检索规则说明:AND代表“并且”;OR代表“或者”;NOT代表“不包含”;(注意必须大写,运算符两边需空一格)
检 索 范 例 :范例一: (K=图书馆学 OR K=情报学) AND A=范并思 范例二:J=计算机应用与软件 AND (U=C++ OR U=Basic) NOT M=Visual
作 者:杨新兵[1] 余新晓[1] 孙庆艳[1] 陈慧新[1]
机构地区:[1]北京林业大学水土保持学院水土保持与荒漠化防治教育部重点开放实验室,北京100083
出 处:《水土保持学报》2007年第3期170-172,182,共4页Journal of Soil and Water Conservation
基 金:北京市科委2006年度科技计划重大项目(D0706007040191-07);"十一五"国家科技支撑计划课题(2006BAD03A02)
摘 要: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。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.
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在载入数据...
正在链接到云南高校图书馆文献保障联盟下载...
云南高校图书馆联盟文献共享服务平台 版权所有©
您的IP:3.144.87.133