Milfoil Project

CLF began Eurasian watermilfoil control in 2008 and, with donor support, efforts have continued each summer since then. The CLF has used a variety of methods including hand-harvesting, benthic matting and suction harvesting to control the milfoil.

We are continually evaluating new methods of control and speaking with our partners throughout the Adirondack Park to learn more about how to address the significant issues facing us. The highest priorities for control are heavily infested sites that are sources for spreading the milfoil due to wind and water currents or heavy boat traffic.

Surveys show that Eurasian milfoil infests 360 acres of the lake system, including 227 acres that are densely infested (where milfoil covers more than 25 percent of the lake bed). To date, about 100 acres have had two or more years of treatment. Milfoil density declines sharply following treatment, but treated areas must be maintained.

The ongoing challenge is to raise funds to maintain and expand the areas brought under control.

Maps and Surveys

The CLF relies on surveys and mapping to track the location, size and density of milfoil beds. The extent of the lake’s milfoil beds prior to the start of control is shown in a 2006 map prepared by the Adirondack Watershed Institute. In 2010, AWI revisited the Narrows and Lower Lake, resulting in more detailed maps of milfoil density. In 2014, AWI produced a map of milfoil density for the South Inlet of the Upper Lake. Since 2019, maps of the South Inlet have been updated each year by volunteers using the Lake Management Tracker survey method to track milfoil conditions at specified GPS waypoints. In 2021, a comprehensive survey of the entire shoreline was conducted to map aquatic vegetation lake wide, including the current location and density of milfoil beds. These surveys and maps help with planning treatment.

Milfoil Control

The CLF contracts with a dive company each summer to do selective hand harvesting of the Eurasian watermilfoil and any other aquatic invasives they discover in our lake. These divers are specially trained to remove invasives without harming the native vegetation. The crews generally consist of two divers below the surface breathing through a tube system called a hookah rig floating above and a spotter in a boat on the surface. Divers pull milfoil from its roots, place the plant in a mesh bag, and swim the filled bags to the surface. The spotter then loads the bags onto a boat for removal at the end of the day to a dump trailer. This is labor intensive, highly specialized and expensive work.

For the last several summers, CLF has contracted with Invasive Solutions Dive Company to perform the hand harvesting work. Through your contributions, we have been able to maintain a four – to six week harvesting schedule, contracting for milfoil removal work in each part of the lake.   In 2022, the divers harvested a total of 12 tons of milfoil from trouble spots throughout the lake, including the boat launch, upper Narrows sand bar, inlet to the Lower Lake and the south inlet of the Upper Lake.

Composite Treatment Maps

Invasive Solutions Dive Company reports their harvesting efforts showing the location of each harvested bag of Eurasian Watermilfoil represented as a colored dot. In 2020, they reported the results as a composite of milfoil harvested over a three year period. Yellow dots represent 2018, orange dots represent 2019, and red dots represent 2020. In addition, the dive crew harvest any curlyleaf pondweed, another invasive aquatic plant, when they locate it. Curlyleaf pondweed is represented on the map in shades of blue and as individual plant stems harvested.

Spread Prevention

Marker Buoys

The CLF has buoys that mark a large dense bed in the South Inlet of Upper Chateaugay Lake. We urge all boaters to keep clear of the marked zone in this portion of the lake. If you must enter this area, reduce your speed and remove any accumulated milfoil from your boat and motor before exiting this area. Always dispose of milfoil on land.

In 2022 marker buoys in the inlet to Lower Chateaugay Lake to mark a milfoil free boating lane.

Boaters should travel between the buoys as they go to and from the narrows.

Boat Stewards

Boat Stewards

Since 2012 the Adirondack Watershed Institute (AWI) has provided boat stewards at the DEC boat launch located on the Narrows. Funding is currently provided by the NYSDEC under a five year plan. These stewards inspect boats entering and leaving Chateaugay Lake during the height of the summer season. Recently, a decontamination station was added to the boat launch allowing for boats and trailers to be cleaned to prevent the spread of invasives.