The undertaker must take all reasonably practicable measures to prevent the permanent disturbance of artificial or natural drainage systems/paths. Where disturbance does occur, it must be notified immediately to the owners of the system and any landowners who are affected. Disturbed systems must be restored to the requirements of the owner; see S11.4.
For any works site where the authority is aware of a history of flooding or drainage problems, it should inform the undertaker in advance. In such situations the undertaker and the authority should liaise closely to identify a suitable method of working.
If site conditions indicate to the undertaker that the use of some reinstatement materials may be detrimental to drainage, advice on the selection of suitable materials should be sought from the authority.