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Watercourse

Fish classification of watercourses

Updated on 26/10/2022
Définition
Sens réglementaire
Legal classification of a watercourse based on the dominant species and worthy of protection. In principle, the river is classified in the first category when the dominant group consists of salmonids (salmon, trout) and in the second category, when the dominant group is composed of cyprinids (carp, barbel, roach, etc.). This classification determines the fishing practices.
Source
According to OFB

River improvement

Updated on 13/07/2018
Définition
Sens technique

Action on a river for recovering the entire bed and river banks of the watercourse to achieve the priority goal of increasing the hydraulic capacity of the targeted segment. This implies flow acceleration and therefore an increased flood

Source
According to Rhone-Mediterranean and Corsica Water Agency

Alluvial plain

Updated on 13/07/2018
Définition
Sens commun
Generic term generally used to designate the area built at the bottom of a valley by the deposit of alluvium of a stream. In a broad sense, it includes different environments and associated zones: riverbed, floodplain, open space, water dependent areas, etc.
Source
According to Rhone-Mediterranean and Corsica Water Agency

Dredging

Updated on 13/07/2018
Définition
Sens technique
According to the SDAGE and Order of 22 September 1994, this means removing alluvial deposits accumulated on the riverbed. Indeed, Article 11 of the Decree of 22 September 1994 provides that the extraction of materials in the riverbed of watercourses and bodies of water crossed by streams is prohibited. If extraction of alluvial materials is necessary for duly justified maintenance, or for the development of a watercourse or a
Source
According to Rhone-Mediterranean and Corsica Water Agency

Departmental quality objectives map

Updated on 13/07/2018
Définition
Sens technique
Map of rivers in a Department (administrative division) showing with colours (yellow, green, blue) the different levels of quality objectives to be achieved. The reference values of different parameters constituting these objectives are provided in a list appended to the card. These objectives are usually subject to a prefectural order established after dialogue.
Source
According to Rhone-Mediterranean and Corsica Water Agency

Flood flow

Updated on 13/07/2018
Définition
Sens technique
For a given year: it is either the highest flash flood flow rate (QIX) or the highest daily flow rate (QJX). For several years, by using a sample including the highest number possible of annual flood flows, it is the value associated with different theoretical return periods (2, 5, 10 and 50 years in Hydro), determined by a statistic study. A confidence interval is calculated based on the number of available years, their homogeneity, the…
Source
According to SCHAPI

Minimum annual mean flow

Updated on 13/07/2018
Définition
Sens technique

Minimum annual mean flow calculated for n consecutive days. The VCN3 is used to characterize a situation of severe low water over a short period (3 days). The VCN30 gives information on the minimum resource over a month. Unlike low-flow (QMNA), it is calculated over a period of any 30 consecutive days. Using a sample of values of a

Source
According to SCHAPI