淮河上游生态需水量计算分析

为分析计算淮河上游河流生态需水量,提出了丰水期、枯水期、平水期保证率分别为45%,75%,50%的淮河上游适宜生态径流计算方法,选用淮河上游干流息县、长台关以及大坡岭3个主要控制站1960～2005年历年天然来水量资料,计算了淮河上游最小生态径流和适宜生态径流,并运用Tennant法进行评价.结果表明,最小生态径流在很大程度上有损于河流生态系统稳定与健康;总体而言,3站适宜生态径流均可以使淮河上游河流生态环境状况达到最佳,但在某些年份各站实测月均流量小于其适宜生态径流量,而且丰水期适宜生态径流破坏率较枯水期的要高.因此,在某些年份为满足淮河上游适宜生态需水要求,还应增加河道内生态用水量.

Calculation of ecological water demand in upper reaches of Huaihe River

To compute and analyze the ecological water demand in the upper reaches of the Huaihe River, a method for determining optimal ecological flows was proposed, with different guaranteed flow rates: 45% for the wet season, 75% for the dry season, and 70% for an average season. According to the natural discharge time series data (1960-2005) from Xixian, Changtaiguan, and Dapoling hydrological stations on the trunk stream in the upper reaches of the Huaihe River, the minimum ecological flow and the optimal ecological flow were calculated and evaluated using the Tennant method. The results show that the minimum ecological flow does not provide for the stability and health of the river ecosystem. Generally speaking, the optimal ecological flows at the three stations can lead to the optimal river ecosystem in the upper reaches of Huaihe River. However, in some years the observed average monthly flows are less than the optimal ecological flows, and the destruction rate of the optimal ecological flows in the wet season is larger than that in the dry season. This indicates that the ecological water amount in the river should be raised in some years so as to satisfy the requirements of the optimal ecological water demand.