in the well. This type of response is often encountered in conjunction with highly permeable aquifers. The theory is applicable for nearly all such cases except those where the oscillation is very quickly damped out. Theoretical predictions compare well with empirical results and indicate that the theory may be used to obtain estimates of aquifer transmissivity. This theory for the underdamped case together with existing theory for overdamped response makes it possible to obtain an estimate of transmissivity from well response tests for almost any aquife

ISSN:0043-1397    

DOI:10.1029/WR012i001p00071

年代:1976

数据来源: WILEY

摘要:

Solute distributions within a soil profile during the leaching of water‐soluble salts applied to the soil surface were measured at six depths to 182.4 cm within 20 subplots of a 150‐ha field. Estimates of the pore water velocity based upon measures of solute displacement within each subplot and the entire field were found to be logarithmically normally distributed and in agreement with volumetric measures of water infiltration rates. Such agreement was only possible because it was recognized that the observed values were not normally distributed, and their mean values were calculated accordingly. The number of observations required to yield an estimate of the mean pore water velocity within a prescribed accuracy is shown to depend upon the nature and extent of the spatial variability of the field soil. For the field examined, 100 observations would allow the mean pore water velocity to be estimated within ±50% of its true value. The functional relation between field‐measured values of the apparent diffusion coefficient, also found to be logarithmically normally distributed, and pore water velocity is examined and interpreted in terms of solute distributions likely to be measured at specific sampling

ISSN:0043-1397    

DOI:10.1029/WR012i001p00078

年代:1976

数据来源: WILEY

摘要:

The possibility of applying reliability programing for determining the monthly contract volumes to be released by a reservoir is discussed in this paper. While in standard chance constraint programing the risk of the solution is fixed a priori, here constraint reliabilities are considered as extra decision variables. Hence the optimal operation results from a compromise between profit and risk. It is shown that under quite general assumptions the reliability program enjoys a concavity property that allows the application of an efficient solution algorithm.

ISSN:0043-1397    

DOI:10.1029/WR012i001p00085

年代:1976

数据来源: WILEY

摘要:

Simple perturbation methods are employed to analyze the horizontal absorption of moisture in unsaturated soils. The special case treated assumes the diffusivity to be an exponential function of the concentration and the concentration at the boundaries to be constant. The solution emerges as an explicitly determined power series in the Boltzmann variable.The resulting profiles are compared with some others found in the existing literature. A discussion about the relevance and advantages of this type of analysis forms the concluding part of the paper.

ISSN:0043-1397    

DOI:10.1029/WR012i001p00089

年代:1976

数据来源: WILEY

摘要:

The objectives of this study are to develop and use a novel and simple method of analysis of the urban combined sewer and overflow problem. An aggregated method is presented which relates a few significant variables to produce a scalar that describes the severity of pollution for an urban area. Typical values of the variables are assigned, and sensitivity analysis of urban storm‐induced pollution to various control measures is demonstrated. Digital computers are not necessary. The method takes a macroanalytic perspective which should produce comparisons adaptable to decision rules for funding priorities. Work on specific cities is necessary to refine the approach and rank alternatives. The method should be able to screen out poor candidates for funds early in the decision‐making process and concentrate feasibility studies and analysis upon needy sites and viable alternatives. The method as applied to typical values leads to the following conclusions: (1) the method has utility for first‐level screening of alternatives at the national or state decision‐making level; (2) the hydrologie variables, formerly thought to be very complicated factors in studies of this problem, with the exception of receiving water streamflow at the start of a storm, do not enter into the assessment of the maximum pollutional impacts of storms; (3) a relatively small set of variables, several relating to water use and the sewer treatment system and the others defining the quality of receiving waters, storm wash and raw sewage, are used to conduct the analysis using the simplified method; and (4) the maximum storm‐induced water quality is several times the water quality associated with the dry weather engineering design limits of sewage treatment pe

ISSN:0043-1397    

DOI:10.1029/WR012i001p00094

年代:1976

数据来源: WILEY

摘要:

Sequencing the expansion of water supply projects to minimize discounted operating and capital costs can be formulated graphically as finding a least cost path from the present to the fully expanded future. In light of this model a simple dynamic programing algorithm or minimal cost network algorithm can be readily used in conjunction with a computer to solve the problem.

ISSN:0043-1397    

DOI:10.1029/WR012i001p00101

年代:1976

数据来源: WILEY

摘要:

A series of laboratory experiments were conducted to determine the magnitude of laminar flow interference effects at fracture intersections. Circular conduits were used in these experiments to maintain strict dimensional tolerance, and the intersection head loss, if expressed in terms of equivalent length of straight conduit, should be the same order of magnitude for a circular pipe as for a parallel plate fracture model. The results indicate that interference effects at intersections are negligibly small in most fracture systems when flow is in the laminar regime.

ISSN:0043-1397    

DOI:10.1029/WR012i001p00102

年代:1976

数据来源: WILEY

摘要:

The finite element approximation of the convective diffusive transport equation can be expressed in terms of well‐known finite difference notation. Examination of the relationship obtained reveals that in contrast to finite difference schemes, which approximate the differential equation at a point, the finite element method can be interpreted as an approximation of the integrated form of this equatio

ISSN:0043-1397    

DOI:10.1029/WR012i001p00105

年代:1976

数据来源: WILEY

摘要:

A generalized algorithm provides the daily total of potential solar radiation on any sloping surface at any latitude. The algorithm can be coded as subroutines of a computer model that requires solar radiation as a variable. The required inputs are Julian dates and the latitude, inclination, and aspect of the slope. In addition to computing potential solar radiation, the routine provides estimates of actual radiation on any slope on the basis of measured solar radiation for a nearby horizontal surface that has the same cloud cover.

ISSN:0043-1397    

DOI:10.1029/WR012i001p00108

年代:1976

数据来源: WILEY