An Anchorage engineer thinks there’s a way to satisfy all parties competing for water in Eklutna Lake

For the last century, generating electricity has been the de facto priority for the water that collects in Eklutna Lake. Successive dams built for hydropower cut salmon off from their spawning grounds in miles of Eklutna River, the lake and its tributaries.

Now, parties with competing stakes in that water are several years into a process to rebalance how it’s shared. One major goal of that process is to address the injury the Eklutna Hydroelectric Power Project inflicted on fish. 

“The problem really is there’s not enough water in Eklutna Lake, as is, to meet all the needs,” said Mark Corsentino, an engineer who’s led the Anchorage Water and Wastewater Utility since 2019. 

As the water utility boss, Corsentino participated in the work that led up to the electric utilities’ proposal last year to divert about 10% of the water available away from electric generation to partially restore the river, a plan that does protect the water utility’s interest. But it never won over the Anchorage Assembly, the Native Village of Eklutna or environmental and fisheries interests. Previous Anchorage Mayor Dave Bronson did support it, but the current Mayor Suzanne LaFrance does not. 

Soon after taking office in July, LaFrance appointed and the Assembly confirmed an additional role for Corsentino as director of the city enterprise that holds a 53% stake in the Eklutna project. Instead of focusing on protecting the water utility, he said he started looking at the overall problem.  

And now, he thinks everyone overlooked relatively modest engineering solutions that could satisfy all parties competing for the water that collects in Eklutna Lake – but more time is needed to evaluate them.  

The pitch comes as Gov. Mike Dunleavy’s office prepares to hear legal arguments on Monday to help him decide how to balance demands for hydroelectric power generation that serves Anchorage and nearby Railbelt communities, about 90% of the city’s drinking water, and restoration of fish habitat that the Native village used to rely on. 

Right now, when water naturally collects in Eklutna Lake, it’s like charging a giant hydroelectric battery. Corsentino says the lake could also be unnaturally recharged. 

“The way I see this is that if just for three months of the year, you pump up into that lake, you’ll meet everyone’s needs and then some,” Corsentino told Anchorage Assembly and Eklutna Tribal Council members last month. 

With new, reversible hydropower turbines, he said water could be pushed uphill, back into the lake through the same tunnel the electric utilities use to draw water from now. 

“It’s a modified, pumped storage hydro concept with wind and solar at Eklutna Lake with river restoration and fish passage,” he said. 

It’s a mouthful. But essentially, what that means is adding more water to the system, enough for fish to swim back up to the lake without sacrificing power generation. 

The wind and solar element is about where the electricity would come from to pump the water uphill. These forms of renewable energy generation are finicky; the utilities can’t control when the wind blows or the sun shines. And the best times for wind and solar often don’t line up with when the electricity is actually needed. 

Connecting wind and solar to the pump system Corsentino has in mind would essentially let the utilities store excess power in the lake, for when it is needed. 

Renewable energy advocates pitched a version of this in 2020. At the time, Gov. Dunleavy was a fan. He even tried to woo the billionaire Warren Buffett to invest. 

That version was way bigger in scale – estimated to cost $5 billion.  

“And everybody said ‘Forget it, it’s too much,’” Corsentino said. “What I’m saying is, use the existing infrastructure that’s there. You can do the same thing at a much smaller price tag and still provide everything everyone wants.”

While the concept isn’t totally new, it also wasn’t analyzed in the years of study that have led up to the decision making stage the governor is in now over the future of Eklutna Lake and Eklutna River.

“And what we’re asking for,” Corsentino said, “is give us some time as part of this pre-implementation period, to further vet this process, to see if it really can solve all of these issues.” 

Under the 1991 agreement that set up this rebalancing process, the governor has an Oct. 2 deadline to make a decision. Mayor LaFrance, the Anchorage Assembly and the Native Village of Eklutna Tribal Council want two more years to work things out.

Julie Hasquet, a spokesperson for Chugach Electric Association said her utility and the Matanuska Electric Association still want the governor to go with their proposal, to give up some water from power generation to partially restore the river.

“We are still very confident in the results of our process,” she said. “We feel like it was thorough, it was inclusive, it was a public process, and we definitely still stand behind that program that is now in front of the governor.” 

There are a lot of unresolved legal issues about who has what authority in this process. Gov. Dunleavy recently requested briefs and invited all of the parties to an in-person meeting on Monday for them to present their legal arguments.