Opens NutrientMonkey. Pick The Broads & Wensum SACs from the catchment list and the nutrients lock to match.
Stuck behind a River Wensum nutrient condition?
The River Wensum — a protected Norfolk chalk river running through Fakenham and Norwich — is a dual-nutrient catchment. Its nutrient assessment is now run through Natural England’s combined Broads & Wensum calculator.
If your site drains to River Wensum SAC, 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 Wensum SAC itself is designated for phosphorus, but because the river drains on into the nitrogen-and-phosphorus Broads system, developments here are assessed for both nutrients — which is why Natural England merged the Wensum calculator into the combined Broads & Wensum one. That matters, because the methodology and the credits differ by nutrient — and neighbouring catchments often differ. NutrientMonkey flags the River Wensum catchment for both nutrients and locks the tool to match, so the assessment is right from the start.
Credits in the River Wensum catchment
Norfolk Environmental Credits covers the Wensum with the same pricing as the Broads: permanent credits £5,420–£8,220 + VAT per 0.1 kg of phosphorus (banded by the site’s P:N ratio — roughly £54,200–£82,200 per kg P/year), nitrogen mitigation included; temporary credits (£4,250 + VAT per 0.1 kg, about £42,500 per kg P/year) are available in the lower Wensum only. Mitigation is geographically constrained — phosphorus mitigation must sit upstream of the impact — so confirm eligibility and availability with the scheme. Wendling Beck also offers private credits on application.
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 Wensum calculator works
- Pick The Broads & Wensum SACs from the catchment list — it's pre-flagged for both nutrients.
- 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).
- Add land use & SuDS — current vs future land cover and any sustainable drainage, with editable export coefficients for the Norfolk catchment values.
- 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 Wensum 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 Wensum 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
Which nutrient applies in the River Wensum SAC catchment?
The Wensum SAC itself is designated for phosphorus, but because the river drains on into the nitrogen-and-phosphorus Broads system, developments here are assessed for both nutrients — which is why Natural England merged the Wensum calculator into the combined Broads & Wensum one. A compliant scheme has to be neutral for both nutrients. NutrientMonkey locks the nutrient toggle to match the River Wensum catchment automatically, so you can't pick the wrong one.
Is the River Wensum 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 River Wensum 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. 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
- 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 Axe 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.