MANAGING SEDIMENTS IN THE WATERSHED: LINKING DREDGED MATERIAL AND WATERSHED PLANNING

摘要

The annual dredging of several hundred million cubic yards of sediment is essential for the maintenance of the United States' navigation system. Historically, dredged material management has focused on site-specific solutions to address sedimentation of port channels and berths, and waterways on which US commerce and military depend. At the same time, water resource projects that are designed to remedy local sediment problems may sometimes create even larger problems some distance away. Excessive sediment in rivers, reservoirs, and estuaries may contribute to high turbidity, loss of flood-carrying capacity, and sediment deposition in navigable waterways. In other locations, a shortage of sediment causes coastal erosion, streambank erosion, and wetland loss.The National Dredging Team (NDT), a federal interagency group established to promote consistency and information exchange on dredging issues, recognizes that dredged material and sediment management planning often occur outside the context of watershed management plans. In recognition of the need for greater coordination among dredged material managers and watershed stakeholders, the NDT held a national conference in 2006 on dredged material management in the watershed to bring together these stakeholders to identify current roles, activities, areas of technical and planning overlap, and gaps in knowledge and management of sediment in the watershed. Using a watershed approach in development of dredged material management plans (DMMP) and including early communication and coordinated planning among federal and state dredged material regulators, watershed planners, and other interested parties can ensure that sources of sediment (and sources of contamination carried by sediment) are addressed, the broadest range of beneficial use and disposal alternatives for dredged material is evaluated, and adequate funding for dredged material reuse or disposal is secured. DMMP planners should be linked with upstream watershed planning efforts to ensure that watershed plans include consideration of downstream impacts of sediments, i.e., the potential of sediment to become material to be dredged downstream. EPA and the Army Corps of Engineers are working together to identify next steps to integrate DMMP with other watershed planning efforts.