The operating conditions of Nordic hydropower plants are expected to change in the coming years to work more in conjunction with intermittent power production, causing more frequent hydropeaking events. Hydropeaking has been shown to be detrimental to wildlife in the river reaches downstream of hydropower plants. In this work, we investigate how different possible future hydropeaking scenarios affect the water surface elevation dynamics in a bypass reach in the Ume River in northern Sweden. The river dynamics has been modeled using the open-source solver Delft3D. The numerical model was validated and calibrated with water-surface-elevation measurements. A hysteresis effect on the water surface elevation, varying with the downstream distance from the spillways, was seen in both the simulated and the measured data. Increasing the hydropeaking rate is shown to dampen the variation in water surface elevation and wetted area in the most downstream parts of the reach, which could have positive effects on habitat and bed stability compared to slower rates in that region.

中文翻译：

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旁路范围内的瞬态动力学案例研究

预计未来几年北欧水电站的运行条件将发生变化，更多地与间歇性发电结合工作，从而导致更频繁的水峰事件。水峰已被证明对水电站下游河流中的野生动物有害。在这项工作中，我们调查了未来可能出现的不同水峰情景如何影响瑞典北部 Ume 河旁路河段的水面高程动态。河流动力学已使用开源求解器 Delft3D 进行建模。数值模型通过水面高程测量进行了验证和校准。在模拟和测量数据中都看到了对水面高程的滞后效应，随着下游距溢洪道的距离而变化。