摘要:

ABSTRACT:Both color infrared aerial photography and Landsat data are being used to provide information to meet present and future management goals for the Great Dismal Swamp National Wildlife Refuge. High and low altitude color infrared photographs are being used to study the hydrology and map the present vegetation of the swamp. A variety of significant ecologic units have been identified using these photographs. The completed maps will be used to evaluate analyses of landsat digital data. Once the present data base is compiled, it is hoped that routine analysis of Landsat data can be used for updating or to indicate areas where low altitude coverage or ground checking is desirable. The data base will also aid in identifying and evaluating trends that may provide guidelines for wetland management.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01985.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:This paper presents a mathematical model of multiple‐use in natural areas. The model represents a unified system for the assessment of cases where some form of development is proposed for relatively natural areas. The focus of the model system is a benefit‐cost analysis. Provisions for the full consideration of easily measured monetary costs and benefits as well as semitangible benefits accruing from environment‐related activities such as outdoor recreation are contained in the model. Means for incorporating desirability as a measure of aesthetics, uniqueness, and environmental quality into the evaluation are provided. Serveral types of constraints have been imposed on the system to increase model realism. A family of compatibility constraints was designed to limit inter‐use conflicts arising from incompatible activities. A form of the gradient optimization algorithm was utilized to facilitate the evaluation. The model system has application in a wide range of problems frequently encountered in environmental planning and assessment as well as natural resources man

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01986.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:Critical design characteristics of ephermal runoff such as hydrograph rise time, duration, mean peak discharge, volume, peak‐volume ratio, and maximum flood were related to physical basin parameters such as area, shape, slope, drainage density, basin relief, stream length, and combinations of these in intermontane watersheds representative of the Mexican Highland section of the Basin and Range Province. Parameters used were restricted to those easily obtainable from maps or aerial photographs. A parameter expressing basin shape and size was developed which proved to be as accurate a predictor as others used in existing prediction equations tested and was simpler and faster to derive. Simple prediction equations derived for hydrograph characteristics were all significant except for volume at the 5% level; three were significant at the 1% level. Relationships determined are applicable in semi‐arid basins of the Southwest up to 60 square miles (155 km2) in a

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01987.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:Inter‐station analysis was employed to evaluate the adequacy of the precipitation network in topographically complex West Virginia. A 25‐year period was determined as the minimum lingth of record needed for relatively stable and fairly accurate estimates of long‐term (50‐year) precipitation and in frequency analysis. Data from the 83 National Weather Service stations with 25‐year records were adjusted for consistency and evaluated separately by zones east (31 stations) and west (52 stations) of the Appalachian divide. Correlation coefficients (r) and average standard errors of estimate were computed for all station pairs within 50 miles distance and 1000 feet elevation difference of each other. The third polynomial equation of inter‐station distance eliminated using elevation and land slope as the criteria in network design in this mountainous terrain. A network with (r) = 0.9 estimates annual precipitation with accuracy as great as 5 percent, but requires about 250 additional gages (i.e., about 200 percent of the prese

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01988.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:The income and proce elasticity of demand for domestic water is estimated for Penang Island, Malaysia. A cross‐sectional analysis of a random sample of 1400 households indicated an income‐elasticity of zero for low‐income families (per capita income less than US$300) and an elasticity of 0.2‐0.4 for higher‐income families. A time‐series analysis of a subsample of individuals of varying income levels suggests a short‐run price elasticity of ‐0.1 to ‐0.2. The implications of these results for demand forecast

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01989.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:A deterministic dynamic programming optimization model with a refining sectioning search procedure is developed and implemented to find least cost withdrawal and release patterns for water supple from a multiple reservoir system serving a metropolitan area. Applications are made to teh four reservoir system operated by the city of Dallas, Texas. A realistic cost structure, including nonlinear power consumption, block rate unit power costs, and flow dependent power consumption for intracity water distribution, is utilized. Applications are made to find least cost operating patterns and, as well, by inclusion of a water loss penalty function, supply patterns which will reduce evaporation water losses for the Dallas system.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01990.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:A 0.31‐ha pond was treated with 5.0 mg/l dipotassium endothall on May 31, 1973, and the effects of this treatment on the rooted aquatics, on bluegill reproduction, survival, and growth, and on the buildup of endothall residues in bluegill flesh was investigated. The treatment eliminatedMyriophyllum exalbescens, Ceratophyllum demersum, Potamogeton crispus, andAnacharis canadenisduring the first season, however, all butC. demersumbecame reestablished the following year. Little endothall was incorporated into edible bluegill flesh. The dipotassium endothall did not affect the number of young‐of‐the‐year (YOY) bluegills produced by the original adult stocking during the year of treatment and the year following treatment and did not affect the reproduction of first generation bluegills. The survival of adult and first generation bluegills was not affected by the herbicide. Bluegills were slower growing in the treatment than the control pond, when similar densities were present in each pond. It is not known whether this was due to some unknown effect of the dipotassium endothall or to other

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01991.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:The total suspended sediment loads of four north Mississippi reservoirs were determined from measurements of concentrations of suspended sediment in a vertical profile at several locations on each reservoir made during the year. These data were combined with the stage‐height and known stage‐volume relationships for each reservoir in a numerical integration to determine the total suspended sediment in the water body. Total suspended sediments were estimated using the product of the suspended sediment concentration in the surface water by the appropriate reservoir volume. The averaged ratios of the estimated to measured suspended sediment loads for each reservoir exceeded 0.90. Since the concentration of suspended sediments in surface waters of north Mississippi reservoirs has been shown as highly correlated with spectral reflectance, estimating the total suspended sediment of these reservoirs using remotely sensed spectral reflectance data is possi

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01992.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:Society has many objectives, many of which are not commensurable. This incommensurability problem is generally referred to as the multiple objective problem and leads to the notion of tradeoffs. Various approaches to calculating tradeoffs in water resource development have been advocated by several authors. Many have made errors in the context of the conceptural model presented in this paper. It is argued the correct framework for tradeoff analysis is the neoclassical economic model. The relevant tradeoffs, then, are really price ratios. These, in turn, must be calculated in such a manner as to allow comparison of product mixes where the expenditure on resources is the same. This is where several authors have erred. An empirical example which illustrates the correct application of the model is presented.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01993.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT:The project described in this report was undertaken by the Louisiana State Planning Office to establish the extent of backwater flooding in Louisiana in April 1975. Band 7 Landsat imagery, enlarged to a scale of 1:250,000 was used to visually identify flooded areas. Inundated areas were delineated on overlays keyed to 1:250,000 U.S. Geological Survey topographic quadrangles. Tabular data identifying acres flooded, according to land use type, were derived by merging the flood map overlays with computerized 1972 land use data. Approximately 1.12 million acres of the state were inundated by flood waters. The total acreage and land use types affected by flooding were determined within 72 hours from the time the flood areas were imaged. Flooded maps were prepared for 26 parishes. Field observations were made by Louisiana Cooperative Extension Service county agents in order to determine the accuracy of parish flood maps and flood acreage figures by land use type. Results indicated that this was a fast, accurate, and relatively inexpensive method of compiling flood data for disaster planning and postflood analysis.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1977.tb01994.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY