干旱区流域生态需水量估算原则分析

运用河流廊道原理 ,提出了生态需水量计算公式。以额济纳地区为例 ,分析研究了该地区不同景观的生态需水量。结果表明 ,河流两岸的乔灌木林和灌丛草甸的生态需水量为 3 .91× 1 0 8m3,占总需水量的 39.388% ,加上河流和湖泊的蒸发耗水量 0 .55×1 0 8m3及河流自身生态用水 ,四者占总需水量的 73 .61 %。可见 ,只要保证了四者的生态需水量 ,即可保证现状河流廊道的基本功能。但从长远来考虑 ,河道的流量要确保抗性最小面积对生态需水量的要求。

Estimation of Ecological Water Requirement of a River Basin in Arid Areas

A formula to calculate ecological water requirement of a river basin has been put forward based on theories of river corridors. In a case study in Ejina oasis, ecological water requirement was calculated for its different landscapes. The results showed that ecological water requirement of the oasis is mainly composed of four parts: 1) water needed by arbor/shrub woods, 2) shrub/meadow in the riverbank; 3) amount of evaporation of rivers and lakes; and 4) the ecological water needed by the river itself, which accounts for 73.61% of the total ecological water requirement. According to this estimation, the authors concluded that basic ecological feature of the oasis would remain intact on condition that the water requirements of the above four parts could be met, but it is more important to maintain the river runoff that can satisfy the ecological water requirement of the minimum function area.