18 Aug Lin Cheng
Presentation Title:Re-operation of the Three Gorges Dam for Environmental Flows.
The construction of the Three Gorges Dam, along with other development in the Yangtze River basin, has had a profound impact on the flow and sediment regime of the Yangtze River. This has had major impacts on the geomorphology and ecology of the river downstream of the TGD, with related impacts on biodiversity, livelihoods, and water security in the middle and lower Yangtze. Changes to biodiversity have included a fall of around 90% in the total number of fish fry for the four major Chinese carp species, caused at least in part by changes in the flow regime. In response, there has been significant research into the significance of flow for Chinese carp, as well as other aspects. A partnership between the Chinese Government, the dam operator, scientists, and conservationists has led to pilot environmental flow releases over a five-year period to mitigate some of these impacts. Subsequent monitoring has shown that numbers of fish fry are now 10 times their lowest level, in 2008. Following the success of the pilot flow releases, in October 2015 the official joint regulation of the Three Gorges Dam/Gezhouba cascade was amended to incorporate additional objectives and operational requirements that now provide for e-flow releases as part of the routine operation of the dam. This paper describes the process and findings related to the pilot environmental flow releases, the subsequent amendment of the dam cascade operating rules, and prospects for further environmental flows in the Yangtze River in coming years.