22nd October 1960

The desalination plant opened

Guernsey’s ability to produce its own fresh water received a significant boost on 22 October 1960. That was the day that the Right Honourable R A Butler, the Secretary of State for the Home Department (effectively the British Home Secretary) opened the seawater distillation plant at La Hure Mare, Vale. It was capable of distilling 80,000 gallons of seawater into 20,000 gallons of raw water every hour.

A facility like this was particularly important on an island such as Guernsey, which still relied on agriculture – and tomato exports in particular – for a portion of its income.

In 1960, Guernsey had 1,100 acres of greenhouses, all of which needed a steady and reliable source of fresh water. It could store around six months’ supply in its various reservoirs – around 500 million gallons – which would be enough to see it through a dry summer. However, this left it highly reliant on further rainfall at the end of the growing season to prepare for the next run of crops.

The economics of water

The contract to supply and build the distillation plant was put out to tender. The winning contractor, G & J Weir Ltd, calculated that equipment costs would be £257,000 and running costs would stand at around £32,000 per annum. This took into consideration the prevailing fuel costs and an anticipated use of 2000 hours a year. That equates to an average of five and a half hours per day.

The oil-fired plant was built on a half-acre site close to Juas Quarry. Juas remains one of Guernsey Water’s largest storage reservoirs, able to hold 120 million gallons. The plant worked by using heat to boil off sea water. The water condensed and was captured, leaving the salt behind.

Initially, it proved to be a great success but ultimately proved uneconomical. Within 10 years, had been abandoned in favour of traditional above-ground water storage facilities, particularly in the island’s quarries.