Extraordinarily low spring runoff means Corner Brook mill must draw power from Nalcor
MUN researcher says forestry management could help reservoir as climate changes
At this time of the year, rivers and ponds in western Newfoundland are usually awash with the spring runoff, meaning high water levels and steady power generation for the Deer Lake hydroelectric station.
This spring, however, water levels are at a 54-year low.
Last week the government announced that the Corner Brook Pulp and Paper mill, which uses power from the Deer Lake station, would be getting supplementary power from Crown-owned Nalcor Energy in a temporary exchange.
In the face of a changing climate, though, future water levels might rely more on careful forestry management than predictable rainfall.
Darren Pelley, the mill's vice-president and general manager, said they had been monitoring the water levels at the Grand Lake Reservoir, where they've seen a steady decline over the past few months.
"It's quite a lower level," said Pelley. "We're actually down at the lowest level for precipitation since 1967."
According to Pelley, that's a drop of six to seven feet below full storage from where the water would normally be.
Pelley blamed the lower water levels on not only less rainfall since last spring, but also less snow over the winter.
According to their data, the snowfall this year has been only 20 per cent of what they would normally receive, meaning less potential melt and less water to fill the reservoir for hydroelectricity production.
"When we entered March, and seeing that there were no precipitation events in sight, we began to reduce the mill production output to stem the tide of the dropping level," he said.
Despite slowing equipment by 25 per cent, Pelley said, production simply wasn't sustainable, and with minimal impact to the declining lake level, the decision was made to source power through Nalcor in what he called an "energy exchange."
"Once the lake gets back to what we call the 'rule curve,' which is the average level, we would begin to push the energy back into Nalcor that we've received from them."
Climate is changing
While Pelley is confident that borrowing energy from Nalcor will get the pulp and paper mill over the hump of this dry period, forestry management and close attention to groundwater may be the solution to what could be a long-term issue.
According to Lakshman Galagedara, an associate professor in environmental sciences at Memorial University's Grenfell Campus, climate change is affecting the variability of precipitation in the province.
"We know temperature is increasing," he said, "but precipitation is highly variable."
Galagedara noted that depending on the year the province may get higher or lower amounts of precipitation.
While 2017, for example, was a dry year, 2018 saw damaging floods from increased rainfall in February, due to unseasonably warmer temperatures. "So these kinds of changes are probably due to climate change," he said.
"Total precipitation may not be much changed, but the distribution and timing may change," Galagedara said. "So that may be the main reason for low flow [into the reservoir] during some years."
While it's too early to say if energy exchange programs can sustainably address increasingly unpredictable precipitation, one measure that can be taken to help maintain reservoir levels is to better maintain watersheds, he said.
"If you do not disturb upper watershed areas, then you allow more groundwater recharge and retention within the watershed," he said. "Then you would have a continuous minimum flow to the reservoir."
Though tree harvesting operations for the Corner Brook mill already use replantation, he said it would take years for vegetation to become re-established.
"When you do the large-scale harvesting then you should have some sort of mechanism to reduce the runoff flow during the rain time, until regeneration happens."
In that time, he said, the industry may need to come up with other means of water retention or groundwater recharge. "As far as I know, that is the long-term solution to control this."
While the Corner Brook mill needs trees to produce pulp and paper, trees may also be an answer to keeping water in the reservoir and their equipment running.
"That is the industry, they need trees — but the thing is to plan it very well," said Galagedara. "Plan regeneration properly and then protect sensitive areas — that way you can handle these dry and rainy-period issues related to water needed."
With files from Bernice Hillier and Newfoundland Morning