Is a reservoir the answer to water supply issues?

The reservoir would link up with a network of waterways in Norfolk and Cambridgeshire

Plans to build a reservoir have been described as a "once in a 400 years opportunity" but there were concerns it would not go far enough to solve water supply issues, with one academic warning it was not a "silver bullet".

The Fens reservoir, which is in the planning stages, would be built near Chatteris, in Cambridgeshire, and eventually supply water to 250,000 homes.

The Chancellor, Rachel Reeves, has singled out the project as a key to unlock new housebuilding in the area around Cambridge.

Anglian Water, a co-applicant with Cambridge Water, said it would be "vital to unlocking growth" in the area.

A spokesperson said: "In our region, which is the fastest-growing, the driest and prone to flooding, we need to build infrastructure on a scale never seen before."

The Fens reservoir would have infrastructure in Cambridgeshire and Norfolk

The reservoir would be built between Chatteris, March and Manea, with new infrastructure to transport water, including at the River Nene in Peterborough, and Downham Market in Norfolk.

It would be the first major new reservoir to be built in Cambridgeshire since Grafham Water 60 years ago, and roughly the same size – about 5sq km (3.1 square miles).

Anglian Water and Cambridge Water were currently in a pre-application stage with the Planning Inspectorate, and were expected to submit early next year.

The reservoir will need to be signed off by the secretary of state, and all going to plan was expected to be in operation by the mid-2030s.

Paul Burrows said the reservoir would be a once-in-a-generation project

Paul Burrows, chief executive of the Middle Level Commissioners (MLC), an organisation that manages water levels in the Fens, said the significance of the project "could not be underestimated".

He said: "The Fens reservoir is a once in 400 years opportunity, similar to when the first phase of the great drainage started."

Anglian Water said the Fens reservoir would be operational by the mid-2030s

The reservoir would abstract water from rivers and waterways that would otherwise be pumped out to the sea by the Middle Levels' network of pumping stations.

The MLC raised concerns that as they were a small organisation with limited resources, the project's dependence on its infrastructure could be a significant risk.

"There needs to be investment in the landscape as much as investment in the reservoir," said Mr Burrows.

Aled Jones said the city of Cambridge was at risk of running out of water

Resources from the reservoir will be shared between the two water companies, although Cambridge Water said in a report it expected the reservoir to meet just half of its future needs.

Aled Jones, a sustainability professor at Anglia Ruskin University, said the reservoir would go some way to solving the region's water scarcity problems – but was "not a silver bullet".

He said: "It's absolutely essential if we're going to have housing growth – but it takes up a lot of land, it takes up a lot of investment.

"How we manage the transition and cost while we wait for the reservoir to be built, to be filled, to be connected into the existing water infrastructure, that's a key challenge."

Pippa Heylings welcomed the reservoir but said it would not meet demand from additional homes

The government has announced ambitions to build new housing and infrastructure between Oxford and Cambridge, using the Fens reservoir as an example of how this could be possible.

"It's not enough", said Pippa Heylings, the Liberal Democrat for South Cambridgeshire, an area where the government recently increased housing targets.

She said the reservoir was "really important" but would not meet the demand for additional homes from the government.

"It is not enough to meet the additional homes that the Chancellor has announced," she said, adding: "What we need is to bash people's heads together, get them round the table again, and say how on earth can we unlock these new homes."

The Environment Agency said plans to invest in nine new reservoirs across the country were "much needed".

A spokesperson said: "We will continue to work alongside partners to ensure that development can deliver a reliable, clean and plentiful water supply for the environment and future generations."