Our catchment areas

We used data and maps from Natural England and Wessex water to create catchment areas maps. You can use these maps to see all the areas where you may need to consider mitigation. 

You will need to mitigate in the catchment areas for developments that will: 

  • increase overnight stays, such as homes, hotels and campsites 
  • attract large numbers of people such as tourist attractions 
  • cause significant discharge of wastewater such as industrial processes 
  • increase agricultural activity such as new cattle barns 

You will need to provide mitigation if: 

  • your development is in these catchment areas 
  • wastewater from your development will enter these areas

Temporary or short term mitigation helps mitigate the short-term impact of developments up until 2030. It can be useful where the nutrient impact will vary over time. You may also need permanent or long term mitigation. This will help address the impact of your development over its lifetime.

Poole Harbour Catchment

Register your interest in buying temporary nitrogen credits

We are selling temporary nitrogen credits in the Poole Harbour catchment area. You can use these credits to mitigate your developments impact up to 2030. You may have separate budgets pre-1 April 2030 and post 1 April 2030. Read our guide on temporary nutrient credits for more detail.

The window for expressions of interests for round 1 has now closed. However, there will be another application round open from 11 June until 8 July 2025.

Temporary Credits

Before you start

Each whole credit costs £617. 

If your budget requires part of a credit, the price will be calculated to the nearest pound based on what you need. For example, 0.5 of a credit will cost £309.

We measure nitrogen in kilograms (kg) of Total Nitrogen (TN) per year (yr) or kg TN/yr for budget calculations.

Before you register your interest, you will need:

  • to read our guide on the difference between temporary and permanent credits
  • your planning application number
  • a nitrogen budget agreed by us and Natural England
  • your proposed permanent credits value. We will need this as a post 2030 kilograms of total nitrogen per year (kg TN/yr) figure
  • payment ready for as soon as the sale is confirmed. Credits cost £617 each. If delayed, the credits may be offered to other applicants

What happens next 

We will process applications in and confirm after that if you have secured the credits.
Once you have registered your interest, we will:

  • send you a confirmation email
  • review your proposal 
  • check your nutrient budget 
  • confirm if have successfully secured the credits
  • complete the sale and take payment

Permanent Credits 

Permanent nitrogen mitigation credits for Poole Harbour 

We do not currently have any permanent mitigation credits for sale. This page will be updated when credits become available in the future.

Natural England are selling some permanent nitrogen mitigation credits. Find out more about the next round of credit sales on Natural England’s website.

There may also be other nitrogen mitigation credit providers operating in the catchment.

Available credits from other organisations 

There are credit schemes available in other catchment areas. We are not a part of these schemes so you will need to contact the organisation running them.

Somerset Levels and Moors - Parrett Catchment 

The providers below offer phosphate credits for development in Dorset located in the Parrett Catchment.

  • Burrow Environmental - offsetting@burrow-environmental.com
  • Natural Capital - enquiries@naturalcap.co.uk
  • WCI - nutrientneutrality@wci.co.uk
  • Corton Ridge Ltd - westdownfarm@outlook.com

For other Phosphate credit providers for areas not within Dorset please contact Somerset Council about the Somerset Levels and Moors area.

River Avon

  • Environmental Farmers Group - tvacher@fwct.org.uk
  • Pennyfarthing Homes - benarnold@pennyfarthinghomes.co.uk 

River Axe

  • There are currently no credits available

Chesil and the Fleet

  • There are currently no credits available

Mailing List

Nutrient credit schemes may become available in the future. Subscribe with us if you would like to be notified when schemes become available in any of our catchments.