DEP to hold public meeting regarding proposed aquatic herbicide treatment of a portion of Cobbosseecontee Lake

June 28, 2019

Contact: David Madore, Communications Director (207) 287-5842 or John McPhedran, Invasive Aquatic Plants Program (207) 215-9863

AUGUSTA, June 28, 2019 - Maine Department of Environmental Protection (DEP) will hold a public meeting on a proposed herbicide treatment of a portion of Cobbosseecontee Lake in Winthrop. The meeting will be held on Wednesday, July 10, 2019 at 6:30PM in the Winthrop Town Office multi-purpose room located at 17 Highland Avenue, Winthrop.

DEP's Invasive Aquatic Species Program (IASP) intends to file an application, called an Notice of Intent (NOI), with DEPs Division of Water Quality Management for a permit to discharge the aquatic herbicide Procellacor EC (active ingredient florpyrauxifen-benzyl) into a 4-acre area of 5,516-acre Cobbosseecontee Lake. The proposed treatment area is between Island Park and the mainland were Eurasian water-milfoil was found in July 2018. The treatment will be completed in one day and will occur mid-summer.

The treatment goal is to eradicate Eurasian water-milfoil from the lake. Eradication is difficult to achieve but may be possible since the plant was discovered early in its establishment. The treatment is part of a management plan that includes diver removal of any remaining plants.

Upon treatment, the Invasive Aquatic Species Program will post the following advisories for the 4-acre treatment area:

  • Do not use lake water for hydroponic, greenhouse or nursery irrigation before contacting the DEP to confirm the herbicide has dissipated
  • Do not use lake water for any residential or non-agricultural irrigation (such as shoreline property use for irrigation of residential landscape plants and homeowner gardens, golf course irrigation, and non-residential property irrigation around business or industrial properties) for 3 days following treatment
  • There is NO swimming restriction for the herbicide (florpyrauxifen-benzyl) but the DEP advises residents not to swim within the treated area on the day of treatment as an added safety measure

Lakeside residents, boat operators and vacationers can help reduce the spread of invasive aquatic plants by boats, trailers, and associated equipment to Maine waters by conducting boat inspections before moving boats between waterbodies. DEP recommends the following:

  • Clean off any mud, plants and animals from the boat, trailer, motor and other equipment. Discard removed material in a trash receptacle or on high, dry ground where there is no danger of washing into the water body.
  • Drain all water from boat, boat engine, and other equipment away from the water.
  • Dry anything that comes into contact with the water. Drying boat, trailer and equipment in the sun for five days is recommended if rinsing your boat, trailer parts and other equipment with hot, high pressure water is not an option.

Learn more about the Invasive Aquatic Species Program by visiting Maine DEPs website at: