Q&A
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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.
What will the reservoir offer to Portsmouth Water customers?
As well as being supplied with water from the reservoir, our customers will have the benefit of a new community leisure facility on their doorstep. There will also be a host of environmental benefits locally.
The reservoir site will create a new, healthy and safe place for people to visit – with footpaths for walking, as well as routes for cycling and horse riding, facilities for bird watching, picnic and play areas and car parking.
There will be a visitor centre with a café, toilets and space for community and education activities.
Our proposals for the site so far have been developed over many years with local communities, young people and organisations such as Staunton Country Park and Forestry England.
What will the reservoir offer to Southern Water’s customers?
Building the reservoir will allow us to share water supplies with households in Hampshire (outside of our supply area) who receive their drinking water from Southern Water and where there is a severe shortage.
This means Southern Water’s customers will have reliable water supplies and less water will need to be taken from the River Test and River Itchen, which will be better for the environment.
Our customers in Hampshire who we supply water to are also customers of Southern Water for their wastewater services, so everyone in the area will benefit from the community and leisure facilities at the reservoir.
What will the reservoir look like?
The reservoir will 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 will be up to 18 metres deep and have embankments on three sides. The below image shows what the reservoir could look like when completed and open to the public.
What activities will 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 will also be footpaths for walking, cycling and horse riding, facilities for bird watching, such as bird hides, and picnic and play areas. Furthermore, there will 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 offering, 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 needed to remove 12.5 hectares of ancient woodland to build the reservoir and we 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 will 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 that needed to be removed 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(External link) 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 are needed through woodland, then the road follows 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.
How much will the reservoir cost and who will pay for it?
It will cost about £340 million to plan, build and fill the reservoir with water.
The scheme will be funded by payments from Southern Water to purchase the water it needs to supply its customers. Southern Water has considered a number of options to supply water to its customers and the reservoir is considered to be good value.
Only Southern Water customers who receive drinking water supplies from them will have the cost of the reservoir reflected in their bills. So, this does not include our customers who receive drinking water from us and wastewater services from Southern Water.
How are you involving residents and communities and other organisations?
As well as securing drinking water supplies and creating new homes for wildlife, the reservoir has the potential to become a new leisure and community focus point for Havant.
We’ve been working hard to involve the local community in every stage of this exciting opportunity, such as the public consultation we ran during May and June 2020. During this, hundreds of people were able to find out about our updated plans and have their say – feedback that helped shape the planning applications we submitted to Havant Borough Council and East Hampshire District Council.
In August 2020, we published our ‘You said, we did’ report(External link)(External link), summarising what people told us during the consultation and how we’re responding to the points raised. The reservoir planning application documents are available to view on the councils’ planning web-pages, plus you can download our Havant Thicket Reservoir Design & Access Statement.
Our plans also continue to be shaped by the 70+ members of our Havant Thicket Reservoir Stakeholder Advisory Group, which was established in 2004. The group is made up of representatives from a range of organisations, including local councillors and community and environmental groups. You can view the presentations and minutes from the regular stakeholder group meetings via our Library page.
As well as visiting this website, you can stay in touch with the reservoir project’s progress in the following ways
Get in touch if you’d like to find out more or be involved.
Schools and education
The reservoir project offers fantastic opportunities for education locally – not only when the reservoir is complete, but also during the planning and construction stages.
Local pupils have been involved since the start of the project, with local young people providing feedback during both our 2008 and 2020 public consultations.
And as the reservoir progresses, the reservoir will become a great venue to learn about the water cycle, climate change, the environment and wildlife, and STEM subjects (Science, Technology, Engineering and Maths).
We’re also involving young people in our environment work to grow and plant trees and hedgerows.
When built, school parties will be welcome at the reservoir to use the education space, bird hides, interpretation boards and the leisure facilities.
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.