Ottawa Lake Fen

State Natural Area (No. 128)

Location: Within the Ottawa Lake Recreation Area, Southern Unit Kettle Moraine State Forest, Waukesha County. T6N-R17E, Section 34 W½NW¼. 50 acres.

Access: From the intersection of County Highway Z and State Highway 67 in Dousman, go south on 67 4.9 miles to a parking area west of the highway. The easiest access is by canoe from a boat landing on the southwest side of Ottawa Lake.

Description: Ottawa Lake Fen features lakes connected by a deep marsh and extensive shallow marl flats with a unique assemblage of both alkaline and acid-loving plant species. Ottawa Lake is a remnant lake located in an old glacial lake basin at the edge of end moraine deposits. The smaller northern lake is fed by numerous seepage springs, bubbling springs, and cold inlet streams and flows south into the larger Ottawa Lake. An unusually large number of wetland and aquatic plant communities occur within the site including submergent and emergent aquatics, southern sedge meadow, and shrub carr. The extensive fen-like marl flats are dominated by the unusual beaked spike rush (Eleocharis rostellata), which roots from the tips of sterile culms. Other uncommon and rare plants include pitcher plants in a highly alkaline environment, few-flowered spike rush (Eleocharis quinqueflora), common bog arrow-grass (Triglochin maritimum), Ohio goldenrod (Solidago ohioensis), and small fringed gentian (Gentianopsis procera). The natural area is also rich in animal life including Blanding's turtle (Emydoidea blandingii), pickerel frog (Rana palustris), bullfrog (Rana catesbeiana), lake chubsucker (Erimyzon sucetta), clams, and snails. Wading birds and waterfowl frequent the shallows. Birds include green heron, blue-winged warbler, yellow warbler, and willow flycatcher. Ottawa Lake Fen is owned by the DNR and was designated a State Natural Area in 1976.