In the upper reaches of the Deerfield / Cold River watershed, the Mohawk Trail passes through steep terrain, well above the river. Heavy rains spilling down these steep slopes during Irene eroded hillsides and damaged the road in several places. The damage seen here occurred in the vicinity of the confluence of Manning Brook (flowing from the west) and the Cold River (flowing from the south).
Roadside damage, upper watershed
Aerial view. Gray areas in aerial photo indicate damaged areas where rip-rap has been installed during repair process.
The Cold River rose dramatically during Tropical Storm Irene, causing landslides in at least 2 places, severe erosion of hillslopes along the stream, and damage to the road itself in several places. At this location, vegetation and underlying soils were washed into the river, compromising the integrity of the roadway. This section has been extensively rip-rapped since the storm.
Upwards of 7" of rain in the area, falling on steep slopes, created many ephemeral streams that washed water and debris onto and over Route 2, contributing to erosion problems on the downhill side of the road.
Photo taken in May 2015 shows extensive use of rip-rap to stabilize slope leading from road to river.