摘要:

ABSTRACTAn experiment on urban effects of warm season rainfall of a moderately sized city and its downwind towns found no evidence of global enhancement. However, there are grounds for believing that the intra urban distribution of precipitation is influenced by urban variables among which air pollution and urban roughness are considered primary. The presence of an urban heat island did not appear to improve rainfall. On the contrary, it appears to be a factor in the relative aridity of the downtown sector of the city.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01294.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTA study was made to analyze and modify procedures used for stream assimilation capacity and point source wasteload allocation calculations. This paper describes the sources and types of information collected and the analysis of alternative computation methods developed during the study. The calculation of stream assimilation capacity or Total Maximum Daily Load (TMDL), will depend upon assumed stream flows, quality standards, reaction rates, and modeling procedures. The “critical conditions” selected for TMDL calculations usually are low flows and warm temperatures. The complexity of water quality models used for TMDL and allocation calculations can range from simple, complete mixing to calibrated and verified mathematical models. A list of 20 wasteload allocation (WLA) methods was developed. Five of these WLA's were applied to an example stream to permit comparisons based on cost, equity, efficient use of stream assimilation capacity, and sensitivity to fundamental stream quality data. Based on insensitivity to data errors and current use by several states, the WLA method of “equal percent treatment” was preferable in the example

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01295.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTLarge area soil moisture estimations are required to describe input to cloud prediction models, rainfall distribution models, and global crop yield models. Satellite mounted microwave sensor systems that as yet can only detect moisture at the surface have been suggested as a means of acquiring large area estimates. Relations previously discovered between microwave emission at the 1.55 cm wavelength and surface moisture as represented by an antecedent precipitation index were used to provide a pseudo infiltration estimation. Infiltration estimates based on surface wetness on a daily basis were then used to calculate the soil moisture in the surface 0–23 cm of the soil by use of a modified antecedent precipitation index. Reasonably good results were obtained (R2= 0.7162) when predicted soil moisture for the surface 23 cm was compared to measured moisture. Where the technique was modified to use only an estimate of surface moisture each three days an R2value of 0.7116 resulted for the same data set. Correlations between predicted and actual soil moisture fall off rapidly for repeat observations more than three days apart. The algorithms developed in this study may be used over relatively flat agricultural lands to provide improved estimates of soil moisture to a depth greater than the depth of penetration for the senso

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01296.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTThe Streamflow Synthesis and Reservoir Regulation (SSARR) model was calibrated and verified on the Madison and Gallatin watersheds in the upper Missouri River drainage. The study was performed to determine if the SSARR model could simulate snowmelt‐runoff volumes to effect better operation of six multipurpose reservoirs on the Missouri River. Physical watershed characteristics and parameter sensitivity are incorporated into a procedure which expedites model calibration. Criteria are established to facilitate parameter development and to objectively evaluate calibration and verification results. A ratio of simulated to observed snowmelt‐runoff volumes of the Madison River averaged 1.00 and 1.02 for calibration (N = 8 years) and verification (N = 6 years) with corresponding standard deviations of 0.08 and 0.13. Gallatin volume ratios averaged 0.99 and 0.95 for calibration (N = 7 years) and verification (N = 5 years) with respective standard deviations of 0.08 and 0

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01297.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTA ground water development project in the northern part of Thailand was appraised by means of benefit‐cost analysis. This is the first project in Thailand to develop ground water for irrigation purposes and it is also the first project which made use of an underground PVC pipe water distribution system. Results indicate that the project is economically feasible. In comparing different water distribution systems, it is also found that distribution by means of underground PVC pipes is more economical compared to an open ditch system if the life of the latter is relatively short and the rates of inflation are hig

