三峡工程茅坪溪泄水建筑物水文监测分析

Hydrologic measurement and analysis of water release structure for Maopingxi river at TGP

茅坪溪泄水建筑物是三峡工程的重要施工项目之一。茅坪溪流域属于山区性河流，受降水影响，洪水具有暴涨暴落的基本特征，一次洪水过程短则４～５ｈ，长则２０ｈ，产流汇流快。茅坪溪泄水建筑物为四级永久建筑物，承担茅坪溪枯期排水、汛期泄洪的任务，具有泄程长、落差大、断面形状变化大、弯道多的特点。根据茅坪溪泄水建筑物进口明渠中段实测的水位、流量以及降水量等资料，对茅坪溪暴雨洪水的成因、降雨迳流的关系以及隧洞的行洪能力进行分析。

Water release structure of Maopingxi brook is one of TGPs important projects. According to the measured water level and discharge at the middle of the water release structures inlet open channel, and precipitation data etc., the cause of storm flood formation, precipitation runoff relation of Maopingxi brook and flood discharge capacity of the tunnel are analysed. The mountainous Maopingxi brook, influenced by precipitation, has such basic features as sudden rising and falling of flood, short runoff producing and converging process with 4～5 h for a short flood duration while 20 d for a long one. The water release structure is a 4th grade permanent structure and functions as water drainage in dry season, flood release in flood season for Maopingxi brook and has such features as long water release path, high water head, various cross section configurations and many bends.