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Nutrient neutrality advice in the Lenham area

Planning applications or proposals

In July 2020, Natural England issued water quality advice that had an immediate impact on planning applications for new homes or other forms of overnight accommodation in and around both Lenham and part of Boughton Malherbe Parishes. The source of the river system of the Stour Valley river catchment is in Lenham with part of the upper section of the Great Stour being in Maidstone Borough. Additional advice was issued by Natural England in November 2020.

A comprehensive review of the advice was issued in March 2022.

Water quality advice

Natural England has said that an appropriate assessment must be carried out before we can agree any new housing development or any other type of development likely to have a significant adverse impact on water quality in the River Stour catchment.

This assessment must include any necessary mitigation measures. This is to ensure that new residential development  or overnight accommodation does not cause any further deterioration of water quality at Stodmarsh in terms of nitrate and phosphate discharges. This is called 'nutrient neutrality'.

The Stodmarsh Nature Reserve is protected under European Law and is managed by Natural England. Natural England has identified that the water quality in the lakes has deteriorated. The water quality targets have also recently been tightened.

Please note these documents may not meet accessibility guidance as they have been created by Natural England.

Previous Natural England advice

Ciria guidance

We would also suggest reading the sustainable drainage systems (SuDS) documents which were published by Ciria in 2022 and 2023 that relate to reducing phosphorus and nitrogen pollution.

The Stour operational catchment

The advice applies to the Stour Valley river catchment area which covers this eastern area of the borough principally much of Lenham and part of Boughton Malherbe Parishes.

It also applies to developments outside of the Stour Valley river catchment area, including those which would connect (directly or indirectly) to a Waste Water Treatment Works (WWTW) which discharges into the Stour Valley. This includes Lenham WWTW.

What you need to do

We are currently investigating possible solutions a strategic solution is being developed in conjunction with Kent County Council and Natural England. This is expected to be published in Winter 2023/2024.

Work on this was delayed August - November 2023 due to prospective national legislation on the matter, which is no longer being proposed.

However, we will be taking a precautionary approach and will require 'shadow' appropriate assessments for any planning applications including those not yet determined.

If you have a planning application currently under consideration you should:

  • first read the advice from Natural England
  • then speak with the planning case officer to discuss any suggested mitigation
  • if you wish to submit mitigation for phosphorus or nitrogen using SuDs, you may need to pay us to have that SuDS strategy independently assessed

If you are thinking of submitting a planning application, you can: