Rhône flood alarm plan

PROJECT

CLIENT	Vaud Canton Water, Land and Sanitation Department
LOCATION	Aigle et d'Ollon (VD)
DURATION	2007 - 2008

The project aims to set up an alarm and intervention system to deal with the problems caused by the Rhône flooding. This system must allow the research results to be translated into concrete measures and current risks to be managed until protective measures are completed and dykes reinforced.
This involves defining monitoring, alarm and intervention measures covering each of the tasks that must be performed during a crisis.

HIGHLIGHTS

When the Rhône floods, the water level rises to 3 to 4 metres above the plain. There are currently two hazards:
- The dykes, which are old and subject to significant strains and stresses, could break even before any flooding has taken place, if the flooding is exceptional.
- The limited capacity of the bed means that there is a risk of overflowing if the flooding is very exceptional.
- The poor condition of the dykes means that they could crack suddenly and almost anywhere and randomly. According to current knowledge, there is a significant danger of the dykes breaking during an exceptional flood.
When the Rhône’s capacity is insufficient (very exceptional flood), there is an overflow, possibly taking some of the dyke materials with it.

OUR PROVISIONS

Diagnostic of the dangers and risks.
Definition of an alert and alarm strategy.
Installation and use of an automatic station and alarm procedure.
Creation of the general monitoring concept on the Vaud line.
Definition of the type of actions to be carried out for each intervention body.
Creation of an operational tool that also aids decisions relating to mission realisation.
Creation of a preventive information document for the population presenting the measures and behaviour to be adopted if a flood occurs.