The Yukon Water Board has approved emergency amendments to Yukon Energy’s water licence for Mayo Lake.
Significantly low water levels in the lake forced the crown corporation to seek the amendments. The water board granted its approval Aug. 15.
Yukon Energy president Andrew Hall said in an Aug. 20 interview residents of Mayo have likely already noticed water levels of the Mayo and Stewart Rivers already decreased as water flows from Mayo Lake were reduced soon after the amendments were granted.
“We made the change on Friday,” he said.
Officials sought the emergency amendments in an application submitted Aug. 1.
Under the changes, Yukon Energy can reduce its water level of the lake to 663.25 metres above sea level, the minimum required to support fish habitat downstream of the lake.
The water level throughout August is typically more than 665 metres above sea level, according to records for 10 of the last 14 years.
The lake’s water level was at 663.49 metres above sea level on Aug. 20.
With Mayo Lake not refilling as it normally does through the summer, less water is available to flow through the lake to support fish habitat downstream in the Mayo and Stewart Rivers.
The corporation has a responsibility to protect fish habitat near its facilities and had already taken measures to minimize the power generated at its Mayo site in an effort to save as much water in the lake as possible, Hall said in a previous interview.
Included in the emergency amendment are clauses that Yukon Energy must submit a low water level response plan and a fish mitigation monitoring plan by Dec. 31, 2020.
The low water level response plan would outline action to be taken in the event of a drought at the lake, while the fish mitigation and monitoring plan would outline the low water response and impacts for all fish species in Mayo Lake and the river system.
Hall said Yukon Energy had not proposed the plans in its submission for the amendments, but will begin working on both in the coming weeks.
“It makes sense,” he said of the reports.
The Dec. 31, 2020 deadline for both reports provides substantial time for that work to be done, Hall said.
Contact Stephanie Waddell at stephanie.waddell@yukon-news.com