Main river map
The main river map shows which rivers in England are designated as ‘main rivers’. Other rivers are called ‘ordinary watercourses’.
The main river map also shows where the Environment Agency intends to make changes. These are highlighted as ‘additions’ and ‘deletions’.
Main rivers are usually larger rivers and streams. The Environment Agency carries out maintenance, improvement or construction work on main rivers to manage flood risk.
Lead local flood authorities, district councils and internal drainage boards carry out flood risk management work on ordinary watercourses.