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981.
本文运用生态经济系统思想有计划,有步骤地解决水环境问题,针对当前城市水质污染的状况和趋势,找出城市水污染的主要原因,并对城市水环境污染进行经济分析及采取的经济对策,根据城市污水总量污染趋势预测,提出了防治措施,同时,在解决水环境问题时,重视环境效益,经济效益和社会效益的统一。 相似文献
982.
John W. Labadie Dennis A. Bode Andrew M. Pineda 《Journal of the American Water Resources Association》1986,22(6):927-940
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 tool. 相似文献
983.
Henry L. Garie Alan McIntosh 《Journal of the American Water Resources Association》1986,22(3):447-455
ABSTRACT: A study of benthic macroinvertebrate community composition was conducted at eight sites along Shabakunk Creek, a small stream in Mercer County, New Jersey, which receives urban runoff. The relationship between changes in substrate composition and the nature of the benthic macroinvertebrate community has been examined. Organisms were collected seasonally from natural substrates in riffles. Attempts to employ artificial substrates for invertebrate collection proved unsuccessful, as the population on the samplers was not representative of that in the stream bed. Number of total benthic macroinvertebrate taxa collected declined from 13 in relatively undeveloped upstream areas to four below heavily developed areas, while population density decreased simultaneously in the same areas. Periphyton samples collected from natural substrates were analyzed for selected heavy metals. Significantly higher heavy metal concentrations are reported from substrates sampled below heavily developed areas, and changes in these values are discussed with regard to changes in benthic macroinvertebrate distribution. 相似文献
984.
Bruce K. Ferguson 《Journal of the American Water Resources Association》1987,23(1):147-152
ABSTRACT: The increasing use of irrigation for urban landscapes is causing new demands for efficient watering systems. Conservation techniques for irrigated agricultural fields cannot be applied to urban landscapes without amendment. This paper attempts to review methods of urban landscape water conservation in the context of the diversity and complexity of urban landscapes and the demands upon them for quality of the urban environment. A development's initial site layout and planting design fundamentally determine how much irrigation water will be required; the complexity and creativity inherent in urban design open a number of specific possibilities for reducing water demand. Irrigation hardware is then designed to deliver the required volume of water to the specified landscape efficiently by implementing a number of physical and operational principles. Maintenance of the finished development involves monitoring results and making adjustments as the plantings grow and develop. The potential for conserving urban irrigation water is large. Effective conservation need not compromise other qualities of the urban environment such as aesthetics, screening, or shade. Urban design can address both the kinds of landscapes people need, and minimal consumption of irrigation water. 相似文献
985.
ABSTRACT: A model is proposed for allocation of water shortages among competing water uses in the Svarta River basin in Sweden. The three major competing uses in the basin are hydroelectricity generation, irrigation water supply, and urban water supply. Minor uses that impact upon the allocation are minimum river flow requirements for fishlife and for dilution of treated wastewater, and storage level restrictions for recreation purposes in the main storage facility, Lake Sommen. Analysis of the competing demands on the water are modeled through the method-of-weights multiobjective technique using a deterministic mixed-integer optimization formulation. The (0–1) variables in the formulation are required to synthesize the restricted validity of permits for withdrawal of irrigation water from the river and to simulate the complex operating rules of the major regulation facility on the river. Due to the deterministic nature of the formulation, the model is used on a hydrologic scenario basis. Use of the model is demonstrated by application to the Svarta River. 相似文献
986.
Gary D. Tasker Nancy E. Driver 《Journal of the American Water Resources Association》1988,24(5):1091-1101
ABSTRACT: Regression models are presented that can be used to estimate mean loads for chemical oxygen demand, suspended solids, dissolved solids, total nitrogen, total ammonia plus nitrogen, total phosphorous, dissolved phosphorous, total copper, total lead, and total zinc at unmonitored sites in urban areas. Explanatory variables include drainage area, imperviousness of drainage basin to infiltration, mean annual rainfall, a land-use indicator variable, and mean minimum January temperature. Model parameters are estimated by a generalized-least-squares regression method that accounts for cross correlation and differences in reliability of sample estimates between sites. The regression models account for 20 to 65 percent of the total variation in observed loads. 相似文献
987.
