The German National Flood Protection Programme: Evaluating the impact of supraregional flood protection measures on extreme floods using hydrodynamic modelling

Abstract

After the disastrous flood events of June 2013 in the German Elbe and Danube catchments, the German government together with the federal states decided on the joint elaboration of a nationwide flood protection programme (NHWSP, 2015-2027+). Within the frame of this programme, the government supports the realization of large-scale retention measures for the improvement of supra-regional flood prevention. For scientific monitoring, the Federal Institute of Hydrology (BfG) was mandated to conduct a two-part preparatory ad hoc study (2014-2015) and a subsequent research project (2015-2019) evaluating the collective impact of the planned retention measures on flooding processes and flood peak reduction in the Danube, Elbe, and Rhine basins. Findings from the ad hoc study provided the government with first elements of evidence for taking its decision on the elaboration of the NHWSP programme, and supported the development of a modelling strategy for the accompanying research project. By using extensive sets of hydrodynamic models, the research project takes into account the complex interrelations between supra-regional flood formation, flooding process, and retention control concepts when evaluating flood reduction on catchment level. It is expected to technically substantiate the government's NHWSP programme by refining the criteria for identification and prioritization of measures.