Welcome to the website of the Northwood Lake Watershed Association. Through our website, we seek to keep members, non-members and all those who care about Northwood Lake and its watershed informed and involved in maintaining and enhancing the health and beauty of this precious waterbody.
Northwood Lake Milfoil Control- A Review of Where We've Been, and a Look Ahead
By Amy P. Smagula, Limnologist/Exotic Species Program Coordinator at the NH Department of Environmental Services
Variable milfoil (Myriophyllum heterophyllum), an invasive aquatic plant, became established in Northwood Lake around 1990. The size of the infestation has fluctuated over time, growing to cover nearly one-half of the surface area of the lake at one point, and being reduced to less than 20% of the lake area in other years following herbicide treatments.
In the past, both in Northwood Lake and elsewhere, invasive plant management has been more reactive to periods of milfoil growth, where herbicide treatments were performed to reduce growth, and not much was done until the growth was back up to a level that warranted treatment again. Not a lot of progress was being made to reducing the overall biomass of the milfoil for a sustained period of time. Now, a more integrated approach at management is being used, including physical, mechanical and chemical controls, as appropriate, and mapping technologies have advanced to allow lake biologists to better track growth over time in a waterbody.
In recent years, the Northwood Lake Watershed Association (NLWA) has taken a much more proactive and varied approach at milfoil management, including more thorough mapping of the lake to identify areas of milfoil growth, and incorporating other management techniques, such as diver hand removal and Diver-Assisted Suction Harvesting (DASH) to keep milfoil densities low, before they reach high densities in the lake that would necessitate treatment.
In 2014, DES will come out to do a thorough survey of the lake using sonar and handheld GPS units to survey areas of milfoil growth, to ultimately create more detailed maps to help guide management in the future. Maps will be used to identify areas of higher milfoil density that may require possible herbicide treatment. Areas that are identified as sparse or moderate density will be targeted with simple diver hand removal work, or with DASH. The NLWA is also considering having a certified diver perform some survey work underwater, for the areas that are hard to see from a boat due to dark water and greater depths.
Having more detailed maps will allow DES and NLWA to triage areas of active growth, and identify the most appropriate management strategy to target the milfoil plants. While eradication of variable milfoil in the Northwood Lake system may not be feasible, maintaining it at low levels (less than 10% cover) in the lake overall is attainable through this integrated management approach. This will allow for enjoyment of the lake without impairing recreational uses due to thick milfoil beds, and it will help cut down on fragmentation (chopping and spread) of the plants by boats and other lake users.
DES is able to award NLWA a milfoil control grant for 2014, to help offset some of the costs of milfoil management.
Look for more information to be available once DES has performed a spring survey of the lake, and be sure that you will see lots of milfoil control activities underway on the lake this summer.
Check Out the Northwood Lake WebCam!
Updated hourly and positioned on the northeastern shore of the lake, the webcam gives those of you who are not presently on the lake a chance to view current conditions. Though the resolution is somewhat limited, you can still get an idea of weather, ice conditions and water level.
Make Sure You Are In Touch With The NLWA
We are looking forward to making extensive use of our membership email list in order to stay in touch and keep everyone up to date as to what's going on with the NLWA. If you are not receiving email from the association, or have changed your email address, please contact us at firstname.lastname@example.org so that we can keep our list as complete and current as possible. We want to keep everyone in the loop!