摘要:

Recreational activities are more restricted on domestic water supply reservoirs in the Northeast and Far West than in the remainder of the United States. In the Northeast and Far West, recreational activities are usually prohibited from domestic water supply reservoirs, especially bodily contact activities; the water managers view recreation as incompatible with the production of safe potable water, and consumer opinion opposes such reservoir use. In the remainder of the country, recreational activities are not only allowed on domestic water supply reservoirs, but the water managers do not consider reservoir recreation as inimical to the hygienic and aesthetic qualities of the drinking water, and the public favors such reservoir use. From a literature review, the writer concludes that all recreational activities can be permitted on domestic water supply reservoirs without any measurable increase in the risk of water‐borne disease if the water is properly treate

ISSN:0043-1397    

DOI:10.1029/WR005i003p00543

年代:1969

数据来源: WILEY

摘要:

Hurricane storms as they move inland are accompanied by rather widespread rainfall. The effect of the rainfall on crop production depends upon the time occurrence of the storm. A statistical time series analysis of the relation between rainfall by time periods and crop yields indicates that rainfall during the major hurricane season (August, September, and October) is damaging to many crops. The analysis consisted of a multiple regresssion of crop yields on rainfall by ten‐day time intervals. The total benefit or loss from any storm would depend upon the time occurrence and the track of the storm. A summary of change by states in total crop value from one inch of incremental rainfall for their five major crops resulted in both positive and negative totals, depending upon the time period. Predicted changes in yield and crop value for three historic storms indicate net losses for two storms occurring in August and September and net benefits for one storm occurring in Jul

ISSN:0043-1397    

DOI:10.1029/WR005i003p00555

年代:1969

数据来源: WILEY

摘要:

Multivariable distributed parameter control theory has been applied to the optimization of artificial in‐stream aeration of polluted rivers. The optimization was developed for a general integral type of cost functional with weighted energy constraints. Three specific types of aeration control policies were considered: distributed space and time control, distributed time control, and distributed space control. Employing typical hydrologic coefficients with the transient version of Streeter‐Phelps equation, the optimal aeration control surfaces obtained were all found to lie well within the operating characteristics of commercial aeration equipment. Distributed parameter control theory applied to water pollution systems proved to be a powerful mathematical programing method comparable to linear and dynamic program

ISSN:0043-1397    

DOI:10.1029/WR005i003p00563

年代:1969

数据来源: WILEY

摘要:

An investigation of runoff from a 4.64‐acre agricultural watershed included the use of subplots, observation wells, and piezometers to determine the extent of source areas of storm runoff within the catchment. Studies of data collected showed that most of the storm runoff usually originates from a small portion of the total drainage area and that the location and extent of the source area is dependent upon rainfall intensity, antecedent moisture, and the depth of the A horizon soi

ISSN:0043-1397    

DOI:10.1029/WR005i003p00574

年代:1969

数据来源: WILEY

摘要:

Though several investigators have noted the consistent nonlinearity of hydrologic system response to rainfall, nonlinear models have been avoided because of computational difficulties associated with the identification of model parameters from historic records. A few nonlinear models have been proposed, but the parameter identification methods lack generality and the capacity to deal with complex models. Through quasi‐linearization, implicit solutions to a large class of nonlinear models can be written in terms of a maximizing operation on linear equations. This algorithm also provides for systematic determination of the optimal values of model parameters in the identification problem. Furthermore, a complete set of accurate initial conditions need not be supplied. Application of quasi‐linearization to a recent nonlinear conceptual model of watershed response displayed in particular (1) The simplicity of the computer programing through the use of standard subroutines and (2) The rapid convergence characteristics of the algori

ISSN:0043-1397    

DOI:10.1029/WR005i003p00583

年代:1969

数据来源: WILEY

摘要:

