Our Spring 2025 Consultation

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Our Spring 2025 Consultation ran from 5 March to 4 April 2025. We'd like to thank everyone for their feedback. Whilst the Spring 2025 Consultation is now closed, you can still access and read all of the consultation documents in the document library.

The consultation closed at 11:59 on 4 April 2025

Overview

At the Summer 2024 Consultation, we explained that extensive water quality modelling was being undertaken and that the outputs of the modelling and assessment of effects would be fully reported in the Environmental Statement with our Development Consent Order application.

This modelling had since progressed, so we took the opportunity to share this updated information, alongside a number of Project design refinements. Specifically, our Spring 2025 Consultation focused on:

  • Predicted water quality impacts on the Havant Thicket Reservoir, connected downstream water bodies (including Riders Lane Stream, Hermitage Stream, and Langstone Harbour), and the Solent. Scroll down for more information and to view our Environmental Water Quality Report.
  • Proposed refinements to the design of the Project that take into account feedback from the Summer 2024 Consultation and on-going project development and stakeholder engagement, details of which can be found below and in the Consultation Information document.

Environmental water quality

Feedback to our Summer 2024 Consultation highlighted concerns about the impact of the Project on water quality in the environment, especially within Havant Thicket Reservoir and the Solent. The concerns mostly related to the water recycling process and the quality of the purified recycled water.

In response to this, we shared our Environmental Water Quality Report which provides updated information on our latest water quality modelling and assessment work. We wanted to let you know what this work was telling us and what we are doing about it.

In summary, the report predicts that there would be some limited changes to water quality in Riders Lane Stream and Hermitage Stream (both downstream from Havant Thicket Reservoir) but that these changes are unlikely to result in any adverse impacts on biodiversity. Changes in water quality in Langstone Harbour (fed by Riders Lane and Hermitage Streams) would be very small and again are not expected to have any impact on biodiversity. The report also confirms that reject water from the water recycling process, which will be released into the Solent, is unlikely to affect water quality or the biodiversity of the Solent.

Within Havant Thicket Reservoir, the report predicts that the level of phosphorous in the purified recycled water could encourage algal growth, which could potentially limit biodiversity in the reservoir. Our Development Consent Order application will therefore include measures for reducing phosphorous as part of the water recycling treatment process. The Environment Agency, our environmental regulator, will stipulate an Environmental Permit that sets the water quality requirements of the purified recycled water that can go into the reservoir including for phosphorous. We are working with the Environment Agency to determine how these measures are best introduced. Details of this, together with any further modelling and assessment work, will be set out in full in our Development Consent Order application later this year.

Environmental Water Quality Report

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Design refinements

We proposed 25 Project design refinements. Many of the changes we proposed were localised and the Project as a whole has not fundamentally changed..

Each design refinement has an information sheet which details the proposed change, explains why we proposed the change, and how the change may affect the environment and the local community. We produced plans showing the Summer 2024 Consultation design alongside the proposed design refinement.

Below is our design refinements overview map. Each number labels the location of an individual design refinement, numbering 1 to 25. The information sheets provide further detail on each of these design refinements. They should be read alongside the Introductory Information sheet which provides some background information about the design refinements.

Design refinements introductory information

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