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.  In 2025, Cascade Township signed a new multi-year contract with PLM.
 

2025 Weed Management Program Information

UPDATE: The first 2025 river treatment is planned for Thursday, June 5th.  There will be a one day swimming restriction within the posted areas, near shore  The only offshore areas of the river being treated are near the golf course.  This restriction is put in place by EGLE to ensure residents are not in the water at the time of treatment. 

PLM surveyed the river on March 24 and determined that there was river treatment needed.  The areas are to be treated the week of June 2, the week of July 7, and the week of August 11, if needed.  The upstream section of the river will be harvested the week of July 28, if needed. 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.
 

Methods

  • 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 2025 season.

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