Drainage districts occur in
England and
Wales, varying in size from a few hundred acres to over , all in low lying areas of the country where flood risk management and land drainage are sensitive issues. Most drainage districts are administered by an
internal drainage board (IDB), which are single purpose local drainage authorities, dealing with the
drainage and water level management of clean water only. Each drainage district has a defined area, and the IDB only has powers to deal with matters affecting that area.