Geographical concerns regarding flood hydrology in the southeastern area of the Baltic Sea basin

Abstract

ABSTRACT In the Baltic Sea region, the impact of physico-geographical factors is not very clear, although it is relevant in this basin. This study assessed the interaction of geographical factors (lakes, wetlands, forests, watercourse slope, and river network density) with selected flood characteristics (specific runoff of maximum discharge of spring flood (qmax ) and the date of maximum discharge of spring flood (Qmax_date )). In 1985, 2000, 2015, and 2019, the lakes, wetlands, and forests were investigated in 11 catchment areas using satellite images and semi-automatic classification. The highest correlation coefficients were for the average of qmax (0.97–0.98) during the calibration. The validation of Qmax_date revealed a weaker relationship (0.67 to 0.83) with the selected geographical factors. Based on regression models, forests and river network densities were the most influential geographical parameters. The findings of this study can be used to assess spring floods and geographical factors in ungauged catchments.