Hydrographic Surveys of Rivers and Lakes Using a 

Multibeam Echosounder Mapping System

Using Sound Waves to Map River and Lake Bottoms

A multibeam echosounder (MBES) is a type of sound 

navigation and ranging device that uses sound waves to “see” 

through even murky waters (fig. 1: Note that all figures used 

in this report are for an illustrative rather than an interpretive 

purpose, not all geographic locations will be shown). Unlike 

a single beam echosounder (also known as a depth sounder 

or fathometer) that releases a single sound pulse in a single, 

narrow beam and “listens” for the return echo, a multibeam 

system emits a multidirectional 

radial beam to obtain information within a fan-shaped swath 

(figs. 1, 2). The timing and 

direction of the returning sound 

waves provide detailed information on the depth of water and 

the shape of the river channel, 

lake bottom, or any underwater 

features of interest. This information has been used by the 

U.S. Geological Survey (USGS) 

to efficiently generate highresolution maps of river and 

lake bottoms.

The Multibeam Echosounder Mapping System

A multibeam echosounder mapping system (MBMS) is 

an integration of several individual components: the MBES, 

an inertial navigation system (INS), and a data-collection and 

data-processing computer. The MBES that was used for numerous surveys completed by the USGS in Missouri is the Teledyne 

RESON SeaBat® 7125–SV2 (fig. 3), which is operated at a 

frequency of 200 or 400 kilohertz.

Multibeam

echosounder

Survey boat with an 

Inertial Navigation

System (INS)

Fan-shaped

EXPLANATION radial swath

Shallow

Water depth

Deep

Surveyed channel bed

Figure 1. Schematic of a survey with a multibeam 

echosounder mapping system on the Mississippi 

River near the Jefferson Barracks Bridge on 

Interstate 255 near St. Louis, Mo. Photograph by 

Richard Huizinga, U.S. Geological Survey.

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2018–3021

June 2018
Single beam data point

EXPLANATION

EXPLANATION

Shallow

Water depth

Deep

Figure 2. Example of single beam (top) and multibeam echosounder 

(bottom) output (modified from Alvarado and Robinson, 2011).

A B

Piezoceramic

projector array

Piezoceramic

receiver

array

Sound

velocity

probe

(inside

shroud) Head tilt

bracket

Transducer

head

Stabilizer

struts

Figure 3. The 

Teledyne RESON 

SeaBat® 7125–

SV2 multibeam 

echosounder. A, As 

viewed from the 

bottom. B, Mounted 

on the port side of 

the U.S. Geological 

Survey survey boat. 

Photograph by 

Richard Huizinga, 

U.S. Geological 

Survey. Any use 

of trade, product, 

or firm names is 

for descriptive 

purposes only and 

does not imply 

endorsement by the 

U.S. Government.

To accurately position and interpret the data received by 

the MBES, the INS uses two Global Navigation Satellite System 

antennae and an inertial motion unit to provide position in 

three-dimensional space and measure the heave, pitch, roll, and 

heading of the vessel (and, thereby, the MBES). A connection to 

a source of real-time kinematic corrections often is established to 

improve real-time display of a survey. Whether or not a source 

of real-time kinematic corrections is used during a survey, data 

from the INS typically are postprocessed to mitigate the effects 

of degraded positional accuracy of the vessel during the survey. 

After the survey is completed, the acquired data from the MBES 

are processed to remove data spikes and other spurious points 

in the MBES soundings, georeferenced using the postprocessed 

INS data, and visualized as a triangulated irregular network surface or a point cloud (figs. 1, 2). The various components of the 

MBES mapping system are described in detail in studies of the 

Missouri and Mississippi Rivers in Missouri (Huizinga, 2016, 

2017; Huizinga and others, 2010).

Applications of the Multibeam Echosounder Mapping 

System

Channel-Bed Scour

Scour in river channels is the removal of channel-bed 

and bank material by flowing water and is the leading cause 

of bridge failures in the United States (Richardson and Davis, 

2001). Scour at a bridge site is the result of short- and long-term 

geomorphic processes and local effects caused by elements 

of the structure (pier, footing) in or adjacent to the waterway 

(Richardson and Davis, 2001; Huizinga and Rydlund, 2004). 

Scour processes can be exacerbated during high-flow conditions because velocity and depth typically increase. Because the 

effects of scour can be severe and dangerous, bridges and other 

structures over waterways are inspected routinely. Multibeam 

surveys around bridges can reveal the short- and long-term 

effects of bed scour near the bridge structures (figs. 4, 5).
676

682688694700706712718724

Elevation of point, in feet

 above the North American

 Vertical Datum of 1988

EXPLANATION

Flow

Undermined

seal course

Drilled shaft

Echo from sides of

drilled shafts

Flow

715

710

705

700

695

690

685

680

675

Elevation of point, in feet

 above the North American

 Vertical Datum of 1988

EXPLANATION

Figure 4. Examples of three-dimensional representations of scour 

around a bridge pier obtained using a multibeam mapping system. 

