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171.
付晓杰 《中国环境管理干部学院学报》2004,14(1):92
2004年教育工作将突出两大战略重点,其中大力加强高水平大学和重点学科建设,是适应全面建设小康社会的要求,促进高等教育和职业教育与经济社会发展的紧密结合.文章从实践"三个代表"的高度,提出建设"一流大学"或"高水平大学"必须特别注重塑造大学精神;并立足教书育人,结合实际工作探讨了解决问题的对策. 相似文献
172.
Clow David W. Striegl Robert G. Nanus Leora Mast M. Alisa Campbell Donald H. Krabbenhoft David P. 《Water, Air, & Soil Pollution: Focus》2002,2(2):139-164
A chemical survey of 69 high-altitude lakes in seven national parks in the western United States was conducted during the fallof 1999; the lakes were previously sampled during the fall of 1985, as part of the Western Lake Survey. Lakes in parks in the Sierra/southern Cascades (Lassen Volcanic, Yosemite, Sequoia/Kings Canyon National Parks) and in the southern RockyMountains (Rocky Mountain National Park) were very dilute; medianspecific conductance ranged from 4.4 to 12.2 S cm-1 andmedian alkalinity concentrations ranged from 32.2 to 72.9 eqL-1. Specific conductances and alkalinity concentrations were substantially higher in lakes in the central and northernRocky Mountains parks (Grand Teton, Yellowstone, and GlacierNational Parks), probably due to the prevalence of more reactivebedrock types. Regional patterns in lake concentrations of NO3 and SO4 were similar to regional patterns in NO3 and SO4 concentrations in precipitation, suggestingthat the lakes are showing a response to atmospheric deposition.Concentrations of NO3 were particularly high in Rocky Mountain National Park, where some ecosystems appear to be undergoing nitrogen saturation. 相似文献
173.
根据加卸载响应比理论,通过对1991~1996年江苏省部分井孔观测资料固体潮加卸载响应比的计算发现,在中强地震前一年左右的时间震中区附近的井孔出现了响应比高值异常。通过空间图像扫描可以看出:在苍山地震前一年左右,徐州、宿迁地区出现了加卸载响应比的高值集中区;在南黄海地震前一年左右,在镇江、苏州地区出现了高值集中区,之后高值集中区有自西向东迁移即有向震中区迁移的迹象。 相似文献
174.
This paper looks at the rainfall and streamflow patterns over two distinct time periods, i.e., 1950–1970 and 1971–1991 within the two most prominent catchments in the Volta river system – White Volta and the Oti basins. The first period (1950–1970) represents relatively vegetated catchments and low population whilst the latter (1971–1990) represents intense land use practices resulting from increased population that have severely degraded the environment. These two catchments are among the most significant contributors to the Volta lake. The Volta lake, which was formed between 1962 and 1966 in Ghana and created primarily for hydroelectric power generation, will probably be one of the greatest man-made lakes for a long time. It produces 912MW of electricity at its maximum operating capacity. Recently, there have been declines in the lake levels resulting most probably from inadequate rainfall and/or runoff from the river catchments that feed the lake. Comparisons of runoffs for the two time periods show reductions in mean streamflows of 32.5% at Saboba on the Oti and 23.1% at Nawuni on the White Volta. 相似文献
175.
176.
S. F. Shih 《Journal of the American Water Resources Association》1980,16(4):724-727
ABSTRACT: The water budget computation in shallow lakes is complicated because marsh vegetation can transpire large quantities of lake water. Thus, a model including the marsh zone evapotranspiration (WET) was developed to compute the water budget for Lake Okeechobee. Three periods of testing (1969–74), planning (1963–74), and recorded period (1952–77) were used to compare the differences of the sum of storage deviation between the WET and conventional methods (WOET). Results of the WOET method showed that the sum of stage deviations were 87.42 cm (2.868 ft.), 231.80 cm (7.605 ft.), and 284.50 cm (9.333 ft.) in the testing, planning, and recorded periods, respectively. These stage deviations are equivalent in the same order to 29, 76, and 93 percent of the lake volume. In general, the WET method not only was applicable to compute the water budget for the lake but also reduced the sum of storage deviation by about 42, 31, and 49 percent, respectively, in those three periods. The storage deviation in WET method was reduced on an average to about 2 percent each year in all three periods, and the deviations were scattered more randomly than in WOET. 相似文献
177.
Zia Qureshi 《Journal of the American Water Resources Association》1977,13(1):117-123
ABSTRACT: The Fort Walton Beach area is presently faced with an excessive drawdown of the potentiometric level in the upper Floridan aquifer. Based on available data, the potentiometric level in the Floridan aquifer has dropped 162 feet since 1936. This declining potentiometric level can lead to problems and possible loss of the natural resource on a long-term basis. However, if corrective measures or programs for proper management of groundwater resources are undertaken at this time, the potential problems may be averted. 相似文献
178.
Robert H. Kennedy G. Dennis Cook 《Journal of the American Water Resources Association》1982,18(3):389-395
ABSTRACT: Nutrient diversion does not always bring about prompt and sufficient reduction in lake phosphorus concentration due to recycling from nutrient rich sediments. Certain lakes and reservoirs may continue to experience nuisance algal blooms and require additional restorative steps. The phosphorus precipitation/inactivation technique is a procedure to remove phosphorus from the water column and to control its release from sediments in order to achieve P-limiting conditions to algal growth. Aluminum salts have been used in advanced waste water treatment to remove phosphorus and this technology was extended to lake rehabilitation. Guidelines for dose calculation and application are generally lacking, and are provided in this report. The dose determination suggested here allows maximum application of aluminum to bottom sediments and thus emphasizes long term control of phosphorus recycling. Dose can be calculated directly from the alkalinity of the water to be treated. Titration of lake water samples of Varying alkalinity allows the establishment of the relationship between residual dissolved aluminum, alkalinity, and dose which can then be employed for lake scale applications of alum to lakes and reservoirs. Application equipment and procedures are described. These depend on site characteristics and treatment objectives and include lakeside stores, a distribution pipe, and an application barge and manifold. Alum may also be used to meet other restoration objectives including the treatment of problem flows and the reduction of particulate concentrations. 相似文献
179.
Patricia M. Dooris Vance Ley Dean F. Martin 《Journal of the American Water Resources Association》1982,18(4):599-604
ABSTRACT: The choice of a lake rehabilitation technique can be assisted by laboratory experiments concerned with the composition and properties of the sediments. This work on Sawgrass Lake, Pinellas County, Florida, provides an example of the type of laboratory information that can be useful towards making decisions regarding the most effective restorative techniques. Experiments include chemical analysis of sediment (water content, organic content, pesticides, nutrients), rate of sediment compaction and rehydration at ambient conditions, and the effect of treatment with alum and other chemicals. 相似文献
180.
A. V. Trapeznikov P. I. Yushkov V. N. Nikolkin V. N. Trapeznikova M. Ya. Chebotina V. P. Guseva 《Russian Journal of Ecology》2007,38(1):27-33
Radioecological conditions have been estimated in Lake Chervyanoe located on the central axis of the Eastern Ural Radioactive Trace (EURT) about 100–110 km northeast of the Mayak Production Association. Data on the 90Sr and 137Cs contents in the main components of the lake, the distribution of these radionuclides over the profile of bottom sediments, and their amounts in the lake are presented. The experimental data have been used to construct mathematical models for estimating changes in the radionuclide concentrations and amounts in the water and bottom sediments of the lake over a long period after the nuclear accident, as well as the tritium content of the lake water in different periods of time. 相似文献