What is the plan for a new reservoir?

    We are planning to invest £340 million to build a new reservoir in Havant, Hampshire. It is being built in collaboration with Southern Water and will help secure more reliable and resilient water resources for our area and the wider South East.

    Why is it needed?

    The South East, as a whole, is under ‘serious water stress’ and water companies are being asked to take less water from some of their sources – such as the chalk rivers in Hampshire – to keep them healthy and protect wildlife. 

    At the same time, water companies need to find more water to cater for the effects of climate change and a growing population. 

    This major change is going to particularly affect Southern Water, which needs to find new water resources for the customers it supplies drinking water to in Hampshire, to replace water taken currently from the River Test and the Itchen.

    In Portsmouth Water's area, there are underground springs which provide plentiful, clean water. In winter, much of this water is surplus to requirements and flows out to sea, so we could make better use of some of it by capturing it and storing it in the reservoir until it’s needed. 

    This will allow us to share more water with Southern Water’s customers in Hampshire from our network and increase the resilience of water supplies in the South East.

    • We already have agreements to share up to 30 million litres of water a day with Southern Water (in West Sussex and Hampshire).
    • We can share a further nine million litres a day from 2024 from other sources (Hampshire)
    • We can provide an extra transfer from a mix of sources when the reservoir is built, up to 21 million litres a day (to Hampshire)
    • The total would be up to 60 million litres of water per day provided to Southern Water.

    Overall, building the reservoir would make the whole South East much more resilient to droughts, which are likely to happen more often in the future due to climate change.

    Why has the reservoir not gone ahead before?

    We first received planning permission for the reservoir back in 1964 and we carried out a lot of work towards a new planning application in 2008.

    However, at the time there wasn’t enough demand for the water, either from our customers or across the South East.

    Since then, Southern Water has agreed to reduce the amount of water it takes from the Rivers Test and Itchen in Hampshire, to protect the environment, so they need to find new sources.

    As a result, we’re now working in partnership with Southern Water to go ahead with the reservoir to secure more reliable water supplies for the region as a whole. It will also help cater for a growth in the population and housing and more droughts as a result of climate change.

    How much water would it hold?

    The reservoir would be able to hold about 8.7 billion litres of water when full and supply an average of 21 million litres of water each day.

    That’s enough water to supply about 160,000 people during an average year.

    What would the reservoir look like?

    The reservoir would be about one mile (1.6 km) long from east to west and 0.5 miles (0.8 km) wide from north to south. It would be up to 18 metres deep and have embankments on three sides. The below image shows what the reservoir could loo like when completed and open to the public.

    What activities would be on the site?

    We’re planning to build a visitor centre on the site with a café, toilets and space for education and community activities.

    There would also be footpaths for walking, cycling and horse riding, facilities for bird watching, such as bird hides, and picnic and play areas. Furthermore, there would be car parking and cycle racks.

    We’re working in partnership with neighbouring Staunton Country Park and Forestry England, organisations we already work very closely with, to make sure the facilities and activities are a good fit with theirs.

    What about the environment and wildlife on the site?

    Our approach to designing the reservoir has the environment and the community at its heart. Further details are set out below.

    Our masterplan covers all the environmental and community factors we are taking into account. This means we’ve considered the environment as we’ve designed every part of the reservoir, the access roads and pipeline, and we’ll continue to do so.

    We’re also working closely with Forestry England, who own and look after the neighbouring Havant Thicket woodland, and Staunton Country Park (which is owned and run by Hampshire County Council) to see how we can manage the sites together in the future.

    This approach, along with lots of feedback from local communities and environmental organisations, has helped us choose the facilities we’re proposing, namely:

    • A wetland habitat to support threatened bird species and provide areas for endangered bat species to find food
    • A visitor centre with a café and facilities for communities and schools
    • A network of trails and paths for walking, cycling and horse riding, linking to others in the wider area
    • New woodland, hedgerows and wildflower planting
    • A landscaped parking area for vehicles and bicycles.

    The reservoir project will improve existing woodland and create a valuable new wetland, woodland and parkland. A grant scheme will also support wildlife across Hampshire and West Sussex.

    Creating the reservoir will help protect the River Test and River Itchen in Hampshire. By using the reservoir to supply our own customers, we can share supplies from our other water sources with Southern Water. This means they will be able to reduce the amount of water that they take from these rare and sensitive chalk streams, which are home to many species.

    We would need to remove 12.5 hectares of ancient woodland to build the reservoir and we have reduced this as much as possible by changing the design. We’re committed to replanting and improving around 200 hectares of woodland and pasture both on and around the site and further afield to leave an overall positive gain for the environment and communities.

    Where would the road access to the reservoir be?

    We need to create new public roads for vehicles to get in and out of the site, both while the reservoir is being built and when it opens to the public.

    We've been granted planning permission for two access routes to the reservoir – one from the north and one from the south, as set out on the below map.

    We want to create access roads from the north and the south to help minimise the overall impact of traffic and almost halve the amount of ancient woodland we will need to remove along the northern route.

    We will use the northern route for most of the reservoir construction vehicles and people travelling from further afield to the site, with the southern route mainly used by local communities. We’ve designed it so both roads end in the site’s car park and the northern route is single track, to avoid the routes being used as a ‘rat run’, something people told us they were particularly concerned about.

    You can read more in the You said, we did’ consultation report we published, summarising what people told us during our Spring 2020 consultation and how we’re responding to the points raised.

    The northern access route

    A number of routes from the north were considered during the public consultation in 2008 and the preferred one came from the A3(M) Junction 2 (J2) via the B2149. At the time this was supported by a majority of people because it was close to the A3(M) and avoided residential areas in Warren Park and Rowlands Castle. This helped us develop our updated northern access route proposal (see map above) which formed part of the planning applications we submitted in late 2020 and which was then granted planning permission in Autumn 2021. From the B2149, 200 metres of new track will be needed through woodland, then the road will follow the route of an existing Forestry England track in Havant Thicket woodland to reach the reservoir. 

    The southern access route

    As we studied the reservoir site in more detail, through developing our planning applications, we were able to make changes to the design of the embankment. This created more space on the south west side of the site, meaning there is enough room there now to build the embankment, an access road and a separate path for walkers, cyclists and others. 

    So we developed a plan to create an access route from the south, in addition to the northern one. This access point will come off Swanmore Road and follow a new road on the site along the side of the reservoir and up to the car park and visitor centre. 

    What is new and innovative about this reservoir?

    This will be the first new reservoir to be built in the South East since the 1970s.

    The Government is currently calling for water companies to invest in more projects to help supply water, such as reservoirs and regional transfers. Projects like this are needed to secure reliable water supplies for the future, alongside reducing the amount of water lost through leaks and encouraging people to use less water.

    This will help the country tackle extremes in weather such as droughts, which are likely to happen more often and be more serious as our climate changes. It will also help us provide water supplies to more customers in the future as the population grows in the UK.

    The reservoir was selected as part of work carried out by the Water Resources South East (WRSE) group, which includes six water companies in the region and their regulators. It is one of eight ‘big ticket’ schemes which could deliver more than 15 million litres of water each day.

    The reservoir is likely to be the first regional scheme of this type to be developed in collaboration between two companies (Portsmouth Water and Southern Water) for the greater good of the region.

    When would it happen?

    Timeline

    The reservoir will take nine years in total to plan, design and build and is scheduled to be complete, full of water and open to the public by 2029.

    A huge amount of work has already been completed to share information, draw up detailed plans, carry out environmental mitigation work and prepare the site for building work

    This diagram below sets out our timescales, with construction taking place in phases.

    Construction

    The task of building the reservoir is a large one which will take a number of years. It will involve the combined expertise of a team of engineers, planners and a large workforce to complete this major project. As the site is in a natural valley and made up of clay, we expect to be able to dig this to shape the reservoir without having to bring in extra material or remove it. During the construction we would liaise regularly with communities to keep disruption to a minimum and create opportunities for local employment and education.

    Projected timeline

    2021-2022:

    • Ongoing creation of new woodlands and habitats for wildlife migration
    • Prepare planning applications for the detailed design of the reservoir operational and visitor facilities, access and recreational routes and the pipeline route
    • Build the access roads
    • Start work to prepare the site
    • Divert paths
    • Community engagement.

    2023 – 2026:

    • Dig out the clay and move it within the site to shape the reservoir bowl
    • Build the embankment
    • Lay the pipeline which will transfer the water from the springs to the reservoir
    • Community engagement.

    2027 – 2029:

    • Create a new network of paths
    • Pump water from the springs to fill the reservoir (during winter)
    • Build the visitor centre and other facilities
    • Open to the public.

    How are you involving residents and communities and other organisations?

    Since 2019, we’ve carried out a range of activities to raise awareness about the reservoir and encourage people to find out more and tell us their views. This has included: 

    • Sending out a letter from Portsmouth Water CEO Bob Taylor in October 2019 to 27,000 local homes and businesses to tell them about the reservoir and direct people to where they can find out more
    • Carrying out customer research to gauge people’s attitudes on the reservoir, with the vast majority of those surveyed supportive of the project
    • Setting up a dedicated Facebook page and these web pages for Havant Thicket Reservoir, making it easier for people to learn more and get in touch to ask questions
    • Holding a series of public exhibition events in November 2019, with face to face discussions with residents
    • Liaising closely with a wide range of community representatives to get their input into our proposals – e.g. we’ve been talking to local MPs, councillors, council officers, environmental and community groups and organisations like Forestry England and Staunton Country Park
    • Holding a public consultation on the reservoir project proposals from 11 May to 8 June 2020.

    How can I find out more?

    There’s lots more information on this website, where you can also give us your questions and comments using the 'Ask us a question' tool on each page. 

    You can also get in touch with us via email, phone or post. See our Get in touch page for more.

    Where would the new pipeline run?

    We’re carrying out a public consultation, until 22 March 2023, on a proposed new route for the pipeline we need to build - to transport water from Bedhampton Springs to Havant Thicket Reservoir, as well as take water out for supply to customers, when needed.

    Further details are set out below. You can also find out more in our public consultation leaflet, which we’re distributing to local households and businesses. 

    We would welcome your comments on our proposals, to help to shape and inform the new planning application we are due to submit to Havant Borough Council in June 2023. So, please make sure to complete our online feedback survey that can be found at the bottom of this page.

    Proposed new approach

    We received outline planning permission for a pipeline to run from Bedhampton Springs to Havant Thicket Reservoir in October 2021. However, since then, together with our appointed pipeline construction contractor (Ward & Burke Construction Ltd), we have investigated ways to improve the route of the pipeline, to further reduce its impact on local communities and the environment.

    This is in light of alternative and well-proven construction techniques, which would allow the scheme to be delivered more efficiently and effectively. As a result, a new pipeline route and design have been identified, which will need a new planning approval. A map of the proposed new route for the pipeline is set out below. You can also download a copy of the map from the Documents section of this page, along with a copy of our public consultation leaflet.

    Under the original plan, much of the pipeline would have been installed using an open cut method – where engineers would dig down from the road or land, lay the pipe and then fill in the ground above it.

    With the proposed new plan, micro-tunnelling would be used to put in the majority of the pipeline, building it section by section via eight access shafts – four shafts of 6 metres diameter each and four shafts of 13 metres diameter each. This avoids the need to dig a trench for the pipe to go in. The shafts would be spread out along the 3km pipeline route at intervals of between 300 and 500 metres. As a result, the new pipeline would be 1km shorter than the originally planned route, so around 3km in total length. More information on micro-tunnelling can be found in our public consultation leaflet.

    We’re now starting to prepare a new planning application for this new pipeline scheme and are consulting with community representatives, local residents and others until 22 March 2023, to allow people to find out more about the proposals and have their say. All feedback is welcomed via our online consultation survey.

    Under the current timeline, work to build the new pipeline would start in late 2023, with completion by early 2026. The overall timeline for Havant Thicket Reservoir remains the same, with the reservoir completed, filled with water and open to the public by 2029.

    Southern Water Hampshire Water Transfer and Water Recycling Project

    In Summer 2022, Southern Water consulted on separate plans to top up Havant Thicket Reservoir with highly treated, recycled water, under its Hampshire Water Transfer and Water Recycling Project. These proposals, which would help maintain essential water supplies during times of drought, are in the very early stages and are subject to further consultation and planning approval.

    If approved, the recycled water would need to be transported to the reservoir via a tunnelled pipeline. As we’re now proposing a tunnel between Bedhampton Springs and Havant Thicket Reservoir, we’re exploring the possibility of incorporating part of Southern Water’s pipeline within this tunnel. This provides a significant opportunity to further reduce disruption in the area, if Southern Water’s project is approved, by avoiding the need to build another tunnel along a similar route. It may also enable more of our pipeline to be tunnelled, again reducing disruption for residents, businesses and wildlife.

    Installing Southern Water’s pipeline within the proposed Portsmouth Water tunnel would not allow Southern Water to operate its pipeline and would not, in any way, pre-empt the approval of Southern Water’s scheme. Rather, it would mean if Southern Water were to receive permission for its plans, the overall impact locally would be vastly reduced, as no additional pipeline between Bedhampton Springs and Havant Thicket Reservoir would be needed.