Erosion and sedimentation are natural processes that move material from one place and deposit it onto another. It is the process that both builds beaches and clogs up waterways. Dredging is the mechanical process humans employ (primarily the Army Corps of Engineers, or their contractors in the United States) to manage sediment, utilized to make waterways deeper and safer for navigation. According to Neeraj Bhatia’s, Expanding Dredge Geologics, “The movement and management of sediment is arguably the largest continuous project of spatial manipulation on the planet.”
The complex system of gathering, transporting, and disposal of sediment is the subject of the Dredge Research Collaborative and the Dredge Fests symposiums that have been occurring in cities around the United States, most recently in San Francisco. The focus of the Dredge Research Collaborative is to explore beneficial uses for sediment to benefit coastal ecologies and help protect coastal communities from the impacts of sea level rise.
Having lived in Louisiana during Hurricane Katrina and studying the complex hydrological cause-and-effect of dredging practices — like how maintaining and deepening navigational canals amplified land loss and created efficient paths for the tidal surge waters that inundated New Orleans — I became aware of the urgent need for strategies to harness the beneficial use of dredge material (See:Sea Change: Urban Design and the Global Challenge of Vulnerable Coastal Cities”).
This past year, Congress approved $1.2 billion for dredging and other maintence at the Ports of Long Beach and Los Angeles. This is a critical time for landscape architects, scientists, and engineers to put our minds together and push for a dredging strategy that positions this sediment as a resource – a sediment management practice focusing on environmental health, creating topsoil, aquaculture facilities, beach nourishment, and habitat restoration, all while performing the explicit intent of funding to enable the ports to operate more efficiently.