南水北调西线一期工程调水对下游水文情势影响

南水北调西线一期工程从雅砻江、大渡河上游7条河流调水80亿m3,调水河流下游的水文情势将发生变化。根据雅砻江、大渡河现有水文站网收集的水文资料,主要从径流、水位两方面研究西线一期工程调水后对下游河流的影响。参照国际惯例和现行规范标准,将调水对水文情势的影响分为3类研究区。西线一期工程调水对径流影响较大的时段主要为连续枯水年和每年的丰水期,调水使得一类研究区水文过程均一化,小流量常态化。调水对水位的影响主要集中在一类水文情势研究分区的近坝河段。

Impact of WRP's Stage-I works of South-to-North Water Diversion on the hydrologic regime of downstream rivers

The Stage-I works of west route project(WRP) of South-to-north Water Diversion will transfer an amount of 8 billion m3 water from the upstream of the Yalong River,the Dadu River etc.totalling 7 rivers,the downstream hydrologic regime of the 7 rivers will be changed.The hydro-meteorological characteristics in 7 river basins is analyzed,and according to collected hydrologic data of the existed hydrologic station network on the Yalong River and the Dadu River,the impact of water diversion of Stage I works on the downstream river is researched mainly from runoff and water level.Referring to international practice standard in force,the impacted zone is divided into 3 classes of research areas.The main impacting period of Stage I water diversion works on runoff mainly includes the successive dry years and the flood season in each year.The water diversion will make the hydrological process homogenized and small discharge normalized. The impact on water level is mainly concentrated in the river reaches near dams of Class I research area.