Guidance

Water grants 2015: installation of piped culverts in ditches (RP6)

Eligibility and requirements to install piped culvert in ditches.

This guidance was withdrawn on

Capital items for improving water quality are now available through the Mid Tier of Countryside Stewardship.

Farmers and other land managers can apply for water grants.

Read the accompanying guidance to find out more about Countryside Stewardship water grants 2015.

How much will be paid

£340 per unit.

Where the item is available

This item can be used:

  • in areas that are affected by water pollution caused by farming;
  • to divert water flow under a track used to take farm machinery or livestock onto land;
  • to provide access to fields in an agreement; or
  • to minimise traffic or livestock movement though the water-course.

When this item can’t be used

This item can’t be used if it:

  • is managed under another agri-environment scheme;
  • might drain or change water levels in habitats designated as:

    • Sites of Special Scientific Interest
    • County Wildlife Sites
    • Sites of Nature Conservation Interest
  • is on waterlogged land that isn’t linked to an agri-environment agreement;
  • causes known archaeological features to dry out;
  • is used to replace existing culvert structures;
  • damages environmental or historical features; or
  • restricts the movement of migratory fish or eels.

How this item will benefit the environment

This item will reduce erosion on watercourse crossings. If successful, this item will lead to:

  • an adequate flow of water;
  • runoff of expected flows diverted under a track so farm machinery and livestock can cross; and
  • farm machinery or livestock crossing tracks safely.

Requirements

Get advice and consents before applying

Before applying, applicants will need to consult with the Environment Agency (EA) to check if they need land drainage consent to work in the watercourse or main river. Make sure to send a copy of the EA’s advice and consent with the application for this item. If needed, get and send advice and consent from the:

  • flood defence consenting authority;
  • local planning authority; or
  • internal drainage board.

See the advice on flood defence consent for more information.

Applicants will also need to send dated photographs of the existing site with their application for this item.

With permission from Natural England, advice and consent can be received up until 29 May 2015; applicants can discuss this with their local Catchment Sensitive Farming officer.

On the land

Successful applicants will need to make sure:

Lay the pipes

These specifications are dependent on the weight of machinery crossing the culvert. Successful applicants will need to get advice from a drainage or bridge engineer before starting this work. Successful applicants will also need to:

  • install a concrete or twin wall (twin-walled extruded plastics) pipe that’s at least 450mm in diameter;
  • ensure that pipes have a positive joint to preserve alignment;
  • make sure that the pipe lengths give a width at ground level that’s appropriate for the normal traffic using the crossing, with the minimum width for a culvert:

    • 4m for wheeled traffic
    • less than 4m acceptable for footpaths and bridleways;
  • set the pipes on a firm bed and in true alignment;
  • make sure that the pipe gradient is approximate to that of the ditch bed;
  • make sure that the pipe invert (the level of the inside bottom of the pipe) at the upstream end is fractionally below the bottom of the true ditch bed;
  • grade the ditch bed downstream if any deepening is needed to accommodate the culvert; and
  • maintain the culvert for the duration of the agreement, removing debris that builds up so as to maintain flow.

Keeping records

Successful applicants will need to keep:

  • a series of before, during and after dated photographs to show each stage of the work (submit these for verification and control purposes);
  • any relevant consents or permissions relating to this work; and
  • receipted invoices and bank statements relating to this work.

What must be done

Don’t use construction spoil to fill and level on or next to sites of archaeological or ecological importance.

How to carry out this item

The following section gives advice on carrying out this item successfully.

Consider location and alignment

Successful applicants should:

  • avoid active river areas, particularly meander bends;
  • avoid depositional areas;
  • make the crossing perpendicular to the river;
  • consider floodplain crossings;
  • reduce the risk of pollution (such as the release of fine sediments) to protected species and their habitats; and
  • check if they need to minimise erosion; if so erect protection measures (such as stone pitching or slabs) downstream of the culvert and on the sides of the ditch as needed.

Embedding and maintaining culverts

Successful applicants should:

  • pack stone-free filling tightly at the sides of the pipe and at least 300mm above it;
  • build up the filling in layers up to 150mm thick, making sure it’s thoroughly consolidated before adding the next layer;
  • follow the manufacturer’s guidance on how deep to cover backfill; and
  • leave the finished backfill surface so it’s crowned above the surrounding levels.

Consider using a concrete pad to stabilise the bridge or track over the culvert. Make sure the pad is at least 150mm thick, adding an extra 300mm if the total depth of fill cover over the pipes is less than its diameter.

For twinwall pipes:

  • place fill material evenly on both sides of the pipe and compact it at least 100mm above the pipe crown;
  • keep backfill material on headwalls, either side of the pipe to ease load pressure from traffic crossing over it; and
  • key (fasten) headwalls into each bank at least 450mm along the height of the whole culvert structure (including the pipe, bedding, cover and concrete pad).

Try using sloping earth ends as headwalls where appropriate, with the slopes no steeper than 1 in 5. There should be a 1m extension on either end of the culvert beyond the required width of expected traffic.

This item can be used on the same area as Livestock and machinery hardcore tracks (RP4).

Published 2 March 2015