土地利用变化对城市洪涝灾害的影响

选择经历了快速城市化过程的深圳地区一典型小流域——布吉河流域，使用分布式水文模型就土地利用变化对城市化流域暴雨洪水汇流过程的影响进行了模拟。模拟结果表明，土地利用结构与格局的变化，使得暴雨洪水的最大洪峰流量和洪量加大，汇流时间变短。与1998年相比，2000年在前期土壤较干的情况下，频率为1％，2％和5％的3种设计暴雨洪水的最大洪峰流量，其增大幅度分别为20．2％，23．0％和28．9％。同时，土地利用状况对暴雨洪水的影响还与土壤前期湿润程度和暴雨强度有关：随着前期土壤由较干向较湿润变化和暴雨强度的增大，土地利用状况向城市化方向的发展对暴雨洪水的影响趋于减弱。深圳1980年以来洪涝灾害加剧的统计结果证实了这一模拟结果。

Impact of land use change on urban flood disaster

Choosing Buji River Basin, a small typical river basin in Shenzhen region undertaking rapid urbanization process, the impact of land use change on the runoff concentration of storm flood is simulated by distributed hydro- logical model. The modeling result shows that land use structure and pattern change results in the increase of maxi- mum flood peak and flood discharge and the decreases of runoff concentration time. While the soil antecedent mois- ture condition is dry, the increment of maximum flood peak of the rainfall frequency of 1%, 2% and 5% is 20. 2 percent, 23. 2 percent and 28. 9 percent respectively from 1980 to 2000. Moreover, the effect of land use change on storm flood is restricted by soil antecedent moisture condition and rainfall intensity. The increase of rainfall in- tensity and the change of soil antecedent moisture condition changing from dry to wet decreases the influence of land use on the storm flood. The impact of land use change on the storm flood process is approved by the statistic result of flood disasters occurred in Shenzhen from 1980 to 2000.