Use of Aquatic Herbicides

To Lake Front Property Owners:   Please report sightings to the DEP of suspected invasive plants instead of taking action on your own.  Recent news about the invasive plant Eurasion watermilfoil have led some people to take inappropriate action against valuable lake plants. These actions range from physical removal to the illegal use of aquatic herbicides.

While aquatic herbicides can be easily purchased in stores, mail order catalogs and over the Internet, people may have the misimpression that these chemicals are safe when they are not. Herbicides can be hazardous to the environment as well as the applicator. That’s why applying these without proper permission is a serious legal offense. Most catalogs and other product information sheets do not mention the Maine permit requirement.

Maine requires a permit from the DEP* and an applicator’s license from the Pesticide Control Board to apply aquatic herbicides (or any other pesticides) to waters of the state. Homeowners are allowed to hand-remove a swath of vegetation 10 feet wide perpendicular from their shoreline out into the lake. This will allow a place to swim and a passage for boats. To do this, an owner needs to get a “Permit by Rule” from DEP. Although a quick and simple process, PBR carries clear standards which must be met.   For information about permit by rule or if you have questions, contact your nearest regional DEP office.  Chapter 305 (which contains standards for various PBR activities) and PBR forms are also available on the Natural Resources Protection Act Page.

*Putting any aquatic herbicide or algicide into any waters of the state requires a wastewater discharge permit from the DEP.   Applications for permits to apply aquatic pesticides are rarely approved, and successful applications usually are submitted by state resource management agencies or their contractors. Approved projects must provide for application only by licensed applicators.

“Waters of the state” means “any and all surface and subsurface waters that are contained within, flow through, or under or border upon this State or any portion of the State, including the marginal and high seas, except such waters as are confined and retained completely upon the property of one person and do not drain into or connect with any other waters of the State, but not excluding waters susceptible to use in interstate or foreign commerce, or whose use, degradation or destruction would affect interstate or foreign commerce.” 38 MRSA 361-A(7)

If a seemingly closed system actually overflows to a nearby stream, pond or  hydrologically-connected wetland, it is considered waters of the state.

February 2020: DEP document regarding use of herbicides on established invasive aquatic plant infestations

2024  

The Warmest Year in History on Thompson Lake

Each year, TLEA retains Scott Williams, Limnologist with Lake & Watershed Associates (Turner, Maine) to take samples and assess the current status of Thompson Lake water quality.  In late June 2024, Scott measured the surface temperature of Thompson Lake at 78.8 F. This is unusually warm compared to historical data.  Lake temps everywhere are about 10 degrees warmer than they were 30 years ago, and the temps this summer are the highest on record for most lakes. This is a trend affecting all Maine lakes because of the effects of climate change.

Also, Thompson Lake presently has a high level of humic compounds from vegetative runoff that darkens the water and absorbs heat. This, combined with the unusually hot weather, results in greater heat retention.  The humic compounds are mostly from the heavy rains of 2023 and will flush out in about three years.

Warmer lake water causes dissolved oxygen levels to be lower, which could adversely affect the salmonid fish, such as salmon and lake trout. So far, Scott has not seen reduced dissolved oxygen levels in the deep regions of the lake.

Higher temps also favor the growth of algae such as cyanobacteria (aka: Bluegreen algae). To date, we have not observed any elevated levels in Thompson – due largely to the fact that phosphorus levels in the lake continue to be low (a good thing!). Fortunately, very little precipitation occurred during the recent lengthy hot period. Stormwater runoff containing phosphorus, combined with the unusually warm water might have otherwise significantly increased cyanobacteria levels.

To date, our Secchi disc readings of water clarity for May, June and July have been somewhat lower than historical numbers, due partly to the fact that the water color level remains higher than the historical average, and likely from the moderate rain in the spring and early summer. Weather in early August will have a critical bearing on how the lake fares in August and September.

Annual Water Quality Reports can be found under “Programs”, “Water Quality” and at https://thompsonlake.org/programs/water-quality/.

Also check out “Update”, “Ice Out” to see 122 years of data for the Ice Out date for Thompson Lake; also at  https://thompsonlake.org/ice-out/.

And you will also be interested in this report from Maine Public- https://www.mainepublic.org/climate/2024-08-26/climate-change-is-overheating-maines-pristine-lakes

 Thompson Lake Watershed Survey

The Watershed Survey Report is available!

In May of 2023 TLEA volunteers and Technical Leaders surveyed the entire watershed of Thompson Lake. This nonregulatory survey was done to identify erosion sites and develop a Watershed Protection Plan for the next 10 years. We identified 299 sites that had significant erosion. Erosion, a form of non-point source pollution (NPS) is the biggest threat to the water quality of the lake. Property owners can go to the “Watershed Survey” page under “Programs” on this website to see the results of the survey. The Report lists sites of erosion, their level of impact, and what kind of remediation measures are recommended. Check it out by clicking:

2023 Watershed Survey Report

 Thank You

to Everyone

who attended Our

2024

Annual Meeting

2024 Summer

   OBSERVER

   NOW

   AVAILABLE

See “Publications” above

Youth Conservation Corp —  a Busy 2024 Summer

Local Students Receive Summer Employment and Environmental Education

TLEA’s YCC Program for Summer 2024  was busier than ever!   YCC Project Coordinator Chris Stoehner and TLEA YCC Board Member Jim Skinner worked closely with Thompson Lake homeowners to inspect erosion issues, develop work plans, obtain any necessary permits, provide cost estimates and complete the remediation work.

If your property needs attention, please contact Jim Skinner at YCC@ThompsonLake.org.

For info,  email:  YCC@thompsonlake.org

Learn More About the Youth Conservation Corps

Learn more about Youth Conservation Corp crews who focus on erosion-control efforts and other activities that improve lake and water quality. At the Maine Lakes Conference in 2023, Whitney Baker from 30 Mile River watershed association shared an overview of the YCC program, and her perspective from a staffed regional watershed organization. Jim Skinner from Thompson Lake Environmental Association will share his perspective from a lake association that relies on volunteers to run and manage the program. Both speakers will share “lessons learned”, ideas for success, and some of the challenges they’ve faced organizing YCC crews for their lake and their region.
More information can be found at the Maine Lakes Conference website.