USA - USACE discovering new ways to put dredged sediment to use
Dredging is a central part of the U.S. Army Corps of Engineers’ (USACE) largest mission – to maintain clear, safe and navigable waterways.
Without periodic dredging, many harbors and ports would be impassable, and so more than 400 ports and 25,000 miles of navigation channels are dredged throughout the U.S. each year.
One byproduct of these extensive dredging operations is the large amount of sediment that is collected during the process. There is a growing interest to find new ways to repurpose this material, and USACE recently set a goal to recycle 70 percent of its dredged sediment by 2030, placing it in ways that will provide benefit to the system, such as coastal storm risk reduction, recreation or habitat creation.
Currently, 30 to 40 percent of all dredged material from federal navigation channels is used beneficially for such purposes as nourishing beaches and enhancing wetland habitats.
“The previous mindset was that the material was a nuisance and something that we needed to dispose of,” said Katie Brutsché, an associate technical director for USACE Navigation Research, Development and Technology and program manager for the USACE National Regional Sediment Management (RSM) program. “In the last several decades, we’ve realized that sediment is a resource — it has a value to it — and if we can return it to the system and find ways to place the material such that it gives us some sort of benefit, that would be ideal.”
“In the coastal system, oftentimes, when we place material beneficially, we use it as beach nourishment or nearshore placement that provides storm protection to our beaches and coastlines. On the inland side, we use it for riverbank nourishment that helps reduce the amount of mass wasting along riverbanks, which benefits the local community as a whole,” added Brutsché.
A USACE Tiger Team is focused on ways to increase the beneficial use of dredged sediments. Meanwhile, workshops have been conducted and a working group is being created. The U.S. Army Engineer Research and Development Center (ERDC) even has a strategic focus area that concentrates on ways to better manage sediment, including beneficial use. Research and development programs like RSM and Engineering With Nature® investigate new techniques and uses for this material.