Influence of Runoff Variation on Ecological Environment in the Tarim River Basin

Based on observations of 21 meteorological stations and 10 hydrological stations in the Tarim River Basin,the changes of temperature,precipitation and runoff from 1961 to 2000 were analyzed.Four conclusions were drawn as follows:(1) The runoff of the headstreams at their debouchures increased by 14.97% since the 1960s,whereas the total discharge into the Tarim mainstream decreased by 17.41% at the same time.(2) Water in lower reaches decreased by 76.13% in recent 40 years,and the reduction of water was closely related to the rapid exploitation of the agricultural area and the sharp use of the water resources in the upper and middle reaches.(3) Owing to the increasing water requirement of the upper and middle reaches,the lower reaches' inflow was decreasing year by year.Therefore,the environment in the lower reaches changed greatly,mainly showed as serious water salinization,increasing of disaster weathers,frequent zero-flow,declining of groundwater table,decreasing of forest and aggravating of desertification.(4) The unified management of water resources in this basin is the foundation of ecological rehabilitation and reconstruction.