摘要:

Rules for correctly dealing with price and interest rate projections when one conducts benefit‐cost analysis during inflation are derived, Recommendations of the Water Resources Council and those adopted in the Water Resources Development Act of 1974 are critiqued. The use of real prices and real opportunity cost interest rates is recommended as an improvement over the present practice of employing real prices and nominal financial interest rate

ISSN:0043-1397    

DOI:10.1029/WR011i004p00511

年代:1975

数据来源: WILEY

摘要:

An economic evaluation was made of the effects of increasingly restrictive waste water effluent standards and higher costs of water withdrawals on resource use, waste discharges, and costs of producing chlorine and caustic. Both mercury cell and diaphragm cell methods of production were studied for large modern plants at the design stage. Zero discharges of total solids in diaphragm cell plants increased production costs 5.6%; zero discharges of total solids in mercury cell plants increased production costs 12.1%. Zero‐discharge restrictions of mercury may only be accomplished by use of diaphragm cells. Similar results were obtained for assumed Houston and Saginaw location

ISSN:0043-1397    

DOI:10.1029/WR011i004p00515

年代:1975

数据来源: WILEY

摘要:

Application of linear multiple regression techniques to discharge measurement and water temperature data collected for selected Missouri River forecast points resulted in development of a successful quantitative technique for prediction of seasonal rating curve shifts. By utilizing 20 yr of discharge measurement and water temperature data for Omaha, Nebraska, and St. Joseph and Kansas City, Missouri, it was found that the addition of the independent variable water temperature (degrees Fahrenheit) to the stage‐discharge relationship increased multiple correlation coefficients significantly. In all cases studied, increased temperature reflected an increase in stage for a constant flow. The maximum effect of water temperature is indicated for low flows. Water temperature is thought to cause the alterations of bed form configuration resulting in seasonal rating curve shift

ISSN:0043-1397    

DOI:10.1029/WR011i004p00526

年代:1975

数据来源: WILEY

摘要:

Hydrologic decision making usually occurs in an uncertain world and should combine inferences about uncertain outcomes with the decision makers’ preferences toward these outcomes. The decisions associated with flood protection are considered in detail where there exists uncertainty in the frequency of future flood discharges. Procedures are developed for analyzing and accounting for both statistical uncertainty of competing flood frequency models and statistical parameter uncertainty for the individual models. Inferences about flood frequency are combined with a decision model for which the decision rule is the maximization of expected monetary benefits. A case study to determine the optimal size of local flood protection by using prior information from a regional regression model, historical data, and realistic flood cost and damage functions is presente

ISSN:0043-1397    

DOI:10.1029/WR011i004p00533

年代:1975

数据来源: WILEY

摘要:

A model proposed earlier (Brutsaert, 1965) for evaporation as a molecular diffusion process into a turbulent atmosphere is extended by joining it with the similarity models for turbulent transfer in the surface sublayer. The assumed mechanisms were suggested by available flow visualization studies near smooth and rough walls; the theoretical result is in good agreement with available experimental evidence. The important dimensionless parameters governing the phenomenon near the surface are the Dalton (or Stanton) number (i.e., mass transfer coefficient), the drag coefficient (u*2/U2), the roughness Reynolds number (u*z0/v) (except for smooth surfaces), and the Schmidt (or Prandtl) number (v/k). The proposed formulation allows the evaluation of the effects of some parameters, such as surface roughness or molecular diffusivity, that were hitherto not well understood. An important practical result is that in contrast to the drag coefficient, the Dalton number is relatively insensitive to changes in roughness lengthZ0.

ISSN:0043-1397    

DOI:10.1029/WR011i004p00543

年代:1975

数据来源: WILEY

摘要:

During periods of glacial ablation, excess water often concentrates in supraglacial melt streams, which typically exhibit meandering. Herein a stability analysis of straight supraglacial streams is carried out to determine the nature of meandering tendencies. Instability leading to meandering in the flow results from a combination of hydrodynamic and differential heating effects. The heat involved is apparently largely frictional. The analysis indicates that instability occurs only for supercritical flow and that the meander pattern does not migrate downstream. Meander wavelength is determined by channel width, depth, and Froude number. The results agree with field observations.Summary and entire article are available on microfiche. Order from American Geophysical Union, 1909 K Street, N.W., Washington, D.C. 20006. Document W‐75‐002; $1.00. Payment must accompany or

ISSN:0043-1397    

DOI:10.1029/WR011i004p00551

年代:1975

数据来源: WILEY

摘要:

Artificial recharge basins or spreading sites commonly exhibit reductions in infiltration rates after prolonged periods of submergence. This loss in infiltration rate has often been shown to be associated with a large population of anaerobic or facultative anaerobic bacteria in the material underlying the basin floor. An artificial recharge experiment in a spreading basin at Lubbock, Texas, showed a significant change in the chemical quality of recharged water that was associated with the growth of anaerobic bacteria. Sulfate‐reducing bacteria reduced the sulfate concentration of the recharge water at this location by 80 mg/l. The bicarbonate concentration was increased by more than 150 mg/l, and thepH decreased 1 unit during the same time period. The change in chemical quality occurred suddenly and corresponded to a dramatic decrease in the infiltration rate in the basin. These observations on the chemical changes in recharged water make it possible to differentiate between anaerobic bacteria and other causes of reduced hydraulic conductivity in this recharge basin. The anaerobic conditions appear to start at depth and work toward the surface, thereby suggesting a process that involves adsorption of organic material and consumption of dissolved oxygen with dept

ISSN:0043-1397    

DOI:10.1029/WR011i004p00553

年代:1975

数据来源: WILEY

摘要:

The influence of storage conditions and duration of storage was studied by using about 100 stream samples from Fall Creek collected near Ithaca, New York. Freezing and refrigerated storage were found to be unsatisfactory, since changes in measured concentrations were usually observed after relatively short periods of time (24 hours). An isobutanol extraction procedure is described which minimizes storage problems and is useful for routine analysis of water samples for dissolved inorganic phosphate.

ISSN:0043-1397    

DOI:10.1029/WR011i004p00559

年代:1975

数据来源: WILEY

摘要:

A method to solve the inverse problem is developed. This method does not require the iterative solution of the aquifer equation, which is an essential characteristic of many current identification schemes. The shape of the surface representing the observed dependent variable (which may be hydraulic head, chemical concentration, or temperature) is approximated from measured samples by means of various interpolation algorithms. Once the various derivatives of the dependent variable are approximated, the identification problem reduces locally to algebraic equations of small dimension. It is shown that aquifer conditions of general heterogeneity and anisotropy are amenable to this method. Input may be treated as an unknown to be evaluated. The method is appraised by application to scattered solution points of a simulated solution to a nonhomogeneous aquifer equation.

ISSN:0043-1397    

DOI:10.1029/WR011i004p00563

年代:1975

数据来源: WILEY

摘要:

The development of an initially confined aquifer for river regulation is considered. Model investigations cover a range of groundwater abstraction regimes and a number of aquifer systems typical of those found in the United Kingdom. The various factors affecting net gains are discussed. The main conclusions are that high net gains can be sustained only if unconfined storage is developed around the abstraction site. In practice this requires a high density of abstraction wells. Also higher net gains are obtained from those aquifers having a large response time.

ISSN:0043-1397    

DOI:10.1029/WR011i004p00571

年代:1975

数据来源: WILEY