Havant Thicket Reservoir

Markets

Water
Services

Engineering & design

Consulting, strategy & advisory
Location

UK
Client

Portsmouth Water
Completion date

2018 - Ongoing

Joanne Farrar

Technical Director, Planning and Environmental Consenting, London, UK contact form+44 20 3214 8889

Sophie McPhillips

Practice Manager, Design and Advanced Technology, Bristol, UK contact form

For more than a generation, no new surface water reservoir had been built in the UK. Havant Thicket Reservoir set out to change that by responding to growing water scarcity in the South East while protecting some of the country’s most sensitive chalk stream environments. Working with Portsmouth Water, AtkinsRéalis brought together engineers, planners, environmental specialists and project managers to shape a scheme that balances long term water resilience with environmental stewardship and community value.

The project delivers a new strategic water resource capable of supplying drinking water to the region, including a bulk supply to Southern Water, while safeguarding the internationally important River Test and River Itchen catchments. From the outset, the team focused on integrating sustainability, operational efficiency and public benefit to create infrastructure that works with its landscape rather than against it.

The challenge

Developing the UK’s first major surface water reservoir in 30 years required navigating complex technical, environmental and regulatory challenges. The scheme spanned three local planning authorities and involved sensitive habitats, ancient woodland, geotechnical risk and stringent Water Framework Directive requirements under intense public and stakeholder scrutiny. At the same time, the project needed to deliver a resilient, operationally efficient asset that would meet future water demand while offering tangible benefits to local communities

Havant Thicket Reservoir in numbers

8.7bn Litres

Reservoir capacity (equal to 3500 Olympic swimming pools)

21m Litres

Water supplied each day

160 K

People supplied with water in a year

Our role

AtkinsRéalis provided multidisciplinary leadership across the outline design and planning stages, including:

Outline design for the reservoir and associated infrastructure, including upgrades to water treatment works, a new pumping station and a pipeline connecting the reservoir to the regional network
Environmental Impact Assessment and environmental management across ecology, water quality, landscape and heritage
Planning strategy, coordination and submission of planning applications across three local planning authorities
Stakeholder and community engagement, supported by digital consultation tools and visualisation

By establishing a clear planning strategy from the outset and embedding early stakeholder engagement, the team identified and addressed risks early; reducing uncertainty and enabling smoother decision making.

AtkinsRéalis is continuing to support Portsmouth Water as a ‘Design Guardian’ providing assurance on the contractor deliverables during the construction of the reservoir, pipeline and water treatment works. We also supported site enabling works, discharged the first reserved matters application, secured permission for a revised tunnelled pipeline scheme and are providing a technical assurance role in relation to Southern Water’s Hampshire Water Transfer and Water Recycling Project which will connect to the reservoir.

Delivering environmental and community value

Environmental considerations shaped the project from day one. The reservoir design integrates operational and visitor facilities within the surrounding landscape to minimise visual impact and preserve the site’s rural character. In parallel, the team developed an ambitious Biodiversity Mitigation and Compensation Strategy, including more than 200 hectares of off site compensatory habitat.

Innovative approaches were used to mitigate the loss of ancient woodland, optimise embankment design and manage fluctuating water levels to deliver environmental enhancements while reducing cost and carbon. The scheme also provides new recreational and educational assets, including wetlands, trails and a visitor centre, leaving a legacy for the local community.

AtkinsRéalis' in-house agency Creative Design developed 3D visualisations of the proposed reservoir and surrounding areas.

Collaboration and innovation

Specialists in hydrology, pipeline, geotechnical and highway engineering, ecology and landscape design worked collaboratively using advanced digital tools, including a WebGIS based system, BIM and 3D visualisation. Digital public consultation – including a 3D fly through – helped bring the proposals to life, gaining significant public support and meaningful engagement.

This collaborative, digitally enabled approach contributed to securing planning permissions first time, with no post submission design changes and no objections from statutory environmental bodies.

A blueprint for future water infrastructure

Havant Thicket Reservoir demonstrates how complex, environmentally sensitive infrastructure can be delivered through strong technical leadership, early engagement and collaboration and a commitment to sustainability. The project sets a benchmark for future water resource schemes – showing how resilience, environmental protection and community benefit can be delivered together.