Simulating flood events in mesoscale watershed:a case study from River Xitiaoxi Watershed in the upper region of Taihu Basin

Abstract

以太湖上游西苕溪流域为研究对象，通过分布式水文模型HEC-HMS模拟次降雨洪水过程:采用可视化数据存储系统HEC-DSS建立水义气象数据库，利用Geodatabase地理数据库技术集成流域自然属性数据库，通过距离平方倒数法对雨量数据进行空间插值，SCS曲线数法计算水文损失，运动波法计算直接径流与河道洪水演进，选用基流指数退水法模拟流域基流，并对模型中水库模拟部分进行适当修正．经模型校验，模拟结果表明，计算流量与观测流量拟合较好，效率系数大于0．8．洪峰流量误差低于4%，峰现时间误差低于2 h，该模型在土地利用变化对洪水水文要素的影响研究方面有较好的应用前景．;Flood events in River Xitiaoxi Watershed in the upper region of Taihu Basin were simulated by distributed hydrologic modeling system HEC-HMS. The database of hydrology and meteorology in studied region was set up by visual storage system HEC-DSS. The database of the natural attributes of basin was integrated by the technique of GIS Geo-database. The total storm mean area precipitation was calculated by inverse-distance-squared method. SCS Curve Number Loss Model was selected to compute runoff volumes. Kinematic-wave Model was used to model direct runoff and channel flow. Base flow was modeled by Exponential Recession Model and the reservoir model was improved. After calibration and validation, the simulated flow and observed flow fit so good that the efficiency coefficient was more than 0. 8, with error of peak flow within 4% , and error of peak flow time within 2 hours, which illustrated that HEC-HMS may be applicable area in simulating the impacts of land use change on hydrological regimes such as floods.