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Expert says EGLE doesn't have enough information to approve Line 5 tunnel

Lester Graham
Michigan Radio
The Mackinac Bridge across the Straits. Enbridge wants to construct a tunnel just west of the bridge to house its Line 5 oil and natural gas liquids pipeline.

A scientific expert says Canadian pipeline company Enbridge Energy has not submitted enough information to the state for permits to build a tunnel under the Straits of Mackinac. The groups Oil and Water Don’t Mix and the National Wildlife Federation included a geological engineer who build tunnels in an online news conference.

Brian O’Mara reviewed the reports in the tunnel proposal submitted to the Michigan Department of Environment, Great Lakes, and Energy. O’Mara says Enbridge did not take nearly enough core samples of bedrock along the route of the tunnel, and what they did take showed it’s not solid bedrock all the way across.

“What has been submitted is in no way adequate for EGLE to complete a review, let alone approve,” O’Mara said.

When preparing to dig a tunnel, he said it’s typical to take core samples for a tunnel every 50 to 200 feet. Enbridge took samples every 950 feet.

He also noted a number of other issues including the risk of a methane explosion underground, or a sink hole immediately below one of the existing Line 5 twin pipelines (Line 5 splits into two pipelines in the Straits).

“What Enbridge has submitted to the state of Michigan at this point doesn't come close to what you need to properly design and prepare for a tunnel beneath open water,” he said.

Enbridge disagrees. Spokesman Ryan Duffy said they’re working with leading tunnel experts on the plan.

“The work we did, coupled with other available information about the Straits, provides ample information on the conditions in which the tunnel is going to be built,” he said.

Duffy dismissed the other issues O’Mara mentioned.

“We believe those geological conditions are favorable. And our geologists and engineers continue to study those core samples we took and that will continue to guide the project going forward,” Duffy said.

A former employee of the Michigan Department of Environmental Quality (EGLE’s previous name) also expressed concerns. Mike Wilczynski was a senior geologist for the agency. He is concerned about a chemical mixture that will be part of the tunneling process. He says Enbridge wants to discharge up to five million gallons of wastewater into Lake Michigan every day the tunnel is under construction. He said a substance called bentonite clay stays suspended in water and could hurt fish.

Enbridge’s Duffy said the wastewater would first be sent to settlement ponds and the water that would be discharged would meet state guidelines.

Three State of Michigan agencies are reviewing several permit requests by Enbridge in its effort to construct the tunnel under the Straits of Mackinac, the waterway which connects Lake Michigan and Lake Huron.

Editor's note: Enbridge is one of Michigan Radio's corporate sponsors.

Lester Graham reports for The Environment Report. He has reported on public policy, politics, and issues regarding race and gender inequity. He was previously with The Environment Report at Michigan Public from 1998-2010.
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