Variable milfoil (Myriophyllum heterophyllum) is an invasive plant that became established in Lake Winnisquam sometime around 1995. Milfoil growth has been primarily confined to the northern end of the lake near the loon sanctuary, Winnisquam Marine, Jay’s Marina, Sunray Shores (a dredged channel to developed land in Belmont), Ephraim’s Cove and Mallards Landing. NHDES surveys the lake each year to document where the areas of infestation are, and to determine if there are any new areas of growth. See the Milfoil Management Areas documented by NHDES.
Prior to the creation of the Winnisquam Watershed Network in 2017, milfoil management in Lake Winnisquam was conducted on a localized basis and some areas of infestation had not been treated in more than 10 years. The WWN’s approach is to conduct milfoil management throughout the lake each year with the ultimate goal of reducing or eliminating the milfoil growth in infested areas and preventing further spread. Funding for the program comes from State grants, local matches from each of the five municipalities on the lake, and contributions from neighborhood associations and members. For more details on variable milfoil, see the Environmental Fact Sheet from the NHDES.
For the second consecutive year the WWN will implement a lake-wide management plan for invasive variable milfoil. This year’s plan calls for a controlled herbicide application in approximately 30 acres of the lake (primarily in the northern channel, Jay’s Marina and Ephraim’s Cove), and up to 20 days of professional diver-assisted harvesting in areas of the lake with less-dense milfoil growth. Bids for the 2019 program total about $46,000. The WWN has been awarded an $11,600 Exotic Plant Control Grant from NHDES that will fund 25% of the work, and we’re in the process of lining up matching contributions from each of the five municipalities on the lake. In order to fully fund the program we’re also soliciting contributions from neighborhood associations and asking for your support.
The 2018 Comprehensive Variable Milfoil Management Program for Lake Winnisquam included the removal of variable milfoil from a number of locations along the lakeshore (including new locations identified by our new Weed Watcher Program volunteers) by diver-assisted harvesting by Gilford-based Aqualogic Inc. Throughout the summer a total of 843 gallons were removed. This was followed in September by a controlled herbicide application by SOLitude Lake Management in 19.5 acres where the milfoil growth was the densest. We were not able to treat the milfoil in Jay’s marina this year due to the recent reactivation of a public water supply well in close proximity to the treatment area there. We’re looking to treat this area next spring with an alternative herbicide that has recently become available and does not have the same use restrictions.
Our milfoil management program was funded through a grant from the New Hampshire Department of Environmental Services (NHDES), local matches from the towns of Meredith, Belmont, Tilton and Sanbornton and the City of Laconia, and contributions from several neighborhood associations, as well as our members. We extend our deep appreciation to all. This is the first time that management of variable milfoil has been undertaken on a comprehensive, lake-wide basis on Winnisquam, and it’s our intent to continue this collaborative effort for as long as is necessary to control the growth of the milfoil and prevent further spread. We’re currently working with the NHDES to finalize next year’s comprehensive milfoil management plan and have begun soliciting bids for the work.