后湾水库以上流域下垫面变化对洪水影响分析

摘要

Because of the influence of human activities, the underlying surface of the Haihe River Basin has changed, which leads to the change of the runoff?characteristics. In this paper, to master the situation of the watershed underlying surface changes impact on the floods, we used the im-proved Xin'anjiang-Haihe model to study the Houwan Reservoir watershed. A great amount of historical data show that the Houwan Reservoir watershed underlying surface changes happened around 1980, the effect is?better when the improved Xin 'anjiang-Haihe model being applied in the flood simulations at different magnitudes. Because of changes of the underlying surface, comparing to the parameter before 1980, the runoff parameter of the improved Xin'anjiang-Haihe model after 1980?has a tendency to increase, and under the same rainfall condition, the flood vol-ume after 1980 shows a decreasing trend. What's more, the smaller the flood magnitude, the greater the flood volume decreases.%由于人类活动影响导致海河流域下垫面发生变化,造成流域产、汇流特性的变化。为掌握流域下垫面变化对洪水的影响情况,对后湾水库流域采用改进的新安江—海河模型进行分析、研究。结果表明,后湾流域下垫面发生变化的年代为1980年左右；改进的新安江—海河模型用于不同量级的洪水模拟,其效果较好；由于下垫面的变化,改进的新安江-海河模型的产、汇流参数1980年后比1980年前有增大趋势,并在相同降雨情况下,1980年后的洪量比1980年前呈减少的趋势,且洪水量级越小减少幅度越大。