The Minneapolis Park and Recreation Board led a team to reconstruct Hall’s Island, located in the Mississippi River just north of Boom Island. While the original island was destroyed by industrial development in the 1960s, the restoration of the island is intended to provide a rich source of habitat along the Mississippi River. It is part of a larger project within the RiverFirst Initiative — a broad vision for repairing our relationship with the Upper Mississippi Riverfront through parks and trails.
As a multi-partner project, many organizations were involved in the successful restoration of Hall’s Island, including the Minneapolis Park and Recreation Board, Mississippi Watershed Management Organization (MWMO), Barr Engineering, Landbridge Ecological, Metropolitan Council, Veit, and the Minneapolis Parks Foundation. Last week, I was fortunate enough to speak with the Hall’s Island Project Lead at MWMO, Marcy Bean, now a Senior Landscape Architect with Barr Engineering. Her knowledge of the development, landscape, and habitat restoration of Hall’s Island was crucial in creating this list.
#1. Introduction of Freshwater Mussels
One major form of ecological restoration on the island was the reintroduction of a habitat suitable for freshwater mussels. A large focus of the type and size of rock/sand that was brought in (nearly 32,000 tons) to rebuild the shoreline was to include the specific rock substrate that is conducive for mussel populations. These mollusks perform a variety of important functions within their ecosystems:
- They keep our streams and rivers clean. Mussels filter out large quantities of harmful algae and bacteria. They also absorb heavy metals and filter silt and fine particulates that harm aquatic ecosystems.
- They are indicators of water quality, and are used to measure how clean the surrounding water is.
- They are a food source for aquatic and terrestrial animals. By-products of filter feeding also provide food resources for plants and aquatic insects.
- Mussel shells can provide habitat for other fish, crayfish, aquatic insects, and larval salamanders.
Additionally, freshwater mussels are one of the most endangered organisms in North America, and are one of the upper midwest’s wild and rare species, as outlined in Adam Arvidson’s Wild and Rare (MN Historical Society Press, 2018). Adam Arvidson is the Director of Strategic Planning for the Minneapolis Park and Recreation Board, and will be the featured speaker at our upcoming Next Generation of Parks Event. Learn more about and register for this free, virtual event here!
#2. Optimization of Habitat Growth
One important component on Hall’s Island, was the introduction of native species that would provide the most food, homes, and overall positive impact. Native White Oak trees were planted on Hall’s Island specifically because this tree is known to provide food and/or habitat to nearly 250 different bird species. Additionally, the White Oak species survives well in both dry and wet environments, which is necessary due to the fluctuating water level at this location.
#3. Creation of a Backchannel
Another major feature that resulted from the reconstruction of Hall’s Island was the creation of the channel of water between the island and the river’s edge, which is approximately 120 feet to 150 feet wide and 6 feet deep (depending on river conditions). The creation of this backchannel changed the flow of water within the Mississippi River, and created a space that invites a variety of species to sit and rest, including many migratory birds.
#4. Mimicking Natural Environments
The creation of a habitat suitable to turtle species, including the Blanding Turtle – which is considered endangered in much of the United States – came from thoughtful design and construction of the Island’s woody features that they inhabit. Specific woody materials were brought in and designed to mimic the underwater landscape that would be created naturally within this region.
#5. Planning for a Changing Climate
A considerable amount of thought went into the species that were brought to Hall’s Island. Both the reintroduction of species that have survived in the area throughout history, but also the understanding that as our climate changes, the species that thrive and provide necessary life to a healthy ecosystem may begin to shift. One example of this is with the Sycamore tree. While the Sycamore doesn’t typically grow in this zone, as temperatures shift, this species is expected to follow suit. Anticipating these changes will hopefully create safer, more sustainable ecosystems within the region.
Thank you again for the breadth of knowledge from Marcy Bean and MWMO.
Images courtesy of MWMO.