U.S. Department of the InteriorU.S. Geological Survey

Shallow Water Hydrographic Surveying using a High Resolution Multibeam Echosounder

Richard C. Wilson, P.E., andBrenda K. WoodwardNebraska Water Science Center

2010 Tri-Agency MeetingOct. 5, 2010

Hydrographic Surveying• Aristotle observed that sound could

be heard in water• Allies invent the sonar during

World War I• Coast and Geodetic Survey deployed

the Fathometer in 1925 • U.S. Navy deployed a multibeam

echosounder in the 1960s

Hydrographic Surveying - Purposes

• Navigational aide• Quantity surveys• Inspections of dams, bridges, and water control structures• Habitat assessments• Hydrodynamic and sediment-transport models• Geomorphic assessments

Single-Beam Echosounder

Multibeam Hydrographic Surveying

• Wide yet narrow swath perpendicular to the boat direction• Multiple beams in just one ping• SURVEYS the ENTIRE RIVER or LAKE BED

Shallow Water Multibeam Hydrographic Surveying•Minimum depth is 1 meter•Swath angle 128° or width-to-depth ratio 3.5 to 1 •Rotation of the transducer for surveying horizontal features•Use Single and Multibeam Echosounders, together•Flat keel boat•Obstructions

Multibeam Echosounder

RESON Seabat 7125 Multibeam Echosounder System

•Digital beam-former •400 kHz•256 or 512 beams•128° swath angle•200 meter range•Bathymetry data and Side-Scan imagery

Multibeam Echosounder Components

ProjectorArray

ReceiverArray

SoundVelocityProbe

Multibeam Echosounder Components Real-Time Kinematic Global Positioning System (RTKGPS) or Differential Global Positioning System (DGPS)

InertialMeasurementUnit (IMU) Navigation computer

Position and OrientationSolution (POS-MV) motion control unit

7-P sonar signal processor

Sonar display

Patch Test CalibrationRoll correction

Pitch correction

Yaw correction

Nadar Beam

Collapsed Historical Bridge Deck near Warsaw, Missouri

Bridge Piers near Warsaw, Missouri

Bridge Pier near Warsaw, Missouri

Multibeam Data Processing

•Dell Precision T7500•Intel Xeon Quad Core Processor 3.46 GHz•12GB DDR3 SDRAM, 1333MHz, •2 GeForce GTX 480 2.0 Graphics Card

Multibeam Data Processing

Line-by-line swath editing is necessary

Multibeam Data Processing

Gavins Point Dam Multibeam SurveyPurpose:

•Document change from 1957-2008

•Verify the integrity of energy dissipation structures

•Create updated bathymetric contours

Gavins Point Dam Spillway

Energy Dissipation Structures

•Determined the structural integrity

•Divers were not needed, eliminating a safety hazard

•Measured change to 0.1 M

Gavins Point Dam - Spillway Intake

Missouri River BendsMissouri River Habitat Assessment and Monitoring Program (HAMP)

• Habitat improvement through structure modification• Wing dike notches• Chevrons• Parallel dikes• Revetment removal

Hydrographic Surveys of Glovers Bend

•Single-beam echosounder•Glovers Bend, Missouri River•2007

Hydrographic Surveys of Glovers Bend

•Multibeam echosounder•Glovers Bend, Missouri River•2009

Hydrodynamic Modeling of the Missouri River using MD_SWMS

Experimental Advanced Airborne Research LiDAR (EAARL)

Water penetrating LiDAR

Uses Blue-green laser

NASA/USGS Technology

Shallow water EAARL survey, Central Platte River

Side-Scan Sonar: Using Backscatter Intensity to Classify Substrate

Robert B. SwansonDirector(402) 328-4110rswanson@usgs.gov

Richard C. Wilson, P.E.Associate Director of Hydrologic Studies (402) 328-4120wilson@usgs.gov

Ronald B. ZeltAssociate Director of NAWQA Studies(402) 328-4140rbzelt@usgs.gov

Jason M. LambrechtAssociate Director of Hydrologic Data(402) 328-4124jmlambre@usgs.gov

CONTACT INFORMATION: Rick Wilson USGS Nebraska Water Science Center (402) 328-41205231 South 19th St. wilson@usgs.govLincoln, NE 68512-1271 http://ne.water.usgs.gov