BIDDEFORD — A portion of the embankment along the Saco River at the North Dam Mill complex in Biddeford that had washed away in heavy rains Oct. 30 into Oct. 31 has been temporarily shored up with the application of tons of stone.

Work could start as soon as the end of the week on construction of a temporary structure called a cofferdam that diverts the river flow to allow cleanup of the damaged section of the wall and completion of an engineering assessment. Plans will be created for the repairs once the assessment is complete, said Biddeford Communications Coordinator Danica Lamontagne.

“We are waiting for authorization from the U.S. Army Corps of Engineers to move forward,” said Lamontagne.

Contractors are now building a temporary road along the riverbank that will facilitate the construction of the cofferdam.

The storm dumped 6.72 inches of rain on Biddeford from Oct. 30 into Oct. 31, according to the National Weather Service Office in Gray. The heavy rain took out 77 feet of embankment wall, damaged part of the Overlook portion of the RiverWalk and came close to the 250-foot mill smokestack, built in 1916. The stack underwent repairs in 2020, according to an Aug. 10, 2020, MaineBiz story.

While it awaits the signal to move forward from the USACE, the city is working with the York County Emergency Management Agency and its state and federal counterparts on a proposed emergency declaration that if approved, could see the Federal Emergency Management Agency shoulder much of the repair cost. Under approved declarations, FEMA picks up about 75 percent of the cost of repairs, 15 percent would be paid by the state and 10 percent by the city.

York County EMA Director Art Cleaves said the threshold of $2.3 million in storm damage statewide would have to be met — along with a threshold within each county impacted — to request that Gov. Janet Mills ask President Joe Biden for an emergency declaration.

“It is clear with Biddeford, we’ll meet the threshold,” said Cleaves, also noting storm damage in numerous municipalities in Waldo and Knox counties.

On Monday afternoon, Lamontagne said the preliminary repair estimate remains at $1.5 to $2 million.