In 1630, King Charles I granted a drainage charter to the 4th Earl of Bedford who engaged the Dutch engineer Cornelius Vermuyden to construct the two Bedford rivers. The purpose of the new rivers was to facilitate drainage of the Great Ouse between Earith and Downham Market. The area between the rivers is 20 miles (32 km) long and almost a mile wide and acts as washland, i.e. a floodplain during the winter and, increasingly, also in summer. When they are flooded this causes a 30-mile (48 km) detour for local residents.