干旱内陆流域河道外生态需水量评价——以黑河流域为例

Water demand evaluation of riverside ecosystem in arid inland river basin: the case of Heihe River Basin

河道外生态系统需水量的合理评价是干旱区水资源合理配置与管理、生态环境保护与建设中最为关键的科学问题。基于不同植被蒸散发潜力估算模型,依据不同生态系统及同一生态系统在不同气候与地理区域具有不同生态需水规律的特点,提出了可模拟和评价不同时期生态系统需水量的方法,不仅能体现生态系统需水量的年际变化,也能反映年内不同时间段(月、季节甚至每日)的需水量变化,并提出干旱区生态适宜需水量在不同时期是一个区间。以黑河流域中下游地区为研究区域分析其生态需水量,结果表明:黑河中游地区年平均生态需水量(11.16±2.67)×108m3,其中绿洲生态系统需水(9.13±2.29)×108m3;下游地区生态需水量(16.16±4.04)×108m3,现状绿洲生态体系需水(11.06±2.77)×108m3,现阶段实施的下游分水9.7亿m3/年的方案,可以促使现有绿洲生态系统有一个良好的结构与功能,并给出了不同典型年不同月份的生态需水量及其变化。

Rational evaluation of water demand of the riverside ecosystem is a key scientific problem in the reasonable allocation and management and the eco-environmental protection in arid regions of northwest China. Based on the evaluation model of evapotranspiration potentials of different vegetation types and the water demand laws of different and similar ecosystems in different climatic and geographic zones, a method used for modeling and evaluation of water demands of different ecosystems was put forward. The results showed that this method not only reveal the interannual variations of water demands of different ecosystems but also reflect the variation processes of their water demands at different time intervals （month and season or day）. The optimal ecological water demand of an ecosystem in different periods in the arid region varied in a certain range. With the mid and downstream reaches of the Heihe River as the study area, it has been obtained the analytical results of ecological water demand as follows： mean annual ecological water demand in the midstream region of the Heihe River is 911.16 ± 2.67）×10^8m^3; ecological water demand of oases ecosystem is （9.13 ± 2.29）×10^8m^3 ; ecological water demand in the downstream region is （16.16±4.04） ×10^8m^3; but the water demand of oasis ecosystem at present time is （11.06±2.77） ×10^8m^3. In addition, the ecological water demand and their variation processes in different months in different typical years are given out.