Heavy rain hazards - Extreme heavy rain, water depths, model rain 2021

Maximum water depths (in m) for blanket block rain with 180 mm in 6 h, based on the main phase of the extreme storm of 14 July 2021 in the Ahr Valley. The determination was carried out using the hydrodynamic-numeric software HYDRO_AS-2D, which is based as a 2D simulation on the numerical solution of the shallow water equation with the finite-volume method (DGM status 2019, taking into account evaporation, seepage, sewerage by flat-rate reduction of precipitation in terms of land use; Lockwitzbach/Weißeritz with HQ 20; see also explanation in the thematic city plan).