Study On Suitable Water Levels Of Baghrash Lake

This papers through on Baghrash Lake near half century water cycle process of research, reveals lake water cycle elements, and hydrological state indicators and ecological system state indicators in movement process in the mutual relationship, established lake water cycle model, based on water cycle model to determines different ecological protection target, and specific out Lake volume and water area of Lake suitable level, main conclusions following:(1) through on Baghrash Lake near half century climate for analysis found, Baghrash Lake precipitation in fluctuations in the is increased trend, Linear changes tendencies rate for 5.7mm ?(10a)-1, more annual precipitation about 130mm;Baghrash Lake near 50 years evaporation is slow of declined trend, linear changes tendencies rate for 3.97 mm ?(10a)-1, more annual evaporation for 734.1mm; Baghrash Lake near 49 years into Lake water is show slow rose trend, linear changes tendencies rate for 111 million m3 ?(10a)-1, annual into Lake water 2.239 billion m3; The Lake presents an obvious upward trend, the average water volume of 61.724 billion m3, linear tendency rate of 15.786 billion m3(10a)-1.(2) by analyzing the hydrological status indicator change of Baghrash Lake, in the mid 1950 of the 20 th century to 1987, the lake water level falling in waves, and at its lowest level of 1044.72 m, which is pre-1955 the highest water level dropped 3.67 m, an average annual decline of 0.11 m 。 From 1987 onwards, Baghrash Lake water levels continued to rise, and the speed of rise, Baghrash Lake, the water level rose to 1049 m from 1045 m only 15 years time in the mid 1950 of the 20 th century to 1987 as the lake level drops, water area of narrowing the 298 km 2.(3) the amount water through rainfall and a model parameter calibration: a water tower stores hydrologic station to 1982-2000 mean monthly flow data for curve fitting and 2001-2010 parameters mean monthly flow data inspection, error is less than 5%, the efficiency coefficient and correlation coefficients closer to 0.8, simulation with good results. Average rainfall in 1960-2000 data based on curve fitting, with average rainfall of 2001-2010 test and error is less than 10%, the efficiency coefficient and correlation coefficient close to 0.9, simulation with good results.(4) has the typical hydrological characteristics of Baghrash Lake, lake water circulation model was established. Based on water circulation model, established a lake surface area and a functional relationship between Lake and 2005-2010 lake surface area for model testing. Lake surface area calculated values are in good agreement with observations, Water circulation model results are acceptable.(5) based on the simulation model of water circulation, Baghrash Lake hydrological status indicators, establish responses of surface area on Baghrash Lake water into the Lake. Baghrash Lake water into the Lake and the average surface area of roughly the same trend, the year more water into the Lake, water surface area is larger, and fewer years of water into the Lake, the water surface area is relatively small, that is, with increasing frequency, lake surface area decreases.(6) this chapter is based on simulation calculation method of ecological water requirement for lakes of water circulation is calculated under different hydrological target of suitable water levels of bosten Lake. Assume magna cum laude 10% frequency of ecological water requirement under water as the most suitable water levels of Baghrash Lake, that is 1041.953 m,50% frequency for optimum water levels of Baghrash Lake’s water level, namely 1040.284 m,75% frequency bosten Lake’s water level below the minimum desirable level, namely 1039.723 m,95% frequency of ecological water requirement for critical suitable water levels of Baghrash Lake, which is 1038.712 m. This study compared with similar research results can be seen, the core understanding of suitable water level of Lake water cycle process, based on Lake water circulation model and its natural eccentricity of thought to determine the ecological area and suitable water level, from the perspective of the whole lake water cycle to determine the appropriate water level of Lake, the calculated results with high reliability.