The ownership of roadside ditches is usually the adjacent landowner.
The owner of the ditch has a responsibility to maintain the ditch, and ensure that water can flow unobstructed.
Adjacent owners should not carry out any other work on the ditch, which would interfere with its proper operation, or restrict road surface water draining into it.
Any proposals to put a pipe in a ditch, or otherwise alter it will require land drainage consent. Completed land drainage consent forms should be sent to email@example.com.