Flood risk reduction by the use of retention areas at the Elbe River

Abstract

The paper presents research results on flood risk mitigation by the controlled flooding of a retention area on the middle reaches of the Elbe River. The retention area consists of six large polders and the floodplain of a tributary, the Havel, and is located near the Havel's confluence with the Elbe River. The total retention volume of both the polders and the Havel floodplain amounts to approximately 250 million m³.

The controlled flooding of the retention area was simulated by the use of a conceptual model and assessed economically for two flood scenarios. In a cost‐benefit analysis, the damage to agriculture, the road network, buildings and fishery caused by the flooding of the polders was compared with the resulting reduction in potential damage in the town of Wittenberge, 30 km downstream. On the basis of a monetary assessment it was concluded that the use of the retention area for flood protection is highly cost‐effective in economic terms.

Keywords:

• Flood risk management
• flood modelling
• Elbe River
• polders
• damage potential
• cost‐benefit analysis