River Axe Nutrient Neutrality Calculator

Stuck behind a River Axe nutrient condition?

The River Axe, running through Somerset, Devon and Dorset, is a phosphorus catchment where new dwellings may need to demonstrate phosphorus neutrality.

If your site drains to River Axe SAC, the planning authority can't grant permission until you've shown the scheme is nutrient neutral — that it won't add phosphorus to a catchment that's already overloaded. NutrientMonkey gets you the number: build the assessment on screen, watch your budget in kg/year update as you go, and export the planning-ready report when it's right.

Which nutrient applies here

The Axe is assessed for phosphorus, which threatens its protected chalk-stream and wetland habitats. That matters, because the methodology and the credits differ by nutrient — and neighbouring catchments often differ. NutrientMonkey flags the River Axe catchment for phosphorus and locks the tool to match, so the assessment is right from the start.

Credits in the River Axe catchment

There is currently no credit scheme here — Dorset Council confirms no nutrient credits are available for the River Axe, so mitigation has to be arranged bespoke for each scheme (for example on-site measures or a private land-based agreement).

One credit is 1 kg of nutrient/year. The number you need is your governing budget — the greater of the pre- and post-2030 figures, floored at zero. NutrientMonkey shows this live so you can gauge how much mitigation you'll need before you commit. Scheme availability and prices change — always confirm the current position with the provider or your planning authority.

How the River Axe calculator works

1. Pick River Axe from the catchment list — it's pre-flagged for phosphorus.
2. Enter the dwellings & waste water — occupancy, water use (125 or 110 l/p/d plus NE's allowance) and the drainage route (septic, package plant or mains permit).
3. Add land use & SuDS — current vs future land cover and any sustainable drainage, with editable export coefficients for the Somerset, Devon & Dorset catchment values.
4. Export when ready — a branded, planning-ready PDF with the budget in kg/year and every input documented.

Honest about what it is

This is a nutrient-methodology assessment built to support your River Axe planning application — fast, clear and ready to discuss with your case officer. The official Natural England catchment calculator remains the statutory tool, and your figures should reproduce in it; the report states this plainly. Want it handled end to end? We also prepare nutrient neutrality assessments for River Axe as a service — we run the budget, size the mitigation and produce the report your ecologist and case officer sign off. Tell us about the site and we will quote, usually the same day.

Frequently asked questions

In a different catchment?

NutrientMonkey covers every Natural England catchment. If you are not certain which one a site falls in, the catchment map shows all 27 on one map of England, coloured by the nutrient that applies.

Or jump to another part of the country:

• Poole Harbour N
• Solent N
• Tees (Teesmouth) N
• Lindisfarne N
• Stodmarsh N & P
• The Broads N & P
• River Wensum N & P
• Chesil & the Fleet N & P
• Hornsea Mere N & P
• Oak Mere N & P
• Rostherne Mere N & P
• West Midlands Mosses N & P
• River Clun N & P
• River Avon (Christchurch) P
• Somerset Levels & Moors P
• River Itchen P
• River Camel P
• Derwent & Bassenthwaite P
• River Eden P
• River Kent P
• River Lambourn P
• River Lugg P
• River Mease P
• Esthwaite Water P
• Peak District Dales P
• Roman Walls Loughs P

Or go back to the main NutrientMonkey calculator.

Wider planning support

Nutrient neutrality is rarely the only condition on a scheme. Our energy statements service and the wider SAP & compliance team cover the rest of the planning and Building Control picture — get a quote and we'll talk it through.