Based On Multi-source Remote Sensing Data Research On Vegetation Changes Caused By Che’ Erchen River Downstream Of River Diversion

The Qarqan River researched in this paper is the largest one among the riversoriginated from Kunlun mountains and arjin mountains, and ends in the Taitema Lakeas the same of Tarim River. It’s of great importance to maintain the ecosystem in thelower reaches of Tarim River and slow down the step of spreading and joining ofKuruktag Desert and the Taklimakan Desert.The lower reaches of Qarqan River changed its route during the comprehensivetreatment period of Taitema Lake by the Tarim River Government forces in the yearof2002, causing lots of damages to the nature coverage there. The MODIS graphs,from the year of2000to2010, was used In this paper to research the coveragechanges in this area. The results shows: in the new river route region, the average ofthe well-vegetation-covered area (where the NDVI degree is above0.3) values duringthe researched11years, is about3.96km~2; both of the new and old river route regionreaches their highest vegetation coverage in2010because of the high precipitationthat lead to a high flow year in Xinjiang, and the well-vegetation-covered area reachesto about26km~2; the values of well-vegetation-covered area in old-river-route areafrom2000to2003are2.4km~2,0.9km~2,1.8km~2,3.2km~2respectively, and there’s nowell-vegetation-covered places in2007to2009, these all indicate that a seriousvegetation degeneration had occurred in the old-river-route regions, and thevegetation is fading out year by year. Owing to the river route change, the vegetationcoverage in old-river-route area is obviously vanished away, while the new-river-routearea goes in a contrary way. However, the vegetation disappearance in old-river-routearea is much faster than the recovery of vegetation in new-river-route area.The vegetation coverage values in old-river-route area are7.4km~2in2000,6.7km2in2005,8.6km~2in2009, while the ones in new-river-route area are2.3km~2in2000,8.6km~2in2005,8km~2in2009. The researched vegetation covered area is totallydescending; the well-covered area values in old-river-route region decreased year by year; the vegetation coverage increased after2005in a low speed.The ecological water requirement in the lower reaches of both new and old riverroute areas are estimated to compare with the evapotranspiration and infiltrationlosses according to the recovery experiences in Tarim river and the actual facts inQarqan river. According to the estimation, we need at least3687185m~3water to holdup with the ecological water requirement, based up on the water supply assurance tonew-river-route areas and Taitema Lake.