Milfoil Control
February 2026 Update | In 2025, the VLAP team, Jim LaDine, Frank Belfsky and Russ Phillips, sampled the lake waters in June, July and August. We were pleased to see CLAPA members participate in sampling. Thanks to Bob Lincourt and Tom Whitney. Samples are generally taken at eleven locations, but as the summer progressed several tributaries dried up due to lack of rain. The water quality remained generally good. Trends in lake water quality seemed to benefit from the thick ice and heavy snow of ‘24-’25, and the favorably harsh winter seems to be repeated in the ’25-‘’26 season.
The lake was able to substantially reduce some nutrients, but not others, and we look forward to seeing if the trend line sustains a second year of improvement
The collection of annual results is presented below. In 2026, we aim to reduce testing to once per year and we are evaluating ways to evaluate the lake on an infrequent basis for pollutants as well as aquatic nutrients.
The lake was able to substantially reduce some nutrients, but not others, and we look forward to seeing if the trend line sustains a second year of improvement
The collection of annual results is presented below. In 2026, we aim to reduce testing to once per year and we are evaluating ways to evaluate the lake on an infrequent basis for pollutants as well as aquatic nutrients.
| vlap_chemical_parameter_explanations.pdf |
| contoocook_jaffrey_july.pdf |
One of our major ongoing maintenance efforts has been to control the invasive species variable milfoil in our lake. Our monitoring, diving, and treatment efforts have resulted in a significant reduction of new plants since 2018. Click HERE for an update! And attend one of our yearly meetings to learn more and get involved. Click this LINK to be directed to our contact page. Thank you for your support.
In August of 2025 we applied for a grant from the NH Department of Environmental Services (NHDES) to help control the variable milfoil in
Contoocook Lake.
In November we went out for bids from four local vendors for both SCUBA hand harvesting and Diver-Assisted Suction Harvesting (DASH).
In late December CLAPA received word from NHDES that it was awarded a2026 Exotic Aquatic Plant Control matching grant. The total grant award of $7,360.00 will pay up to 50% of the milfoil abatement cost associated with up to 12 days of S CUBA diver hand or DASH harvesting. CLAPA will be using Twin State Expedited Dive Services, LLC, (the low bidder) again this year to perform the milfoil harvesting services. NHDES will conduct a survey of Contoocook Lake in early spring to determine where on the lake dive services will be required. We are optimistic that the ProcellaCOR herbicide treatment that was applied last year will provide slower growth of variable milfoil in our lake for the coming season. Once NHDES has completed their lake survey in the spring we will be provided with an updated map indicating where variable
milfoil was identified. The map below was generated last fall after the herbicide treatment. The lake required only one day of SCUBA diver hand harvesting because the herbicide treatment was so effective.
In August of 2025 we applied for a grant from the NH Department of Environmental Services (NHDES) to help control the variable milfoil in
Contoocook Lake.
In November we went out for bids from four local vendors for both SCUBA hand harvesting and Diver-Assisted Suction Harvesting (DASH).
In late December CLAPA received word from NHDES that it was awarded a2026 Exotic Aquatic Plant Control matching grant. The total grant award of $7,360.00 will pay up to 50% of the milfoil abatement cost associated with up to 12 days of S CUBA diver hand or DASH harvesting. CLAPA will be using Twin State Expedited Dive Services, LLC, (the low bidder) again this year to perform the milfoil harvesting services. NHDES will conduct a survey of Contoocook Lake in early spring to determine where on the lake dive services will be required. We are optimistic that the ProcellaCOR herbicide treatment that was applied last year will provide slower growth of variable milfoil in our lake for the coming season. Once NHDES has completed their lake survey in the spring we will be provided with an updated map indicating where variable
milfoil was identified. The map below was generated last fall after the herbicide treatment. The lake required only one day of SCUBA diver hand harvesting because the herbicide treatment was so effective.
DES Letter 2025
Help reduce invasives in our lake: if you see milfoil, please report its location ASAP via email to [email protected]. Milfoil float markers to mark sightings will be available for members and the public at the boat ramp during Lake Host hours or pick-up can be arranged via email: [email protected] or 978-257-1865.
For more information on milfoil and other invasives currently threatening New Hampshire lakes visit: www.nhlakes.org/wp-content/uploads/Lake-Host-AIS-Identification-2019-1.pdf
For more information on milfoil and other invasives currently threatening New Hampshire lakes visit: www.nhlakes.org/wp-content/uploads/Lake-Host-AIS-Identification-2019-1.pdf