The top image is the Interstate 635 Bridge on the Missouri River at 

Riverside, Mo., and the bottom image is the Interstate 435 Bridge on 

the Missouri River at Randolph, Mo. (Huizinga 2016).

Channel-Bottom Characteristics

In rivers, the channel-bed features reflect dynamic 

interactions between flowing water and the mobile sediment available on the bed. These interactions generate a 

wide range in channel-bed characteristics depending on 

the hydrologic and geologic context and provide a variety of aquatic habitat conditions for fish and invertebrates. Knowing when and where selected channel-bed 

conditions are found, how these features are used by 

aquatic species of interest, and how these features may 

change with time are all valuable pieces of information for fisheries managers. For example, channel-bed 

features acquired using the MBMS, in conjunction with 

velocity distribution data provided by an acoustic Doppler current profiler (Mueller and others, 2013), were 

used to assess pallid sturgeon habitat in the Missssippi 

River near a proposed bridge construction site (fig. 6; 

Huizinga and others, 2010).

Multibeam echosounder surveys have been completed by the USGS at numerous bridge locations along 

the Missouri and Mississippi Rivers to determine channel-bed characteristics. At all the surveyed locations, a 

variety of fluvial features were detected in the channel, 

ranging from a planar or nearly planar bed—indicating minimal bedload transport in these areas—to large 

dunes that indicate substantial transport of bedload. 

Rock outcrops also were detected at several sites where the alluvial material of 

the channel bed had been washed away. 

Repeated surveys at these locations have 

allowed for the quantification of bed 

changes (deposition and scour) with time 

and provide some indication of the bed 

volume change and the relation between 

streamflow changes and the associated 

channel-bed responses (fig. 7).
94°39'10"

94°39'05"

94°39'00"

94°38'55"

94°38'50"

39°9'20"

39°9'15"

39°9'10"

94°39'15"

FLOW

0 50 100 150 200 250 FEET

0 25 50 75 METERS

Channel-bed elevation,

 in feet above North American

 Vertical Datum of 1988

EXPLANATION

735

730

725

720

715

710

705

700

695

690

685

Pier 3

Pier 2

Rock outcrop

Stone revetment

Figure 5. Planar view of mapped Missouri River channel reach 

indicating substantial scour around a bridge pier and other channel 

substrate features (Interstate 635 Bridge over the Missouri River at 

Riverside, Mo.; Huizinga, 2016).

Estimation of Bedload Transport

Bedload, defined as “the sediment that slides, rolls, or skips 

along in almost continuous contact with the streambed” (Hubbell, 1964, p. 2), currently (2018) is not measured consistently 

in most rivers. Direct measurement of bedload in large sand-bed 

rivers is highly inaccurate (Hubbell, 1964; Edwards and Glysson, 1999), and unconfirmed theoretical estimates commonly 

are used (Gomez, 2006). Techniques using time-lagged MBMS 

surveys (as demonstrated in figure 7), such as about an hour, 

have been developed to estimate bedload transport based on 

dune movement and the associated change in areas of scour and 

fill (Abraham and others, 2011).

Lake Surveys and Volume Calculations

Sedimentation in lakes and reservoirs can result in reduced 

capacity for flood storage and water supply and a loss of usable 

aquatic habitat over time. A detailed bathymetric survey allows 

for an accurate determination of available lake capacity for 

various uses. The MBMS has been used to map and determine 

accurate volume estimates for lakes in Missouri (fig. 8) and 

surrounding States. Such information can be used to determine 

water-supply availability, reservoir sedimentation rates and projected lifespans, and the spatial distribution of selected aquatic 

habitat.

References Cited

Abraham, D.D., Kuhnle, R.A., and Odgaard, A.J., 2011, Validation of 

bed-load transport measurements with time-sequenced bathymetric 

data: Journal of Hydraulic Engineering, v. 137, no. 7, p. 723–728.

Alvarado, A., and Robinson, D., 2011, Hydro survey—Multi-beam vs. 

single beam (part 1): Ayres Associates web page, accessed January, 

2018, at http://ayresriverblog.com/2011/08/02/hydro-survey-multibeam-vs-single-beam-part-1/.

Edwards, T.K., and Glysson, G.D., 1999, Field methods for measurement of fluvial sediment: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 3, chap. C2, 89 p.

Gomez, B., 2006, The potential rate of bed-load transport: Proceedings of the National Academy of Sciences of the United States of 

America, v. 103, no. 46, p. 17170–17173. [Also available at https://

doi.org/10.1073%2Fpnas.0608487103.]

Hubbell, D.W., 1964, Apparatus and techniques for measuring bedload: 

U.S. Geological Survey Water-Supply Paper 1748, 74 p., accessed 

April 15, 2015, at https://pubs.er.usgs.gov/publication/wsp1748.

Huizinga, R.J., 2012, Bathymetric and velocimetric surveys at highway 

bridges crossing the Missouri River in and into Missouri during summer flooding, July–August 2011: U.S. Geological Survey Scientific 

Investigations Report 2012–5204, 166 p.

