基于RS的新疆哈密地区生态环境需水分析

Eco-environmental water demand in Hami,Xingjiang,based on RS

干旱半干旱地区水资源缺乏,准确地计算区域生态环境用水和生态环境需水,可以对稀缺水资源进行合理调配,同时起到生态保护的作用。研究过程主要分为两个步骤:(1)采用RS技术,对新疆哈密地区1990年、2000年、2005年中巴资源一号卫星(China Brazil Earth Resources Sat-ellite)数据进行解译,形成1990年、2000年、2005年哈密地区土地覆被图形数据和相应的属性数据,确定相应年份各景观类型的面积;(2)参考有关研究并结合哈密地区实际情况,确定各景观类型的单位生态用水定额和需水定额,进而计算出1990年、2000年、2005年哈密地区的生态用水量,并以2005年哈密地区生态用水量为主要依据计算出保持哈密地区生态环境现状的生态需水量。研究结果表明,为了实现哈密地区生态环境整体保持在现状水平不致恶化、局部区域生态环境(巴里坤湖区)有所改善的生态治理目标,区域内生态环境需水总量为7.526×109m3,这一庞大的需水量将对该地区水资源配置造成巨大的压力;而当结合各类景观的地物空间位置特征进行分析时,发现该区域生态用(需)水量最大的景观(低覆盖草地)可以利用山地积雪融水进行自给,区域内实际需要规划配置的生态环境需水量为2.66×108m3,仅占区域生态环境需水总量的3.53%。在区域生态用(需)水计算过程中应考虑各种景观类型的生态用(需)水量的时空差异性,以保证水资源调配的科学与合理。

Owing to lacking of water precisely the amount of water use and resource in the arid and semiarid area, it is of great importance to calculate water demand of eco-environment so that the scare water source could be allocated reasonably and the ecological environment is also able to be protected. With the aid of RS, the change process spatio-temporal difference of eco-environment water use was analyzed from 1990 to 2005 in Hami area, Xinjiang. The analysis result showed that the ecosystem in Hami is getting worse little by little. Considering the spatiotemporal difference of water demand for all sorts of vegetation is needed to calculate the regional ecosystem water demand ＆ use. To satisfy the water demand of the eco-environment with low-covered grasses would result in unreasonable water resource allocation, so it is necessary to introduce the spatial position character of surface features to collocate the regional water resources in Hami area, or there is no choice to solve the unbalance of water resources distribution. The above research didnt consider other effect factors such as physiognomy and climate, which would be under the further study.