Video: It's Not The First Time A Landslide Has Blocked The Presumpscot River, State Geologist Says

Sep 18, 2020

A landslide blocked the Presumpscot River In Westbrook River Wednesday.  And as the water rose behind it, the city declared a state of emergency, while the National Weather Service put the area on notice that flash floods could result. But so far, so good.

Around 9:30 Wednesday morning, some workers behind the Les Wilson & Sons Excavation Company, a little downstream from the Sappi paper mill, noticed the ground shifting. Company CEO Chris Wilson says they watched trees start to move, a pole barn buckle. And then, the land just disappeared.

Thousands of tons of dirt and rock, trees and debris piled into the river, creating a near-instant dam.

Westbrook Landslide drone video from Maine Public Video Production on Vimeo.

"The river is impeded, and rising," said Westbrook Mayor Michael Foley, as he declared a local state of emergency, and the National Weather Service put coastal Cumberland County on flood watch.  Local, state and federal officials responded.

By late afternoon, Westbrook fire chief Andrew Turcotte said the situation had stabilized - in part because Sappi engineers were able to reduce water flows coming through the mill.

"We are actually starting to see a reduction in the height of the river, so right now we've got a lot of subject matter to experts to really determine and assess this further," Turcotte says. "At this point it does not appear to be an imminent public safety threat, outside of folks coming to the site and potentially having more of this section fall into the landslide area."

The area where the landslide occurred, seen from above.
Credit Rebecca Conley / Maine Public

Turcotte was standing a dozen yards or so from the lip of that crater with Lindsay Spigel, a state geologist who specializes in landslides. She typically studies evidence of events long past, such as an even bigger landslide in 1868, on the other side of the Presumpscot.

"It also blocked the river, similar to this," Spigel says. "So the cause of all this is, if you can see it down in there, is that blue-gray clay known as the Presumpscot formation. And it's what geological engineers call a sensitive clay, which means that if it's left unsupported or if it's disturbed, it can liquify and flow, which causes the landslides."

River levels are being closely monitored by Sappi and the National Weather Service. And city officials are scheduled to convene Thursday morning to consider next steps, including assessments of any harm done to downstream ecosystems and fish populations, as well as to human life and property.

Originally published at 6:40 a.m. Sept. 17, 2020.