Spatiotemporal changes of soil erosion rate in the pre-and post-dam construction periods (1990-2018) determined through RUSLE and GIS: the case of the Kavak River Basin, East Thrace, Türkiye

Abstract

In the last few decades, spatiotemporal changes in soil erosion rate have changed dramatically with the construction of dams, resulting in increased sedimentation in dam reservoirs and significant shoreline changes in deltas in rivers downstream. This article aims to investigate the effect of dam construction on the change of soil erosion rate through the RUSLE and GIS in the Kavak River Basin in Thrace Peninsula (Türkiye). The impact of the dam built in the source part of the river on soil erosion in the basin was analyzed by the conditions for characterizing the pre-and post-dam construction periods (1990–2018). The RUSLE soil erosion model and GIS were used to organize and evaluate the study data. Model estimation outputs were compared with the shoreline changes in the delta, SOC loss and dating of sediment deposits, and volume changes in the dam reservoir. Finally, the average soil loss (ASL) in the Kavak River Basin was demonstrated to be 5.31 t haˉ¹ yrˉ¹ and 4.68 t haˉ¹ yrˉ¹ in 1990 and 2018, respectively. In the same period, it was determined that there was a -80 m shoreline regression in the delta. According to the study’s results, the erosion phenomenon may lead to a decrease in the economic life of the dam reservoir and a narrowing in productive agricultural areas in the delta.