Master in Design for Distributed Innovation (MDDI)
Biobased Wetlands
A chance to restore biodiversity to our cities
by trusting in the power of nature.
by trusting in the power of nature.
I grew up walking along the Chicago River as it underwent a sustainability transformation over the last 20 years. Fences along the water were removed, dams were demolished in favor of water rapids, and more people started recreating on the river. There's even a non-profit called Urban Rivers (run by friends of mine) building the world's first floating eco-park, The Wild Mile, right in the Chicago River.
However, the Wild Mile is being built with floating garden modules that consist largely of metal and plastic -- all assembled in places as far away as Scotland. I have distinct memories from times when the team at Urban Rivers would stress over shipping delays. The floating gardens are not the only plastic component: all of the boxes holding freshwater mussels are also made of plastic.
Why are freshwater mussels so important?
At the beginning of my project, I worked with the biologists at Urban Rivers to showcase the filtering abilities of some of the largest Giant Floater mussels at the Wild Mile. I set up an experiment in which I filled two aquarium tanks with water from the Chicago River. One tank had mussels while the other had none. Then, I left both tanks outside (in February) to sit in front of a GoPro over an 18-24 hour period. The video is linked below.
The difference in turbidity -- or cloudiness -- between the two tanks became obvious over the course of the video, which really highlights the importance of these Giant Floater mussels. They are a keystone species with an outsized influence on all of the other organisms living in the Chicago River. Unfortunately, because of extreme muddiness and pollution of the river bottom, they cannot live in many parts of the Chicago River without assistance. That is why Urban Rivers has been using plastic bins to contain them within floating gardens.
How can we safeguard the mussels without plastic bins?
The world of biomaterials has expanded enormously in recent years (to my delight). I used a sizable amount of my MDDI program to experiment with three options: mycelium, willow branches, and calcium carbonate. These were prioritized for their biocompatibility, abundance in Chicago's local ecosystem, versatile manufacturing and, most critically, resistance to water. One of the major challenges with biomaterials is that they tend to not resist water well, so that factor made my search more difficult.
Mycelium
If mushrooms are the "leaves" of fungi, then mycelium refers to the "wood". Usually, this type of biomass grows underground, but more companies are applying mycelium as a Styrofoam alternative, among other applications. I originally thought that I could use mycelium as a kind of reef for the mussels. However, my first prototype was far too buoyant to sink underwater. The mycelium proved to be a more promising medium for the floating gardens themselves!
If mushrooms are the "leaves" of fungi, then mycelium refers to the "wood". Usually, this type of biomass grows underground, but more companies are applying mycelium as a Styrofoam alternative, among other applications. I originally thought that I could use mycelium as a kind of reef for the mussels. However, my first prototype was far too buoyant to sink underwater. The mycelium proved to be a more promising medium for the floating gardens themselves!
Calcium Carbonate
The mussel shells themselves consist of proteins and calcium carbonate (aka limestone). Potentially, waste mussel shells could be recycled into underwater containers for live mussels.
However, I found that consolidating a calcium carbonate powder into a solid piece was difficult. Even if a piece dries and mineralizes in dry conditions, it could completely dissolve underwater, unless it is previously fired in a kiln with the right chemicals.
The mussel shells themselves consist of proteins and calcium carbonate (aka limestone). Potentially, waste mussel shells could be recycled into underwater containers for live mussels.
However, I found that consolidating a calcium carbonate powder into a solid piece was difficult. Even if a piece dries and mineralizes in dry conditions, it could completely dissolve underwater, unless it is previously fired in a kiln with the right chemicals.
Willow Basket
The most successful biomaterial turned out to be a weaved willow basket! Willow trees are known for growing in and near bodies of water, holding back soil and minimizing bank erosion. Native Americans have known for a long time that the young branches of these trees are quite flexible. The one challenge is that willow trees are not as common as they should be in Chicago. There's another explanatory video below.
The most successful biomaterial turned out to be a weaved willow basket! Willow trees are known for growing in and near bodies of water, holding back soil and minimizing bank erosion. Native Americans have known for a long time that the young branches of these trees are quite flexible. The one challenge is that willow trees are not as common as they should be in Chicago. There's another explanatory video below.
Where do all of these explorations lead?
What started as a project for replacing plastic bins for mussels became an opportunity to design an ecosystem.
The willow baskets protect and hold freshwater mussels, which clear water of fine particulates.
The willow trees keep the river from eroding its sediment.
Mycelium, grown from a city's waste, enables plants to thrive in floating gardens.
The willow baskets protect and hold freshwater mussels, which clear water of fine particulates.
The willow trees keep the river from eroding its sediment.
Mycelium, grown from a city's waste, enables plants to thrive in floating gardens.
Placing native sedge plants into mycelium planter boxes
A contrast between two approaches: the large industrially-made garden and the mycelium planter box.
In the summer of 2023, I succeeded in floating a small mycelium planter box in Bubbly Creek -- once the most polluted section of the Chicago River -- in combining all of the biomaterials and organisms into the same tank, and in observing changes to the wetland over time. The buoyancy remained impressive. Additionally, the planted sedge seemed to thrive in its watery conditions, and the mycelium encouraged a high amount of algae growth, a key source of food for freshwater mussels.
Going forward, I intend to quantify the effects of this biobased wetland design and increase the sizes of the wetlands. By 2033, perhaps there could be large biobased islands installed in the Chicago river, built by volunteers of a new River Lab as an example for other Fab Cities.
