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71.
Arthur R. Giaquinta Thomas E. Croley II 《Journal of the American Water Resources Association》1981,17(3):423-429
Power plant water consumption (evaporative water loss) for various river temperature standards is presented for existing and proposed power plants located along the Missouri and Upper Mississippi Rivers in the MAPP geographical area. Thermodynamic and economic models are combined to evaluate the cooling related water consumption at various river thermal standards. The existing thermal standards and a number of other hypothetical thermal regulations including the extreme cases of no thermal standards and no allowable heated discharges are examined to show the dependence on thermal standards of power production related water consumption. A critical appraisal of the cost of thermal standards in terms of water consumption is thereby possible so that subjective assessments of the standards can proceed with full knowledge of the tradeoffs involved between the “water costs” of power production and environmental enhancement. 相似文献
72.
ABSTRACT The effect of hydrologic and chemical processes on salinization of stored waters was determined for two small floodwater-retarding structures located in western Oklahoma. One structure, already designed to accommodate a large influx of sediment, was further overdesigned hydrologically by upstream diversion of approximately one-half the inflow. Over a 2-year period, the total salinity of stored waters increased approximately 22 times and the stored water volume decreased to 1/33 its initial volume in the overdesigned structure, while both volume and salinity of stored waters remained comparatively stable in the other structure. The lack of sufficient dilution by better quality surface runoff and the increased residence time of water in the impoundment apparently caused most of the salinity increase. The bulk of the salt load entering the over-designed structure, to be concentrated later by evaporation, was associated with base rather than storm inflow. After base inflow ceased, substantial losses of salt load and stored water occurred concurrently. The loss was not adequately explained by chemical precipitation in association with evaporation. Seepage and evaporation-associated variables appeared to account for much of the hydrologically unexplained loss of stored waters. 相似文献
73.
Elwyn S. Krous Joseph P. Wagner Harold L. Parkinson Milton S. Sachs 《Journal of the American Water Resources Association》1971,7(4):810-822
ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied. 相似文献
74.
Bruce P. Van Haveren Eugene E. Farmer 《Journal of the American Water Resources Association》1971,7(6):1250-1252
Evaporation was measured from a circular evaporation pan, 18 inches in diameter and 8 inches deep. The pan was insulated on the sides and bottom using 2 inches of freon-blown polyurethane foam. A U.S. Weather Bureau Class A evaporation pan was used to obtain reference evaporation measurements. Water evaporation from the Class A pan and the insulated pan were highly correlated. Using a water-methanol mixture, the insulated pan may be operated at temperatures below 32 F; the equivalent liquid water evaporation may be determined using a regression equation. 相似文献
75.
Abdul Rahim Hj. Nik Richard Lee J. D. Helvey 《Journal of the American Water Resources Association》1983,19(1):47-50
ABSTRACT: This study tests the hypothesis that climatic data can be used to develop a watershed model so that stream flow changes following forest harvest can be determined. Measured independent variables were precipitation, daily maximum and minimum temperature, and concurrent relative humidity. Computed variables were humidity deficit, saturated vapor pressure, and ambient vapor pressure. These climatic variables were combined to compute a monthly evaporation index. Finally, the evaporation index and monthly precipitation were regressed with measured monthly stream flow and the monthly estimates of stream flow were combined for the hydrologic year. A regression of predicted versus measured annual stream flow had a standard error of 1.5 inches (within 6.1 percent of the measured value). When 10, 15, and 20 years of data were used to develop the regression equations, predicted minus measured stream flow for the last 7 years of record (1972–1978) were within 16.8, 11.5, and 9.7 percent of the measured mean, respectively. Although single watershed calibration can be used in special conditions, the paired watershed approach is expected to remain the preferred method for determining the effects of forest management on the water resource. 相似文献
76.
国内甲醇废水处理技术应用现状 总被引:12,自引:2,他引:10
介绍了汽化法、厌氧生物处理法和好氧化生物处理法在国内甲醇废水处理中的应用情况,存在的问题,并提出了一些改进建议。 相似文献
77.
船舶油运中油气污染,控制及石油发试验研究 总被引:1,自引:0,他引:1
船舶装卸运输石油时,油气蒸发是船舶大气污染的主要问题之一。它不仅损失大量货油,也对船舶环境造成严重污染。试验表明, 油气蒸发过程随油种不同。蒸发速率差别较大,第一类如工业汽油、煤油,初始发量高达每小时5%-10%,第一天蒸发逸散量可在50%,第二类如柴油、原油也有较大蒸发速率,第一天的蒸发量可达3%-11%,第三类蒸发量较小,如机油、重油、渣油等。第一天蒸发量仅约0.5%以下,但蒸发衰减不快。前两类油种蒸发衰减较快。油气蒸发过程也与环境温度、风速有关。文中最后讨论了控制油气蒸发造成污染的3项措施。 相似文献
78.
79.
80.
The purpose of this study was to predict quantitative changes in evaporation from bare soils in the Mediterranean climate
region of Turkey in response to the projections of a regional climate model developed in Japan (hereafter RCM). Daily RCM
data for the estimation of reference evapotranspiration (ET
r) and soil evaporation were obtained for the periods of 1994–2003 and 2070–2079. Potential evaporation (E
p) from bare soils was calculated using the Penman–Monteith equation with a surface resistance of zero. Simulation of actual
soil evaporation (E
a) was carried out using Aydin model (Aydin et al., Ecological Modelling 182:91–105, 2005) combined with Aydin and Uygur (2006,
A model for estimating soil water potential of bare fields. In Proceedings of the 18th International Soil Meeting (ISM) on Soils Sustaining Life on Earth, Managing Soil and Technology,
Sanliurfa, 477–480pp.) model of predicting soil water potential at the top surface layer of a bare soil, after performances of Aydin
model (R
2 = 94.0%) and Aydin and Uygur model (R
2 = 97.6) were tested. The latter model is based on the relations among potential soil evaporation, hydraulic diffusivity,
and soil wetness, with some simplified assumptions. Input parameters of the model are simple and easily obtainable such as
climatic parameters used to compute the potential soil evaporation, average diffusivity for the drying soil, and volumetric
water content at field capacity. The combination of Aydin and Aydin and Uygur models appeared to be useful in estimating water
potential of soils and E
a from bare soils, with only a few parameters. Unlike ET
r and E
p projected to increase by 92 and 69 mm (equivalent to 8.0 and 7.3% increases) due to the elevated evaporative demand of the
atmosphere, respectively, E
a from bare soils is projected to reduce by 50 mm (equivalent to a 16.5% decrease) in response to a decrease in rainfall by
46% in the Mediterranean region of Turkey by the 2070s predicted by RCM, and consequently, to decreased soil wetness in the
future. 相似文献