Winnisquam Watershed Network’s Milfoil Management Plan Getting Traction…

Continuing with its focus on strategic long-term milfoil management for all of Lake Winnisquam, the Winnisquam Watershed Network (WWN) is pleased to announce that it has been awarded an Exotic Plant Control Grant from the New Hampshire Department of Environmental Services.  This award of $11,380 for the management of variable milfoil in Lake Winnisquam catapults the WWN forward in taking its first step to address invasive milfoil growth across the entire lake.  Variable milfoil is an invasive aquatic plant that spreads rapidly and ousts beneficial native plant life, impacting water quality and aquatic habitat. It also makes swimming difficult and can devalue waterfront property.

The Winnisquam Watershed Network was formed in July 2017 with a mission to preserve and protect Lake Winnisquam for future generations. According to Lisa Eggleston, WWN President, milfoil management efforts on Winnisquam in recent years have been performed on a site-specific (spot-treatment) basis, depending on who had the resources and the wherewithal to get it done. Meanwhile, the milfoil infestations in areas that were not consistently treated have increased in size and density, and pose an ongoing risk of continued spreading to other parts of the lake. One of the first priorities of the WWN is the coordination and implementation of a strategic long-term milfoil management plan for all of Lake Winnisquam. The group believes that this, in conjunction with the prevention, public education and early detection measures that they will also implement, will be the most successful and cost-effective means of preventing the spread of variable milfoil in the lake and limiting its impact in areas that have already been infested.

Working with the WWN, staff from the Exotic Species Program of the New Hampshire Department of Environmental Services (NHDES) surveyed the lake in 2017 and mapped locations of variable milfoil throughout the shoreline areas of Lake Winnisquam. NHDES subsequently prepared a 2018 Long-Term Variable Milfoil Management Plan for Lake Winnisquam, calling for a controlled herbicide application in areas with the densest infestation (approximately 21 acres), and up to 25 days of professional diver-assisted harvesting in additional areas of milfoil growth.

The WWN has obtained competitive bids for the recommended work and estimates the total cost of the program for the 2018 growing season at $45,519. In addition to the NHDES grant covering 25 percent of the program costs, the WWN has requested local matches from each of the five municipalities bordering the lake, and is soliciting additional grants and donations to help fund the program. Donations (payable to Winnisquam Watershed Network) can be mailed to PO Box 502 Winnisquam, NH 03289, or made online at Together, we can all make a difference to preserve and protect our great lake!


2017 Water Quality Results Reported


“The 2017 water quality data from Mohawk Island, Pot Island, and Three Island indicate that the lake represents ideal water quality conditions in comparison with NH state water quality standards and thresholds. Lake Winnisquam sup-ports an oligotrophic lake classification as phosphorus and chlorophyll-a levels are consistently below the oligotrophic thresholds, and water clarity and dissolved oxygen levels are high. The decreasing (improving) phosphorus trend sug-gests that nutrient loading into the lake (from fertilizers, pesticides, agricultural runoff, septic failure, etc.) has been decreasing throughout the watershed over time. Apparent color measured in the epilimnion indicates that the overall lake color is clear with little dissolved organic matter that imparts a tea color to the water. Turbidity is consistently low (good) suggesting minimal suspended solids and particulate matter. This is further supported by the high water clarity (transparency). Conductivity levels are slightly elevated and higher than the state median of 40.0 uS/cm and have sig-nificantly increased (worsened) over time. Chloride levels are between 10 and 20 mg/L, which is above the NH state median of 4 mg/L, but well below the NH state chronic chloride standard of 230 mg/L. The increasing conductivity lev-els are most likely a result of road salt usage on impervious surfaces that enters the lake through stormwater runoff and groundwater discharge. Lake pH levels are generally within an ideal range for aquatic life. The ANC level indicates that the lake is moderately vulnerable to changes in pH from acid rain and other pollutants. Best management practic-es for road salting, development, and stormwater should be implemented throughout the watershed as increased fre-quency and intensity of precipitation events will continue to impact water quality. Refer to “Ready, Set, Action” on the next page for collaborative watershed management considerations that can be executed to effectively protect lake water quality health.”


Lake Winnisquam Report-Final