This study was conducted by the USGS in cooperation with the USACE as a component of the IUGLS. Barry J. Irwin of the USGS provided expertise in the field in operation of the RV Rafael, navigation, and survey operations, and Charles W. Worley, also of the USGS, supervised technical operations and data acquisition. The U.S. Coast Guard Station at Port Huron provided dockage and facilities for mobilization. This report was improved by technical reviews by USGS personnel Matthew A. Arsenault and David C. Twichell and the advice of Peter Ashmore of The University of Western Ontario.