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Lake Ronkonkoma Watershed Management Plan



Lake Ronkonkoma is the largest freshwater lake on Long Island. Lake Ronkonkoma was once a popular Long Island summer resort in the late 19th and early 20th centuries. Suffolk County, the Town of Brookhaven, Town of Islip, and Town of Smithtown all own parts of the lake surrounding shoreline. Working together as members of the Lake Ronkonkoma Inter-Municipal Organization and Lake Ronkonkoma Advisory Board these groups advance issues pertaining to the lake surrounding the watershed.


circa 1915

Lake Ronkonkoma is listed on NYS Department of Environmental Conservation’s 303(d) List of Impaired Waters requiring water quality development. Water quality is threatened and public bathing and recreation is impaired. Known pollutants include pathogens such as cyanobacteria and phosphorous and suspected sources include but are not limited to urban/storm runoff.

Suffolk County received $60,000 in grant funding provided by the New York State Department of State under Title 11 of the Environmental Protection Fund to hire Cashin Associates, a professional consultant who was publicly procured through a Request For Proposal (RFP) process, to create a comprehensive Watershed Management Plan. Working with the community, Cashin will gather input, collect and analyze watershed data, and develop management recommendations for both restoration and protection of water quality and public access within Lake Ronkonkoma and its watershed. You can help too by providing your input.



The goal of the project is to outline priorities and projects that will help restore the Lake to a fully functioning recreational space, improving water quality and contributing to a greater quality of life. The restoration of the Lake and surrounding watershed will contribute to economic development at the future, fully completed Ronkonkoma Hub by serving as a free cultural attraction that will enhance downtown living and help create a stronger sense of place within the community. Matching funds for this project will be provided through in-kind services of Suffolk County staff to assist in Watershed Management Plan preparation and project management.

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901