宋增芳 程玉菲 李莉

摘 要：祁连山区水电站建设改变了下游河道的水文条件，枯水期减水河段出现断流，河流自净能力减弱，河道污染加剧，为了恢复祁连山区水生生物的生态环境，运用改进的Tennant法评价标准对年内展布法、改进年内展布法、逐月最小生态流量、NGPRP法4种常用的生态流量计算方法进行合理性检验，选用评价结果较好的NGPRP法与改进年内展布法，计算了莺落峡站各月最小生态流量，在此基础上，结合水文比拟法计算了黑河干流7座引水式电站各月最小生态流量。黑河干流各水电站最小生态流量各月均值为8.43～83.99 m3/s，呈现先增大后减小的变化趋势，从1月开始逐渐增大，7月达到最大值，8—12月最小生态流量持续减小。

关键词：引水式水电站;Tennant评价标准;改进年内展布法;黑河干流

Abstract：The construction of hydropower stations in Qilian Mountains has changed the hydrological conditions of the lower reaches of the river. In the dry season， the flow of the reduced river reaches is cut off， the self purification capacity of the river is weakened and the pollution of the river is aggravated. In order to restore the ecological environment of aquatic organisms in Qilian Mountain area， the improved Tennant method was used to test the rationality of four commonly used ecological flow calculation methods， namely， the improved annual distribution method， the monthly minimum ecological flow， the annual distribution method and the NGPRP method. The evaluation results of NGPRP method and improved year distribution method are the best， which are combined to calculate the monthly minimum ecological flow of Yingluoxia Station. On this basis， the monthly minimum ecological flow of 7 diversion power stations the main stream of Heihe River was calculated by hydrological analogy method. The average monthly variation of the minimum ecological flow of each diversion type power station in the main stream of Heihe River is 8.43-83.99 m3/s， showing a trend of increasing at first and then decreasing， gradually increasing from January to reaching the maximum value in July and decreasing continuously from July to December.

Key words： diversion hydropower station; Tennant evaluation standard; improved year distribution method; main stream of Heihe River

祁連山区水能资源丰富，近年来，利用山区特殊的地理优势，在祁连山区河流上进行了较多引水式水电站的开发[1-2]。水电站建成后，改变了下游河道的水文条件，在大坝和下游厂房之间形成减水河段，减水河段对河流的生态环境造成极大破坏，尤其是枯水期减水河段出现断流，水生生物因丧失栖息地而死亡，局部生态系统由水生演变成陆生，河流自净能力减弱，河道污染加剧[3]。为了恢复水生生物的生态环境，引水式水电站在建设、运行时要考虑最小生态流量，以满足下游生态环境的最低要求。生态流量的确定是目前水利水电工程中一个较为复杂的问题，由于其关系到水资源的合理利用、生态保护和工程最大效益的发挥，因此合理确定水利水电工程的生态流量和运行管理方式十分重要。……