A random walk model of a drainage network is generated on an underlying matrix by selecting at random the drainage direction out of the elementary areas. In a random roughness model, roughness heights of the elementary areas rather than drainage directions are assigned at random. The resulting topography of that model then uniquely determines the drainage pattern. An equivalence of the two models is suggested by the similarities, found in the mode of construction and by the equality of the probabilities of occurrence of some simple configurations. The random roughness model can yield values of primary probabilities, i.e., probabilities which can be used in the construction of a random walk model. The various types of drainage patterns are classified by the sets of primary probabilities which would generate them. Thus outcomes of homogeneous and isotropic matrices are classified as pure dendritic patterns. Outcomes of homogeneous matrices with probability sets derived from a sloping plane roughness model are classified as general dendritic (including parallel) patterns. Trellis, annular, and other patterns are considered as subgroups of the class of patterns generated on all other possible matrices.

ISSN:0043-1397    

DOI:10.1029/WR005i003p00591

年代:1969

数据来源: WILEY

摘要:

Coherence and partial coherence between cyclic components of hydrologic time series show strong correlations among annual oscillations in precipitation and runoff for stations located in the Pacific Coast region of the United States. To distances of 1000 km the annual cycle of precipitation can be considered practically the same for all stations. Similar relations exist between records of streamflow, but the coherence is less because of variable watershed characteristics, evaporation, storage, and other factors influencing runoff.

ISSN:0043-1397    

DOI:10.1029/WR005i003p00608

年代:1969

数据来源: WILEY

摘要:

Three analytic and two emperic methods are described to calculate the surface resistancersof crops transpiring at a measured rate. The profile method is applicable when detailed temperature, humidity, and wind profiles are measured; for the residual method, measurements of surface temperature, wind, and humidity are enough; for the heat balance method, the calculation is based on the ratio of potential to actual evaporation. For rough estimates, an empiric equation of Monteith or a relation between leaf area and surface resistance can be used. In southern England and in California all three analytic methods agree closely. Hourly values ofrsin California demonstrate the effect of water stress on an irrigated grass canopy by midday, whereas in England thersof a barley crop is maintained constant for almost the whole day. From Aslyng's measurements of evaporation, the relation ofrsto soil‐water potential is calculated and used to show how relative rates of transpiration and photosynthesis may change in response to water stress. For an equatorial rain forest in Kenya, mean monthlyrsvaried systematically with soil moisture deficit, ranging between 0.3 and 1.1, sec cm

ISSN:0043-1397    

DOI:10.1029/WR005i003p00622

年代:1969

数据来源: WILEY

摘要:

A 22‐acre catchment in the southern Appalachians was cleared of hardwood forest in 1958 and 1959 and seeded to Kentucky 31 fescue grass in 1959 and 1960. The amount of evapotranspiration by the grass cover was closely related to the amount of grass produced. During years when grass production was high, water yield from the catchment was about the same as or less than the expected yield from the original forest. As grass productivity declined, water yield gradually increased until it exceeded the predicted yield from the forest by over 5 inches annually. The grass appeared to evaporate more water early in the spring and less water late in the summer than the original forest cove

ISSN:0043-1397    

DOI:10.1029/WR005i003p00634

年代:1969

数据来源: WILEY

摘要:

A model recharge well was constructed to simulate recharge into wells in a fine sand aquifer. The sand in the model aquifer was uniform fine sand and had a uniformity coefficient of 1.25 and an effective diameter of 144 microns. Both clear tap water and sediment laden water were used for recharge. Sediment laden water was obtained by mixing 50% bentonite and 50% kaolinite with tap water. Sediment concentrations were 100, 200, and 500 ppm. The piezometric surfaces near the recharge well were measured during the tests. Migration of sediment into the aquifer was determined by sampling the aquifer sand after the tests at predetermined distances from the well. The sediment in the recharge water highly affected the rate of recharge. During the period of the tests a reduction in hydraulic conductivity of the model aquifer of 15–46% occurred as a result of recharge with sediment laden water. Most of the sediment deposited in the aquifer was retained near the well scree

ISSN:0043-1397    

DOI:10.1029/WR005i003p00641

年代:1969

数据来源: WILEY