RP8: Constructed wetlands for the treatment of pollution

Find out about eligibility and requirements for the constructed wetlands for the treatment of pollution item.

How much will be paid

50% of costs.

Where to use this item

Available for Higher Tier


  • in areas targeted for the reduction of water pollution from agriculture
  • to treat field and farmyard diffuse runoff
  • in conjunction with a Feasibility Study or a Catchment Sensitive Farming (CSF) commissioned design plan

Where this item cannot be used

  • to treat slurry, silage liquor, heavily fouled water, or concentrated pesticide spills and washings (as defined as such under the Nitrate Action Plan Regulations, Slurry Silage and Agricultural Fuel Oil Regulations or Health and Safety Executive)
  • on historic or archaeological features identified in the HEFER
  • without relevant advice or consents from the Environment Agency (EA), or Internal Drainage Board

How this item will benefit the environment

It will create and maintain a wetland features to treat lightly fouled or polluted water, generated from normal agricultural activities. This will help reduce the risk of sediment and other pollutants entering a nearby watercourse.


Agreement holders are likely to need to:

  • complete works according to the specification set out in the Implementation Plan or Feasibility Study and as agreed with a Natural England adviser
  • follow the instructions set in a management plan (agreed with a Natural England adviser) for constructing and maintaining the wetland area
  • get 3 quotes for completion of the work

The agreement will set out what must not be done. It is likely successful applicants will not be allowed to:

  • place spoil on any environmental, historic or archaeological feature

Keeping records

Agreement holders will need to keep the following records and supply them on request:

  • any consents or permissions connected with the work
  • please see the record keeping and inspection requirements as set out in the Higher Tier manual for more detail

Agreement holders will need to keep the following records and supply them with the claim:

  • receipted invoices, or bank statements where a receipted invoice is not available
  • 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 works in place and installed

Before applying, applicants must seek advice from the Environment Agency, Local Planning Authority and where relevant the Internal Drainage Board to check if consent is required to carry out the planned work.

Applicants will have to send the following with their application:

  • the 3 quotes for completion of the work
  • photographs of the site before the work takes place
  • a copy of any advice or consent received from the EA and (where relevant) the Internal Drainage Board
  • a copy of the Feasibility Study or CSF design plan (Water-Holding Feature Management Plan)

Advice and suggestions for how to carry out this item

The following section gives advice on carrying out this item successfully but does not form part of the requirements for this item.


A detailed specification will be produced, tailored to the site. A likely design would be a treatment structure built in at least 3 stages.

Stage 1 - The first stage is to create an open pond to act as a sediment trap without much wildlife value. The pond should be accessible to farm machinery for routine maintenance.

Stage 2 - The second stage should have some planting to encourage settlement and remove nutrients.

Stage 3 - The third stage should be a shallow wetland that is heavily vegetated to reduce pollutants in the water such as:

  • nitrates or ammonia
  • biological oxygen demand (BOD)
  • faecal indicator organisms (FIOs)

Throughout each stage:

  • restrict livestock access to reduce the risk of eroding or degrading the treatment area
  • build on a non-permeable substrate (made up of 20% clay) or line the area so that there is a permanent pool of water for most of the year
  • avoid building on sandy, gravelly and excessively wet soil in order to prevent contact with groundwater before treatment
  • build gentle slopes with a gradient of no more than 1 in 4, the edges should provide good wildlife habitat and act as a safety feature
  • make sure the pond edges are undulated to provide more edge habitat
  • make sure outlet pipes are larger than inlet pipes to prevent water backing up along the system
  • obtain a waste exemption if excavated material is to be removed (this information should be included in the agreed management plan)

Manage outfall

  • ensure any outfall of water is of high enough quality before it is discharged into the local watercourse

Applicants will need to agree acceptable water quality standard with EA before directing any outfall.

Further information

CSF operates in parts of the country where there are water quality issues linked to farming. Find out more about CSF support.

Read the constructed wetland user guide produced by the Wildfowl and Wetland Trust for further help carrying out this option.

See the Higher Tier manual to find out more about the scheme and how to apply.

Published 2 April 2015
Last updated 10 March 2017 + show all updates
  1. In 'Keeping records' section: * change to records that agreement holders need to keep and supply with a claim * change to handling of the 3 quotes for completion of the work * addition of sending photographs of site before work takes place with application
  2. Information updated for applications in 2016
  3. First published.