By Hywel Griffith
The merit of a national network to pump water from wetter parts of Britain to drier areas is being considered by the Environment Agency.
But is such a system a viable way of solving summer shortages?
The Environment Agency is carrying out a study on the cost of a national water network, which it expects to complete in the next few weeks.
The Elan Valley's reservoirs could be expanded to feed a water grid
It will look at the implications of creating a system to pump water from wetter, western parts of Britain via pipes, canals and rivers to the drier east.
The Institution of Civil Engineers says the idea should be taken seriously, as it would offer one answer to summer shortages.
Professor Roger Falconer, from the institution, thinks existing reservoirs in North and Mid-Wales could be enhanced as a source of the water.
"From lake Vyrnwy (in North Wales) for example," says Prof Falconer, "that could be the equivalent of 150 swimming pools full of water a day, to transfer that via canals to the Thames, and then distribute to other parts of the UK, or via the Trent to East Anglia."
Prof Falconer says a national water grid is viable and could be "one of the options to address the current and future problems we have with water supply for various parts of the UK."
But creating larger reservoirs would also draw strong local opposition in rural areas.
In the Elan Valley in Mid Wales, reservoirs which opened in 1904 provide water to parts of the Midlands.
Building larger dams to increase supply levels would be unpopular.
"I think we're in a very different world today from the world we had a hundred years ago", says Peter Cox, from local community group CARAD.
"These days there's far more education about environmental matters, cultural matters and national politics have changed massively since then as well - I think there'd be a lot of resistance."
His objections are echoed by local councillor John Jones - but he is anxious that the scheme could still go ahead.
"They're talking of building another dam up at Graig Goch," says Mr Jones.
"At this present time you're hardly allowed to walk on the grass up here because of some rare plant or other.. But if this dam comes off - and it will come off as surely as night follows day - they won't have a quibble about flooding all these rare plants, you mark my words."
An Environment Agency spokesman said the idea of a national water grid had been looked at many times: "In engineering terms, a national grid is feasible, but the question is whether we should build one.
"It needs to be looked at in terms of the pressures on water resources and what is the most sustainable solution".
He said its study looking at how much a major pipe
network would cost and its environmental impact was due to be completed in the next few weeks.
Building a national grid would also need the water companies to be on board.
Water UK regards it as too costly an option that could harm the environment.
But Prof Falconer warns that answers must be found: "We've got a redistribution of the population which exacerbates the problem - we need more water in other parts of the country."