​Why beavers?

What are we doing in the Milwaukee River Watershed?

​The Superior Bio-Conservancy is working to restore the hydrology and biological integrity under the Clean Water Act of the Milwaukee River Watershed through beaver restoration efforts. The 2020 study titled “Hydrological Impact of Beaver Habitat Restoration in the Milwaukee River Watershed” modeled how beaver restoration would support flood mitigation, biodiversity, and provide billions of dollars in ecological services. The study was done in partnership with the Milwaukee Metropolitan Sewage District (MMSD), University of Wisconsin in Milwaukee, and Milwaukee RiverKeeper.

To restore hydrology and biological integrity, we are asking for a “recovery zone” for aquatic mammals in the Milwaukee River Watershed - 900 square miles which equals 1.2% of Wisconsin’s area – for the implementation of the study to protect the citizens and waters of Wisconsin. This would end lethal trapping of beaver, otter, muskrat, and mink within the Milwaukee River Watershed. Halting lethal trapping over aquatic mammals will allow for the beaver population to recovery and restore the watershed hydrology and hyporheic zones by building pond wetland complexes in the watershed. This could allow citizens to receive the benefits from a potential of over $3 billion in ecosystem services through flood mitigation.
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We are working towards the immediate creation of a recovery zone for aquatic mammals in the Milwaukee River Watershed for the next 25 years. This request includes full administrative support by the WDNR and government agencies to achieve the goals for recovery. All aquatic mammals are included in the recovery zone to avoid high levels of bycatch that occurs with body-gripping traps. These types of traps often accidentally capture and kill non-targeted species and in some cases dogs. This will ensure the safety of relocated beavers that are reintroduced at selected sites from trapping to allow for their repopulation and expansion that is necessary to achieve the full benefits outlined above. Beavers on watersheds achieve their highest potential when they can restore wetlands as colonies of family groups. Similarly, it can take a few decades for full ecological benefits to develop as beaver naturally restore the natal hydrology of watersheds, making a long-term recovery zone essential to the success of implementing the study. 

​Beavers are aquatic mammals essential to the natal hydrology and landscape of Wisconsin. Unique as a keystone species and ecosystem engineer, they create wetland ponds that are critical for water quality, biodiversity, critical species habitat, and significant flood mitigation. These wetlands can have a strategic society value for flood reduction as a climate resilience solution. Through canals and damming of beaver ponds, beavers reconnect river complexes to the flood plains while providing green infrastructure of stormwater storage systems. Further, birds, waterfowl, amphibians, reptiles, insects, mammals, and plants biodiversity thrive in beaver wetlands.
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A key feature of beaver structures is that they vastly increase the hyporheic zone in rivers that provide numerous ecological benefits that support the goals of biological integrity in the “Clean Water Act.” 

1. Creating habitat and shelter for fish, plants, and organisms. 
2. Reductions of pollutants, especially nitrates.
3. Cleaner water through filtration and recharging groundwater.
4. Stabilizes water temperatures to be cooler in summer and warmer in winter. 

The hyporheic zone is the area of sediment and porous space under a stream bed where there is mixing of ground and surface water. This region is critical in filtering pollutants out of the stream for cleaner and higher quality water.

​​Climate change is increasing the storm intensity experienced across Wisconsin. Beaver wetland complexes will be essential to building Wisconsin’s resilience against these high-intensity storms as they create stormwater storage, recharge aquifers, and support natural water filtration for clean, safe water.

Potential benefits to communities in the Milwaukee River Watershed from the 2020 study:

1. Modeled storm events showed that on average, peak flood levels were reduced by 37%. In all cases, this reduction of flood peaks will reduce flooding impacts to communities, especially in the lower, more urbanized zone of the watershed. Reducing flooding will fortify communities like Milwaukee from costly damage to business, infrastructure, and homes that could occur with high flood events. Especially with the increasing threat of heavy storms that promote greater flooding, reduction of peak flooding is critical to building climate resilience into the future.
2. The study identified over 500 homes that would be removed from the flood plain, specifically in Glendale, Whitefish Bay, Shorewood, Brown Deer, and Milwaukee as a direct result of the reduction of peak flood levels from beaver pond storage upstream. This would also reduce potential flood damage to thousands of additional properties upstream.
3. Under the model, with full stage development after beaver reintroduction, beaver complexes have the potential to increase stormwater storage by 1.7 billion gallons of water. According to cost metrics given from MMSD, this would equate to a potential of about $3.346 billion in ecological services. Not only does this match MMSD’s goals of promoting green stormwater storage infrastructure through their Greenseam’s program, but it could potentially reduce funding needed to rebuild damaged communities and bridge infrastructure from high water events.

What could this mean for future management practices?

Scientific studies are conducted to benefit communities with solutions to on-going problems. As the Milwaukee River Watershed is at high risk to flooding and degradation of water quality that impacts Lake Michigan from the increasing threats of climate change, it is urgent we utilize promising and groundbreaking studies to promote long-term solutions. Outcomes from reintroduction of beavers to the Milwaukee River Watershed could provide valuable insight into how to manage beavers across Wisconsin and the Great Lakes, where their implementation may protect high-risk communities from flooding and poor water quality in the future. With the looming threat of the climate crisis, it is urgent that we find meaningful and feasible solutions to build-up climate resilience within communities. Creating a recovery zone within the Milwaukee River Watershed for the promotion of green infrastructure through beaver habitat provides an opportunity for communities in Southeast Wisconsin to trail blaze a path towards climate resilience that could be utilized as a model to support other communities in the fight against climate disasters.