植被对流域水文特征响应研究

通过2001～2005年连续5年的密云水库集水区的流域水文监测数据结果表明：流域内年平均降雨量为594.7 mm,主要集中在6～8月份,占全年降水的70%～80%。表层土壤含水量年均6.8%～11.3%,年内变化与降雨量趋势基本一致,先上升后下降。随着植被的恢复,流域内产流量和产沙量逐渐降低,植被的消减率最大可达77%。流域内的多次水质抽样检验结果表明：多数水质指标都达到一类水质标准,超标指标主要是总氮和总磷。

Study on Response of Vegetation to Watershed Hydrological Characteristics

By monitoring Miyun reservoir watershed for 5 years from 2001 to 2005,the study showed that: the average annul precipitation in watershed was 594.7 mm,mainly concentrating from June to August,and being 70% to 80% of the annual precipitation.The average annual surface soil moisture was 6.8%~11.3%,and the annual variation increased firstly and then decreased later,which was similar to that of precipitation.With the improvement of vegetation coverage,runoff and sediment yields in watershed reduced gradually,and setback ratio of vegetation reached 77%.By sampling inspection on water quality of watershed,the results showed that most indexes of water quality achieved the government standards of First water,while over-leveled indexes were total N content and P content.