Exhuming the Rust Belt: Metrics and Ecologies at Pointe Mouillee
Michael Ezban (MLA I AP) and Jana Vandergoot (MLA I AP)
In the Great Lakes region, dredging regimes bring the depths of lake bottoms to light. Every year 3-5 million cubic yards of sediment are exhumed from federal harbors, navigation channels, and degraded waterways by the US Army Corps of Engineers. Of this amount, nearly half the sediment is contaminated to the degree that the EPA mandates its storage in a CDF. The 47 constructed open-air island, peninsula, and upland CDFs together comprise over 3,700 acres. As these infrastructural elements reach the end of their engineered lifecyles, inquiries need to be made into the role CDFs play as cultural amenities, ecological systems, and stimulus for economies. What potential is offered by CDF infrastructure when it is viewed as a feature of the Great Lakes cultural landscape? What are the ecological processes that dredging and dumping of sediment catalyze on CDF sites? Do CDFs have market value as polyfunctional infrastructure, public space, and ecological habitats? Exhuming the Rust Belt investigates the metrics of dredging and the natural and cultural ecologies of Pointe Mouillée, largest of the Great Lakes CDFs.
Exhuming the Rust Belt
CDFs are transitional landscapes. Every deposit of sediment brings a mix of seed, agricultural fertilizer, and biophysical remnants of an industrialized watershed, all of which support spontaneous, sometimes invasive, vegetation. A handful of active CDFs are networked into local industrial ecologies in order to provide material for road construction and landfill caps. As CDFs close, they are either incorporated into other types of infrastructure, such as airports and harbor facilities, or cultivated as wildlife preserves.
The 20 currently active CDFs in the Great Lakes region are more than 80% full, and a dredging backlog is accumulating.  Harbors on Lake Erie, situated in the heart of the American Rust Belt, are approaching a point of crisis. CDFs at Toledo, Cleveland, and Lorain Harbor have less than five years capacity remaining and among the highest demand for disposal in the Great Lakes. Pointe Mouillée, located at the mouth of the Rouge River, is the largest CDF ever created but will reach capacity within ten years. The day is rapidly approaching when new CDFs will need to be constructed, existing CDFs will need to be modified, or new export trajectories for moving dredgeate into a wider industrial, commercial, and residential matrix will need to be devised. This set of challenges situates CDFs within landscape design and discourse.
Sediment in Motion
Sediment management is a continuous infrastructural process that facilitates economic, ecological, and cultural imperatives. It is an energy-intensive activity that dovetails into natural biophysical processes of erosion and sedimentation. And in some cases, such as Pointe Mouillée, dredging and strategic deposition of sediment can generate robust infrastructural landscapes.
The USACE has been involved in maintaining waterways for navigation since the passage of the Rivers and Harbors Act in 1824, which allocated federal money towards the clearing of sandbars, shoals, and other hindrances to fluvial trade on the Ohio and Mississippi Rivers.  Dredging became an economic imperative in the Great Lakes region during the first half of the 20th century. Upland urbanization and agricultural practices in the first half of the century increased soil erosion and sedimentation in the waterways of the region. Conveyance of coal, ore, grain, and other bulk natural resources across the Great Lakes in the hulls of cargo ships depended on the maintenance of deep navigation channels that connected a regional network of federal harbors. Increasingly larger tanker sizes led to higher volumes of exhumed sediment. Until the 1960s, all dredged sediment was simply dumped off shore.
Emerging environmental awareness and concern for the biophysical condition of the lakes prompted new regulations for contaminated sediment disposal. Since 1970, these diked landscapes have taken the form of artificial islands, peninsula, and upland fields, and ranged in size from 6 to 700 acres. CDFs can be found along the coasts of all the lakes except Lake Ontario. Federal funding for construction of these landscapes is typically augmented by local sponsors, such as municipal governments, that cover 25% of the construction cost and receive title of the land once the CDF is filled to capacity.
Constructing Pointe Mouillée
Historically, Pointe Mouillée was a natural spit of marsh just south of the Huron River estuary on the west coast of Lake Erie. The flow of water from the Detroit River, which opens into Lake Erie to the north, pushed sediment in the Huron River estuary southward, where it collected and formed a series of low barrier islands. These islands allowed tidal flux to saturate upland areas but protected the area from storm surges. This set of conditions was ideal for a freshwater marsh. Pointe Mouillée (translated from the French language into English as “wet point”) was part of millions of acres of cattail marsh in the Western Basin of Lake Erie. This area was known by French trappers, hunters, and Native Americans in the mid-18th century to be particularly productive. 
