Risks to Sustainable Great Lakes Navigation: Watershed Contaminants.

Water navigation in our Great Lakes ports and harbors is at great risk of impairment in the immediate future if a consensus cannot be reached on cost-effective management of sediments that clog navigation channels.  The US Army Corps of Engineers has the mission to maintain congressionally authorized channel depth in federal navigation channels and is the permitting agency for all other dredging and sediment discharge into waters of the U.S.  Prior to the passage of the Clean Water Act (CWA) most dredged sediments were simply dumped into the open water of the lakes.  Contaminant issues required dredged sediments to be placed in confined island or upland disposal facilities with the intent of returning to the more cost effective practice of open water disposal once the CWA resulted in cleaner sediments after 10-20 years.  The legacy of unregulated industrial and municipal discharge of contaminants into waters of the U.S. has been largely mitigated by the CWA and through the continued removal of sediments to maintain navigation channels.  However, soil disturbance from development and agriculture continues to discharge soil and associated nutrients, pesticides and other impairments to water quality that are now driving state regulatory restrictions on open water placement of dredged sediments.  Effective solutions to ensure sustainable navigation and future growth of water-borne commerce in the Great Lakes requires both improved soil and nutrient conservation best management practices and cost-effective, science-based approaches to management of watershed resources at the dredging end.  Contaminant based restrictions will be discussed.