RP10: Silt filtration dams or seepage barriers
Source: gov.uk (2025-02-03)

Find out about eligibility and requirements for the silt filtration dams or seepage barriers 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

£198.14 per unit.

How this item benefits the environment

Silt filtration barriers and seepage barriers slow the movement of water in ditches to allow pollutants to settle to the bottom. This helps improve water quality and may reduce downstream flooding. Preventing sediment being carried and deposited into water (due to surface runoff) also helps improve water quality.

This item can help you protect, recover and improve biodiversity on your land.

Where you can use this item

You can only use this item in ditches alongside a feasibility study, implementation plan or a Catchment Sensitive Farming water holding structure action plan developed with Natural England either:
- in areas targeted to reduce water pollution from agriculture
- to reduce flood risk
- in catchments where permeable soils and geology allow for recharge of groundwater
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 consents from the Environment Agency, (https://www.gov.uk/guidance/check-if-you-need-an-environmental-permit) lead local flood authority or internal drainage board (https://www.ada.org.uk/member_type/idbs/) before you start any work.

You must also contact your local planning authority to check if planning permission is needed.

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

You must complete the construction as set out in your approved feasibility study, implementation plan or Catchment Sensitive Farming water holding structure action plan developed with Natural England.

Evidence you must keep

You must also keep and provide with your claim:
- photographs of the completed work
- 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
- a copy of your feasibility study, implementation plan or Catchment Sensitive Farming water holding structure action plan developed with Natural England
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 items you can use with this item

You can use this item with these items:

RP7 Sediment ponds and traps (https://www.gov.uk/countryside-stewardship-grants/sediment-ponds-and-traps-rp7)

RP8: Constructed wetlands for the treatment of pollution (https://www.gov.uk/countryside-stewardship-grants/constructed-wetlands-for-the-treatment-of-pollution-rp8)

RP11: Swales (https://www.gov.uk/countryside-stewardship-grants/swales-rp11)

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.

The feasibility study, implementation plan or Catchment Sensitive Farming water holding structure action plan developed with Natural England should include site-specific guidance for locating and constructing the barriers. It’s likely you’ll need several barriers to successfully slow down the flows throughout the length of the water course.

Designing and constructing the dams or barriers

The design of the structure and the materials you use will depend on the conditions set out in the plan. You could use a range of materials including:
- timber piling or horizontal planks (with gaps between the boards to allow water flow)
- stone filled gabions
- recycled plastic drainage material (for example Aquadyne)
- willow stakes and woven branches for a more natural appearance
- dams that allow for overflows in the centre – this prevents scouring of the ends of the barrier or dam
Using willow stakes will help anchor the structure, as the willow may grow. This style of construction may not last very long so allow time for repair or reconstruction.

The main function of the barrier is to slow, clean and filter water flow through ditches or temporary water-holding features, rather than dam and hold water. Other capital items are available to dam or hold water.

Removing trapped silt

You should monitor and remove trapped silt at least once a year and deposit reapplying it back to the field. Carry out maintenance carefully and regularly to avoid polluting sensitive bodies of water downstream or sensitive habitats on land.