Walker Brook shows we still don’t know the extent of Enbridge Line 3’s construction damage

Waadookawaad Amikwag is working to find out

Screen grab from a Waadookawaad Amikwag 2022 video. The wood-plank road allowed Enbridge to bring heavy equipment into a wetland.

Enbridge work crews officially finished building the new Line 3 tar sands pipeline across northern Minnesota in late September, 2021. The last section completed ran through the Walker Brook valley, a forested peat bog in Clearwater County.

Less than a year later, work crews returned to Walker Brook to fix problems created by this ill-considered and poorly permitted project.

State regulators haven’t talked about problems at Walker Brook publicly. Members of the public don’t know how many other Line 3/93 construction damage sites exist that they haven’t been told about. (Regulators don’t talk about them until they have been investigated and, if appropriate, levied fines, which leaves the public in the dark for long periods of time.)

I wouldn’t have known about the problems at Walker Brook but for friends who volunteer with a group called Waadookawaad Amikwag (Anishinaabemowin for Those who help beaver). They coordinate with drone pilots who monitor the Line 3/93 corridor looking for potential trouble spots. When problem areas are identified, volunteers go in on foot for a first-hand look.

On a recent Sunday, I joined my friends in what they call a “ground truthing” of the Walker Brook site.

Standing near Walker Brook looking east at the pipeline corridor cleared for Line3/93. Note silt fencing and straw bales for erosion control. (March, 2023).
Standing on the valley’s east side, mid-slope, looking west. (March 2023)

Once the new pipeline became operational, Enbridge changed the name Line 3 to Line 93. This post will refer to it as Line 3/93.

The stretch of Line 3/93 running through Walker Brook is in a brand-new pipeline corridor. It created more environmental damage than would have occurred had Enbridge rebuilt in an existing, already disturbed corridor. The original Line 3 is in Enbridge’s Mainline Corridor (orange line in map below), which crosses the Leech Lake Reservation.

Leech Lake opposed rebuilding Line 3 across reservation lands.

Enbridge proposed a reroute, which included the Walker Brook crossings.

The new route is in 1855 Treaty Territory, where Anishinaabeg maintain treaty-protected rights to hunt, fish, and gather.

The new Line 3/93 (green route) crosses Walker Brook, which is due east of the White Earth Reservation’s northeast corner.

Those living near Walker Brook knew something had gone wrong when they started seeing construction trucks returning after Line 3/93 was supposedly finished.

Groundwater had started upwelling above the pipeline in several places.

Volunteers on an early Waadookawad Amikwag ground truthing visit found erosion controls in place, such as erosion socks and silt fences. They found a large, deep sink hole. They saw three black drainage pipes emptying into the wetlands and ultimately the brook. A reading on the temperature gun said it was 45-degree water, strongly indicating it was deep groundwater, not surface water.

It now appears that L3/93 construction “altered this landscape in a way that impacted the natural movement of groundwater/surface water,” a volunteer wrote in a field report.

Water-filled sink hole of unknown origin. It was four feet by six feet across and deeper than you could reach with a ski pole. Aug. 26, 2022. On a return visit, it was filled in.

Waadookawaad Amikwag volunteers called regulators to get more information about the problem. They were told this was a “groundwater issue,” a “subsidence in land” and “crowning in the land,” they said.

A Waadookawaad Amikwag video released today says it could be more than “a groundwater issue.” “The nature of the upwelling strongly suggests that a confined aquifer has been breached here,” said narrator Laura Triplett, a geologist who is serving Waadookawaad Amikwag.

(I asked the MPCA on Friday for clarity on how it understands the nature of the problem and what triggered the repair work. I will update the blog when it responds.)

Enbridge is now on its third try to fix the Walker Brook problem, Triplett said in the video.

Waadookawaad Amikwag volunteers hypothesize the groundwater upwelling around the pipeline raised structural integrity concerns, requiring a fix. (If the pipeline shifts too much in the bog, it puts stress on its joints.)

On the Walker Brook valley’s east side, Enbridge work crews stripped away topsoil next to the pipeline and hauled it away. It replaced it with sand and gravel, apparently to improve water drainage, but also altering the valley’s ecosystem for the worse, Waadookawaad Amikwag volunteers said.

The valley is “full of complicated layers of glacial sediments” and “interconnected wetland systems,” Triplett said in a 2022 Waadookawaad Amikwag video.

Drone’s eye view of work crews stripping top soil on the east side of Walker Brook, and laying sand. Walker Brook, far right. Image: NewEra4K, Jan. 13, 2023.
A close up of the work. Image: NewEra4K, Jan.13, 2023.

Standing near Walker Brook and looking up at the valley, it’s clear this was a bad choice for a pipeline route. It also violates state rules that say pipelines should avoid:

  • steep slopes
  • wetlands
  • areas with high water tables, especially if construction requires excavation.
  • highly erodible soils
  • streams, but if that is not feasible and prudent, cross at the narrowest places wherever feasible and prudent …

The list of things pipeline’s should avoid describe the Walker Brook valley. And the problem went well beyond Walker Brook. The new Line 3/93 crosses 78 miles of wetlands, more than 20 percent of its route.

During Line 3 permitting process, Triplett testified that Enbridge should be required to take multiple soil borings in the valley and monitor groundwater for at least a year before the state should consider approving a route there. The state didn’t require such study, she said.

I don’t know if Enbridge did its own geotechnical assessment. If it did, it did a poor job. The valley is a mess.

“It just doesn’t look like they know what they were doing.”

Waadookawaad Amikwag volunteer

We got to this point through a rushed regulatory review and a failure to give weight to those agencies with environmental expertise.

The Minnesota Public Utilities Commission (PUC), a quasi-judicial body with no environmental expertise, approved the Line 3 route, including the Walker Brook crossing.

The PUC relied heavily on Line 3’s environmental impact statement (EIS) to make its decisions. The statutory deadline to complete the EIS — 280 days — was inadequate for a project of this massive scale. Enbridge wouldn’t agree to an extension. As a result, the EIS was rushed and lacked details, such as any analysis of the challenges of Line 3’s Walker Brook crossing.

The Minnesota Department of Commerce was the EIS’s lead author, not the Minnesota Pollution Control Agency (MPCA) or the Department of Natural Resources (DNR) both of which have much more environmental expertise than Commerce. The MPCA and DNR only played supporting roles.

The DNR’s and MPCA’s EIS comments were kept from the public. According to EIS comments the Friends of the Headwaters filed in 2017: “The relevant agencies—the Minnesota DNR and the MPCA—have entered into an agreement with the Department of Commerce that they will not submit comments that the public can review and incorporate into their own advocacy efforts.”

The failure to disclose the agency comments violated Minnesota Environmental Protection Act (MEPA), the Friends wrote. MEPA spells out EIS requirements, which in this case included giving the public access to the MPCA and DNR comments.

Waadookawaad Amikwag volunteers say the DNR and MPCA staff have told them in conversations that they had opposed the route that included the Walker Brook crossing, when the issue was before the PUC.

The PUC approved Enbridge’s preferred route, which included the Walker Brook crossing.

Line 3/93 still needed many other approvals, including a License to Cross Public Waters from the DNR. In approving the license, the DNR wrote that the route met state standards (including the ones that said pipelines should avoid wetlands and steep slopes).

“DNR has conducted a rigorous review of the Application to ensure that adverse impacts on the environment from construction of the project are minimized,” it said.

It’s rigorous review did not minimize impacts on Walker Brook.

Looking at Walker Brook today, it begs the question: What went wrong? Why didn’t Enbridge and state regulators figure this out prior to construction?

As one Waadookawaad Amikwag volunteer observed: “It just doesn’t look like they know what they were doing.”

A large dirt pile remains from the repairs. March, 2023.

I have asked the MPCA last week whether it was pursuing an enforcement action against Enbridge for the Walker Brook damage. (Again, still waiting for a response.)

The MPCA already reached a voluntary $5 million settlement with Enbridge for earlier environmental damage, such as frac outs, caused by Line 3 construction. Under an Oct. 17, 2022 stipulated agreement, Enbridge agreed to pay an $895,000 civil penalty, perform $2.6 million in supplemental environmental projects, and pay the MPCA $1.5 million for ongoing oversight.

However, the agreement also included a “release of claims” provision, which states: “The MPCA hereby fully and completely releases the Regulated Party [Enbridge] (including its affiliates, subsidiaries, successors, agents, and assigns) from liability for any Alleged Violations or related conduct known on or before August 4, 2022.”

I’ve asked the MPCA if the liability waiver applies to the Walker Brook damage.

The sooner Enbridge opened the new Line 3/93, the more money it would make.

The original Line 3 was corroded and running at limited capacity: 390,000 barrels per day. Once the new Line 3 was fully operational, capacity would jump to 760,000 barrels per day, or a 370,000 barrels-per-day increase.)

Transporting crude oil through pipelines costs roughly $5/barrel, according to a 2014 Congressional Research Service report. Costs will vary by distance and the type of oil transported.

As a back-of-the-envelope calculation using conservative numbers, $3-$5 per barrel, Enbridge would increase revenue by $1.1 million to $1.8 million a day once the new Line 3/93 was fully operational.

