DURHAM – The $5.56 million second phase of an ongoing construction project is set to begin this fall on a severely eroded section of Route 136 in Durham.

According to Scott Bickford, assistant highway program manager for the Maine Department of Transportation, the project involves building a new section of road inland from the existing roadbed for 1.25 miles from Snow Road southbound.

“While not deemed an immediate emergency, an investigation of the Androscoggin River banks revealed erosion issues and a cause for concern,” said Bickford.

The scheduled construction will be the second and final stage of a project that was triggered by flooding after a heavy rainfall last June. According to Bickford, the rain caused severe cracking and settling along the portion of Route 136. The resulting damage meant a portion of the road was in jeopardy of collapsing into the river.

“The sandbanks were undercut by the river and the riverbanks, including portions of the roadway, were beginning to slowly slide into the water,” Bickford said.

In response, the state established one-way alternating traffic to keep weight off the northbound lane, resulting in minor traffic delays but few complaints, said Durham Town Administrator Janet Smith.

“We haven’t heard of any huge headaches,” Smith said. “People have been pretty patient.”

The shifting and sandy soil of the Androscoggin has been blamed for previous road woes. In June 2010, a section 11?2 miles south of the current project collapsed, forcing the road to be closed while it was redesigned and repaired.

Bickford pegged the total cost of the first phase, including design, right-of-way acquisition, construction and construction inspection, to be roughly $4.73 million. The Federal Highway Administration is providing $3.5 million toward the cost of the initial phase. The state will pay for the remaining costs.

Construction equipment on Route 136 in Durham last week, where crews are continuing a project to address erosion issues along the well-traveled road.