Prevention document aimed at controlling urbanization in areas exposed to a hazard. Established by the State, the risk prevention plans (PPR) are public utility easements and must be appended to the
Period of lowest water levels in streams and groundwater (usually summer for rainfall regimes).
Exceptionally low flow period of a watercourse, or exacerbation of its low water (sometimes assimilated to low seasonal flows). Low water is therefore considered to be a limited period in the year when the flows drop lower than a statistically calculated threshold value, function of each stream.
Low flow value below which the supply of drinking water for essential needs for human and animal life, and for the survival of the species found in the environment, are endangered. At this low-flow level, all possible measures to restrict consumption and
"Threshold" value of the flow that triggers the first restrictions for some activities. These measures are taken at the initiative of the prefectural authority in connection with a crisis cell and in accordance with a crisis plan. Below this threshold, one of the functions (or activities) is compromised. To partially restore this function, it is necessary to limit temporarily another: withdrawal or discharge (first restriction measures)…