Study on lowest water level of Xingkai Lake for ecological safety

Based on the hydrograph of the annual water levels from 1941~1957 and the water level-area-storage curves of Xingkai Lake, the water balance is analyzed in combination with the water demands of both the recent and long term through the calculation of the mean annual inflow and the inflow of the year with the guaranteed rate of 80% for the lake. The analysis results show that Xingkai Lake has a larger regulation capacity of water, and then can surely meet the water demands of both recent and long term, even the mean annual water level declines to the historical lowest level during a continuous period 6 years. After the analysis, calculation and ratiocination concerned, it is considered that it is reasonable to take the water level of 67.88 m of the lake occurred in 1925 as the lowest ecological water level therein.