Lake Mendota is a 4000 ha, clearwater, eutrophic lake in an agricultural and urban watershed in southern Wisconsin, USA. It is one of eleven primary study lakes of the North Temperate Lakes Long-Term Ecological Research program. With a maximum depth of approximately 25 meters, Lake Mendota is stably stratified during the summer, mixes in the spring and fall, and is ice-covered during the winter. Because of the agricultural nature of the watershed, non-point phosphorus loading is a central issue confronting lake managers and the public.

Madison Lakes. Courtesy of UW Environmental Remote Sensing Center

Lake Mendota Characteristics

Latitude: 43° 5′ 54.00″ N
Longitude: 89° 24′ 19.00″ W
Lake Area: 3,938 ha
Maximum Depth: 25.3 m
Mean Depth: 12.8 m
Chlorophyll a: 8.6 ug/L
Secchi Disk Depth: 3.4 m
Total Phosphorus: 118 ug/L
Total Nitrogen: 1,080 ug/L
Acid Neutralizing Capacity: 3,714 ueq/L
Dissolved Organic Carbon: 6.4 mg/L


* Chlorophyll a: average of surface values for open water season
* Secchi Disk Depth: average of June through August samples
* Total Phosphorus: average of spring mixis values
* Total Nitrogen: average of spring mixis values
* Acid Neutralizing Capacity: average of spring and fall mixis values
* Dissolved Organic Carbon: average of surface values for monthly measurements since 1996

More Information

For more detailed information about Lake Mendota and other lakes in the area, please visit the Lakes page of the North Temperate Lakes Long Term Ecological Research Project, one of MeRG’s outside collaborating groups.