Walters J Goh KS Li L Feng H Hernandez J White J 《Environmental monitoring and assessment》2003,82(3):265-280
Carbaryl insecticide was applied by ground spray to plants in urban areas to control a serious insect pest the glassy-winged sharpshooter, Homalodisca coagulata (Say), newly introduced inCalifornia. To assure there are no adverse impacts to human health and the environment from the carbaryl applications, carbaryl was monitored in tank mixtures, air, surface water, foliage and backyard fruits and vegetables.Results from the five urban areas – Porterville, Fresno, Rancho Cordova, Brentwood and Chico – showed there were no significanthuman exposures or impacts on the environment. Spray tank concentrations ranged from 0.1–0.32%. Carbaryl concentrationsin air ranged from none detected to 1.12 g m-3, well below the interim health screening level in air of 51.7 g m-3. There were three detections of carbaryl in surface water nearapplication sites: 0.125 ppb (parts per billion) from a water treatment basin; 6.94 ppb from a gold fish pond; and 1737 ppbin a rain runoff sample collected from a drain adjacent to a sprayed site. The foliar dislodgeable residues ranged from 1.54–7.12 g cm-2, comparable to levels reported forsafe reentry of 2.4 to 5.6 g cm-2 for citrus. Carbarylconcentrations in fruits and vegetables ranged from no detectableamounts to 7.56 ppm, which were below the U.S.EPA tolerance, allowable residue of 10 ppm. 相似文献
988.
城市环境中磁学响应的研究进展 总被引:5,自引:0,他引:5
利用磁学方法研究城市环境中重金属元素的污染受到普遍关注和重视。比较系统地探讨了城市环境中磁性矿物的来源和特征,阐述了城市环境磁学的研究内容,探讨了城市磁学研究的发展趋势,强调了运用简便、经济的磁学方法研究城市环境中重金属等污染物是今后环境磁学的一个重要的发展方向。 相似文献
989.
Monitoring of atmospheric lead from the Dalbergia sissoo treewas undertaken at Lucknow urban centre of the Ganga Plain, India.Atotal of 26 leaf samples were collected in spring, monsoon and winter seasons from 16 sampling sites and was analysed by Atomic Absorption Spectrophotometry method. Lead concentrations were low in spring season, increased in monsoon to winter seasons and range from 2.1 to 28.2 μg/g (dry wt.). This accumulative response of lead in the tree leaves is directly linked with the exposure time of automobile emission that is considered to be the predominant source for it. Highway localities show higher lead concentrations by a factor of 2 as compared to urban localities. Highest concentration was recorded at Sitapur Road (National Highway No. 24) in winter season. A linear quantitative relationship between urban air-lead levels and lead-in-the Dalbergia sissoo leaves is used to infer the qualitative assessment of present day atmospheric lead pollution. Reported results suggest a drastic reduction in mean lead concentration in Lucknow urban air from 1.32μg/m3 in 1994 to 0.19μg/m3 in 2002. Similarly, mean lead concentration in the tree leaves during winter season also dropped from 17.9 μg/g in 1994 to 8.1 μg/g in 2004. Despite of increasing urban population, urban area, vehicle population and traffic density, the introduction of unleaded-petrol (vehicular fuel) keeps lead level in the urban environment of Lucknow much lower than the past. Like Lucknow, other urban centres of the Ganga Plain are also on way to the exponential increase in pressure of urbanization. An appropriate urban public transport planning is required to provide healthy atmospheric environment for millions of people especially future young generation. 相似文献
990.
The Las VegasWash, which drains the Las Vegas valley watershed and provides the second largest inflow to Lake Mead, is being dramatically altered with erosion control structures and wetland restoration efforts. The impact of these changes on the cycling and distribution of Hg and Se is of particular interest because of their tendency to bioaccumulate and because of a lack of information on these contaminants in the Wash. In this study, we determined concentrations of Hg and Se in surface water (monthly), groundwater (once) and sediments (quarterly) from strategic locations within and along theWash during 2002 and 2003. The data was used to characterize Se sources and loading into theWash. Samples containing resurfacing groundwater and urban runoff (LW10.75 and Duck Creek) had significantly higher yearly means (13.7 ± 4.4 and 23.8 ± 4.1μg/L, respectively) compared with mainstream samples containing primarily treated wastewater (2.8 ± 0.8μg/L). Investigation of Se in tributaries, street runoff and rain suggest that the source of the elevated Se is likely groundwater seeps located within a relatively narrow geographic band on the southeast side of the valley. Se content of sediments was similar, except for LW10.75 which was rich in organic matter. Hg concentrations in the water and sediments were low, averaging 4±5 ng/L and 34±20 ng/g, dw, respectively. Overall, this study suggests that water quality remains relatively stable despite changes in theWash and managers of developing wetlands should not use tributary water as source water. 相似文献