Abingdon Reservoir: Thames Water under pressure on population estimates


12th April 2018

After questions from CPRE, Thames Water says it will reconsider the growth targets it is working to, undermining the case for the Abingdon Reservoir – but much more to be done.  HAVE YOUR SAY! TW consultation closes 29 April.

STOP PRESS:  See CPRE Oxfordshire’s final response to Thames Water’s consultation below.


After pressure from campaigners, Thames Water has said that it is substantially lowering its long-term population growth estimates, pushing back the need for the Abingdon Reservoir until the late 2040s. However, we say the figures are still over-estimated and that, combined with a reduction in leaks, there would be no need for the reservoir at all.

Thames Water is currently consulting on its draft Water Resources Management Plan setting out its plans for providing a sustainable water supply through to 2100. The Plan suggests the ‘mega-reservoir’ at Abingdon would be needed in the early 2040s.

CPRE and local campaign group GARD challenged Thames Water on its population figures for the latter half of the century which were based on a bespoke methodology. Now Thames Water has agreed to use Office of National Statistic (ONS) projections, which lowers the estimated 2100 population for the region by 2 million, from 16 million to 14 million. Thames Water says this means the Abingdon Reservoir may now not be needed until the late 2040s.

However, concern remains that Thames Water’s short to medium term population estimates are also way out of line. Unrealistic numbers will result in unnecessary investment, pushing up water bills. Thames Water’s customers deserve better numbers and lower bills.

Speaking for CPRE Oxfordshire, Professor Richard Harding, said: “CPRE still disputes Thames Water’s figures. Its projections of population up to 2045 rely on local authority growth plans which we know are highly ambitious and quite probably unachievable. For example, for Oxfordshire the growth projections are three times those of the Office of National Statistics, leading to an additional 170,000 people by 2040. If ONS figures were used throughout the planning period the need for the Abingdon Reservoir would probably disappear completely, especially if Thames Water also improved its poor leakage reduction rates.”

GARD Chairman Derek Stork said: “The fact that Thames Water’s population figures have been so rapidly exposed as non-credible is just one example of how their draft document attempts to sneak unsustainable arguments and figures past the public, local councils and the regulators. Their projected figures on leakage reduction will still leave them in bottom position of UK water companies, and their very poor projections for improving the water efficiency foresee levels of household consumption in the middle of this century which are still above those already achieved elsewhere. Proper action on leakage and water efficiency could save Thames the equivalent of twice the water provided by this unnecessary reservoir vanity project.”


We’re pleased to see that Oxfordshire County Council has also shared its concerns – see this article from the Oxford Mail, 11 April:




PLEASE respond to Thames Water’s consultation, which runs until 29 April.

See more here:



You can also see more information on the GARD (Group Against Reservoir Development) website here:



CPRE Response to Thames Water dWRMP April 18