The survey was conducted using Odom Hydrographics' Echoscan™ Multibeam System, in order to provide complete coverage of the river bottom. Local Existing Horizontal and Vertical control, which was provided by the Corps, was verified using tr Navigation Dual Frequency 4400 receivers, and additional control was set by RTK (Real-Time Kinematic). Velocity of Sound in the water column was obtained using an Odom Digibar™. Gages at each Lock and Dam were also tied in the GPS Network control survey, and adjustments were made for any errors in the relationship between the vertical datum and zero gage readings. Elevation of the water surface was determined by RTK and gage readings. The gage readings were taken every hour at each Lock & Dam and interpolated for the survey area. RTK (Real-time Kinematic) was used to position the survey vessel in areas where possible, and DGPS was utilized when RTK postiions were not available. An Odom Hydrotrac™ Single Frequency Echosounder was also used, during portions of the survey, to verify Multibeam data. Hydrographic Survey data was collected and edited with HYPACK's™ HYSWEEP™ software.