Extreme runoff formation in the Krkonoše Mts. in August 2002

Abstract

The role of the water movement and retention during extreme runoff formation was demonstrated in the Modrý Důl catchment (Krkonoše Mts., Czech Republic). A cyclone, which moved from Hungary to Poland, caused an extreme rainfall (120 mm) and subsequent extreme runoff in August, 2002. The precipitation, discharge, air and soil temperatures, tensiometric pressure, and soil moisture were recorded. The maximum retention capacity of the catchment was evaluated (70 mm). Depending on the actual retention capacity and the precipitation amount, two situations were recorded: (1) the precipitation amount lower than the actual retention capacity where the precipitation was fully absorbed in the catchment and the discharge in to the stream was not influenced by rain, (2) the precipitation amount higher than the actual retention capacity where the precipitation caused a saturation excess of the soil profile, generating extreme outflow into the stream. Neither the soil cover in the catchment or fluvial deposits along the Modrý potok stream were able to retain the extreme rain and inhibit the catastrophic flood.