Laboratory of Hydrology, Lithuanian Energy Institute, Kaunas, Lithuania.
Laboratory of Fish Ecology, Nature Research Centre, Vilnius, Lithuania.
Sci Total Environ. 2024 Jan 1;906:167541. doi: 10.1016/j.scitotenv.2023.167541. Epub 2023 Oct 4.
The water sector is one of the priority areas of the European Union; therefore, legislation encourages the development of methods to protect the river ecosystem. The key to this is the characterization of the river's physical features with respect to ecological quality. Rivers are a complex system in which geomorphic conditions, hydrological regime, and ecological indicators interact. The group of hydropower plants (HPPs) that forms a hydropower cascade disturbs the natural continuity of river system components. Analysis of the spatial and temporal alterations in the river environment is important for understanding the potential impact of the hydropower cascade on ecological indicators. In a current study, the multicomponent assessment was used to evaluate the impact of the hydropower cascade of five HPPs on fish metrics as ecological indicators in the case study Varduva River. The research involved field surveys to collect hydrological data in highly affected ungauged river to estimate indicators of hydrologic alterations under HPPs operation, use of Unmanned Aerial Vehicles and digital photogrammetry to map geomorphic units, fish sampling to estimate composition of fish species and guilds, and fish habitat availability modelling based on the collected data and the conditional habitat suitability criteria using the MesoHABSIM modelling approach. Results revealed that the technical characteristics of HPPs determined their individual operation mode, which had a crucial impact on the hydrologic alterations of the river and, together with the distance between the dams, on the variation of fish metrics in the hydropower cascade. The intensive operation of the hydropower cascade created adverse effects for intolerant fish but was advantageous for tolerant fish species. The proposed HPP multimetric correlated with the fish metrics and showed similar tendencies between HPPs as habitat integrity index (IH), derived from MesoHABSIM modelling.
水领域是欧盟的优先领域之一；因此，立法鼓励开发保护河流生态系统的方法。这方面的关键是对河流的物理特征进行生态质量特征描述。河流是一个复杂的系统，其中地貌条件、水文状况和生态指标相互作用。形成水电级联的水电厂（HPP）组扰乱了河流系统组件的自然连续性。分析河流环境的时空变化对于了解水电级联对生态指标的潜在影响非常重要。在当前的研究中，使用多组分评估来评估五个 HPP 的水电级联对鱼类指标作为生态指标的影响，在 Varduva 河案例研究中。研究涉及实地调查，以收集在受高度影响的未测河流水文数据，以估算 HPP 运行下的水文变化指标，使用无人驾驶飞行器和数字摄影测量来绘制地貌单元图，鱼类采样以估算鱼类物种和 guilds 的组成，以及基于收集的数据和使用 MesoHABSIM 建模方法的条件栖息地适宜性标准进行鱼类栖息地可用性建模。结果表明，HPP 的技术特征决定了它们的个体运行模式，这对河流的水文变化产生了至关重要的影响，并与大坝之间的距离一起，对水电级联中鱼类指标的变化产生了影响。水电级联的密集运行对不耐受鱼类产生了不利影响，但对耐受鱼类有利。所提出的 HPP 多指标与鱼类指标相关联，并表现出与 MesoHABSIM 建模得出的栖息地完整性指数（IH）相似的趋势。
