HOMES in Oxfordshire could run out of water over the coming decades.

A combination of population increases and climate change could cause major shortages in the Thames basin, according to new predictions.

The threat could eventually see the mothballed Reservoir project between Abingdon and Wantage revived.

The Thames Basin currently provides 2.6 billion litres of water a day to London and the Thames Valley.

But a report from the Department for the Environment, Food and Rural Affairs’ – co-authored by an expert from Wallingford – predicts shortages of 478 million litres a day by the 2020s, and 1,700 million litres in the 2050s, if the population keeps growing.

In worst case scenarios, the region will be short of 2.57 billion litres of water a day by the middle of the century.

HR Wallingford’s head of water management Steve Wade, who helped author the Climate Change Risk Assessment, said it flagged up the need for long-term solutions.

He said: “In the short term, over the next 30 years, we are probably OK.

“But we are highlighting big issues in the longer term, in the 2050s and beyond.”

The population is expected to grow by a million in London and 200,000 in the Thames Valley by 2035, with extra pressure being put on water supplies by rising numbers of smaller households.

Hotter summers, with lower rainfall and more evaporation, could lead to shortages, while wetter winters could also lead to more floods in the Thames Valley, Mr Wade said.

He said studies showed using water more efficiently would not be enough on its own to stop long-term shortages.

“On the demand side, there are leakage issues and we’ve all got to use a bit less water, but on the supply side we are talking about things like the possibility of water transfers or the reservoir going back on the agenda in the future.

“There is the potential for more sharing of water between different parts of the county, but it is heavy and expensive to transfer.”

The projections echo an Environment Agency study published last year which shows that the Thames river basin will face the biggest challenge in shortages by the 2050s.

Thames Water spokesman Natalie Slater said: “Our water resources management plan takes into account the predictions of climate change and includes supply schemes to ensure there is enough water to serve our customers across the region long into the future.”

Peter Rawcliffe, of the Oxford Flood Alliance, said there was a need for a medium-term plan to cope with an increased risk of floods.

Group Against Reservoir Development (Gard) vice-chairman Michael Robson said: “We are not worried in respect of water supplies because there are better ways of supplying London than the reservoir.

“We also believe Thames Water has over-stated the demand.”