These 6 basins are managed by :
The most important basin is Rhône-Méditerranée-Corse. In this region, the rivers show a strong mediterranean regime; there are also littoral lagoons between the Rhône and the Pyrénées.
DIREN was created in 1992. Its mission is to collect data (this is sometimes done by different services depending on the Ministry of Agriculture).
DIREN has to face a quasi real time response to water problems.
When DIREN decided to modernise the network, the main objective was to find out the right equipment. Several types of equipment and programmes were tested. The choice was made on 2 brands : CR2M and Auteg.
Autonomous stations that could be monitored so that any user or a specialist could interrogate from any distance were choosen. Of course, specialists have special access code that let them check, load, store and process the data.
For the acquisition, three choices were at their disposal : radio, telephone or satellite. Satellite was too expensive, so the choice was rapidly done on telephone so that a maximum of users could be connected to the stations.
Mr Tailhan is in charge of a 40 stations network on two zones (Hérault and Gard), for data installation, maintenance, collection and processing.
He proceeds to a demonstration of the monitoring and interrogation of a station close to the PRC.
The "Tramontane" wind coming from Atlantic Ocean and crossing the mountains, blows strongly and increases drought. The floods are very important. The contrast in the altitude (Mount Canigou is 2,785 m high and the sea is 50 km further) is at the origin of cooling of the wet marine air. This provokes precipitations of high intensity, and very quick floods (that are amplified by the slope).
The reference flood occurred on October 16th 1940 : the rainfall reached 1,000 mm in 24 hours (the snowy rock face of the Pyrénées emphasized the intensity).
The "département" tried to study these phenomena. For this, a service was set up in 1965 in the Departmental Direction of Agriculture and Forest (D.D.A.F.) and this pilot service went on when DIREN services were created.
The hydrographic network is composed of 3 main rivers : from North to South, the Agly, the Tet and the Tech. One of the five Med-Hycos stations that will be installed in France will be located in this region.
All the collected data are sent to the data bank of the Ministry of Environment, named Hydro.
Diren uses the data collected for the last 30 years.
In this "département", another service, the Departmental Direction of Equipment (D.D.E.), manages flood warning stations. This Direction modernised its system with Noe stations, and took advantage of the modernisation to incorporate 15 stations D.D.A.F. in their network; thus those 15 stations can be accessed both by Minitel and by the flood warning system. 3 dams were built for irrigation in the "département" during the last 20 years. These dams provide water for irrigation, but they also permit, in autumn, when they are empty or almost, to smooth the floods of the rivers.