Reaches surveyed - cross section securing point

The map shows the reaches of watercourses which are currently surveyed periodically under the leadership of the FOEN. They are usually surveyed every 10 years or after major floods which cause significant morphological changes. The aims of periodic surveying are to identify morphological trends (erosion, aggradation) at an early stage as well as their effects on the stability of flood protection structures or discharge capacity, to provide long-term time series on channel changes as a basis for quantifying the bed-load regime, and to provide current data for planning and risk assessment. The survey data is managed by the Risk Management section of the Hazard Prevention Division