A new operating plan for Gardiner Dam on Saskatchewan’s Lake Diefenbaker will be developed in light of a report assessing operations during last year’s flooding.
The report by hydrologists John Pomeroy and Kevin Shook from the University of Saskatchewan outlined several concerns about how the Saskatchewan Watershed Authority operated the dam.
Downstream users, including farmers and market gardeners, suffered significant losses as a result of the flood.
The report said the dam cut in half the amount of water the farmers would have received if the dam wasn’t there.
However, it also said the dam didn’t reduce the duration of flooding in the area between Moon Lake and Saskatoon.
The report said the authority used antiquated tools and procedures to manage the dam.
It said the amount of melt coming from the spring snow pack was underestimated and the number of gauges measuring flow on the Saskatchewan River system was inadequate.
The lack of hydrometric stations downstream from the confluence of the North and South Saskatchewan rivers makes it impossible to accurately measure the impact of water releases, the report said. It called this “an extraordinary omission.”
A map included in the report notes the number of stations in Alberta far surpasses the number in Saskatchewan.
“The paucity of stations for the Saskatchewan portion of the Lake Diefenbaker drainage make this region almost entirely ungauged, which resulted in the inability to measure April inflows in to the lake in 2011,” the report said.
The report also said that the minimum lake level has been rising over time, making it more difficult to use the reservoir for flood protection.
The authors said an operating plan with formal rules and priorities based on the accepted goals of the lake and dam must be a priority.
Dustin Duncan, the minister responsible for the watershed authority, said the trouble is that different lake users have different goals.
“Some think it’s primarily for downstream flood control; other people think it’s for water supply,” he told reporters.
“Certainly, SaskPower has an interest because it produces electricity, and the irrigation district obviously uses it for water.”
Every sector thought it was the priority during last year’s flood, he added.
“There is no clear prioritization.”
Duncan said the watershed authority will now work with all users and stakeholders to develop the new operating plan. The process will be public, he said.
The report also recommended computer systems that align with Alberta’s to get real-time information, as well as additional hydrometric stations.
The report said the SWA forecasters “did a superb job with the limited tools and resources, complex operating system and unspecified operating rules available to them.”