Influence of three-gorge-dam on downstream ecosystem and counter-measures

with population and economic growth, hu 1 man needs more water to support the development, and more and more dams are constructed at rivers' gorges, consequently many unpredicted disasters to the downstream ecosystem appears. Similar to many other places, these disasters also happens in the Dongting Lake after the construction and operation of Three-Gorge-Dam (TGD) in Yangtze River. Its water shortage problem in the lake plain becomes very severe and frequent, especially in dry seasons. This paper presents an innovative countermeasure to cater the dam's negative impacts on the middle reach, i.e., the application of SPP scheme to get rid of its water crisis (floods, droughts, deterioration of water quality and sedimentation caused by too much, too little, too dirty and too turbid waters, respectively). The so call SPP stands for "separation, prevention and protection", the feasibility of SPP application is discussed in terms of economically affordability and environmentally sustainability. The SPP scheme is compared with other schemes proposed by local governments, the results show that the payback period is almost same, but the SPP scheme is much better than alternatives in every aspect.