基于物理栖息地模拟的减水河段鱼类生态需水量研究

Ecological water demand of fish in flow reducing reach based on physical habitat simulation

河流生态需水量的研究从基于统计学Tennant法、7Q10法等简单估算发展到综合运用水文学、水动力学、环境水力学、生态学进行成因和机理分析。本文运用物理栖息地模拟模型计算西南山区二台子引水式电站减水河段的鱼类生态需水量。以省级保护性鱼类—青石爬鮡为目标鱼类,考虑流速、水深、水温、断面形态等主要影响鱼类适宜生境的影响因子对鱼类产卵期、育幼期、成年期等不同生命时期的需水要求进行分析。计算结果表明,青石爬鮡产卵期需水流量3.68 m3/s、育幼期4.25 m3/s、成年期3.26 m3/s,分别占坝址处多年平均流量的38.33%、44.27%、33.96%,对水生态系统结构与功能认识和研究的不断深化,为坝址下游减水河段维持健康生态系统、保护珍稀性生物资源提供了有力依据。

Methods of ecological river flow demand have advanced from simple statistical estimate, such as Tennant method and 7Q10 method, to complicated analysis of hydrology, hydrodynamics, environmental hydraulics, ecology, etc. Ecological water demand of fish in a flow reducing reach of the Ertaizi hydropower station in the southwest mountain area of China was calculated with a physical habitat simulation model in this work. Aiming at protection of Euchiloglanis davidi, a provincial fish, this model considers＇influence factors on the water demand of fish and its suitable habitat, including velocity, water depth, water temperature and cross section shape for periods of spawning, juvenile and adulthood. Results indicate that ecological water demand of Euchiloglanis davidi is 3.68 m^3/s in spawning season, 4.25 m^3/s in juvenile and 3.26 m^3/s in adulthood, or 38.33% , 44.27% and 33.96% of the mean annual discharge at damsite, respectively. This work sheds light on the ecosystem health and fish preservation and the structure and function of aquatic ecosystem.