摘要:

An elementary exposition of choice criteria for social investment is presented. The two causes for discounting the future benefits, time preference and opportunity cost, are discussed. The general reasons for special methods of measuring benefits are brought out. The subsequent discussion is a more detailed analysis of the application of these general principles, together with some remarks on the measurement of costs.

ISSN:0043-1397    

DOI:10.1029/WR001i001p00001

年代:1965

数据来源: WILEY

摘要:

A workable procedure is devised for incorporating optimal amounts of nonstructural measures in flood‐control planning, determining proper project timing, and providing review as new developments unfold. Optimality is based on the economic efficiency criterion, or minimizing the sum of the four flood control cost components: flood damage, structural measure cost, the cost of floodproofmg, and the cost of land use adjustment. Optimum timing is estimated by minimizing independently the total cost in successive 10‐year stages. Periodic review is obtained as the plan for each upcoming stage is reviewed before it is applied. The technique was used to analyze a small watershed in Sacramento County, California, and it produced a flood‐control program significantly less costly than that obtained by current procedures. Structural measures for flood control were found most applicable at the two extremes of extensive agricultural or urban damages. Nonstructural measures were favored in situations involving rapidly expanding urban development suffering fairly frequent flooding or unusually costly structural measure construction. Residual flood damages were found to increase with time even after the optimum combination of structural and nonstructural measures was ap

ISSN:0043-1397    

DOI:10.1029/WR001i001p00009

年代:1965

数据来源: WILEY

摘要:

The provision of navigable inland waterways has been an important part of the water resources development and conservation program of the United States. Two problems, one public and one private, arise in connection with such waterways: (1) the determination of optimal scale of waterway projects in terms of length, depth, and width; (2) the selection by private operators of the best equipment (boats, barges, and their configuration) to be used on particular water‐ways. This paper provides functional relationships that permit prior evaluation of the effects of waterway scale variables on ton‐mile costs of cargo transportation. The same relationships can be used to determine least‐cost tow configurations for a given waterway. Finally, substitution possibilities between towboat and barge inputs are investi

ISSN:0043-1397    

DOI:10.1029/WR001i001p00025

年代:1965

数据来源: WILEY

摘要:

This paper describes the application of systems analysis and digital computer simulation to the control of waterlogging and salinity in West Pakistan. The details of the project are not nearly so important here as the nature of the systems approach and the demonstration of digital computer applicability to civil engineering problems. The history of waterlogging and salinity of agricultural lands in West Pakistan is the by‐product of a truly remarkable system of crop irrigation which has been employed in increasing intensity over a period of some 3000 years. During the early part of this century British hydraulic engineers initiated the barrage system of irrigation and began to divert large quantities of water from the mighty Indus River and the five great tributaries that drain the Punjab region of the subcontinent. The economic and technologic aspects of the remedy, a well field of truly heroic proportions, are discussed; the role of the digital computer is seen to be essential to the concept and thrust of an operations research solutio

ISSN:0043-1397    

DOI:10.1029/WR001i001p00041

年代:1965

数据来源: WILEY

摘要:

The manner in which chloride, applied to the soil surface as KCl, moves through Panoche clay loam was investigated under field conditions. Three soil water treatments were established: (1) continuous ponding, (2) intermittent ponding with 6 inches of water, and (3) intermittent ponding with 2 inches of water. Frequent measurements of the chloride concentration in the soil solution at 1‐foot depth intervals to a depth of 5 feet were used to ascertain the redistribution of the surface‐applied chloride relative to the movement of soil water. The experiment revealed that chloride movement results from a dynamic process that may be altered or controlled with the method of water applicat

ISSN:0043-1397    

DOI:10.1029/WR001i001p00063

年代:1965

数据来源: WILEY

摘要:

Two methods are used to detect the presence of methane gas in water from wells in southwestern Louisiana. A commercially developed combustible gas indicator proved reliable when using proper collection and analytical techniques and mathematical formulas, provided no hydrocarbons other than methane are present. Data obtained from a gas‐entrapment device showed that methane is the only hydrocarbon occurring in these waters. Values obtained for the quantity of methane present utilizing both methods agree within 10%. To aid the better understanding of the use of these two methods and to demonstrate what physical constants are used, the equations utilized in calculating the amount of methane are derive

ISSN:0043-1397    

DOI:10.1029/WR001i001p00075

年代:1965

数据来源: WILEY

摘要:

