Watercourses — Métropole 2017 — BD Carthage

The main concept of hydrographic cutting is the hydrographic entity defined by circular n°91-50. The hydrographic entity is a natural or managed stream, a natural or managed arm, an artificial waterway (channel,...), a body of water or a coastal line. The nature of a hydrographic entity is not constant throughout the entity. For example, a natural stream can be set up on a part. All of these changes can be indicated by distinguishing sub-milies on the entity. Hydrographic entities are broken down into two types: — linear hydrographic entities or streams, — surface hydrographic entities corresponding to bodies of water and linear entities whose wide areas (above 50 metres) are represented by surface elements. A surface hydrographic entity may be traversed by a watercourse, which will be called the main watercourse. Each entity shall be identified by a unique generic code at national level. This alphanumeric code on 8 positions consists of dashes and characters. For example, a water course that crosses multiple zones or subsectors will have a generic code in the format of the following generic codes "V12-4000" or "R5--0420" (see below for the construction rule). In addition, a hydrographic entity has a so-called main denomination. Rule for constructing the generic code of the hydrographic entity: Each hydrographic entity shall be assigned a unique 3-digit (5, 6 and 7th character) number for the environment and the river basin area(s) to which it belongs: it is the number of the hydrographic entity. A hydrographic entity belonging to more than one zone retains its number d' entity in all the areas concerned. Two hydrographic entities d' the same medium belonging to two different sub-milies will have numbers of #x27; separate entity. The first four characters of the generic code correspond to all the invariant codes of the river basin areas, the rest of the characters being replaced by dashes ‘-’. For example, the “Viveronne” watercourse has the entity’s number: 050 and for middle code: 0. This watercourse is located within a single hydrographic area: P737. Its generic code is therefore: P7370500 The river “La Dronne” has the entity number: 025 and for middle code: 0. This watercourse crosses several hydrographic areas (even several sub-sectors): P746, P744, P742, P70, P734, P731, P730, P716, P715, P714, P711, P710, P702, P701, P700. Of these codes, only the two characters are invariant. Its generic code is therefore: P7--0250 Similarly, the Garonne has as its entity number: 000 and for middle code: 0. This course runs through several hydrographic areas (starting with “0”. Its generic code is: 0---00000 __Origin__ Updated by l'IGN following requests from Agences de l'Water according to an annual cycle. The consolidated version is then sent to the Sandre. __Partner organisations__ Ash, Agence de l'eau Adour-Garonne, Agence de l'eau Artois-Picardie, Agence de l'eau Loire-Bretagne, Agence de l'eau Rhine-Meuse, Agence de l'Rhone-Méditerrannée water and Corsica, Agence de l'eau Seine-Normandie __Links annexes__ * [see scenario d' geographical exchange of the hydrographic reference](http://www.sandre.eaufrance.fr/urn.php?urn=urn:sandre:scenario-d-echanges-geographique:eth:FRA:::ressource:1:) * [see interactive dictionary online](http://id.eaufrance.fr/ddd/ETH/2002-1#CoursEau) * [see Dictionary & Hydrographic Reference (ETH)" on the Sandre website](http://www.sandre.eaufrance.fr/?urn=urn:sandre:notice:dictionnaire::theme:ETH:ressource:2002-1:::html) [See this page on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/ee5c709c9b7ff928ab2529b79ce6e879c4de6950)