A landscape forensic investigation of the 2021 flood in the Ahr Valley, Germany

Abstract

The Ahr River experienced a catastrophic flood in July 2021, damaging or destroying nearly every home and piece of infrastructure in the valley. Though the river has had serious floods in history, contemporary methods to measure risk failed to account for the qualitative descriptions available and instead referenced a limited qualitative data set that has been collected since 1947. This drastically underdimensioned the risk of flooding for the Ahr during low pressure system "Berndt", which led to approximately €40 billion in damages in the region and the deaths of 135 people in the Ahr Valley alone. A comprehensive plan for disaster risk reduction is necessary but still completely lacking nearly a year after the disaster. The understanding of what is needed to reduce risk has developed through history, with several paradigms that underwent major shifts in how we see nature, spaces, and people as having a role. These paradigms are used to understand the benefits and limitations of planning concepts in each, so that an optimal risk reduction plan can be produced for the Ahr Valley reconstruction.