The Scottish Environment Protection Agency (SEPA), in its latest update on June 16, forecast that 28 out of 83 areas - a third - will be at 'significant' water scarcity level by June 30 if there is no recovery in river levels. The Inner Hebrides reached 'moderate scarcity', the second highest level.
"The hot, dry weather is expected to continue into late June and early July, with any further short periods of intense rain unlikely to help water levels recover sufficiently," SEPA said.
It follows a drier than average winter and a dry May when Scotland only had 44 per cent of its average rainfall.
"The severity of the situation now means we must consider suspending abstraction licences in the coming week in the worst affected areas," SEPA said.
The Highland Council said there are more than 2,700 private water supplies in the region, supplying 40,000 people. On June 14, it warned some could run low due to lack of rainfall and advised people to take preventative steps to preserve drinking water.
Tiree Community Council secretary Dr John Holliday told a meeting on June 14: "There is a problem with low rainfall and water supplies running out. Our water supplies every five years or so have virtually run out in the busy parts of the summer and they've had to turn the pressure down occasionally.
"And if you look out the window, it looks as though this might be one of those years. One doesn't want to be alarmist. On the other hand, being ready early is probably a good thing."
Convener Phyl Meyer added: "If this weather keeps up until Tiree Music Festival time, we are probably going to have problems."
Water shortages also came up at Mull Community Council on June 7. Mull community councillor Dr Mark Aston told The Oban Times there are a number of stresses and strains on the island's water supply, caused by capacity and ageing infrastructure.
One issue is the treatment works in Tobermory which, at times, has not kept up with demand. Earlier this month, commercial properties were disconnected to conserve water, reported a social media post, asking residents to reduce use "otherwise disconnections will start getting more common and longer-lasting".
A second issue is how Mull's infrastructure can keep up with all the new homes and campsites. "We have got up to 800 more people in peak tourist season drawing water on an existing mains system," said Dr Aston.
A third is the island's various mains water systems, which are supplied by treated loch water or tankered in to holding tanks. This relies on tankers getting through from the mainland, Dr Aston said, which could be an issue when ferries are disrupted.
Last weekend, Cabinet Secretary for Transport, Net Zero and Just Transition Mairi McAllan authorised "an exceptional, short term measure to ensure maintenance of the public water supply to Broadford on Skye".
Ms McAllan allowed Scottish Water to increase abstraction levels from the Allt a’ Mhuilinn burn which flows from a loch designated as a Special Area of Conservation for macrophytes, a type of plant.
SEPA's next update, after some rain at the beginning of this week, is due on Friday.
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