Buckinghamshire Council Culvert Policy

As LLFA, Buckinghamshire Council is the statutory consultee for surface water on major planning applications and as part of this role we provide comments on works relating to Ordinary Watercourses. When submitting a planning application please consider the following guidance relating to culverting an Ordinary Watercourse.

The requirement for Ordinary Watercourse land drainage consent is independent of the need for planning permission (from the Local Planning Authority) and the granting of planning permission does not imply or guarantee that consent will be granted.

Our position as LLFA is to oppose planning permission for any development which proposes a culvert where there are reasonable alternatives. Such alternative solutions might include a revised site layout or an ecologically acceptable diversion of an open channel.

Our position as LLFA is also to oppose planning permission where any proposed structure(s) are over an existing culvert, as the culvert may, in the future, need to be repaired, replaced or upgraded if conditions in the catchment change. There is also the need to maintain an overland flow route if the culvert is blocked or its capacity exceeded.

Where an Ordinary Watercourse is already culverted on a proposed site and there is opportunity to re-open the full or partial length of it, this will be encouraged by the LLFA and justification for not doing so will need to be provided as part of the planning application. Where an applicant does propose to re-open a culvert, the LLFA encourages the use of best practice guidance, for example the River Restoration Centre’s Manual of River Restoration Techniques Section 1.6 Opening up a culverted stream.

It is recommended that maintenance strips either side of open or culverted watercourses are designed for, a minimum of 9m should be given on one bank side and a more flexible approach could be taken on the other bank. The maintenance strips should not include any built development; this includes any open space furniture.