RP6: Installation of piped culverts in ditches
Source: gov.uk (2025-02-03)

Find out about eligibility and requirements for the installation of piped culverts in ditches item.

This item is part of Capital Grants 2025. You must read the Capital Grants 2025 guidance (https://www.gov.uk/government/publications/capital-grants-2025) to understand the rules and how to apply. If you’re applying for this item as part of a Countryside Stewardship Higher Tier (CSHT) application, you must read the CSHT applicant’s guide (https://www.gov.uk/government/publications/countryside-stewardship-higher-tier-csht) to understand the rules and how to apply.

How much you’ll be paid

£376.23 per culvert.

How this item benefits the environment

A watercourse crossing provides access for farm machinery or livestock. This reduces disturbance to the watercourse, so maintains flows and helps reduce sedimentation and bacterial levels in the water.

Where you can use this item

You can use this item either:
- in combination with actions or options to create, restore or manage habitats or features with the support of a Natural England adviser
- to install a new culvert or to replace an existing collapsed structure in areas targeted to reduce water pollution from agriculture
Catchment Sensitive Farming (https://www.gov.uk/guidance/catchment-sensitive-farming-reduce-agricultural-water-pollution) provides advice where there are water quality or flood risk issues linked to farming.

You’ll need to get relevant advice, permits or necessary consents from the Environment Agency (https://www.gov.uk/guidance/check-if-you-need-an-environmental-permit), local council (https://www.gov.uk/find-local-council) or internal drainage board (https://www.ada.org.uk/member_type/idbs/) before you start any work.

You cannot use this item:
- where it’ll restrict the movement of migratory fish or eels
- on historic or archaeological features identified in your Historic Environment Farm Environment Record (https://hefer-data.org.uk/) (HEFER)
- where it could damage an environmental feature identified on your Farm Environment Record (FER) or on MAGIC (https://magic.defra.gov.uk/MagicMap.aspx)
What you must do to use this item

You must install a concrete or rigid plastic twin-wall pipe either:
- according to the dimensions required in any consent or permit
- according to the dimensions agreed with your Natural England adviser when creating or restoring habitat
- at least 450 millimetres (mm) in diameter (following the manufacturer’s instructions)
You must also:
- make sure the pipes are correctly aligned to prevent leak
- make sure the pipes are wide enough for the traffic using the crossing – they should be at least 4 metres (m) wide for wheeled traffic or less than 4m for livestock footpaths and bridleways
- set the pipes on a firm bed and in alignment with each other
- make sure that the pipe gradient approximates 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
- make sure the pipes are wide enough for the watercourse to keep its natural course
- install retaining sidewalls to local style and backfill with scalpings to field level – you may also need a membrane to prevent stone washing out
- maintain the culvert for the duration of the agreement, removing debris that builds up to maintain flow
- complies with the Culvert design and operation guide (C689) (https://www.gov.uk/flood-and-coastal-erosion-risk-management-research-reports/culvert-design-and-operation-guide)
You must make sure all work meets relevant British Standards (http://www.bsigroup.com/en-GB/standards/british-standards-online-database/). You must construct culverts using concrete pipes that comply with the latest versions of BS 5911 and BS EN 1916. Lay pipework in accordance with BS 8000. You can also use HDPE rigid plastic twin-wall manufactured to BS-EN50086-2-4.

If the above standard specifications are not suitable for the weight of machinery using the crossing, you must get advice from a drainage or bridge engineer. You must follow their advice when completing the works. You’re responsible for ensuring the culvert does not collapse.

You must not place spoil on any historic or archaeological feature or wildlife area identified on your FER, HEFER or on MAGIC.

Evidence you must keep

You must keep and provide with your claim:
- photographs of the site during the different stages of construction or contracts, invoices or other documents confirming the technical specification for the completed works
- photographs of the completed work
- advice from a drainage or bridge engineer (if required)
- any consents or permissions connected with the work
You must also keep and provide on request:
- receipted invoices or bank statements where a receipted invoice is unavailable
- photographs of the site before works start
Read the record keeping and site visit requirements in the Agreement holder’s guide: Capital Grants, Higher Tier capital grants and Protection and Infrastructure grants (https://www.gov.uk/government/publications/agreement-holders-guide-capital-grants-higher-tier-capital-grants-and-protection-and-infrastructure-grants-2025) for more information.

If you’re applying for this item as part of a Countryside Stewardship Higher Tier (CSHT) application, read the record keeping and site visit requirements in the CSHT agreement holder’s guide (https://www.gov.uk/government/publications/countryside-stewardship-higher-tier-csht).

Other capital items you can use with this item

You can use this item in the same area as RP4: Livestock and machinery hardcore tracks. (https://www.gov.uk/countryside-stewardship-grants/livestock-and-machinery-hardcore-tracks-rp4)

Advice to help you use this item

The following advice may help you to use this item, but you do not have to follow it to get paid. It’s not part of this item’s requirements.

British Standards

Check to make sure the works meet relevant British Standards (https://www.bsigroup.com/en-GB/products-and-services/standards/).

What to consider when installing a culvert

When siting culverts you should:
- avoid active river areas (particularly meander bends)
- avoid depositional areas
- make the crossing perpendicular (at a 90-degree angle) to the river
- consider floodplain crossings
- reduce the risk of pollution to protected species and their habitats (for example, the release of fine sediments)
- minimise erosion by installing protection measures such as stone pitching or slabs downstream of the culvert and on the sides of the ditch (where necessary)
Embedding and maintaining culverts

You should embed and maintain the culvert by:
- packing a stone-free filling tightly at the sides of the pipe and at least 300mm above it
- building up the filling in layers up to 150mm thick, making sure it’s thoroughly compacted before adding the next layer
- following the manufacturer’s guidance on how deep to cover backfill
- leaving the finished backfill surface so it’s 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. Add an extra 300mm if the total depth of fill cover over the pipes is less than its diameter.