Automated Remote Measurement of Flash-Flood Discharge in Mountain Torrents

Mountain torrents are a considerable threat in mountain regions. Many mountain communities are threatened by thunderstorm related flash floods and need efficient protection measures to minimize damage. Especially discharge in small mountain torrents can rise very fast from a few liters per second to some cubics per second as reaction to heavy rainfall and are then able to carry off trees and debris. The estimation of peak flows of such mountain torrents is based on empirical formulas.

However, there is only little known about the total discharge volume of such events. But these are very important for the planning and dimensioning of permanent protection measures. This involves two kind of risks: a) oversizing of constructions and the costs involved, b) protection deficit along with follow-up costs in case of flooding.

In case of oversizing unnecessary costs arise for the community in question and also imposing constructions that hardly fit into the landscape. However, if there would exists a protection deficit after the permanent protection measure is constructed, it would involve very high follow-up costs forteh community in case of flooding.

The biggest problem with the dimensioning of protection measures is the lack of peak discharge measurements of mountain torrents, which would allow the calibration of estimation methods.

The permanent instrumentation of a mountain torrent is an expensive investment for a community and the measurement of peak discharge is a dangerous exercise.