水电能源科学

流域下边界水位是影响流域洪涝灾害的重要因素，为定量分析下边界水位变化对流域防洪排涝的影响，以苕溪流域及其下边界小梅口为例，采用Mann-Kendall检验方法，分析小梅口水位站近67年水位变化趋势，通过一维河网模型定量分析典型暴雨遭遇不同下边界水位条件时苕溪流域的洪水位和入太湖水量。结果表明，小梅口站各统计口径下的水位均呈现明显上升趋势，其中年最低水位上升趋势最明显；小梅口水位抬升后，对苕溪流域洪水位的影响主要在下游区域，其中杭长桥站最大影响幅度0.07 m,对代表站洪峰流量的影响相对较小，但因水位抬升影响整个洪水期的流量，流域排入太湖的总水量将减少2.5%～5.0%。研究结果可为苕溪流域乃至其他流域的防洪排涝提供科学依据与理论支撑。

The downstream boundary water level is a crucial factor influencing flood disasters in the basin. In order to study the variation of water level at the downstream boundary of the Tiaoxi Basin and its impact on flood control and drainage, this paper calculated the trend of water level changes at the Xiaomeikou Station over the past 67 years by using Mann-Kendall method. Furthermore, a one-dimensional river network model was built to quantitatively analyze the differences of water level and inflow volume into the Taihu Lake when typical rainstorm encountered different downstream water level conditions. The results show that the water level at Xiaomeikou Station had a significant upward trend under various statistical calibers, with the most pronounced increase observed in the annual minimum water level. When the water level at the Xiaomeikou Station rised up, the impact on flood levels in the Tiaoxi Basin was mainly concentrated in the downstream areas. The maximum change of water level at Hangchangqiao Station was 0.07m, and the impact on the peak flow was relatively small. However, because the elevated water level affects the flow throughout the flood period, the total discharge into the Taihu Lake will be reduced by 2.5%-5%. The research findings can provide a scientific basis and theoretical support for flood control and drainage management in the basin.