Movement of contaminants from many waste sites into the subsurface water circulation system results in contaminated zones, or enclaves, in the zone of saturation (below the water table). Difficulty in predicting the areal extent of a contaminated zone stems from the multiplicity of factors that need consideration, including: the great variety of waste materials, their range in toxicity and adverse effects; man's variable pattern of waste disposal and of accidental release of contaminants in the ground; man's variable pattern of water development from wells; behavior of each contaminant in the soil, water, and rock environment; ranges in geologic and hydrologie conditions in space; and ranges in hydrologie conditions in time. Two opposing tendencies need to be in focus before an evaluation of contaminated zones is undertaken: (1) the tendency of contaminants to be entrained in groundwater flow and (2) the tendency for contaminants to be attenuated to varying degrees by dilution in water, decay with time, or some other ‘die‐away’ mechanism, and sorption on earth materials. Once a contaminated zone is approximately stable, an increase in concentration may cause it to remain about the same size under some conditions and to enlarge in others, according to combined attenuation effects. Where attenuation occurs only by dilution, the contaminated zone will become enlarged with increased concentration, and, where dilution is also slight, it may become greatly elongated in the direction of groundwater, and perhaps also of surface‐water, flow. Where attenuation occurs also through decay or sorption, or through both mechanisms, the contaminated zone may not enlarge appreciably, even if the concentration of contamination is increased. The upper part of the zone of saturation in populated parts of the Earth may be considered as a galaxy in which millions of enclaves of contaminated water are scattered in uncontaminated groundwater. Interspersed with these enclaves are millions of water‐supply wells, some of which pump contaminated water or help to disperse it even if it does not reach them. Although too few contaminated zones have been delineated to enable a statistical analysis of areal patterns, an approximation of their patterns of distribution can b

ISSN:0043-1397    

DOI:10.1029/WR001i001p00083

年代:1965

数据来源: WILEY

摘要:

Studies have been made of the relationship between the rainout of radioactivity in convective storms and three rainfall factors: rainfall volume, storm duration, and rainfall rate. Data were used from four densely gaged sampling networks operated during the spring and summer of 1962–1964 in central Illinois. The network areas ranged from 10 to 6000 mi2and provided data on both microscale and mesoscale relationships. Analyses of spatial variability showed a trend for the relative variability of radioactive rainout to (1) exceed the storm rainfall variability, (2) decrease with increasing rainfall volume and storm duration, and (3) increase with increasing network size. Investigation of the point representativeness of single measurements of radioactive rainout in a 15‐storm sample indicated that an average error of 20–25% is introduced when a single observation is assumed to represent the mean rainout over areas of 10–12 mi2. Correlation analyses indicated that the rainfall at a given point is not strongly related to the radioactive rainout at that point. However, when areal patterns of rainfall and rainout are compared and allowance is made for displacement of high and low centers due to various meteorological influences, a strong association is indicated between the major features of the patterns in most

ISSN:0043-1397    

DOI:10.1029/WR001i001p00097

年代:1965

数据来源: WILEY

摘要:

Naturally occurring stable or radioactive isotopes may be used in some places to identify the origin of saline water that contaminates some coastal aquifers. In a recent study to determine the origin of saline water in the Ocala Limestone aquifer near Brunswick, Georgia, the following sources were analyzed for C14and deuterium concentrations: potable water from the Ocala Limestone, contaminated water from the Ocala Limestone, saune water from the underlying Claiborne Group, and nearby ocean water. The chloride concentration of the groundwater ranges from about 25 ppm in the potable water to more than 2000 ppm in the deeper part of the Claiborne Group. From an interpretation of piezometric maps and other hydrologic data, previous investigators had concluded that the source of the contaminating water was the Claiborne Group and not the nearby ocean. The essentially uniform range of low values of −965 to −987‰ of the modern standard (National Bureau Standard C14oxalic acid) for the C14activity of the groundwater samples (regardless of the degree of contamination) is in agreement with this conclusion. If recent ocean water, which had a C14value of +285‰, were the source of contamination, the contaminated water would have had a C14activity higher than the activity of the fresh water. Deuterium analyses are not inconsistent with the interpretation that water from the Claiborne Group, rather than recent ocean water, is the source of the contaminating water. The concurrence of the hydrologic and the isotopic data in this area where the hydrology is well known suggests that isotopic analysis may be used to identify the origin of water in different portions of a hydrologic envi

ISSN:0043-1397    

DOI:10.1029/WR001i001p00109

年代:1965

数据来源: WILEY

摘要:

An analysis was made to determine the amount of annual and seasonal water yield, flow duration, and peak flow frequency for seven major physiographic units in the northeast. AU watersheds (137) in the northeast that were less than 100 square miles in area, that had continuous records from 1940 to 1957, and that were not appreciably affected by regulation and diversion were included in the analysis. In addition, streamflows of four small forested experimental watersheds were compared with average streamflow values of the physiographic units in which they were located. The longest simultaneous record available was for a 3‐year period from 1959 to 1962. Results indicate significant differences in water yield between physiographic units as well as between watersheds within units. Water yields from the small experimental watersheds, although based on a shorter and different period of time, were found to correspond closely with average water yields of their respective physiographic unit

ISSN:0043-1397    

DOI:10.1029/WR001i001p00115

年代:1965

数据来源: WILEY