OTISFIELD — Selectmen are moving forward with an engineering plan to reduce erosion on Cobb Hill Road.

They recently reviewed an updated engineering plan to keep sediment from Cobb Hill Road from entering Thompson Lake. They agreed to fund the first two phases of a three-phase plan.

“We’re looking for the $6,000 rather than the $17,000 for the full-blown thing,” Board of Selectmen Chairman Hal Ferguson said.

The updated proposal includes two phases. A third phase, to determine exactly what work would be accomplished and in what order, will require additional money, he said.

The $6,000 will get the town through Phase I, information gathering and analysis, and Phase II, computer modeling of the assessment. Selectmen are looking to take the money from the road account.

A 2010 grant program through the Thompson Lake Environmental Association to help control erosion from sites, including Cobb Hill Road, into Thompson Lake was considered successful, preventing an estimated 52 tons of soil from entering the lake at various sites. But selectmen later agreed that damage from major storms has left the situation unresolved despite the installation of three large culverts to help improve drainage on Cobb Hill Road.

According to the draft agreement dated Feb. 17, Phase I will take about 12 hours and cost an estimated $1,140.

The second phase will study the watershed through the use of aerial maps and U.S. Geological Survey quads. A preliminary surface hydrology model of the watershed will be created, any necessary field work will be conducted and recommendations will be made to the town, including impacts and design recommendations for Cobb Hill Road. Secondary recommendations will be provided for roads which are found to be directly or indirectly affected, such as Scribner Hill Road, Ivory Hill Road, Ohivo, Beehive Lane and Jillson Camp Road, according to the proposal.

The purpose of the second phase, according to the contract, is to support and confirm the hypothesis that multiple culverts, more ditching, additional plunge pools, properly sized riprap and private and public storm water diversion are the solutions to the problem.

This part of the project is expected take about 43 hours and be billed at a total of $4,655, making the total estimated engineering costs for Phases I and II $5,795.

The work will be conducted by Ross Cudlitz, the engineer for the Oxford County Soil & Water Conservation District.

“The OCSWCD is a resource that Otisfield turns to for multiple issues regarding environmental impact on Otisfield’s resources,” Selectman Rick Micklon said. “For years Ross and the SWD have assisted us with road designs, Planning Board review of subdivisions, DEP Permit by Rules for storm water runoff, inspections of one of our bridges at Crooked River, design and implementation for a boat landing at Saturday Pond … just to name a few.”

Once the first two phases of the project are finished, Ferguson said the board may ask voters to fund the additional $10,000 needed to finish the assessment.

ldixon@sunjournal.com