Hydrographic regions — Metropolitan 2017 — BD Carthage

The hydrographic breakdown is the four hierarchical partitions of the French territory carried out according to decreasing hydrographic areas:
— hydrographic region (1st order),
— hydrographic sector (2nd order),
— hydrographic sub-sector (3nd order),
— hydrographic area (4nd order).
A hydrographic region is divided into a maximum of 10 sectors.
The list of hydrographic regions was adopted in Circular No 91-50 of 12 February 1991 but the determination of their limits is the responsibility of the Water Agencies.