Sask. $4B irrigation project could impede hydro production: expert

Unintended consequences to irrigation Watch: CTV Saskatoon’s Francois Biber learns how a $4 billion irrigation project could affect hydro production.

SASKATOON — A $4 billion irrigation project announced by the provincial government could hurt SaskPower’s ability to produce hydroelectricity, according to a University of Saskatchewan professor.

Saman Razavi, associate professor and principal investigator at the Global Institute for Water Security, said the project may boost crop production and crop yield - but the environment, farmers, and SaskPower may suffer.

“When you transfer dry-land agriculture to irrigated agriculture you can have more expensive crops, get more yield and it means more economic benefits,” Razavi said. “We’re talking about major water resource problems that includes many stakeholders and many jurisdictions and there are a lot of competing interests.

On July 2, Premier Scott Moe announced the first steps of a generational project to ensure irrigation to 500,000 acres of land from Lake Diefenbaker. The province said it would more than double the irrigable land in the Saskatchewan.

In a news release the province said the project will span the next 10 years in three main phases at an estimated cost of $4 billion.

Based on the models at the Global Institute for Water Security, after phase three is complete the province will be diverting vast amounts of water from Lake Diefenbaker for the new irrigation system, Razavi said.

“After implementing phase three we are going to be taking about 50 cubic metres of water per second from May through September. In dry years they need more water and at that point at peak times it can get as high as 150 cubic metres per second.”

For perspective, Razavi said the South Saskatchewan River passing through Saskatoon sees about 250 cubic meters per second on average.

These reductions in the water level of Lake Diefenbaker could mean less hydroelectricity produced at the Gardiner Dam.

“When you divert water out you are reducing the lake level in the reservoir and hydropower needs head, it needs some level above the turbine to generate more power,” Razavi said.

“So technically when you take the water out you’re going to be generating less power.”

Depending on amount of water diverted from Lake Diefenbaker, Razavi said it could reduce hydroelective output by five to 50 per cent.

“Because whatever you take out of the river is not going to come back to power the turbine,” he said.

Scott McGregor with SaskPower said the Crown has done modelling regarding the hydro-generation capability for 500,000 acres of irrigation and it expects to see a slight drop in power generation depending on precipitation.

However, any lost power generation at Gardiner Dam can be make up elsewhere, he said.

“It doesn’t impact the total generating capacity,” McGregor said. “Lost energy can easily be made up in other parts of the system. There’s capacity to make up any potential lost energy.”

McGregor could not confirm if SaskPower was consulted before the province’s announcement for the project.

He added it’s too early to tell what the real impact of the water diversion will have and that more analysis is needed for when the project is fully deployed.

Joel Cherry, a spokesperson with SaskPower, said “high-level consultations” did take place between SaskPower executives and representatives from the government.