洞庭湖最小生态需水量研究

STUDY ON THE MINIMUM ECOLOGICAL WATER DEMAND FOR THE DONGTING LAKE

从湿地水文的角度对典型通江湖泊——洞庭湖3个时期的最小生态需水量进行了研究。结果表明:(1)1974和1988年的最小生态水位均为24m,而1998年为24.6m;(2)1974、1988和1998年的最小生态蓄水量分别为21.06×108、18.04×108和18.80×108 m3;(3)1974～1987、1988～1997和1998～2007年的最小出湖生态需水量的平均值分别为3 396、3 379和4 717m3/s,最小入湖生态需水量的平均值分别为2 657、2 704和3 745m3/s。可见,随着洞庭湖的演变,1974年最小生态水位比1998年大幅减少,最小生态蓄水量明显增加,出、入湖最小生态需水量不均衡增加。最后,对洞庭湖最小生态需水量的变化原因进行了分析,并提出了生态恢复对策。

On the basis of wetland hydrology, the minimum ecological water demand in three different periods was investigated for the Dongting Lake, a typical river-connecting lake in China. The results showed that：（1） the minimum ecological water level was 24 m in either 1974 or 1988,but 24. 6 m in 1998;（2） the minimum volumes of ecological water storage were 21.06 × 10^8 , 18.04 ×10^8 and 18. 80 ×10^8 m^3 in 1974, 1988 and 1998, respectively; （3） the average minimum ecological water demands of lake outflow were 3 396,3 379 and 4 717 ma/s,and the minimum ecological water demands of lake inflow were 2 657 ,2 704 and 3 745 ma/s in 1974- 1987,1988-1997 and 1998-2007, respectively. Therefore, along with lake succession, the minimum ecological water level was significantly increased and the minimum ecological water demands of lake outflow and lake inflow were imbalanced in creased, but the minimum volume of ecological water storage was significantly decreased in 1998 compared with 1974. Finally, the reasons for the changes of the minimum water demand were analyzed, and the strategies for ecological restoration were also provided.