Dataset Direct Download Service (WFS): PPR flooding zone of the DUROLLE and DORE basin to the right of THIERS(63DDT20070008) approved on 22-12-2008 — Puy-de-Dôme

The hazard map was carried out using the following methods: Concerning DUROLLE: As part of the preparation of the risk prevention plan, the State has appointed a specialised research office (the BCEOM) in order to compare the various existing studies, to update the knowledge of the events and complete data on certain parts of the territory based on the methodology hydrogeomorphological. On DORE: Due to the presence, important issues (industrial area of Felet, commercial area of Varenne, area reserved for Travellers...) and data available through previous studies, the State has mandated the BCEOM study office in order to carry out a hydraulic modeling. The purpose of this modelling was to validate previous studies and to clarify the knowledge of flood risks. Thus, a hydraulic model was carried out by BCEOM in October 2007 in order to clarify the hazard limits on the Dore/Durolle confluence sector, to the law of Thiers and Peschadoires. The modelling carried out as part of the PPRI was carried out on a 5.7 km stretch extending from the upstream south of “la Varenne” to the municipal boundary of Thiers downstream. The hydraulic model was carried out from topographic surveys on 14 profiles across the study area line (see figure on the next page). To ensure that the results provided are representative of reality, the model was tested on the basis of data collected from the April 2005 flood with a flow rate of 290 m³/s in the end, 3 hazard zones are defined: 1/The area of strong hazard mainly corresponds to the areas of large flow with heights of water greater than one metre or at significant speeds greater than one metre per second. The medium and low hazard areas represent areas of expansion or even storage of floods with lower characteristics: 2/for average hazard, water heights between 0.50 m and 1 m or flow velocities between 0.5 m/s and 1 m/s; 3/for low hazard, water heights less than 0.50 m and flow velocities less than 0.50 m/s.