with gallery: DTE Energy calling cleanup of riverfront MichCon site in Ann Arbor a huge success

Wiesemann said DTE will continue to work with the city, Huron River Watershed Council and other community stakeholders to determine the proper final end use for the site.

"If all the stars align perfectly, we are likely looking at a year or two before any redevelopment work begins," he said. "There may be additional remediation work required onsite, based on the proposed final end use, but that work would likely be performed during site preparation activities."

The state required DTE to complete soil and sediment remediation at the site of the former MichCon plant at 841 Broadway St.

MichCon has been a subsidiary of DTE since 2001. It ran a manufactured gas plant along the south bank of the Huron River decades ago and left the site polluted — a problem DTE inherited and has been working cooperatively with the Michigan Department of Environmental Quality to address.

The recent remediation work was done by Terra Contracting with oversight by TRC Engineers, MichCon, the city of Ann Arbor and the DEQ.

Just before Christmas, crews completed excavation of more than 47,000 tons of impacted material from the site, backfilling, capping along the shoreline, and the bulk of the restoration work.

Because the scope of the project was increased (27 percent more material was excavated than originally planned), some shrub and tree planting along the eastern shore will be finished in the spring, Wiesemann said, suggesting the site should look a little nicer and greener once spring has come and the grass and trees are nicely vegetated.

DTE closely coordinated the cleanup efforts with the city's parks and recreation department and the Argo canoe livery to make sure the work had a minimal impact on livery operations, the Border-to-Border Trail and other recreational uses within the area.

"As we planned and discussed at multiple public meetings, MichCon and Terra paid very close attention to the project traffic, odor, dust and surface water controls to ensure the project did not cause any nuisance issues within the city," Wiesemann said.

Mayor John Hieftje said he looks forward to seeing the results of DTE's efforts. He said it's been a general goal of the city for decades to acquire more riverfront land for park use.

"I'm very happy to see the cleanup has made progress," Hieftje said. "When you're talking about property becoming parkland, it has to be cleaned up to a specific standard, and I haven't seen any of that data yet. It needs to be cleaned up to a very high level."

Hieftje said the city doesn't want to assume any liability for future environmental cleanup work. As for how the transfer of the land from DTE to the city might occur in the future, Hieftje said, that's yet to be determined, and the ball is largely in DTE's court at this point.

DTE's plan all along was to dredge contaminated sediments from the main channel of the Huron River between Argo Dam and the Broadway bridges and also remove contaminated soils along the river banks to achieve an unrestricted residential cleanup standard.

That means, for instance, the area being cleaned up could be considered safe to use as a public park.

DEQ District Supervisor Mitch Adelman said it seems DTE has hit its mark and the DEQ is pleased to see the pollutants removed from the environment according to plan.

"It looks pretty good out there, from what we've seen," he said. "We look at it as a good next step in terms of bringing (the overall property) to closure."

The remediation work done along the river's edge didn't address contamination elsewhere on the property. For instance, there are cyanide-contaminated soils on the western portion of the property that haven't been cleaned up, Adelman said, noting that's a situation that both MichCon and the DEQ are aware of and it might require additional cleanup depending on the future use of that area.

While it appears DTE has cleaned up the portion along the river's edge to the point where there essentially are no more restrictions on it, Adelman said, DTE/MichCon still will be responsible for continuing to monitor and maintain the impermeable cap it put in place along the shoreline.

Wiesemann said MichCon ultimately is liable for remediating the remainder of the site to an "industrial" or "non-residential" cleanup level consistent with its use and zoning. He said that additional work likely will be performed during the redevelopment phase to take advantage of project synergies.

"However, if potential future developers or owners plan to change the property use to 'residential' or would like to construct a park, they will need to fund the additional cleanup that may be required in order for the property to meet the more stringent cleanup standards," he said.