Abstract
Reservoir storage capacity is a fundamental parameter for design and operation. Over time, sedimentation—driven by factors such as geology, hydrology, and flow velocities—reduces usable volume, often significantly. In the context of climate change, opportunities for natural sediment flushing have become increasingly rare, while extensive dredging is often economically unsustainable. Moreover, sedimentation is closely linked to erosion processes that may endanger bank stability or compromise bridge piers. This study presents a case analysis of the Sĺňava Reservoir on the Váh River in Slovakia, a typical shallow, lowland reservoir within the Váh Cascade hydropower system. In recent years, sediment-related issues have intensified due to declining flow rates and limited options for reusing excavated material. To address these challenges, several mitigation measures were proposed, including riverbed dredging, groins, and sedimentation pits. These measures were evaluated using a two-dimensional numerical model developed in HEC-RAS (Hydrologic Engineering Center's River Analysis System) to simulate sediment transport and morphological changes. The results indicate that the most effective approach combines targeted dredging with the implementation of sedimentation pits. Additionally, the findings highlight the importance of monitoring erosion processes near bridge piers to ensure long-term structural stability.