Council Meeting Update 09 March 2026

Stakeholder Role of Horndean Parish Council (HPC)

  1. HPC is represented on the Havant Thicket Reservoir Stakeholder Group and forwards notes of meetings and gives regular short updates at Full Council meetings.
  2. This paper is a short summary to bring together many of the issues as they stand at the current time including why the project started and some of the benefits (many of which are happening throughout the construction phases). As there can be confusion about where the Southern Water project fits into the scheme, it has been included in this summary.
  3. There is a significant amount of information about the project on the Portsmouth Water and Southern Water websites including you tube videos and an artist’s impression of the site.

Two Projects

  • Havant Thicket Reservoir is part of a wider package of work to secure Hampshire’s water supplies and protect our precious chalk streams and rivers. Portsmouth Water and Southern Water are working on linked but separate projects that will fit together over time.

Protecting the Chalk Streams

  1. Hampshire’s chalk streams are some of the rarest and most precious habitats in the world – about 85% of the world’s chalk streams are found in southern England, and they support unique wildlife.
  2. Taking too much water from chalk streams damages these fragile ecosystems, so storing surplus winter water in a reservoir reduces abstraction pressures in dry periods and helps protect the streams while still meeting demand.

What Portsmouth Water is doing now

  1. Portsmouth Water is building the new Havant Thicket Reservoir itself, along with the local pipelines between Bedhampton Springs and the reservoir.
  2. Planning permission was granted in 2021, and the scheme is now in its main construction phase: the dam and embankment works are underway, and a major 13‑metre‑high, 20‑tonne steel cut‑off wall has already been installed.
  3. The twin pipelines (one to bring surplus spring water into storage, one to take water out in droughts) were approved in 2025 and are being constructed as part of the project.
  4. The reservoir will hold about 8.7 billion litres of water – enough to supply around 21 million litres a day during droughts.
  5. The original aim was to be “completed and operational by 2029”, but the current programme now points to completion in the early 2030s, with a firm date still to be confirmed.

What Southern Water is doing (separately)

  1. Southern Water is developing the Hampshire Water Transfer and Water Recycling Project, which is a separate, longer‑term scheme.
  2. If fully approved, this would add a highly treated recycled‑water source (taking wastewater through multiple advanced purification stages), pump that water into Havant Thicket Reservoir in dry periods and then transfer additional water through Southern Water’s network to customers across Hampshire.
  3. This could provide up to an extra 90 million litres of water per day once operational, further protecting chalk streams and improving regional resilience.
  4. This project is still going through consultation, design, funding and regulatory stages, with an indicative aim of around 2034, so it should be seen as a follow‑on to the reservoir build rather than something that is happening immediately.

Benefits- Wetlands and woodlands

  1. Once completed, the reservoir is expected to create new wetlands and enhanced habitats across around 160 hectares, improving biodiversity and providing feeding and breeding areas for birds, amphibians and invertebrates.
  2. New woodland planting, hedgerows and grassland around the reservoir will help connect existing habitats, support pollinators and other species, and provide a more resilient local landscape in the face of climate change.

Benefits- Visitor centre and access

  1. The plans also include a visitor hub/centre, car parking and new walking routes, giving local communities new accessible green space and recreational opportunities on our doorstep.
  2. The main 2021 planning permission included an outline element for a visitor centre/café, car park, play areas, picnic areas, bird hides and associated access routes, with the detailed design to come forward in reserved‑matters applications. It will be built once the main dam is complete, so it is expected to open to the public in the early 2030s.
  3. The visitor centre is intended to be a community hub next to the water, with space to explain how the reservoir works, why chalk streams and wetlands are important, and the history and archaeology of the site, as well as supporting health and wellbeing through access to nature.

Benefits- Education and Employment

  1. The reservoir and visitor centre will provide a local outdoor classroom, offering schools and colleges opportunities for fieldwork in geography, science, ecology and climate‑change topics, linked to real‑world water‑management infrastructure.
  2. Education programmes and resources are expected to include guided visits, talks and curriculum‑linked materials on water supply, chalk streams, wetlands and biodiversity, helping young people understand their local environment and how it is managed.
  3. During construction and once operational, the project will continue to support jobs and skills in areas such as civil engineering, environmental management, visitor services and education, creating apprenticeship and work‑experience opportunities for local students and residents.

Benefits – Access and Recreation

  1. The wider recreational package will include walking and cycling routes, bird hides and viewing platforms, picnic and play areas, fishing platforms and parking with EV charging, so residents gain a significant new leisure and wildlife destination as well as a strategic water resource.
  2. It is hoped that there will be connectivity from Horndean through to the Reservoir site and Horndean Parish Council is working on this with other parties.

Conclusion

  1. In the longer term, and in addition to the benefits above the combined Portsmouth Water and Southern Water schemes are intended to make local supplies more resilient in droughts, reduce the risk of hosepipe bans and water‑use restrictions for households and businesses, and help protect our precious chalk streams for future generations.

Cllr Teresa Attlee

9 March 2026

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