Division of Fluid and Experimental Mechanics, Department of Engineering Sciences and Mathematics, Luleå University of Technology, 971 87 Luleå, Sweden.
Norwegian Institute for Nature Research - NINA, NO-7034 Trondheim, Norway.
Sci Total Environ. 2021 Nov 20;796:148999. doi: 10.1016/j.scitotenv.2021.148999. Epub 2021 Jul 14.
Hydropower plant operating conditions are expected to change to be more in tandem with intermittent power production so as to meet the requirements of the Paris Agreement, which in turn may negatively impact ecological conditions downstream of the hydropower plants. The current study investigates how highly flexible hydropower operating conditions may impact several salmonid species (European grayling, Atlantic salmon and brown trout) in the River Umeälven, a major river in northern Sweden; specifically, how changes in hydropeaking frequency may affect the area of the downstream watercourse that is hydraulically suitable for spawning (potential spawning area) and how changes in spill gate closing time may affect the propensity to stranding. River hydrodynamics were modeled using the open-source solver Delft3D, with a range of hydropeaking frequencies (from 10 to 60 starts and stops per day) and a range of spill gate closing times from (1-30 min). Increasing the hydropeaking frequency caused a reduction in potential spawning area, but also a reduction in dewatering of potential spawning area at low flows. Increasing spill gate closing time caused a decrease in propensity to stranding. Effects were dependent on both species and life-stage, and declined longitudinally with distance downstream from the spillway outlet. The modelling approach used here provides an effective method for predicting likely outcomes of flexible hydropower operating conditions, taking into account fish species and life-stages present and watercourse characteristics.
水力发电厂的运行条件预计将发生变化，以更加与间歇性发电相匹配，以满足《巴黎协定》的要求，而这反过来又可能对水电站下游的生态条件产生负面影响。本研究调查了高度灵活的水力发电运行条件如何影响瑞典北部主要河流于默奥河中的几种鲑鱼物种（欧洲灰鳟、大西洋鲑和褐鳟）；具体来说，水力发电频率的变化如何影响下游适合产卵的河道面积（潜在产卵区），以及泄洪闸关闭时间的变化如何影响搁浅的倾向。使用开源求解器 Delft3D 对河流水动力学进行建模，水力发电频率范围为每天 10 到 60 次启动和停止，泄洪闸关闭时间范围为 1 到 30 分钟。增加水力发电频率会导致潜在产卵区减少，但在低流量时也会减少潜在产卵区的脱水。增加泄洪闸关闭时间会降低搁浅的倾向。影响取决于物种和生命阶段，并随距离泄洪闸出口的下游而纵向下降。这里使用的建模方法提供了一种有效的方法，可以预测灵活的水力发电运行条件的可能结果，同时考虑到存在的鱼类物种和生命阶段以及河道特征。
