摘要:

The following paper was presented by Dr. Abel Wolman at the Plenary Session of the 22nd Annual Conference of the American Water Resources Association in Atlanta, Georgia, November 10, 1986.Dr. Wolman is Professor Emeritus of Sanitary Engineering at The Johns Hopkins University. He was educated at Johns Hopkins and has received an Honorary Doctor of Engineering (1937) and Honorary Doctor of Laws (1969) from his alma mater.Dr. Wolman held a number of positions before joing the faculty of The Johns Hopkins University as Professor and Chairman of the Department of Sanitary Engineering (1937–1959). He has served as consultant for many studies and projects, in the United States and overseas, and has a long‐term record of service to communities, states and governments. A long list of awards and honors include the Sedgwick Memorial Award, APHA; Arthur Sidney Bedell Award, WPCF; Hemisphere Award, inter‐American Association of Sanitary Engineers; U.S. Award of the National Medal of Science; Tyler Award, Ecological Society of America; Ben Gurion Award from the State of israel; and the Gordon Maskew Fair Award, WPCA. He is author, co‐author or editor of four books and over 3000 technical publications, most in refereed j

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00761.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:The SMEMAX transformation, its modified versions and power transformation were applied to 55 long‐term records of annual maximum flood flows tested previously for independence, homogeneity and completeness. Even though SMEMAX transformation reduced the coefficient of skewness to near zero for flood data, their distribution was not a true normal distribution. In almost all cases, the coefficient of kurtosis was quite different from 3.0 of the normal distribution. Empirical criteria showed that SMEMAX transformation performed well only for 40 (70 percent) of the 55 stations tested. Its performance level dropped, especially for stations which had both the coefficient of skewness and kurtosis greater than 3.0 and 10.0, respectively. Power transformation was generally better in transforming the flood data to a normal distribution. It performed well for 50 (90 percent) of the 55 stations tested. The coefficient of skewness in case of the data transformed by power transformation was much closer to the zero value than in the case of SMEMAX transformed series. The SMEMAX transformation and its two modified versions yielded identical results when flood frequency analysis was performed. Computationally, all three methods were equally simple and easy to apply for flood frequency analysis. In some cases, the coefficient of kurtosis for the transformed distributions obtained both by SMEMAX and power transformations deviated farther from that for the normal distribution than for the parent distributio

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00762.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:Current procedures for setting site‐specific water quality criteria consider abiotic and biotic factors. Suspended solids were shown to be important in reducing zinc toxicity to water column organisms. At zinc concentrations of ∼ 1 mg/L in solutions with<100 mg/L of all suspended solids tested, zinc toxicityto D. magnawas reduced. Sorption of zinc to suspended solids and/or changes in water chemistry due to the addition of suspended solids appear to have been the factors causing reductions in zinc toxicity toD. magna. Only suspended solids levels of 483–734 mg/L of a type that increased total alkalinity, total hardness, and total dissolved carbon clearly reduced the toxicity of ∼ 20 mg/L zinc toP. promelas. The toxic form of zinc to these organisms appears to reside in the aqueous phase. Characteristics of suspended solids did not influence the partition coefficient of zinc in sorption experiments of 96 h. The slopes of dose‐response curves proved to be useful for assessing the potential of an organism to respond to changes in aqueous phase zinc concentrations, and may be a useful biological parameter when considering site‐specific water quality criteria fo

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00763.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:An alum treatment in Long Lake (mean depth, 2 m) in 1980 has been effective at controlling internal loading of phosphorus for four years. The fifth summer after treatment, the lake returned to its pro‐treatment state. Lake P content decreased from a summer average of 65 μg/L during 1976–1978 to about 30 μg/L during four years following treatment. In 1985, summer P content was 61 μg/L. Algal abundance, species composition, and transparency have responded proportionately with P.Alum effectiveness apparently declined because the floe layer tended to sink and become dispersed at a deeper level in the sediment, as well as become covered with new, P‐rich sediment. Iron‐reduction may be the principal mechanism for internal P loading, although the lake is unstratified and anoxia is usually not

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00764.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:A water supply network optimization model called MODSIM3 is presented as a decision‐support tool for aiding city staff in determining how best to utilize and exchange existing and potential water supplies with other users in a river basin. The model is applied to the City of Fort Collins, Colorado, water supply system as a means of determining optimum ways the City can utilize direct flow rights, storage rights, and exchangeable waters from various sources. Results clearly confirm both the benefits of the use of exchanges and the value of MODSIM3 as a water supply planning and management too

