Senator Harckham Lauds Innovative Treatment of Lake Mohegan for Harmful Algae Blooms

Pete Harckham

April 23, 2019

Treatment could improve water quality after decades of pollution

(Mt. Kisco, NY) Senator Pete Harckham held a press conference today, along with Ken Belfer, president of the Mohegan Lake Improvement District and Ilan Gilbert, Town of Yorktown Supervisor, to highlight the application this week of an innovative treatment for Lake Mohegan. The lake, which has very high levels of phosphorus, has been plagued by harmful blue green algae blooms for decades causing closure of its swimming beaches when heavy blooms were present.

“Human activity and development around Lake Mohegan over the past century, have created conditions responsible for the growth of toxin producing algae blooms, “ said Senator Pete Harckham, 40th Senate District. “We must leave the next generation healthy waterways. I want to congratulate the people from the Mohegan Lake Improvement District for their tenacity and hard work over many years to make this pilot program a reality. If this treatment is successful and water quality improves, we’ll have a new, powerful tool in our arsenal to clean up lakes with high phosphorus levels and excessive harmful algae growth in our district and the state.” 

"This treatment could be a 'game changer' for Lake Mohegan, immensely improving the water quality in the summer beach season, and eliminating the potential health risks from the blue green algae blooms,” said Belfer. “We want to thank Senator Harckham, Governor Cuomo and the DEC for making this pilot program possible."

Last winter, the Mohegan Lake Improvement District, a special tax district formed to improve the quality of the lake, asked Governor Cuomo and the State Department of Environmental Conservation, to use Lake Mohegan for a pilot project to test the effectiveness of nutrient inactivation in decreasing blue green algae.  Both Lake Mohegan and Peach Lake were chosen for the pilot program.

Lake Mohegan has very high levels of phosphorus that has accumulated in the sediment at the lake bottom which fuels the excessive algae growth. The pilot project involves treating the lake with Alum (aluminum sulfate). Alum forms a stable bond with phosphorus in the water column, precipitating it out of the water column and binding it in the sediment so that it is not bio-available to fuel excessive algae growth in the summer. 

The pilot project includes two years of study of the impacts of nutrient inactivation on all aspects of the lake ecology. Lake Mohegan is a natural lake of 103 acres, approximately one mile long. The lake is used for swimming, boating and bass fishing.

New York State Senate District 40 includes parts of Northern Westchester (Briarcliff Manor, Buchanan, Cortlandt, Croton-on-Hudson, Lewisboro, Mount Kisco, Mount Pleasant, New Castle, North Salem, Peekskill, Pleasantville, Pound Ridge, Sleepy Hollow, Somers, Yorktown) Putnam (Brewster, Carmel, Patterson, Southeast) and Dutchess (Beekman, Pawling).