Lake Susan
Located in Chanhassen, Lake Susan is a part of the Riley Creek Chain of Lakes. It is the third lake that Riley Creek flows through as it makes its way to the Minnesota River.
Lake size: 88 acres
Watershed size: 1,231 acres
Average lake depth: 10 feet
Maximum lake depth: 17 feet
DNR - Lake Susan/Rice Marsh Lake depth mapDNR Shoreland classification: Recreational Development
MPCA lake classification: Shallow lake (average depth less than 15 feet)
MPCA Impaired Waters status: Impaired for nutrients; Impaired for mercury in fish tissue
Invasive species: Eurasian Watermilfoil, Curlyleaf Pondweed, Common Carp, Brittle Naiad, Purple Loosestrife
Water Quality
Lake Susan is classified as a “Shallow Lake” by the MPCA. To be considered healthy, the lake must have very low average phosphorus and chlorophyll-a levels and an average water clarity of 1.0 meters (3.3 feet) or greater.
From June through September every year, District staff visit this and other lakes every two weeks to collect water samples and take readings. Samples are sent to a laboratory to be tested for nutrients and other compounds. Staff also measure water clarity by lowering a Secchi disk into the water and measuring how deep it goes before it is no longer visible. The data indicates the lake’s health based on standards set by the MPCA.
For water quality summaries for this and other lakes, visit the factsheets page.
Lake Grade
RPBCWD staff assigned this letter grade to the lake based upon how well it is meeting water quality goals. Learn more about lake water quality grades.
For more information about waterbody impairments, visit the Minnesota's Impaired Waters List webpage managed by the Minnesota Pollution Control Agency.
