Matthew deluge may not solve parched Nova Scotia's problems
Tuesday, October 11, 2016, 10:49 AM - The intense system that drenched Atlantic Canada this holiday weekend has dumped as much as 200 mm of rain so far over parts of Nova Scotia, but will it help when it comes to the severe drought? Maybe not as much as you'd think.
Water use restrictions
Mandatory water restrictions have been in place for communities supplied by the Lake Major Water Treatment Plant since September, after a record dry summer over much of the province.
Halifax Water reports that it has seen usage drop by 3 million litres/day since restrictions came into effect last month, but Lake Major - which supplies water for residents of Dartmouth, Cole Harbour, Westphal, North Preston, and Eastern Passage - remains at critically low levels. Despite conservation efforts, water levels in the lake continue to fall as the typical reservoir recharge that begins in late summer and early fall has yet to materialize this year.
Graph courtesy Halifax Water.
Provincial parks open for drinking water, showers
While Lake Major has thus far been the only water source at levels critical enough to spark water restrictions, record dry conditions around the rest of the province have also left their mark.
The Nova Scotia Department of Natural Resources has chosen to keep ten provincial parks open beyond their traditional Thanksgiving closing date so that Nova Scotians relying on the parks for potable water and showers can have continued access.
The agency says hundreds of people have been taking advantage of the provided water access over the last few weeks, according to a CBC report, but that the D.N.R. will be unable to keep the parks open for water past the first heavy frosts.
The parks are now scheduled to close for water services on October 27th.
Lake Major water level continues to drop. Water restrictions in place. Visit https://t.co/AUZ5ezbBWF for details pic.twitter.com/oYPo2iBQM3— Halifax Water (@HalifaxWater) October 4, 2016
Dry soil makes runoff a problem
Speaking to the CBC, a spokesman for Halifax Water, James Campbell, estimated "150 mm of rainfall over four or five days" to help the province's water sources start to rebound. "I understand there is a hurricane making its way up the coast," Campbell told CBC last week. "We would rather not get a dose of rain through a hurricane, but it's getting to the point where we'll take rain any way we can get it."
Lake Major on November 15, 2015 (left), and October 4, 2016 (right). Pictures courtesy Halifax Water.
While the downpours from the Matthew-fueled system over the province on Monday will help, a heavy dumping of rain all at once isn't a cure-all for the underlying drought. Given the dry soil, a lot of the water that falls can be lost to surface runoff, as water flows over dry land, into rivers, and back out to sea rather than soaking in deeply. A few inches of wet soil may help turn the grass green, but will do little to benefit the water table or restore dry wells.
As of Tuesday morning, the Halifax area had more than 100 mm of rainfall since the downpours began Sunday evening.
Showers tapered off from south to north across the province through the overnight hours on Monday -- but not before several areas declared a state of emergency.
Residents urged to continue conservation
All told, even with flooding through parts of the province, the parched south will need still more rainfall before water levels return to normal.
James Campbell warned CBC that water conservation will still be necessary. "We do need a lot of water to bring the water table up to a point where these wells are going to hold and retain water," Campbell said, "so that's an ongoing concern."
Sources: Halifax Water | CBC | Province of Nova Scotia |
Thumbnail courtesy: Dorothy Marlor