NEWRY – As compensation for disturbing wetlands while rebuilding Route 2 in Bethel and Gilead, the state is going to undertake improvements to the Sunday River watershed.

“We’re required to undertake mitigation measures whenever we disturb wetlands on one of our highway-bridge projects and the Sunday River watershed has been recommended by local, state and federal entities as a good candidate for opportunities for meaningful regional mitigation efforts,” said Dean Van Dusen, supervisor of natural resource mitigation in the Maine Department of Transportation’s environmental office in Augusta.

The MDOT has hired Parish Geomorphic Limited of Georgetown, Ontario, to complete a watershed assessment study of the Sunday River in Newry, Bethel and Riley Township.

“Parish specializes in riverine watershed assessments and restoration planning, and is currently working on a number of projects in Maine,” Van Dusen said. The study, which was initiated in tandem with the Mollyockett Chapter of Trout Unlimited in cooperation with the Oxford County Soil and Water Conservation District, will lead to a preliminary restoration plan of which MDOT may implement a portion as wetland impacts compensation, Van Dusen said.

The study is based on changes in land use and in the economy of the Sunday River watershed in Newry, Bethel, and Riley Township over the past several decades.

The Sunday River’s main channel is about 13 miles long before it joins the Androscoggin River. The watershed’s steep topographic slopes within the headwaters of the Sunday River and several tributaries enter the lower section of the river before it joins the Androscoggin.

“The Sunday River is experiencing various forms of change, which cause concern, including erosion along the banks, a build-up of silt in the channel, high rates of channel relocation within the flood plain and a scouring of riverbed channels,” Van Dusen said.

The most prevalent problems appear to be silt build-up within the channel and the channel relocations which result from the high sediment load, he added.

“It appears that the lower part of the river has more sediment than the water can carry, increasing the water pressure on the banks, creating erosion and natural relocation of the river channel. The lower part of the river also has experienced some dramatic changes over the last two decades, especially after sizable storm events. Those changes have created greater risk to private property and structures, poorer aquatic habitat and degradation in water quality,” Van Dusen said.

The watershed study will accurately define the size of the Sunday River watershed and other factors.

“The data collected and the resulting analysis will provide us a comprehensive understanding of how the channel system functions. It also will identify the primary factors which influence those functions,” Van Dusen said.

From that information, MDOT will be able to rank potential restoration sites.

tkarkos@sunjournal.com