Given that the Walker Brook crossing was the last section of Line 3/93 completed, it’s a fair to ask whether the construction was rushed to get the new line up and running.

Drone thermal image: Dewatering from Walker Brook valley was pumped east over the Laurentian Divide into the Mississippi Watershed. Lighter areas indicate water. Image: NewEra4K, Jan. 13, 2023.

The Line 3 repair at Walker Brook required a significant amount of dewatering (pumping water away from the work area) for work to proceed.

Enbridge had a DNR-approved dewatering permit for Line 3 construction, which expired June 4, 2022. (Update: The DNR extended Enbridge’s dewatering permit to Dec. 31, 2023. Between Dec. 16, 2022 and Jan. 26, 2023 Enbridge dewatered 36 million gallons from the Walker Brook valley.)

Some of the dewatering from the Walker Brook valley went into a nearby farm field and woodlands (see image below). Some was pumped over the Laurentian Divide, from the Red River watershed, where Walker Brook is located, into the Mississippi River watershed, Waadookawaad Amikwag volunteers said. (Update: The DNR said this is not a permit violation.) (See image above.)

Drone thermal image. The black foreground is a farm field. The white shows water from dewatering activities, flowing into the forest and onto the field. Walker Brook valley at far right. Image: NewEra4k, Jan. 6, 2023.

By the time I visited Walker Brook in early March, Enbridge had removed the wood plank road. The erosion barriers were still in place, as were piezometers which measure groundwater pressure. A large mound of dirt remained at the top of the valley. It appears to be on top of the pipeline. Waadookawad Amikwag volunteers question whether this is to be left a permanent feature or whether it will be smoothed out or hauled away.

The problems at Walker Brook echo problems in St. Louis County, where Line 3 workers breached an aquifer within 400 feet of the Fond du Lac Reservation. Like Walker Brook, it appears there was no historical geotechnical information for this site prior to construction. The breach released 263 million gallons of groundwater.

Walker Brook echoes problems in Line 3’s LaSalle Valley crossing. Independent experts warned the state it was a high-risk area and should be avoided. The DNR worked with Enbridge, required some changes, and approved the crossing. Enbridge breached an aquifer there, too, releasing 10 million gallons of groundwater.

Dewatering flooded a forested area near the Walker Brook valley. Here, it appears water froze on top and the snow underneath melted away, leaving an ice and snow cap held up by small trees. March, 2023.

To fix the LaSalle Valley aquifer breach, Enbridge injected “over 51,000 gallons of grout” into the ground, Triplett said. “Basically, in this delicate system of wetlands, they have created a permanent, underground, reinforced concrete wall, over 20-feet high in places, and 2.5 football fields in length.”

Drone pilots and Waadookawad Amikwag volunteers continue to monitor the Line 3/93 corridor looking for environmental damage not yet reported or made public. Watch for further updates.

3 thoughts on “Walker Brook shows we still don’t know the extent of Enbridge Line 3’s construction damage

  1. Dan and I were at Enbridge’s Access Road into LaSalle Valley on 105th Street yesterday and witnessed Hooker Logging, Inc – Bryan, James, and Rod – clearcutting trees just north of the access road. This is County Land. Is DNR allowing Enbridge to remove MORE of our tree relatives? If so, to what end?

    We suspect Enbridge is planning for more and bigger remediation work in the LaSalle valley, an aquatic management area, and are opening the forest to proceed with more rape and pillage of Mother Earth. https://www.dnr.state.mn.us/fishing/trout/map.html

    https://www.hubbardswcd.org/wp-content/uploads/2016/12/2016-Hubbard-County-LWMP.pdf This document notes: “Trout rivers and streams are: Necktie River; Straight River, Bungoshine Creek; Cold Creek; Hellcamp Creek; Hennepin Creek; Kabekona River; Kawishiwash Creek; LaSalle Creek; Muckey Creek; Pokety (Pickedee) Creek; Schoolcraft Creek, Stall Creek; and Wallingford Brook. These lakes along with the trout streams are considered to be at a higher water quality standards than other area lakes and streams. Special protection strategies need to be used to maintain or improve these waters.”

    What “special protection strategies” are being deployed in Enbridge’s remediation area these days? Is Enbridge just creating even MORE damage? That seems the way of the their L3/93 remediation work we’ve watched to date.

    A year and a half after they started pumping tar sands through their pipeline and STILL they can’t stop the deep underground water bleeding from the land in this watery geology.

    Not like they weren’t warned. 68K+ comments in opposition, many noting LaSalle Valley as the Worst Place for a Tar Sands pipeline.

    No one with authority did the proper work to prevent these Preventable Tragedies.


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