摘要:

A simple, practical method for finding the numbers of skilled personnel necessary for the successful implementation of irrigation projects in developing countries, and for designing a training system to generate this personnel is given. The occupations critical to irrigation development and the agricultural activities in which each occupation is deployed are listed. A series of coefficients, based mainly on the successful irrigation development in northwest Mexico, determines the manpower quantities required as functions of given project parameters. A network flows model and a linear programing model are developed for designing the appropriate training systems.

ISSN:0043-1397    

DOI:10.1029/WR007i001p00001

年代:1971

数据来源: WILEY

摘要:

The preliminary design of an industrial waste treatment plant is considered by using certain aspects of the relatively new theory of geometric programing. A computationally efficient technique of solution is proposed and applied to a well‐known problem previously solved by a dynamic programing approac

ISSN:0043-1397    

DOI:10.1029/WR007i001p00018

年代:1971

数据来源: WILEY

摘要:

The historical record of the cost of pumping groundwater in Arizona is examined. Measures used are the cost per acre‐foot per foot of lift, the cost per acre‐foot, the water cost per acre for important crops, and the total water cost per farm for representative general crop farms. Costs are presented in actual dollars and dollars adjusted by GNP implicit price deflators. Whereas pumping depths have been rising rapidly, costs per acre‐foot per foot of lift have been falling, adjusted costs per acre‐foot have been almost constant, and per acre costs and total farm costs relative to both total costs and total returns have fluctuated throughout the time period examined, sometimes being lower but often being higher than costs at the prese

ISSN:0043-1397    

DOI:10.1029/WR007i001p00023

年代:1971

数据来源: WILEY

摘要:

Counties in the northeastern United States in which large water resource development projects constructed between 1948 and 1958 were examined to determine whether the projects stimulated economic growth. A growth index was developed for use as a dependent variable, which was then tested for its relationship with several independent variables by regression and discriminant analyses. Selected nonproject counties were examined to check further the relationship between the independent variables and growth index. Counties with high growth indices and development projects were found to be near urban areas, whereas counties with low growth indices and no projects were in rural areas. A subsample of rural project and nonproject counties was examined; it showed no significant relationship to the growth index. From these findings we infer that water resource development projects are likely to be poor tools for accelerating economic growth of rural counties in the northeastern United States.

ISSN:0043-1397    

DOI:10.1029/WR007i001p00032

年代:1971

数据来源: WILEY

摘要:

A radiation balance method and a modified radiation balance method were used to determine hourly and daily values of atmospheric thermal radiation on three clear and three cloudy days during February and March 1970 at Phoenix, Arizona. The radiation balance was used over surfaces of bare soil, Bermuda grass, and open water; whereas the modified radiation balance was used over the open water surface only. The modified radiation balance differed from the pure radiation balance method in that net radiation was calculated as the residual in the energy equation rather than measured.The values of atmospheric thermal radiation thus obtained were compared to valuesobtained from measurements of incoming, all‐wave radiation minus incoming solar radiation.From this analysis it appeared that the best alternative to the semi‐direct measurementof atmospheric thermal radiation was the radiation balance over the bare soil surface.Results from this method were of sufficient accuracy, even on an hourly basis, for mostresearch studies, and were even better on a daily basis. Radiation balances over grass andwater surfaces were somewhat less satisfactory, but still better than the modified radiationbalance met

ISSN:0043-1397    

DOI:10.1029/WR007i001p00039

年代:1971

数据来源: WILEY

摘要:

The model ratios applicable to dispersion studies in distorted hydraulic models are investigated for both steady and oscillatory flow, and the effects of both vertical and transverse distributions of velocity on the dispersion process are considered. It is shown that simple transposition of concentration profiles from model to prototype is not valid and that models may magnify or reduce longitudinal dispersion depending on the geometry of the system. For that reason, physical models are unlikely to be useful for studies of pollutant dispersion.

ISSN:0043-1397    

DOI:10.1029/WR007i001p00046

年代:1971

数据来源: WILEY

摘要:

A set of monthly streamflow records is generated and analyzed to give a set of synthetic critical periods. Some characteristics of these periods are derived, and the mean and standard deviation of their values are compared with the appropriate values for the historical critical period. This procedure is repeated with three characteristics for a number of different rivers by using a variety of generating techniques. A study of the results allows a comparison between the generating techniques in regard to both their cost in computer time and their ability to synthesize critical droughts comparable to those recorded historically. The results appear to be influenced by the relative aridity of the watershed and by the size of the reservoir considered. In addition, some general conclusions can be drawn regarding the advisability of using generated streamflow in studies of reservoir design and operation.

ISSN:0043-1397    

DOI:10.1029/WR007i001p00052

年代:1971

数据来源: WILEY

摘要:

The modification of a flood wave due to bank storage effects can be calculated by using numerical methods. The dynamic equations describing one‐dimensional open channel flow and the equation for two‐dimensional transient groundwater flow are solved simultaneously, coupled by an expression for flow through the wetted perimeter of the channel. Numerical experiments indicate that flood waves may be modified considerably by bank storage, particularly in the lower segments of a long reach, and that the degree of modification is influenced markedly by the hydraulic conductivity of the aqui

ISSN:0043-1397    

DOI:10.1029/WR007i001p00063

年代:1971

数据来源: WILEY

摘要:

Water yield has increased substantially on two small chaparral watersheds in central Arizona following brush control and conversion to grass. Winter precipitation is the major source of water yield. Summer rains begin in July and normally account for about one‐fourth of the annual precipitation but generally have little effect on streamflow. When annual precipitation is less than 16 inches, increase in water yield resulting from treatment is likely to be less than 2 inches. However, the efficiency of the conversion for producing extra water improves with rainfall, at least up to 34 inches. At this amount of annual precipitation, the increase in flow may reach 12 inches or more, depending on seasonal distribution of the rai

ISSN:0043-1397    

DOI:10.1029/WR007i001p00071

年代:1971

数据来源: WILEY

摘要:

Nitrogen, phosphate, and potassium concentrations were measured in streams draining woodland and farmland watersheds at Coshocton, Ohio, 1966 through 1969. Temporal variations in the nutrient concentrations were much smaller than the changes in the rate of streamflow. No relationship was found between any nutrient concentration and streamflow, and no seasonal changes in concentration were detected. Nutrient losses from farmland were significantly greater than those from woodland. The nitrate‐N concentration in the farm runoff was below 2 ppm except for one short period when it rose to 10 ppm. The input of nitrogen in the rain was greater than the loss in runoff from both watersheds. The average concentration of phosphate in runoff was 22 ppb (of P) from the farm and 15 ppb from the woodland. The analysis of the data shows that total nutrient losses cannot be calculated meaningfully unless both hydrologic and chemical data are available. The volume of water flow is the most important variable in this calculatio

ISSN:0043-1397    

DOI:10.1029/WR007i001p00081

年代:1971

数据来源: WILEY