Oilfield borehole technology is being used by Scottish Water

Scottish Water said Wester Ross may be among the wettest places in the UK but local rivers do not contain enough water to meet demand all year round.

Underground reservoirs contain water which needs less treatment and provides a consistent annual supply.

Scottish Water has been using oilfield borehole technology to tap into new sources of supply up to 80 metres deep.

It said that supplies on the surface, such as rivers and burns, can dry up in hot weather, freeze over in winter or become polluted by peat and silt when they are in spate.

The supply to the communities will be greatly improved and the water will be a consistent quality all the year round Alisdair More Project manager

It could have laid long stretches of pipe to transport water from larger rivers further away but this was considered a costly operation.

Therefore, the water is to be extracted from deep below the rocks.

Derek Ball from the British Geological Survey said that ground water was present in the very hard rocks which form a lot of the north west Highlands, but only in small quantities.

Mr Ball said this was fine for one or two houses, but for somewhere the size of Ullapool other sources need to be examined, such as the area around Loch Broom.

He added: "There is a thick gravel deposit in the floor of the glen and that can act as a very good source of ground water.

Natural filter

"It is replenished by rainfall coming off the hills and the amount of storage of water here is several millions of gallons."

A new water treatment works will be needed to remove traces of metals.

Scottish Water Solutions said the solution could be applied to other water projects across Scotland.

Project manager Alisdair More said: "Drilling in the ground water gives us the opportunity to use water that's been filtered through the natural gravels and provide less treatment or less chemicals in the water.