Abstract River regulation patterns play a key role in ecohydrology and they directly affect hydrodynamic variables, fish habitats, and fish abundance conditions. In the Kraal River, the Trunk Dam is currently being constructed and very little is known about the dam construction and operation impacts on fish species. In this study, an ecohydraulic model was built and linked to hydromorpho-dynamic, fish habitat, and fish abundance simulations. Two fish species, schizothorax (Schizothorax) and schizothorax (Racoma), representing a main and an endangered fish species, respectively of the Kraal River, were studied; their habitats and abundance statuses were predicted and analyzed based on four different long-term dam operation scenarios. Fish-friendly river regulation scenarios were also examined. The temporal- and spatial-scale hydro-morphodynamic results indicate that the erosion effects are much more significant than the deposition effects. Our study suggests that habitat destruction and fragmentation existed for all presented river regulation scenarios. The analysis indicates that long-term river regulation will result in a decrease in the fish population. However, there will be different levels of decline for fish habitats and populations depending on the dam operation scenarios. This study contributes to a better understanding of the dam-induced temporal habitat fragmentation and response of fish communities. This study also provides quantitative evidence for suitable river regulation scenarios and fish stocking strategies, which can help the fish community recover to a stable level.

中文翻译：

---

基于长期大坝运营计划的影响识别鱼类生态风险模式

摘要 河流调控模式在生态水文学中起着关键作用，它们直接影响水动力变量、鱼类栖息地和鱼类丰度条件。在 Kraal 河，Trunk Dam 目前正在建设中，关于大坝建设和运营对鱼类物种的影响知之甚少。在这项研究中，建立了一个生态水力模型，并将其与水形态动力学、鱼类栖息地和鱼类丰度模拟相关联。研究了两种鱼类，裂腹鱼（Schizothorax）和裂腹鱼（Racoma），分别代表了 Kraal 河的主要和濒危鱼类；基于四种不同的长期大坝运营情景预测和分析了它们的栖息地和丰度状态。对鱼类友好的河流调节方案也进行了研究。时空尺度的流体形态动力学结果表明侵蚀效应比沉积效应显着得多。我们的研究表明，所有呈现的河流调节情景都存在栖息地破坏和破碎化。分析表明，长期的河流调控将导致鱼类种群的减少。然而，根据大坝运营情况，鱼类栖息地和种群数量会出现不同程度的下降。这项研究有助于更好地了解大坝引起的时间栖息地破碎化和鱼类群落的响应。该研究还为合适的河流调节方案和鱼类放养策略提供了定量证据，可以帮助鱼类群落恢复到稳定水平。