U.S. Hydrodynamic Dredging Challenges and Opportunities

Abstract

The issue of sedimentation in navigable waterways continually confronts maritime authorities. Regular maintenance dredging, a costly and arduous exercise, is necessary to ensure safe navigation is achievable throughout the year. Private industry and the U.S. Army Corps of Engineers (USACE) combined to remove roughly 230 million cubic yards of maintenance volume at an estimated cost of $1.7 billion in 2020. The handling and disposal of dredged material are practices affected by numerous regulatory constraints. Once a local or national organization has established the most efficient, lowest-cost dredging alternative with the most flexibility, the next step is identifying and addressing permitting concerns and seeking permits to use the technology. Innovative water injection dredging (WID) has been approved in various locations throughout the U.S.A., including providing a reliable means for the North Carolina State Ports Authority (NCSPA) to provide access to its berths, removing sediment over the Chesapeake Bay Bridge–Tunnel to minimize potential harm to the existing tunnel structure, and maintaining federal navigational depth in the Mississippi River. This paper aims to provide a summary overview of the current state of WID in U.S. waterways, including the discussion of a successful permitting and procurement effort by the NCSPA that secured a custom-built WID vessel for North Carolina. Recent literature has identified parameters correlated with WID performance, such as median grain size, hydrology of the waterway, Richardson number, and the liquidity index, which are explored.