Chesil & the Fleet Nutrient Neutrality Calculator

Work out your scheme's nitrogen and phosphorus budget for the Chesil & the Fleet SAC / SPA / Ramsar catchment — free, live, in your browser. Full Natural England methodology with the 20% buffer.

NitrogenPhosphorus Dorset
Launch the Chesil & the Fleet calculator — free, no sign-up

Opens NutrientMonkey. Pick Chesil & the Fleet from the catchment list and the nutrients lock to match.

See a sample report (PDF) →

Stuck behind a Chesil & the Fleet nutrient condition?

Chesil Beach and the Fleet lagoon on the Dorset coast form a sensitive dual-nutrient catchment, where new development may need to show neutrality for both nitrogen and phosphorus.

If your site drains to Chesil & the Fleet SAC / SPA / Ramsar, the planning authority can't grant permission until you've shown the scheme is nutrient neutral — that it won't add both nutrients 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 Fleet is a rare, near-enclosed lagoon, so it’s assessed for both nitrogen and phosphorus to protect its unusual habitats. That matters, because the methodology and the credits differ by nutrient — and neighbouring catchments often differ. NutrientMonkey flags the Chesil & the Fleet catchment for both nutrients and locks the tool to match, so the assessment is right from the start.

How the Chesil & the Fleet calculator works

  1. Pick Chesil & the Fleet from the catchment list — it's pre-flagged for both nutrients.
  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 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 Chesil & the Fleet 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? That's what we're here for.

Frequently asked questions

Which nutrient applies in the Chesil & the Fleet SAC / SPA / Ramsar catchment?

The Fleet is a rare, near-enclosed lagoon, so it’s assessed for both nitrogen and phosphorus to protect its unusual habitats. A compliant scheme has to be neutral for both nutrients. NutrientMonkey locks the nutrient toggle to match the Chesil & the Fleet catchment automatically, so you can't pick the wrong one.

Is the Chesil & the Fleet calculator free to use?

Yes — selecting the catchment, entering your dwellings and watching the budget update in kg/year is completely free. You only pay £79 +VAT (£94.80 inc VAT) to export the planning-ready PDF report.

How is the Chesil & the Fleet nutrient budget worked out?

It follows Natural England's published nutrient-budget methodology — waste water, current and future land use, SuDS, then the final budget with the ×1.2 (20%) precautionary buffer. For new homes the waste-water term does most of the work and is computed exactly.

Is this the official Natural England calculator?

No — it's a fast, planning-support assessment that implements NE's methodology, and the report says so. The official NE catchment calculator remains the statutory tool, and your figures should reproduce in it.

In a different catchment?

NutrientMonkey covers every Natural England catchment.

Also in the Dorset area:

Or jump to another part of the country:

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.

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