Aquatic Weed Management Program

At the recommendation of the Thornapple River SAD Ad-Hoc Committee, the Township solicited bids for a multi-year aquatic weed management program, which began. in 2022. Through that process, PLM Lake and Land Management Corp was selected to develop and implement a three-year program.

2024 Weed Management Program Information

This year's aquatic weed management program is still in the planning stages. Specific dates for river treatment, mechanical harvesting and water quality monitoring have not been set. Please monitor this webpage for updates, or subscribe to our Thornapple River SAD email updates.

Goals of River Management Program

Summarized from PLM Lake & Lake Management Corp. Letter:

Remove Eurasian watermilfoil: The primary goal of aquatic plant management in the Thornapple River is to control the growth and spread of exotic aquatic plants. Eurasian watermilfoil, a highly invasive aquatic plant species, is the predominant invasive plant found in the SAD section of the Thornapple River.

Preserve and support native species diversity: Growth of native plants that support the Thornapple River fishery (by creating structure and habitat) will be encouraged, provided they do not excessively interfere with recreational uses of the river (e.g., swimming and fishing) in high-use areas.

Manage aquatic cover (native and invasive): In areas of the SAD where native aquatic plants reach recreational nuisance levels, management techniques that reduce the height of these plants without killing them (e.g., harvesting, contact herbicides) will be used whenever possible. Specific areas will be set aside where native plants will not be managed to provide habitats for fish and other aquatic organisms.

Please note: PLM Lake & Land Management Corp. does not manage or monitor levels of PFAS (Per- and Polyfluoroalkyl substances) in the Thornapple River. For more information on PFAS, visit the Township's PFAS webpage.


  • Herbicide and Algaecide treatments
  • Mechanical harvesting (removal) of nuisance species
  • Water quality analysis
  • Conduct pre- and post-treatment surveys
For more details, please read PLM's Letter to the Township for the 2024 season.

If you have any questions about the program, contact Township Manager Jade Smith at or by phone at 616-949-1500.