干旱区典型小流域降水-径流关系研究

Research on Precipitation-Runoff Relationship of Typical Small Watershed in Arid Areas

研究以祁连山排露沟流域为典型案例,使用祁连山排露沟多年水文动态数据,采用ArcGIS水文提取、数据量化分析等方法,研究不同时间尺度下的降水特征、产流特征以及降水与产流之间的响应关系。结果表明:研究区降水的季节性强且分配不均匀,存在明显的旱季(10月至次年3月)和湿季(4至9月)之分;湿季降水量占全年降水近93%,占年总降水频数的83%,年降水主要发生在每年4至9月。年内降水量级频次分析发现,年降水事件以0~5 mm/次为主,占全年降水事件频次约93%,占全年降水量约29%,年降雨事件以<5 mm量级为主。年内降水间隔期频数分析发现,降水间隔期以0~10 d为主,占全年无降水期的48.65%,占全年间隔期频数的92.71%。降雨径流过程分析发现:流域径流同时受次降水量和前期降水的影响,对于前期无降水基础、降雨量<20 mm的降水事件,径流响应迟缓;而对于前期有一定降水过程,次降雨量>25 mm的降雨事件,径流响应明显。本研究对半干旱区降水-径流特征的分析和量化,能够为区域水资源的利用和调配提供一定借鉴,也能为半干旱区极端气候下的山地滑坡等灾害的预防和研究提供数据支持。

The study takes the Pailugou watershed basin of Qilian Mountain as a typical case,using the multi-year hydrological dynamic data of Pailugou watershed in Qilian Mountains,and using the methods of ArcGIS hydrological extraction and data quantitative analysis,studying the precipitation characteristics,runoff characteristics and the response relationship between precipitation and runoff at different time scales.The results show that the precipitation in the study area is highly seasonal and unevenly distributed,and there are obvious differences between dry season(October to March of the next year)and wet season(April to September);Wet season precipitation accounts for nearly 93%of the annual precipitation and 83%of the total annual precipitation frequency.The annual precipitation mainly occurs from April to September every year.The analysis of annual precipitation magnitude frequency shows that the annual precipitation events are mainly 0-5mm/time,accounting for about 93%of the annual precipitation event frequency,29%of the annual precipitation,and the annual precipitation events are mainly<5mm.The analysis of precipitation interval frequency in the year shows that the precipitation interval is mainly 0-10d,accounting for 48.65%of the period without precipitation in the whole year and 92.71%of the interval frequency in the whole year.The analysis of rainfall runoff process shows that the runoff of the basin is affected by the secondary precipitation and the previous precipitation at the same time.For the precipitation events with no precipitation basis and rainfall<20mm in the previous period,the runoff response is slow;For the rainfall events with certain precipitation process in the early stage and rainfall>25mm,the runoff response is obvious.The analysis and quantification of precipitation-runoff characteristics in the semi-arid area can not only provide some reference for the utilization and allocation of regional water resources,but also provide data support for the prevention and research of mountain landslides and other disasters under extreme climate in the semi-arid area.