Section 5.7 - Works adjoining main watercourses

5.7.1 Introduction

This section relates to obtaining authorisation from the Environment Agency. With regard to the design details of structures and other works the relevant sections of this guide must also be consulted.

All works (structures, surfacing, etc.) within eight metres of a 'main watercourse' MUST be authorised in advance by the Environment Agency (EA). This often leads to a delay, and therefore all such works should be planned, and consent applied for, well in advance.

The classification of a river, stream, or ditch as a 'Main Watercourse' is made by the EA , and includes all rivers, plus most named and many un-named streams and ditches. Many small ditches and winterbournes, which are dry for 11 months each year, are included in this category. It is, therefore, necessary to check with the EA whether a stream is included or not. A GIS layer is available to officers, check GEOGIA for further details.

Works for which permission is sought include structures over the watercourses, e.g. bridges, culverts; works to the bank; surfacing on paths within the 8 metres; and any other works within this distance from the watercourse, presumably including stiles, gates, waymarks, etc. Permission must be sought even if the work is simply a like-for-like replacement.

Care must be taken whenever possible pollutants, e.g. paints, preservatives, etc., are used near a watercourse to avoid these substances getting into the water.

5.7.2 Pre-Application Form Negotiation

The Environment Agency is now insisting on a formal application procedure for almost all such works. This involves extensive discussions before the application form is completed. Detailed scale plans of the site, including levels, must be prepared, showing the river and its banks as well as the designs for the works to be completed. These must be submitted in triplicate, with an explanation of what the works are and why they are required.

Preparation of the site plans and designs can be completed by Mouchel/TSC (contacts: Tony Furse [Surveyors] and Jeremy Elderfield [Engineers]). They can also conduct the technical part of the negotiations with the EA, but their charges are substantial. It is best not to nominate Mouchel/TSC as 'Agents' on the application form in order that application forms and permission are sent direct to HCC.

A site meeting with the development control engineer considering the application is usually a good idea, but is now rarely possible. The EA is likely to consult their ecologist, and his/her presence at any site meeting would be a good idea.

Only once all the details have been agreed, will the Environment Agency send an application form to be completed. These contain their reference for the case and is on tinted paper to prevent photocopying. Photocopied versions of the form are not acceptable, and the EA will not supply a stock of forms in advance of this point being reached.

5.7.3 Bridges/Culverts

No structures on the ground surface are normally permitted within one metre of the banks of a watercourse. This is to prevent the narrowing of the channel and to allow for floodwater. Therefore the supports for a bridge, for example, must be set this distance back from the watercourse. Thus a three metre bridge is required to cross a one metre ditch. The exact location of the bank is often difficult to define where, for example, the land slopes down gradually into the watercourse, or where a previous structure has prevented erosion which has occurred on either side. In addition, where a watercourse regularly floods, the EA may define it as including the floodplain. It is not normally possible to define the bank for this purpose in a former location where the bank has since been eroded.

All structures over a watercourse must be at least one metre above the level of the banks. This again brings the problem of defining the bank height. In addition, it means that steps or ramps normally have to be provided to get users up onto the bridge. Two parapets are normally provided where the drop from decking to the bottom of the watercourse is over 1.5 metres, and this will now normally be the case.

These last two requirements mean that all future bridges will be considerably larger, more expensive, and more intrusive than hitherto, bringing the potential for criticism from local residents, landholders, and parish/county councillors. It is necessary, therefore, to explain to these parties the reasons for the design, preferably in advance.

Culverts/pipes are not normally acceptable to the Environment Agency, and must be large enough to take the maximum-recorded/predicted flow of a watercourse during flood conditions, plus considerable allowance for deposition of silt within the pipe.

5.7.4 Bank Restoration/Strengthening

The EA strongly prefer 'soft' solutions to bank erosion. Restoration of banks is often opposed by them on principle. Their ideal solution is to do nothing, allowing for constantly shifting banks and river course, or else to cut back into the adjoining land to provide shallow banks. It is rare that either of these solutions can be considered where public rights of way adjoin or cross a watercourse, but all other solutions must be justified against these ideals.

If banks are to be strengthened, then 'green' options are preferred by the EA, e.g. willow 'Spilling', where a living mat of willow plants is planted to retain the bank. This, is however, very expensive to create and requires some maintenance. It is possible, but more difficult, to justify hard options. Solid concrete walls or concrete bags are unlikely to be permitted, although it might be possible to use them behind a wood facing.

Re-used wood, e.g. old railway sleepers, old telegraph poles, or similar new timber is easier to justify for environmental reasons (use of recycled materials and aesthetic appeal. Gabions (cubic wire cages full of stones) may occasionally be acceptable. The EA is more likely to agree to a solution if the new bank is likely to green over quickly (i.e. vegetation grow on it).

5.7.5 Application Form (Numbering and Headings as on Form)

Details of Applicant: Give 'Hertfordshire County Council' as name of applicant. Give your name as contact.
Agents Details: Leave this blank, unless you want Mouchel/TSC, etc., to receive all communications.
Applicants Interest in Land: state: 'Highway Authority'.
Location: State parish name and path number. Remember to double-check all grid references.
Description and Purpose of Proposed Works: Give very brief description, e.g. 'bank repairs' or 'bridge replacement' and then state ' as discussed between Mr/s XX of EA and Mr/s. XX of Mouchel/TSC'.
Description and Reference Numbers of all Plans and Sections submitted: Even if, as normally will be the case, these have been submitted in advance, the reference numbers must be quoted here, or on an attached letter (one per form) with the County Council’s heading on it (not Mouchel’s headed paper, unless they have been appointed as our agents). It may be best to include a further three copies of all plans. Enclose an extract of the Definitive Map with the location highlighted and refer to this in this box.
Construction Details: These will normally be permanent. State earliest possible start date.
Other Environment Agency Interests: normally the answer will be 'no' to all of these.
If Planning Approval Has Been Granted: Planning permission is not normally necessary for our works.
Name of Person or Organisation Responsible for Maintaining the Structure on Completion: Normally Hertfordshire County Council. (Concerning a private track or stile/gate this may be shared with the landholder.)
Brief Details: State 'As previously discussed/agreed between EA and Mouchel/TSC'.
Declaration: A cheque for £50, payable to 'Environment Agency' needs to be enclosed with the application form. Arrange for this by filling in a requisition form about a week in advance. State 'Please raise cheque for £50 made payable to the 'Environment Agency' and pass to Rights of Way Section.'