新疆车尔臣河下游生态需水量分析

Analysis of ecological water demand in the lower reaches of The Cherchen River,Xinjiang,China

河流生态需水作为维持河流生态系统健康的关键因素,对于维护区域生态安全起着积极作用。该文以新疆车尔臣河下游为研究区,基于1990-2017年遥感数据,分析了研究区生态需水,结果表明:车尔臣河下游林地面积在1990-2017年呈现递减趋势,林地面积减少14.4%。草地面积共减少3.5%。水域面积呈现为增加趋势,水域面积增加419.6%;车尔臣河改道后,老河道内植被面积逐渐下降,至2010年后呈显著退化趋势;植被覆盖度的变化主要发生在离台特玛湖较近的下游段,特别是近10年下游段植被覆盖度呈增加的态势,下游河道两岸和湖区周边植被得以恢复;利用潜水蒸发法计算得到生态需水量为2.25亿m^(3),面积定额法计算得到1.92亿m^(3),综合得生态需水量为2.08亿m^(3)。若将苇场及以上60 km、苇场以下265 km分开计算,得到两者生态需水量分别为1.09亿m^(3)、0.85亿m^(3)。计算成果对于维护车尔臣河下游绿色走廊生态安全、实现流域水资源优化配置与高效利用具有重要参考价值。

River ecological water demand,as a key factor in maintaining the health of river ecosystems,plays an active role in maintaining regional ecological security.The paper analyzed the ecological water demand in the study area based on remote sensing data from 1990 to 2017,using the lower Cherchen River in Xinjiang as the study area:The area of woodland in the Lower Chelsea River showed a decreasing trend from 1990 to 2017,with the area of woodland decreasing by 14.4%.Grassland area decreased by a total of 3.5%.The water area shows an increasing trend,with an increase of 419.6 % in the water area;After the diversion of the Chelsea River,the area of vegetation within the old channel gradually declined and showed a significant degradation trend after 2010;Changes in vegetation cover have occurred mainly in the downstream section closer to Lake Taitmar,especially in the last 10 years,when the downstream section has shown an increase in vegetation cover,and vegetation has been restored on both sides of the downstream river and around the lake;Using the submersible evaporation method,the ecological water demand was calculated to be 225 million m~3,the area quota method was calculated to be 192 million m~3,and the combined ecological water demand was 208 million m~3.If the reed field and 60km above and 265 km below the reed field are calculated separately,the ecological water demand of the two is 109 million m~3 and 0.85 billion m~3 respectively.The calculation results have important reference value for maintaining the ecological security of the green corridor of the lower Chelsea River and achieving the optimal allocation and efficient use of water resources in the basin.