Little Menomonee River

Habitat Restoration Project

The Department, through its Ecological Division – Fish Passage Program, is implementing an aquatic connectivity and large-scale habitat restoration and enhancement project on a publicly owned parcel on the Little Menomonee River in the City of Mequon. Approximately 3.77 miles of mainstem channel on the Little Menomonee River and Little Menomonee Creek between County Line Road and Freistadt Road had historically been altered through construction of road and stream crossings and dredging and artificial straightening of historic wetlands and stream corridors resulting in an incised channel hydrologically disconnected from adjacent riparian floodplain and wetland areas, which provide high quality habitat for spawning northern pike and other aquatic and terrestrial species.


The primary goal of this project has been to develop comprehensive engineering and design plans for permitting and to conduct construction and restoration activities (with aquatic organism passage projects as a priority) at a parcel previously owned by MMSD on the Little Menomonee River to holistically improve aquatic connectivity in the watershed and enhance the channel, riparian corridor, wetland and floodplain systems within the project area. The property was acquired from the Milwaukee Metropolitan Sewerage District in 2021 and added to the Ozaukee County Park System. This site was originally identified by the County as high priority for restoration and preservation.

The Department received funding in 2017, from the Fund for Lake Michigan, and in 2019, from the Wisconsin Coastal Management Program, to support engineering and design to holistically improve aquatic connectivity in the watershed.

Ongoing restoration work by Ozaukee County started in 2019 and these activities have improved the function of the Little Menomonee River by creating a channel that is appropriately sized for its watershed, is connected to a regularly inundated floodplain, and has a self-sustaining, natural meander geometry. The new stream channel provides high quality, diverse in-stream, wetland, wet prairie, and forest habitat for fish, birds, reptiles, amphibians, and mammals, improves water quality, and reduces flooding and erosion risk. In March 2021, the Ozaukee County Highway Department completed the remeandering of the remaining portion of the new stream channel (approximately 400 linear feet), installed woody debris for in-stream habitat, installed the fish passage culvert within the new stream channel with seeding of disturbed areas (and removed the old collapsing culvert), and reconnected the emergent marsh wetland to the Little Menomonee River (new channel).

In addition to the stream restoration, an ephemeral wooded pool has been created to provide habitat for amphibians and reptiles, an emergent marsh has been created to provide habitat for fish, and a deeper wetland with open water and marsh has been created to attract and provide habitat for migratory waterfowl and shorebirds. Forested wetland and wet prairie habitats are being restored around the wetlands and provide additional bird, pollinator, and other wildlife habitat. The wetland system was also designed to store and treat stormwater runoff from adjacent, predominantly agricultural lands, to improve water quality and reduce flooding and erosion risk downstream. 

Overall Outcomes of the Project:

  • Approximately 1,850 feet of the new stream channel was constructed
  • Approximately 2 acres of new floodplain have been excavated and vegetation restoration completed 
  • The 1.5 acre spawning wetland, 1.7 acre waterfowl wetland and 0.4 acre ephemeral wetland are all 100% complete
  • Over 30 large woody debris structures as well as numerous (>15) large rock boulders were placed in the new stream channel and wetland areas
  • Approximately 195 trees were salvaged from onsite and planted in an on-site nursery along with 2,500 purchased seedlings
  • 159 large trees (1-2.5” dbh) were procured and approximately 126 large trees and 630 tree seedlings of 15 different native species were planted throughout the project site according to the restoration and planting plan during the project period
  • A parking lot for public access was created
  • 20 water quality grab sample events were completed and sent to the Wisconsin State Lab of Hygiene for analysis in conjunction with continuous water quality monitoring data collected from 2017– 2020
  • Larval fisheries trapping, electrofishing, passive visual surveys, breeding bird point count surveys, trail camera monitoring, and acoustic recordings (detecting frog and bird calls) were also completed with associated data analysis.

Remaining project elements include additional water quality monitoring, fisheries monitoring, and ongoing restoration and restoration maintenance of all disturbed areas (e.g., additional tree planting, native prairie/wetland seeding, or invasive species management).

Initial Property Restoration Plan

LMR Plans

Overhead View of the Property After Restoration

Project Support

The restoration project has been supported by multiple, significant, competitive federal, state, and private foundation grants from the National Oceanic and Atmospheric Administration, US Fish and Wildlife Service, Wisconsin Coastal Management Program, Wisconsin Department of Natural Resources, Fund For Lake Michigan, Southeastern Wisconsin Watersheds Trust, Brookby Foundation and Wisconsin Energies Foundation. Other key partners include Milwaukee Metropolitan Sewerage District (original landowner, regional governmental agency that provides water reclamation and flood management services in the Greater Milwaukee Area), Mequon Preservation Partners (MPP - assistance with the GIS Tool and public outreach), the City of Mequon, Southeastern Wisconsin Regional Planning Commission (wetland delineations), the Conservation Fund, Wisconsin Wetlands Association (WWA), Milwaukee Audubon Society and Mequon Nature Preserve (public outreach), Milwaukee Community Service Corps (MCSC), Great Lakes Community Conservation Corps (GLCCC), and AmeriCorps NCCC (youth conservation corps groups - site prep and restoration) and riparian landowners.