This document sets out the policy of the Black Sluice Internal Drainage Board on culverting.
The Environment Agency issued a Policy Statement on culverting in March 1999. This is a national Policy and the Board's policy is specifically applicable to a lowland Drainage Board area.
Black Sluice IDB considers that it is beneficial for watercourses to remain open wherever possible for both drainage and environmental purposes.
Culverting can exacerbate the risk of flooding and increase the maintenance requirements for a watercourse. It also destroys wildlife habitats, damages a natural amenity and interrupts the continuity of the linear habitat of a watercourse.
It is sometimes preferable to culvert watercourses in urban areas as these are more likely to become blocked with domestic and industrial waste and have little environmental interest.
Black Sluice Policy
The Black Sluice IDB will generally oppose culverting of long lengths of watercourses in rural situations.
The Black Sluice IDB will therefore only approve an application to culvert a watercourse if it can be justified that there is no reasonable loss of amenity or habitat.
Reasons for the Policy
The Environment Act 1995 places both general and specific duties on the Black Sluice IDB relating to environmental, recreational and nature conservation matters. The Black Sluice IDB must be mindful of these duties. The detrimental effects of culverting watercourse:-
- Loss of and adverse effects on environmental features and wildlife habitat;
- Increased likelihood of flooding due to blockage;
- Loss of floodwater storage;
- Increased difficulties in providing drainage connections;
- Difficulties in the repair, maintenance and replacement of culverts;
- Increased health and safety hazards;
- Increased difficulty in detecting the origins of pollution.
It is recognised that there are situations where culverting may be unavoidable such as short lengths for access where highways cross watercourses, and longer lengths in urban areas. In all such cases the Board will only consent to the culverting if the size of pipe will place no restriction on the flow of water in that watercourse, and where appropriate there are no environmental damages.
The applicant will, except in the circumstances of short lengths for access purposes, need to provide a short environmental assessment to demonstrate that there will be no loss of wildlife habitat.
Consent for Works
Consent is given in accordance with the Land Drainage Act 1991 and is required for any works, including culverting, which are to be carried out in either a Board maintained or a private watercourse. Further consent is normally required from the District Council under the Public Health Act 1936.
The Board will only issue consent to culvert a watercourse if the applicant can demonstrate that the benefits outweigh all of the possible detrimental effects mentioned above. The Board will not only take into account the implications to water flow but also environmental detriment. If consent is given it will normally be subject to meeting various conditions and specifications.
Consent does not override an adjacent landowners' rights nor does it permit interference with legally protected wildlife habitats (e.g. SSSI's, vole habitats, badger sets etc).
Consent may not be unreasonably withheld. There is an arbitration procedure should the applicant wish to appeal against a refusal or what they believe to be unreasonable conditions.
Further information and application forms are available from the Board.