Silt Sand Slurry Shines Light on Coastal Dredging and Sediment Use

­­­The mechanics of that, along with what becomes of all that dredged material, is the starting point for “Silt Sand Slurry: Dredging, Sediment and the Worlds We Are Making,” a new book co-authored by Rob Holmes, Associate Professor and Landscape Architecture Undergraduate Program Chair in the Auburn University School of Architecture, Planning and Landscape Architecture (APLA).

The book, written by Holmes along with fellow landscape architects Gena Wirth and Brett Milligan, examines the wider issues surrounding dredging by examining projects in four areas of the U.S. These include the Great Lakes, New York Harbor, the Mississippi Delta and San Francisco’s Bay-Delta.

Given the contemporary context of sea level rise, environmental change and spatial inequality, the authors explore the limitations of current sediment management practices and seek to suggest an approach to designing with sediment that is adaptive, healthy and equitable.

In addition, using a case study from a joint project conducted in the San Francisco Bay area to illustrate that type of approach, they also outline ways of putting collaborative principles into practice that combine the work of engineers, government officials, technicians and landscape architects.

“My colleagues and I became fascinated by coastal dredging and sediment management,” Holmes explained of the motivation behind the book. “All this work is reshaping landscapes, but most of it is done without the input or participation of landscape architects. It’s like an entire city being constructed without any architects.

“We want landscape architects to be recognized and appreciated for the role they can play in such work,” he added. “They definitely have much to contribute to such projects and there is great potential for more collaboration in the future.”

Holmes notes that with changing climate, predicted rises in sea level and other environmental concerns, dredging and the issues surrounding it are taking on new importance. Given the potential changes dredging and the uses made of the sediment that results can make in natural landscapes, such projects can have major effects on coastal communities.

“Dredging is something most people don’t know much about,” Holmes concluded.” It happens underwater, so it’s out of sight both literally and metaphorically. But the conversation is shifting to a new view of dredged material as a resource and how to use it in more beneficial ways. And landscape architects need to be a part of that conversation.”