B.C. Hydro reducing power generation at Alouette Lake as drought conditions worsen
Water diversions from Alouette reservoir are currently prioritizing key salmon habitat
As dry, unseasonably warm weather across B.C. persists well into October, the crystal blue water at Maple Ridge's Alouette Lake has retreated by at least 10 metres, leaving buoys sitting on dry land and would-be swimmers walking across bone-dry lakebed to access the shallows.
Alouette Lake is a popular summer and boating spot, located about an hour's drive east of Vancouver in Golden Ears Provincial Park. The lake is also a B.C. Hydro reservoir, where water is regularly diverted to generate power and to ensure water levels are sufficient to sustain nearby salmon populations in the Alouette River.
Zafar Adeel, executive director of the Pacific Water Research Centre and a professor at Simon Fraser University, said the drought conditions currently affecting much of the province are unlikely to result in an immediate energy shortage.
But he says they're indicative of a future where water shortages on B.C.'s coast could result in tangible threats to energy supply and animal habitats, and could make previously resilient landscapes more prone to flash flooding.
"It's concerning at a number of levels in terms of water availability — what it does to our ability to generate hydropower energy, what it does to different fish communities, and what it does to birds and other animals that rely on certain levels of water," said Adeel.
He spoke to CBC while standing on dry ground in a location where the water level of the lake would normally be waist-deep.
"Then there's a long term concern about energy security as a result of these droughts. Based on climate change, we're anticipating there will be more hotter and drier summers, prolonged periods of drought down the road. So it's not just what's happening right now, but what it might result in," Adeel said.
Prioritizing fish habitat
B.C. Hydro said in a written statement that water from the Alouette reservoir is diverted into the Stave and Ruskin watersheds for water management "on both systems and for power generation," and also into the Alouette River to maintain critical fish habitat.
It said that due to the ongoing dry conditions, power generation at the watersheds has been reduced to release minimal flow. That, in turn, ensures that flows below Ruskin Dam, which are needed to keep fish alive, can be maintained.
"Flows into the Alouette River have not been reduced and fish flows are being maintained," read the statement in part.
"Based on our modelling, we project being able to continue to maintain fish flows into the Alouette River."
A B.C. Hydro spokesperson wrote that "managing reservoir levels is a normal procedure for our system of dams and reservoirs throughout the province."
Adeel said that despite the communications from B.C. Hydro, sustained dry weather could in the future affect the province's ability to generate power, especially as extreme weather events become more frequent as a result of climate change.
"That's the reality of the situation — that you have to make some compromises in terms of where the water is allocated. There are a number of other ecosystems that depend on certain level of water availability," said Adeel.
"It's kind of hard to imagine that the energy situation and the energy generation capacity would not be impacted."
Flash floods could follow
John Richardson, a professor with the University of B.C.'s Department of Forest and Conservation Sciences, said that across B.C. most lakes are losing flow thanks to continued water losses and a lack of precipitation.
Richardson said that ground soil in B.C. — and particularly in mountainous areas like Alouette Lake — is fairly shallow, with little water storage capacity due to glaciation that occurred 15,000 years ago. With the snow pack from last winter completely melted, the only input into the lake is the small amount of water seeping in from the ground.
"With the continued lack of inputs, we're going to have this same problem with our reservoirs going down and down," said Richardson.
Adeel said that B.C. could soon go from drought to flooding in a matter of weeks, explaining that hot conditions harden the clay layers at the top of ground soil, reducing the amount of water the soil can absorb
"When you do get rainfall because the vegetative cover has been removed, either because of wildfires or because of the dry conditions, that means that they don't have a lot of capacity to absorb and retain water," he said.
"Hopefully we don't get extreme rainfall events, but if that happens then we might be seeing some flash floods, and other flooding situations that we need to be prepared for."
Environment Canada is predicting rain in Metro Vancouver, on Vancouver Island and on the Sunshine Coast on Friday — though experts warn it will take hundreds of millimeters of rain before regions experiencing severe drought fully recover.