Outfalls/intakes

Outfalls and intakes mark points of discharge to, or abstraction from, watercourses. They are classified according to size, so this means that associated aprons, wing-walls and bank protection measures are included as part of the structure. Examples include abstraction intakes, sewer discharges, side weirs and sluices.


Major: permanent structures occupying >=25m of bank-length.

Major water abstraction point (intake)


Intermediate: permanent structures occupying 10-25m of bank-length.

Intermediate outfall

Minor: permanent structures occupying <10m of bank-length. Includes flap valves on feeder streams.

Minor outfall

Do not include agricultural land drainage pipes (typically <150mm diameter).