Huizinga, R.J., 2014, Bathymetric surveys and area/capacity tables of 

water-supply reservoirs for the city of Cameron, Missouri, July 2013: 

U.S. Geological Survey Open-File Report 2014–1005, 15 p., https://

doi.org/10.3133/ofr20141005. 

Huizinga, R.J., 2016, Bathymetric and velocimetric surveys at highway 

bridges crossing the Missouri River near Kansas City, Missouri, 

June 2–4, 2015: U.S. Geological Survey Scientific Investigations 

Report 2016–5061, 93 p. [Also available at https://doi.org/10.3133/

sir20165061.]

Huizinga, R.J., 2017, Bathymetry and velocity data from surveys at 

highway bridges crossing the Missouri and Mississippi Rivers near 

St. Louis, Missouri, October 2008 through May 2016: U.S. Geological Survey data release, accessed January 2018 at https://doi.

org/10.5066/F71C1VCC.

Huizinga, R.J., Elliott, C.M., and Jacobson, R.B., 2010, Bathymetric 

and velocimetric survey and assessment of habitat for pallid sturgeon 

on the Mississippi River in the vicinity of the proposed Interstate 

70 Bridge at St. Louis, Missouri: U.S. Geological Survey Scientific 

Investigations Report 2010–5017, 28 p. [Also available at https://

pubs.usgs.gov/sir/2010/5017/.]
0 100 200 300 400 500 600FEET

0 50 100 150 METERS

Flow

392

390

388

386

384

382

380

378

376

374

372

370

368

366

364

362

360

358

356

354

352

350

348

346

Channel-bed elevation, in feet 

above North American Vertical 

Datum of 1988

6.5 to 7.0

6.0 to 6.5

5.5 to 6.0

5.0 to 5.5

4.5 to 5.0

4.0 to 4.5

3.5 to 4.0

3.0 to 3.5

2.5 to 3.0

2.0 to 2.5

1.5 to 2.0

1.0 to 1.5

0.5 to 1.0

0.3 to 0.5

Vertically averaged velocity,

in feet per second

Centerline of proposed

Interstate 70 Bridge

Proposed location

 of main channel

 piers

EXPLANATION

90°10'55" 90°10'50" 90°10'45" 90°10'40" 90°10'35" 90°10'30"

38°39'

38°38'55"

38°38'50"

38°38'45"

38°38'40"

38°38'35"

38°38'30"

38°38'25"

St. Louis City, Missouri St. Clair County, Illinois

Figure 6. Planar view of mapped Mississippi River channel reach indicating bed features and 

corresponding velocity distribution (Huizinga and others, 2010).
39°9'20"

39°9'15"

94°39'15"

39°9'10"

94°39'10"

94°39'05"

94°39'00"

94°38'55"

94°38'50"

FLOW

0 50 100 150 200 250 FEET

0 25 50 75 METERS

EXPLANATION

Change in channel-bed elevation, in feet 

-45 -30 -20 -15 -10 -7 -5 -3 -1 1 3 5 7 10 15 20 30

SCOUR DEPOSITION

Pier 3

Pier 2 Stone revetment

Rock outcrop

Figure 7. Planar view of mapped Missouri River channel reach at Kansas City, Mo., indicating the change in bed conditions between 

surveys in 2015 and 2011 (Interstate 635 Bridge over the Missouri River at Riverside, Mo.; Huizinga, 2016).

EXPLANATION

Shallow

Water depth

Deep

Figure 8. Planar view of mapped bottom of Reservoir 

3 near Cameron, Mo., from a multibeam echosounder 

survey in July 2013 (Huizinga, 2014). 

Huizinga, R.J., and Rydlund, P.H., Jr., 2004, Potential-scour assessments and estimates of scour depth using different techniques at 

selected bridge sites in Missouri: U.S. Geological Survey Scientific 

Investigations Report 2004–5213, 42 p. [Also available at https://

pubs.usgs.gov/sir/2004/5213/.]

Mueller, D.S., Wagner, C.R., Rehmel, M.S., Oberg, K.A., and Rainville, F., 2013, Measuring discharge with acoustic Doppler current 

profilers from a moving boat (ver. 2.0, December 2013): U.S Geological Survey Techniques and Methods, book 3, chap. A22, 95 p. [Also 

available at https://doi.org/10.3133/tm3A22.]

Richardson, E.V., and Davis, S.R., 2001, Evaluating scour at bridges 

(4th ed.): U.S. Federal Highway Administration Publication FHWA 

NHI 01–001, Hydraulic Engineering Circular no. 18, 378 p.

By Richard J. Huizinga and David C. Heimann

For further information, please contact 

Director, Central Midwest Water Science Center

U.S. Geological Survey

1400 Independence Road

Rolla, MO 65401

(573) 308-3667

https://mo.water.usgs.gov/

ISSN 2327-6916 (print)

ISSN 2327-6932 (online) 

https://doi.org/10.3133/fs20183021