引水型电站对河流底栖动物栖息地的影响及生态需水量

Impacts of a small hydropower plant on macroinvertebrate habitat and an initial estimate for ecological water requirement of Xiangxi River

于2005年12月至2006年5月,对香溪河干流一典型引水型电站——苍坪河电站取水对坝下河段底栖动物栖息地的影响及河道的最小生态需水量进行调查研究,利用加权可利用宽度法(Weighted Usable Width)分别计算了香溪河底栖动物3个主要的目(蜉蝣目、襀翅目和毛翅目)的各断面加权可利用宽度,并对各断面结果进行比较。结果表明,电站引水坝的取水使下游河段部分地出现干涸,3个目的加权可利用宽度显著减小。根据底栖动物加权可利用宽度与流量的回归关系,计算得香溪河底栖动物主要类群的最小生态需水量为3.8m3/s。

A typical small hydropower plant ＂ Cangpinghe＂ was investigated monthly for studying the impacts of small hydropower plants on macroinvertebrate habitat and the ecological water requirement of Xiangxi River. The weighted usable widths （WUW） were calculated for three dominant orders of the macroinvertebrate （Ephemeroptera, Plecoptera and Trichoptera） at each cross section and some comparisons were conducted among cross sections. The results show that the dam＇s diversion caused part of the downstream channel dried up and the WUW of the three orders of the macroinvertebrates declined significantly between the upstream channel and the downstream channel. According to the relationship between the WUW and the river discharge, it was calculated that the minimum ecological water requirement for the main group of the macroinvertebrates in Xiangxi River was 3.8 m^3/s.