Multi-criteria assessment of factors affecting the reduction of retention capacity of dam reservoirs

Abstract

Maintaining the appropriate capacity of a retention reservoir is necessary for the optimal performance of the functions for which it was built, including flood and drought protection. Therefore, to properly manage individual reservoirs and sediments within their catchments, it is necessary to analyze the factors affecting the reduction of the retention capacity of reservoirs. Our study proposes a methodology for conducting a multi-criteria assessment of anthropogenic pressures and natural impacts affecting the reduction of reservoir capacity, such as land use, hydrographic network density, hydraulic development, and land slopes. For this purpose, geospatial analyses were applied to a grid of basic fields (hexagons). The research procedure showed that land slopes in the catchment area are the key factor determining the supply of sediment to the reservoir. Our study focused on the basins of reservoirs located in the southern part of Poland: Goczałkowice on the Vistula, Rożnów on the Dunajec, and Tresna on the Soła. However, our proposed new approach to multi-criteria assessment of reservoirs can be applied to and implemented in other catchments. The application of solutions based on our study may contribute to maintaining or potentially increasing the level of water retention in reservoirs and their catchment areas.