Research on ecological water replenishment scheme of Yilong Lake based on MIKE21 model
Yilong Lake is the lake that is the most easily disturbed by human activities with the smallest area and the least water amount among the nine plateau lakes in Yunnan Province.Due to obvious fluctuations of its water quality in recent years,it is in urgent need of improvement.In view of the lack of hydrological and water quality data in Yilong Lake basin and the obvious disturbance of water quality by climate and human activities,it is necessary to simulate and invert the evolution process of water dynamics and quality in Yilong Lake basin by using numerical simulation technology.In this study,the GPS-based tracking buoy,acoustic Doppler current profiler and intensive monitoring of the water quality of incoming rivers and the lake are used to monitor the hydrodynamics and water quality in Yilong Lake before and after ecological water replenishment,so as to concretely analyze and demonstrate the improvement effect of water replenishment quality and build a two-dimensional coupling model of hydrodynamic and water quality based on MIKE21.The simulation results show that WSW winds are prevalent in Yilong Lake all the year round,with a northwest-to-southeast flow direction at the north and south lakeshores,a clockwise circular current in the center of the lake and a small counterclockwise circular current in the east.In the west of the lake there is an obvious weak flow area,which is not conducive to water and material exchange.The water quality concentration COD during the year generally shows a spatial and temporal distribution pattern of low in the west-high in the middle-high in the east,which is significantly higher in the rainy season than in the dry season.Under the conditions of annual replenishment volume of about 35000000 m3 and multiple points and maximum water supplement capacity of 1.95 m3/s,the average annual COD concentration of three points in the west,middle and east of the lake can be improved by about 27.6%,24.0%and 18.1%respectively during the dry season(from November to May next year),with significant water quality improvement effect brought by replenishment,which can provide references for decision-making for ecological scheduling and lake water ecology restoration in Yilong Lake.
Yilong Lakeecological water replenishmenthydrodynamic-water quality modelwater quality improvement
NETL
NSTL
万方数据
