Silt Sand Slurry

Dredging, Sediment, and the Worlds We Are Making

AUTHORS: ROB HOLMES, BRETT MILLIGAN, AND GENA WIRTH

Despite the urgency of the issues and the centrality of sediment to coastal landscapes, there is no existing work that is directly comparable across topic, format, and content.

Over the last 6,000 years, the quantity of earth moved by human actions has grown continuously. For most of that time, earthmoving was a side effect of activities like plowing fields and clearing forests, which accelerated erosion. Technologies changed slowly, and human influence over sediment expanded in a more or less linear fashion, driven primarily by population growth, which was itself relatively slow. In the past two hundred years, though, the world population grew exponentially, technologies advanced with unprecedented speed, and the rate of earthmoving correspondingly exploded. Picture a “hockey stick” graph— horizontal through most of human history, now rising vertically toward some unknown and novel future.

People today intervene in hydrogeological processes at every scale, accelerating and decelerating flows of sediment, both above and below the waterline, while altering their physical and chemical composition. As sediment moves around on the inclined surfaces of the planet, above and below the waterline, humans play roles both grand (networks of river dams trap enough sediment to produce seismic events) and humble (ubiquitous orange silt fences prevent loose dirt from escaping construction sites). In the United States, an estimated 30 tons of earth is moved annually for every person. This is the highest per capita volume in the world, although only a fraction of the 120 billion tons moved globally.

“Humans move tremendous amounts of soil and rock.
By some measures, the amount of earth that we move exceeds that of any other geomorphic agent.”
—Roger LeBaron Hooke, ‘On the History of Humans as Geomorphic Agents’

“We will either have justice, sustainability, and peace together or we will descend into ecological catastrophe, social chaos, and conflict. Soil, not oil, offers a framework for converting the ecological catastrophe and human brutalization we face into an opportunity to reclaim our humanity and our future.”
—Vandana Shiva, ‘Soil, Not Oil: Environmental Justice in an Age of Climate Crisis’

The mud should be dredged out. This maintenance operation could be treated in terms of art, as a “mud extraction sculpture”... The mud could be deposited on a site in the city that needs “fill.” The transportation of mud would be followed from point of extraction to point of deposition. A consciousness of mud and the realms of sedimentation is necessary in order to understand the landscape as it exists.
—Robert Smithson, ‘Frederick Law Olmsted and the Dialectical Landscape’

To imagine other forms of human existence is exactly the challenge that is posed by the climate crisis: for if there is one thing that global warming has made perfectly clear it is that to think about the world only as it is amounts to a formula for collective suicide. We need, rather, to envision what it might be.
—Amitav Ghosh, ‘The Great Derangement’

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