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00765.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:Percent imperviousness is an important parameter in modeling the urban rainfall‐runoff process and is usually determined using manual methods such as random sampling or conventional accounting methods. In this study two computerized methods are used for estimating the percent imperviousness of urban watersheds using high altitude remote sensing imagery. These methods include the Laser Image Processing Scanner and the Video‐Tape Camera system. Imperviousness is directly estimated in the former method while in the latter it is estimated as a function of the statistics of the responses on emulsions of the imagery. The percent imperviousness computed by utilizing remote sensing imagery was used with the conceptual models of rainfall‐runoff models. The models were applied to four urban watersheds and the runoff prediction results indicate that imperviousness determined by using remote sensing imagery was as accurate as that obtained by the manual methods, and that the use of remote sensing imagery requires significantly less time and

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00766.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:Volusia County, in east central Florida, comprises approximately 1,200 square miles situated between the St. Johns River and the Atlantic Ocean. Most of the County is underlain by a three‐aquifer system. Population centers in Volusia County, which create a large water demand, are located near the coast. Saltwater intrusion into the ground water near these population centers has led to relocation of public water supply wells further inland. Regional management of the county's water resources commissioned construction of a three‐dimensional computer model of the county. Predevelopment simulation results were used as initial conditions for the development simulations, which included well discharge data. The predevelopment model calibration consisted of reproducing field‐determined potentiometric surfaces. As part of the calibration process, sensitivity analyses were performed on boundary conditions, recharge rates, permeability, and leakage properties. Results of the model study indicate the utility of computer models as a management tool for the complex ground‐water system in Volusia

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00767.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Stochastic modeling of vector hydrologic sequences is examined with a general class of space‐time autoregressive integrated moving average (STARIMA) models. The models describe spatial and temporal autocorrelatjon, through dependent variables lagged both in space and time. The model structures incorporate a hierarchical ordering scheme to map the vector of observations into a network configuration. The neighboring structure used introduces a physical/geographical hierarchy to enable the model identification procedures to assist in determining appropriate correlative relationships. The three‐stage iterative space‐time model building procedure is illustrated using average monthly streamfiow data for a four‐station network of the Southeastern Hydropower

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00768.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:Export coefficients (kg/km2/yr) for dissolved ortho‐phosphate (OP), total phosphorus (TP), total inorganic nitrogen (TIN), and total nitrogen (TN) were derived for watersheds in Wisconsin using data bases available for 17 basins from the U.S. Environmental Protection Agency — National Eutrophication Survey, U.S. Geological Survey, and the Wisconsin Department of Natural Resources. Three general land use categories, representative of most regions in Wisconsin, were established: forest, mixed, and agricultural. Data for the 17 basins indicated greater exports of OP. TP, TIN, and TN as the percentage of forest decreased and agriculture increased. These region‐specific coefficients are compared to the values reported in the literature representing much broader areas of th

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT:A comparison of municipal wastewater treatment plant (WWTP) and nonpoint source nutrient loads to Wisconsin's 14,927 inland lakes was performed. Only 65 of the 2,925 Wisconsin lakes having surface areas of at least eight ha and a maximum depth of at least 2.4 m had one or more WWTP's located within 40 km upstream; 99 of Wisconsin's 477 WWTP's were identified to be upstream of these 65 lakes. WWTP total nitrogen and total phosphorus loads to these 65 lakes were estimated using per capita influent loads and removal efficiencies based on wastewater treatment types. Nonpoint source nutrient loads were calculated utilizing nutrient export coefficients derived specifically for Wisconsin. Total nitrogen inputs to the lakes were dominated by nonpoint sources. The effectiveness of various phosphorus control programs to produce water quality improvements visible to the public was estimated to be as follows (going from most to least effective): municipal phosphorus removal and agricultural reductions, municipal phosphorus removal alone, agricultural reduction plus phosphate detergent ban, agricultural reductions alone, and phosphate detergent ban alone. The last option would not be expected to produce water quality improvement visible to the public in any Wisconsin lakes. The differences between the distributions in Wisconsin of population and inland lakes highlights the need to consider regional characteristics in any statewide water quality management plan.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1986.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY