What are IDBs responsible for?

IDBs’ primary role is to manage water levels and reduce the risk from flooding within their districts. Much of their work involves the maintenance and improvement of watercourses and related infrastructure such as pumping stations, weirs, sluices, culverts and embankments within their drainage districts.

Under the Land Drainage Act 1991, each IDB exercises a general power of supervision over all matters relating to water level management within its district. In pursuance of this role they can prohibit the obstruction of watercourses within their district. Thus, anyone constructing or altering a weir, bridge, embankment, culvert or similar obstruction must first seek the consent of the IDB before undertaking works. IDBs also have a series of bylaws relating to the management of watercourses and can designate features and structures within their district which relate to managing flood risk. A designation prevents the owners from altering, removing or replacing the structure or feature without the consent of the IDB.

IDBs input into the planning system by facilitating the drainage of new and existing developments within their districts, and advising on planning applications, specifically the use of sustainable urban drainage systems (SuDS).

IDBs conduct their work in accordance with a number of general environmental duties and promote the ecological wellbeing of their districts. They have a specific duty to further the conservation and enhancement of all designated environmental sites within their districts such as SSSIs.

Some IDBs may also have other duties, powers and responsibilities under specific legislation. For instance the Middle Level Commissioners and Witham Fourth District IDB are also navigation authorities. During drought IDBs play a key role in keeping water levels higher and facilitating the transfer of water.

Defra is the Government department responsible for IDBs and the work of an IDB is closely linked with that of the Environment Agency and Lead Local Flood Authorities (and Local Authorities over planning issues). IDBs are not, however, responsible for watercourses designated as main rivers within their drainage districts; the supervision of these watercourses is undertaken by the Environment Agency.