In the 20th century, increasing urban, agricultural, and industrial development in the Rust Belt region led to massive changes in the landscape of Southeast Michigan. The environmental abuses levied by manufacturing industries in the early to mid 20th century came to a head in the 1960’s, when a burgeoning environmental movement triggered by the writing of Rachel Carson coincided with subtle and explicit indicators of an environmental crisis in Lake Erie and its tributaries. An article in a 1969 issue of Time magazine lamented the transformation of Lake Erie into “a giant cesspool” and famously concluded that “even a great lake can die.” 
It is against this backdrop that new federal legislation was introduced to affect the quality of water in the nation’s rivers and lakes. The Clean Water Act of 1970, along with the River and Harbors Act authorizing construction of CDFs, were attempts to reverse the trends of environmental degradation. In 1979, construction commenced on a massive new CDF at Pointe Mouillée that would sequester the contaminated sediment dredged from the Detroit and Rouge Rivers. By 1981, construction of the 700-acre crescent-shaped CDF segmented into five separate cells was complete. Since then an average of almost 400,000 cubic yards of contaminated sediment has been deposited there annually.  The first environmental remediation project undertaken with the passage of the Great Lakes Legacy Act of 2002, a celebrated international agreement for strict environmental laws, was the dredging of contaminated sediment at the Black Lagoon on the Detroit River in 2004. The project displaced 470,000 pounds of contaminants from the river to the Pointe Mouillée CDF. 
Pointe Mouillée Edge Conditions
The dikes of the Pointe Mouillée CDF are multifunctional. While their primary function is to retain contaminated sediment, they also create or enable the production of habitat for aquatic and terrestrial species, and act as accessible circulation routes for humans.
There are four dike typologies at Great Lakes CDFs: the earthen dike, the layered core dike, the soldier pile stone dike, and the circular sheet pile dike. The earthen dike is a subterranean dike that is typically employed in upland conditions, and is constructed with compacted soils and filter fabric. The layered core dike is among the most common dikes, and it features a sand and limestone core with a stone armored edge at the lake side of the dike to protect against erosion. This type of dike is employed at Pointe Mouillée. The soldier pile stone dike is similar to the layered core construction, but its horizontal width can be decreased due to a structural steel sheet placed vertically in the dike. The circular sheet pile dike is the most rare of the CDF edges and it employs large steel drums that are filled with sand and stone. 
The dikes of Pointe Mouillée are constructed to retain contaminated sediment but allow water to pass through back into the lake. Water passes through these dikes in order to allow the dredged sediment to de-water and settle. As the sediment dries and lowers, it creates room for more material to be placed on top. The EPA monitors the water on the lake side of the CDF periodically and finds the water quality is well within the limits set by the Clean Water Act. This is because the contaminants tend to bind on a molecular level to the sediment, and don’t float freely in the water.
The armored rock edges at the lake side of Pointe Mouillée can provide habitat for fishes and other small aquatic species. In some areas, sand, sediment and driftwood passively accumulate against the rocks to create small pockets of habitat along the edges of the CDF. On the dredge sediment side of the dike, muskrats can often be found burrowing and creating habitat.
Towards a New Economy of Sediment
Shrinking government funding and increasing shipping tanker sizes are challenging designers and engineers to engage opportunistically in flows of sediment and contamination, and to shift from wasteful disposal to strategies of targeted distribution and strategic allocation. Given an increasing facility with this material (tracking sediment at micro and macro scales, processing it according to grain size, remediating it with passive and active technologies, allocating it to specific re-use projects) and given the unique CDF landscapes and ecologies that sediment can sponsor, framing sediment as anything less than a resource would be short-sighted.
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- “America’s Sewage System and the Price of Optimism.” Time. August 1, 1969. May 9, 2013 http://www.time.com/time/magazine/article/0,9171,901182,00.html
- Pointe Mouillée Confined Disposal Facility and State Game Area. April 24, 2005. May 9, 2013. http://www.lre.usace.army.mil/newsandevents/publications/publications/pointemoullee-beneficialuse/
- US Environmental Protection Agency. “First Legacy Act Cleanup Completed.” November 2005.
- US Army Corps of Engineers, Detroit District. Operation and Maintenance Manual. Detroit and Rouge Rivers Confined Disposal Facility. Michigan. 1982.