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Lake Arrowhead:  Fighting the Green Monster

Spiny green fingers reach up from the bottom for most of the motorboat trip around 1,100 acre Lake Arrowhead.  Even in the middle of the lake, where these underwater fields of green stalks are hidden in the deeper water, it is apparent this lake is a milfoil minefield (photo).  As one of 29 lakes in Maine with a milfoil problem, Lake Arrowhead, in Limerick and Waterboro, could be the poster child for the ugly invasive species that wipes out fish populations by destroying native habitat.

The Lake Arrowhead Conservation Council (LACC), a group similar to KLA, began as a homeowners’ group in 2007, to confront the persistent nuisance and growing threat of invasive aquatic plants.  They developed a DASH boat (Diver Assisted Suction Harvester), and protocol, with input from other groups “battling” variable milfoil in Maine, the Volunteer Lake Monitoring Program and Maine DEP.   The DASH unit is a modified pontoon boat, with a vacuum motor and a large flexible tube, into which a certified scuba diver feeds the freshly-extracted milfoil for delivery into baskets on board the boat (photo). In 2010, they launched a second DASH unit, and in 2011, there were two DASH units operating five days a week, for eight hours a day, from June 20 to September 2.  

This clean-up effort employed four scuba divers and four captains, at a cost of about $40,000 a season.   Approximately $6,000 of this comes from grant funding through Maine DEP (the result of the boat sticker program); the rest of the money comes from LACC’s ongoing fundraising efforts – yard sales, fishing tournaments, golf tournaments, 50/50 cash raffles and other activities.  In 2013, the two DASH units harvested 78 baskets (4,368 cu. ft.) of milfoil from Lake Arrowhead.  

Milfoil in Lake Arrowhead will never be fully eradicated, as fragments of the plant can develop into full-blown colonies in just a short time, threatening recreational use of the lake.  The challenge is to stay in the fight against its spread!  That means preventing its spread in Lake Arrowhead and to other bodies of water.

In addition to the development of the DASH, LACC has been a leader in building the arsenal of techniques to contain and reduce the spread of milfoil.  These techniques include:

  • Construction of 250 triangular, relatively easy-to-handle, benthic barriers, which can be placed on thick growths of milfoil to prevent sun from reaching it and thus preventing photosynthesis, effectively killing the plants—for a while!  There have been reports that this technique can effectively kill the plants in 8-10 weeks, but perhaps it can depend on things such as how impenetrable the barrier material is to light, how deep and “intermeshed” the root system is, etc., etc.

  • Raking of beaches to remove the debris, including milfoil that washes up onto them, and putting that debris into appropriate containers to be hauled away.

  • Placement of large boulders at access points to public beaches effectively disabling them for use as launch sites by cars and trucks with trailers.

  • Closing of public launch sites except one.


Pro-active Courtesy Boat Inspection (CBI) program, which runs from Father’s Day to Labor Day, inspecting boats seven days a week (eight hours on weekdays and ten hours on the weekends). As Dave Sanfrason, vice president of LACC, says, “Our inspectors have more documented more