Fload and coastal protection

Site search and evaluation for large flood retention basins in the catchment areas of the Lech, Regen, Naab and Isar rivers

Standortsuche Hochwasserrückhaltebecken Lech, Regen, Naab, Isar

For the main tributary catchment areas of the Danube in Bavaria, the catchment areas of the Regen, Lech, Naab and Isar rivers, possible sites for the construction and expansion of large flood retention basins with a potential supra-regional impact were to be identified and evaluated. Restrictions relating to settlement areas, transport routes, hydropower plants and the specific storage volume had to be taken into account.

A GIS-based screening and evaluation method developed by Tractebel Hydroprojekt was used for the study which considered the existing utilisation and topography. The sites found were filtered out on the basis of minimum criteria. The remaining sites were evaluated in consultation with the client on the basis of their supra-regional effectiveness and the expected conflicts.

In addition to the options for the construction of new flood retention basins in the main catchment, sites for flood retention basins in the secondary catchment, behind existing flood protection facilities and dams as well as possible extensions of existing reservoirs were also included in the investigations. The results for the catchment areas of the Lech, Naab and Regen rivers were used as part of the further investigations into the planned flood polders on the Danube (inclusion of selected sites in an impact analysis using NA modelling by a third office).

Client: Bayerisches Landesamt für Umwelt, Augsburg

Processing period: 2020 – 2022 

Main data:
Size of study area: 18,362 km²
Rain: 2,778 km²
Lech: 2,503 km²
Naab: 4,929 km²
Isar: 8,152 km²

GIS-based site identification for HRB in the main headrace, HRB in the secondary headrace
Expansion options for existing TS and HRB
Site evaluation: supra-regional effectiveness, conflict analysis
Development of a GIS tool for site information for the Bavarian Water Management Administration