Yahara Portal

Explore the legacy and future of the Yahara Lakes and Watershed

Lake Mendota

Lake Mendota is the northern-most lake in the Yahara Chain of Lakes. The lake is 9,847 acres and has 21.9 miles of shoreline. It is 83 feet deep at its deepest spot. It contains 17,834 million cubic feet of water. The lake has a maximum depth of 83 feet deep and a mean depth of 42 feet. About 217 square miles of land drain directly to the lake. The shoreline development factor is 1.57. The closer the shoreline development factor is to one, the more like it is shaped like a circle. A larger number indicates that there is more opportunity for growth along the shoreline. The lake takes about 4.5 years to flush out (0.22/year).

Five major tributaries, or streams, feed into the lake. The first is the northern-most tributary: the Yahara River and the Cherokee Marsh. The headwaters of Yahara River are in Columbia County, and the entire steam flows 127 miles to the Rock River in southern Wisconsin.  The Yahara River, Cherokee Marsh and Cherokee Lake are in the Lake Mendota subwatershed.

Cherokee Lake is 57 acres and about 20 feet deep. The lake was formed in the 1960s when part of Cherokee Marsh was dredged in the 1960s.The lake has a shoreline development factor of 2.27. The lake has 2.40 miles of shoreline.

The second tributary is Token Creek, located in the northeast portion of the Lake Mendota subwatershed. The 10-mile long creek originates near the City of Sun Prairie. Token Creek joins the Yahara River northeast of Cherokee Lake.

Token Creek is on the Wisconsin Department of Natural Resources’ list of impaired waters (303d list) for miles 2.9 – 6.35. This means the stream does not meet water quality standards because of problems related to flow, habitat, sediment, temperature, turbidity and stream migration. The stream should receive high priority for restoration to improve these impairments to meet water quality standards.

The third tributary is Sixmile Creek, a 12-mile long stream that originates northwest of the lake and flows south into the Waunakee Marsh and then east through the city of Waunakee and south through Governor Nelson State Park where it enters the north side of the lake.

Dorn Creek is the fourth tributary to the lake. It originates in the town of Springfield and flows through Governor Nelson State Park before joining with Sixmile Creek which flows directly to the lake. Dorn Creek is six miles long.  Dorn Creek is also on the 303d list for impairments related to bacteria and sediment for miles 1-6.46. It is also ranked as a high priority restoration area. 

The fifth tributary is the Pheasant Branch Creek. The 9-mile creek originates on the western portion of the Lake Mendota subwatershed and flows through the city of Middleton before flowing into Lake Mendota. Pheasant Branch is also on the 303d list of impaired waters for its entire length de to sediment. It is also ranked as a high priority stream.

 

Above: Hydrographic map (depth in meters). Source of map and table below: UW Center for Limnology

 

Surface Area (acres)

Volume (million ft.3 )

Depth (ft.)

Mean Depth (ft.)

Shoreline length (miles)

Direct Drainage Area (mi2)

Total Drainage (mi.2 )

Shoreline development factor

Flushing rate (per year)

Lake Mendota

9847

17,834

83

41.7

21.9

217

232

1.57

0.22