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01298.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTTexas' surface water law began its evolution during the Hispanic period of occupance. Later, the English riparian doctrine was adopted, and finally, in the late 1800's, the prior appropriation doctrine was superimposed, resulting in an exceedingly complex dual system. Though the judiciary, legislature, and state water agencies have wrestled with the problem of coordinating these diverse water rights and more accurately delineating and measuring riparian rights and water use since early in this century, until recently all attempts were unsuccessful. The unknown riparian element, in particular, made coordinated and efficient management and administration of the state's surface water resources impossible. Finally, measurable progress toward solution of these problems began in 1967 with passage of the Water Rights Adjudication Act, aimed at identifying all unrecorded surface water rights claims and eventually merging all claims into the permit system. This paper examines the gradual evolution of Texas' curious blend of Hispanic‐English riparian rights and later appropriate rights; discusses the resultant problems of water resource administration; and traces the progress of the ongoing water rights adjudication, a lengthy, expensive, and complex procedure, which should eventually make possible more efficient administration of all surface water right

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01299.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTDirect ground water seepage measurements were made in Lake Washington, Florida, to determine the importance of seepage as a water and chloride source to the lake and upper St. Johns River. Over 200 seepage measurements were made in the lake and adjoining canals from July through December 1978. Results indicated that seepage into the shore areas of Lake Washington was an insignificant water source to the lake, representing 0.6 percent of the inputs, and was nearly balanced by ground water recharge in the midlake region. Drainage canals entering Lake Washington, however, exhibited high average seepage rates (17.7 L/m2‐day), over eight times the lake average (2.01 L/M2‐day). Discharge from the St. Johns River was the dominant factor in the water budget of Lake Washington and represented approximately 88 percent of the inputs during the study year. Although inputs from the drainage canals represented only 6.6 percent of the St. Johns River annual discharge, these canals represented 20.4 percent of the annual St. Johns River chloride loading and 62.1 percent of the river chloride loading during the five driest months of 1978. Evidence from this study indicates that rising levels of chloride in the river in recent years are largely attributable to ground water seepage in channelized areas, particularly in the headwaters. These chloride inputs assume greater importance during low water/low flow peri

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01300.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTWhile storm water detention basins are widely used for controlling increases in peak discharges that result from urbanization, recent research has indicated that under certain circumstances detention storage can actually cause increases in peak discharge rates. Because of the potential for detrimental downstream effects, storm water management policies often require downstream effects to be evaluated. Such evaluation requires the design engineer to collect additional topographic and land use data and make costly hydrologic analyses. Thus, a method, which is easy to apply and which would indicate whether or not a detailed hydrologic analysis of downstream impacts is necessary, should decrease the average cost of storm water management designs. A planning method that does not require either a large data base or a computer is presented. The time co‐ordinates of runoff hydrographs are estimated using the time‐of‐concentration and the SCS runoff curve number; the discharge coordinates are estimated using a simple peak discharge equation. While the planning method does not require a detailed design of the detention basin, it does provide a reasonably accurate procedure for evaluating whether or not the installation of a detention basin will cause adverse downstream flo

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01301.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTWater conservation is a much emphasized policy of the Federal government. Discussion of water conservation proposals often involves confusion between a conservation “ethic,” which is an end in itself, and conservation as a means for attaining various economic objectives. Analysis indicates that outside of ground water “mining.” water is usually a renewable and reusable resource. During periods of normal precipitation, water conservation should be employed only when the value of the water saved exceeds the cost of effecting the savings. Water conservation is most valuable as a drought contingency tactic. Water conservation as a substitute for structural provision to meet normal water demand growth is apt to prove short

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01302.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACTProcedures have been developed (a) to inject a tracer at a constant rate below the water surface at selected points across a stream and (b) to deal with suspended sediment. Mixing remained far from complete in relatively long channels, owing to channel and flow divergence with uncertainty where to sample downstream and which marginal sample values to include for flow calculation. These problems are encountered when mixing is largely dependent on transverse diffusion. Accurate and replicable results were obtained where dye was injected upstream and detected downstream from riffles that induced thorough turbulent mixing. Dye gaging should be practical in gorges or wherever flow is turbulent across the whole width of a channel.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1981.tb01303.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY