U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2016–5098

Prepared in cooperation with the U.S. Environmental Protection Agency as part of the 

Great Lakes Restoration Initiative

Water Pressure and Ground Vibrations Induced by 

Water Guns at a Backwater Pond on the Illinois River near 

Morris, Illinois
Cover. Photograph showing the 2014 water gun setup. Back cover, Photograph showing the 2015 water gun setup. Both photographs 

taken at a backwater pond on the Illinois river near Morris, Illinois.
Water Pressure and Ground Vibrations 

Induced by Water Guns at a Backwater Pond 

on the Illinois River near Morris, Illinois

By Carolyn M. Koebel and Rachel M. Egly

Prepared in cooperation with the U.S. Environmental Protection Agency as part 

of the Great Lakes Restoration Initiative

Scientific Investigations Report 2016–5098

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia: 2016

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Suggested citation:

Koebel, C.M., and Egly, R.M., 2016, Water pressure and ground vibrations induced by water guns at a backwater pond 

on the Illinois River near Morris, Illinois: U.S. Geological Survey Scientific Investigations Report 2016–5098, 29 p., 

http://dx.doi.org/10.3133/sir20165098.

ISSN 2328-0328 (online)
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................2

Description of the Study Area ............................................................................................................2

Methods and Results for Bathymetry Surveys .........................................................................................2

Methods for Collection of Seismic Data ....................................................................................................4

Equipment...............................................................................................................................................4

August 2014 Study.................................................................................................................................5

May 2015 Study .....................................................................................................................................7

Water Pressure and Ground Vibrations Induced by Water Guns..........................................................9

August 2014 Study.................................................................................................................................9

Pressure Field...............................................................................................................................9

Ground Velocity..........................................................................................................................11

May 2015 Study ...................................................................................................................................14

Pressure Field—Single-Gun Shot...........................................................................................14

Pressure Field—Double-Gun Shot .........................................................................................14

Summary........................................................................................................................................................17

References Cited..........................................................................................................................................17

Appendix 1. Pressure Maps Produced During All Experiments......................................................18

Appendix 2. Underwater Pressure Data and Data-collection Equipment.....................................27

Pressure Data......................................................................................................................................27

Equipment.............................................................................................................................................27

Appendix 3. Ground Velocity Data and Data-collection Equipment ...............................................28

Ground Velocity Data .........................................................................................................................28

Equipment.............................................................................................................................................28

10-Hz surface geophones.........................................................................................................28

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch 

water gun)—August 12, 2014 ..............................................................................................28

Files 81201.dat through 81276.dat............................................................................................28

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch 

water gun)—August 13, 2014 ..............................................................................................29

Files 81277.dat through 81310.dat............................................................................................29

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch 

water gun)—August 14, 2014 ..............................................................................................29

Files 81311.dat through 81356.dat............................................................................................29
iv

Figures

 1. Schematic diagram of a water gun firing...................................................................................................... 1

 2. Location of the study area in a pond on the Hanson Material Service Corporation property, 

Morris, Illinois ................................................................................................................................................. 2

 3. Pit bathymetry data from July 2013 and December 2014, Morris, Illinois ............................................. 3

 4. Location of the water guns and netting to create a simulated lock approach channel within the

backwater pond in 2014 and 2015 ............................................................................................................. 4

 5. Diagram of the equipment setup for the August 2014 study..................................................................... 6

 6. Diagram of the hydrophone setup for the May 2015 study....................................................................... 7

 7. Diagram of the underwater blast sensor setup for the May 2015 study............................................... 8

 8. Comparison of the recorded pressures at various depths between blast sensors and

hydrophones................................................................................................................................................... 9

 9. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for

measurements recorded by hydrophones located at depths of 1 foot, 2 feet, 5 feet, and 

8 feet below the water surface of a backwater pond at Morris, Illinois, August 2014..............10

 10. Plan-view map and cross-sectional pressure maps from two 80-cubic-inch water guns fired

at 1,550 pounds per square inch..............................................................................................................11

 11. Spatial distribution of the relative standard deviation for each five-shot grouping, measured at

depths of 1 foot, 5 feet, and 12 feet below the water surface

 for experiments in August 2014...............................................................................................................12

 12. Geophone component maximum velocity from each shot, recorded during water gun firing at

Morris, Illinois, August 2014......................................................................................................................13

 13. Maximum velocities recorded at each geophone, by component, during the August 2014

water gun firing at Morris, Illinois ...........................................................................................................13

 14. Location map of the underwater blast sensor and hydrophone lines chosen for vertical

pressure map profiling, May 2015...........................................................................................................14

 15. Cross-sectional pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per

square inch, for measurements from underwater blast sensor and hydrophone profile 

lines .................................................................................................................................................................15

 16. Pressure map from a 100- cubic-inch water gun fired at 2,000 pounds per square inch, for

measurements at a depth of 5 feet below the water surface of a backwater pond at 

Morris, Illinois, May 2015...........................................................................................................................15

 17. Cross-sectional pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds per

square inch, for measurements from underwater blast sensor and hydrophone lines 

closest to the water guns, May 2015......................................................................................................16

 18. Pressure map from two 100-cubic-inch water guns fired at 2,000 pounds per square inch, for

measurements at a depth of 5 feet below the water surface of a backwater pond at 

Morris, Illinois, May 2015...........................................................................................................................16

1–1. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for

measurements at depths of 1 foot, 2 feet, 3 feet, and 4 feet below the water surface of a 

backwater pond at Morris, Illinois, August 2014.................................................................................19

1–2. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for

measurements at depths of 5 feet, 6 feet, 7 feet, and 8 feet below the water surface of a 

backwater pond at Morris, Illinois, August 2014.................................................................................20

1–3. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for

measurements at depths of 9 feet, 10 feet, 11 feet, and 12 feet below the water surface of 

a backwater pond at Morris, Illinois, August 2014..............................................................................21
v

1–4. Plan-view map and cross-sectional pressure maps from two 80-cubic-inch water guns fired

at 1,550 pounds per square inch..............................................................................................................22

1–5. Pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per square inch, for

measurements at depths of 1 foot, 3 feet, 5 feet, 7 feet, 9 feet, and 11 feet below the water 

surface of a backwater pond at Morris, Illinois, May 2015 ..............................................................23

1–6. Pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds per square inch, for

measurements at depths of 1 foot, 3 feet, 5 feet, 7 feet, 9 feet, and 11 feet below the water 

surface of a backwater pond at Morris, Illinois, May 2015 ..............................................................24

1–7. Cross-sectional pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per

square inch, for measurements from underwater blast sensor and hydrophone profile 

lines .................................................................................................................................................................25

1–8. Cross-sectional pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds per

square inch, for measurements from underwater blast sensor and hydrophone profile lines 

closest to the water guns..........................................................................................................................26

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square inch (in2

) 6.452 square centimeter (cm2)

Volume

cubic inch (in3

) 16.39 cubic centimeter (cm3) 

cubic inch (in3

) 0.01639 cubic decimeter (dm3) 

cubic inch (in3

) 0.01639 liter (L)

Velocity

inch per second (in/s) 25.4 millimeter per second (mm/s)

Pressure

pound per square inch (lb/in2

) 6.895 kilopascal (kPa) 

International System of Units to U.S. customary units

Multiply By To obtain

Length

meter (m) 3.281 foot (ft) 

meter (m) 1.094 yard (yd) 

Conversion Factors

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Water Pressure and Ground Vibrations Induced by Water 

Guns at a Backwater Pond on the Illinois River near 

Morris, Illinois

By Carolyn M. Koebel and Rachel M. Egly

Abstract

Three different geophysical sensor types were used 

to characterize the underwater pressure waves and ground 

velocities generated by the underwater firing of seismic 

water guns. These studies evaluated the use of water guns 

as a tool to alter the movement of Asian carp. Asian carp are 

aquatic invasive species that threaten to move into the Great 

Lakes Basin from the Mississippi River Basin. Previous 

studies have identified a threshold of approximately 5 pounds 

per square inch (lb/in2) for behavioral modification and for 

structural limitation of a water gun barrier.

Two studies were completed during August 2014 and 

May 2015 in a backwater pond connected to the Illinois 

River at a sand and gravel quarry near Morris, Illinois. 

The August 2014 study evaluated the performance of two 

80-cubic-inch (in3) water guns. Data from the 80-in3 water 

guns showed that the pressure field had the highest pressures 

and greatest extent of the 5-lb/in2 target value at a depth of 

5 feet (ft). The maximum recorded pressure was 13.7 lb/in2, 

approximately 25 ft from the guns. The produced pressure 

field took the shape of a north-south-oriented elongated 

sphere with the 5-lb/in2 target value extending across the 

entire study area at a depth of 5 ft. Ground velocities were 

consistent over time, at 0.0067 inches per second (in/s) in the 

transverse direction, 0.031 in/s in the longitudinal direction, 

and 0.013 in/s in the vertical direction.

The May 2015 study evaluated the performance of 

one and two 100-in3 water guns. Data from the 100-in3

water guns, fired both individually and simultaneously, 

showed that the pressure field had the highest pressures 

and greatest extent of the 5-lb/in2 target value at a depth of 

5 ft. The maximum pressure was 57.4 lb/in2, recorded at 

the underwater blast sensor closest to the water guns (at a 

horizontal distance of approximately 3 ft), as two guns fired 

simultaneously. Pressures and extent of the 5-lb/in2

 target 

value decrease above and below this 5-ft depth, producing a 

relatively north-south-oriented pressure field shaped like an 

elongated sphere.

Introduction

Asian carp, primarily bighead carp (Hypophthalmichthys 

nobilis) and silver carp (Hypophthalmichthys molitrix), 

are aquatic invasive species that threaten to migrate into 

the Great Lakes Basin from the Mississippi River Basin, 

through the Chicago Area Waterway System (CAWS). The 

U.S. Geological Survey (USGS) is studying the potential 

effectiveness of using water guns to produce a pressure barrier 

to direct the movement of Asian carp and reduce the risk of 

interbasin transfer.

Water guns use high-pressure air to rapidly eject a rated 

volume of water (fig. 1). The ejection creates a vacuum, which 

is rapidly filled by water as it collapses back into the empty 

space. This collapse of water back into empty space produces 

a pressure wave.

Several studies have investigated the effects of water 

guns on fish and other marine life. A variety of fish species 

reportedly displayed a startle-like response by quickly 

changing direction and velocity when exposed to an 

underwater pressure wave from a water gun (Boeger and 

Port

hole

Solenoid

valve

High

pressure

air

Firing

chamber

Shuttle

Charged Fired Implosion

Figure 1. Schematic diagram of a water gun firing. Modified 

from Layhee and others (2013).
2 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

others, 2006; Gordon and others, 2003; Hirst and Rodhouse, 

2000). Other studies report results that range from minimal 

changes in behavior (Turnpenny and Nedwell, 1994; Wardle 

and others, 2001) to mortality (Gross and others, 2013).

Fish behavior data, collected as a separate investigation 

during prior pond experiments (Adams and Morrow, 2015), 

indicated that a pressure near 4 pounds per square inch (lb/in2) 

was sufficient to modify the free-swimming movement of Asian 

carp (Romine and others, 2015). A limitation value for pressures 

exerted on structures was set at 5 lb/in2, so a target value of 5 lb/in2

was used as a benchmark for the evaluation of water gun barriers 

in this study.

Purpose and Scope

The purpose of this report is to present measurements of 

the physical magnitude and extent of the pressure field in the 

water and the velocity magnitude on land caused by the firing 

of water guns; these data were collected during two separate 

studies, conducted in August 2014 and May 2015, in a backwater 

pond near Morris, Illinois. Studying the magnitude, direction, 

and impacts of the pressure output on Asian carp, native species, 

structures, and other recipients is a larger USGS goal that is 

not covered in this report. A fish behavior study was conducted 

concurrently (A.R. Cupp, U.S. Geological Survey, written 

commun., 2015). 

Pressure measurements within the water column were 

collected using hydrophones and underwater blast sensors 

(UBS). Velocity measurements on land also were collected 

using geophones for transverse, longitudinal, and vertical wave 

propagation.

Data collection near Morris, Illinois consisted of recording 

pressure values at depth, as well as horizontally, but also 

determining maximum velocities at and away from the edge of the 

water with consistent gun location and continuous firing. Pressure 

maps produced from these two studies may provide a basis for 

studying the size and shape of the pressure field that can be created 

under these conditions.

Description of the Study Area

The study area is a backwater pond connected to the Illinois 

River on the Hanson Material Service Corporation sand and gravel 

mining operation property near Morris, Illinois (fig. 2). The pond 

is about 3 miles (mi) long in the east-west direction, from the 

western shore to the culvert, and about 0.45 mi at its widest, in the 

north-south direction. At the study site, the width of the pond is 

about 300 feet (ft).

Methods and Results for Bathymetry 

Surveys

Bathymetry data of the study area were collected with a 

1,200 megahertz (MHz) Rio Grande acoustic Doppler current 

profiler in July 2013 and December 2014 (fig. 3). Data were 

recorded as depths below the water surface (bws) and were not 

referenced to a known water-surface elevation. These data were 

contoured by using Esri ArcMAP (ver. 10.3, http://www.esri.

com). A kernel smoothing with barriers algorithm was used to 

372500 373000 373500 374000 374500 375000 375500 376000 376500 377000 377500 378000 378500 379000

4576000

4576500

4577000

4577500

4578000

4578500

Area shown in Figure 4

Pond outlet

to the

Illinois River

Illinois

River

Base imagery from USDA National Agriculture

Imagery Program (NAIP), Illinois, 2015. 

Universal Transverse Mercator (UTM) projection, 

Zone 16N, meters, NAD 1983 datum

0 0.5 MILE

0 0.5 KILOMETER

Direction of flow

ILLINOIS

River

Map

area

Illinois Illinois

Figure 2. Location of the study area in a pond on the Hanson Material Service Corporation property, Morris, Illinois.
Methods and Results for Bathymetry Surveys 3

smooth the data and create bathymetry maps. The July 2013 

survey covered the entire west pit. The resulting bathymetry 

showed water depths ranging from 11 to 13 ft (fig. 3A). The 

December 2014 survey covered a quarter mile east and west of 

the study area. The resulting bathymetry showed water depths 

ranging from 5 to 10 ft (fig. 3B). The 2013–2014 bathymetry 

data were used to guide the 2014 and 2015 survey design by 

determining how deep the hydrophones could be set.

372500 373000 373500 374000 374500 375000 375500 376000 376500 377000

4576000

4576500

4577000

373900 374000 374100 374200 374300 374400 374500 374600 374700 374800 374900

4576200

4576300

4576400

4576500

4576600

Base imagery from U.S. Department of Agriculture National

Agriculture Imagery Program (NAIP), Illinois, 2015;

Universal Transverse Mercator (UTM) projection, Zone 16N,

meters, NAD 1983 datum.

0 0.5 MILE

0 0.5 KILOMETER

EXPLANATION

Lake depth, in feet

Less than or equal to 1

Greater than 1 to 2

Greater than 2 to 3

Greater than 3 to 4

Greater than 4 to 5

Greater than 5 to 6

Greater than 6 to 7

Greater than 7 to 8

Greater than 8 to 9

Greater than 9 to 10

Greater than 10 to 11

Greater than 11 to 12

Greater than 12 to 13

Uninterpolated area

A

B

Figure 3. West pit bathymetry data from July 2013 (A) and December 2014 (B), Morris, Illinois.
4 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

Methods for Collection of Seismic Data

Seismic data were acquired at a backwater pond near Morris, 

Illinois, from August 12 to 14, 2014, and from May 26 to 29, 

2015. Data collection consisted of two separate studies using 

hydrophones and UBS with the goal of measuring the magnitude 

and extent of the pressure field produced by firing two water guns. 

Land velocity data were also collected in 2014 to supplement the 

pressure data.

Equipment

Two 80-cubic inch (in3) water guns were deployed in the 

2014 study and two 100-in3 water guns were deployed in the 

2015 study. The water guns were set approximately 1.3 mi east 

from the western edge of the pond and secured in a northsouth line (fig. 4). The water guns were bordered by netting so 

that the only east-west passageway for fish was between the 

water guns.

EXPLANATION

Netting in 2014

Netting in 2015

Water gun location in 2014

Water gun location in 2015

Base imagery from USDA National Agriculture

Imagery Program (NAIP), Illinois, 2014.

Universal Transverse Mercator (UTM) projection,

Zone 16N, meters, NAD 1983 datum

0 0.025 0.05 MILE

0 0.025 0.05 KILOMETER

374350 374400 374450 374500

4576400

4576450

4576500

4576550

Figure 4. Location of the water guns and netting to create a simulated lock approach channel within the backwater pond in 

2014 and 2015.
Methods for Collection of Seismic Data 5

Each water gun was suspended from an anchored, 6 × 6-ft 

aluminum pontoon float and controlled by a HotShot (2014) 

or BigShot (2015) controller tethered to a laptop computer. Air 

was supplied to each gun by a high-pressure, high-volume air 

compressor (rated at 5,000 lb/in2 and 81 standard cubic feet 

per minute) during 2014 and two high-pressure reciprocating 

compressors (rated at 5,000 lb/in2 and 100 standard cubic feet 

per minute), linked in tandem, during 2015.

Hydrophones were used to determine the increase in 

pressure at specific distances from the water guns. These 

piezoelectric sensors measure the impact of the blast front 

moving through the water on a quartz crystal, which produces 

an electrical voltage in proportion to the pressure increase. The 

sensors used were OYO Geospace Hydrophones, modified 

by Instantel, with a sensitivity of 0.0237 lb/in2. They were 

sampled at a rate of 8,000 to 32,000 samples per second (sps) 

by an Instantel Blasting Seismograph.

The UBS are also piezoelectric sensors used to determine 

the increase in pressure from the water guns. The impact 

of the blast front moving through the water produces an 

electrical voltage on a tourmaline crystal in proportion to the 

pressure increase. The sensors used were PCB Piezotronics 

Underwater Blast Sensors being sampled at 8,000 to 32,000 sps 

by a National Instruments data acquisition system linked to a 

computer running National Instruments Labview Signal Express 

software. These sensors have a sensitivity of 0.02 lb/in2.

The UBS and hydrophones both monitor pressure, but 

they have different operational ranges. UBS are rated to 

1,000 lb/in2 and are suitable for collecting high-pressure 

data created at closer distances to the water guns. The 

hydrophones are only rated to 47 lb/in2, but are much more 

sensitive to the 1–10-lb/in2 range and are therefore more 

suitable to record pressures generated at distances greater 

than 30 ft.

Geophones are mechanical sensors that record the 

magnitude of ground motion using calibrated weights and 

springs. A metal weight moving within a coil of wire produces 

a voltage equivalent to the motion at the geophone. This 

voltage is transmitted through wires to the seismograph.

Three-component geophones, with frequency of 10 hertz 

(Hz), coil resistance of 395 ohms, and sensitivity of 27.5 volts 

per meter per second (V)/(m/s), were used in 2014 connected to 

the seismograph. The seismograph sampled these geophones at 

a rate of one measurement every 0.125 millisecond for a period 

of 8 seconds (s). The seismograph was connected to a computer 

running Geometrics Seismodule Controller.

For all setups, the water guns were placed in a fixed 

position and depth and fired at a constant pressure. Sensors were 

suspended in the water column at a fixed distance and depth 

and moved sequentially in the water surrounding the water gun 

to produce the pressure maps. Three to five water gun shots 

were taken at each point location, and the maximum value 

for all shots was recorded. The arithmetic mean values of the 

maximum pressure values recorded at each position were used 

in the pressure map figures.

August 2014 Study

The August 2014 study consisted of collecting water 

pressure and ground velocity data while two 80-in3 water guns 

were fired in order to map the pressures and ground velocities 

produced by the water guns.

Two 80-in3 water guns were positioned along a northsouth line and centered east-west and north-south in the 

pond, with the water guns suspended horizontally so that the 

ejection ports were facing north-south, at a depth of about 

6 ft bws. The water guns were separated by 100 ft, with the 

north gun approximately 100 ft from the north shore and the 

south gun approximately 100 ft from the south shore (fig 4). 

Data were collected over 3 days while the water guns were 

being fired simultaneously, every 10 s at a firing pressure 

of 1,550 lb/in2. Twelve hydrophones were suspended at 1-ft 

increments from 1 to 12 ft. Certain areas of the pond are 

shallower than 12 ft (fig. 3), and the water column is not 

sufficient to suspend the full length of the hydrophone string. 

Such circumstances caused the deeper hydrophones to pile 

up at the bottom of the pond, resulting in data that are not 

true representations of the water pressure at the supposed 

hydrophone depths. For two lines of hydrophone positions, 

water depths were recorded from a winch as it lowered a 

cinderblock, used to weight the end of the hydrophone string, 

into the water. Based on these winch depth values, it could be 

determined if the water was deep enough to support the whole 

hydrophone string. The resulting pressure maps were edited 

so that potentially bad data would not be shown because they 

may not represent the true pressures at these depths. During 

data collection, hydrophones were advanced across the pond 

following an approximate 10-ft grid spacing (fig. 5). Five 

shots were recorded at each position. Measurements were 

made in a square-wave-type pattern, with the hydrophones 

being advanced to the northern or southern extent of the study 

area. The hydrophones were then moved 10 ft in the east-west 

direction to establish a new north-south sampling section. 

This pattern was repeated until the hydrophones became too 

close to the exclusion zone, a 15-ft radius around the water 

guns, to be operated safely.

Four geophones were arranged on the sandy shore, 

pointed north, with 10-ft grid spacing between them (fig. 5). 

The geophones were color coded to more easily distinguish 

between them; herein they will be referenced by their color. 

The transverse component was oriented east-west and the 

longitudinal component was oriented north-south. The vertical 

component was oriented perpendicular to the ground surface. 

The geophone arrangement remained the same throughout 

the study. Ten shots were recorded every hour during working 

hours (approximately 7 a.m. to 5 p.m.) over 3 days.

Equipment was located using real-time kinematic (RTK) 

global positioning systems (GPS). Each position of the buoys 

supporting the hydrophone and a central point on the water 

gun barge were georeferenced. Position data were collected 

using Universal Transverse Mercator (UTM) coordinates.
6 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

Profile view of hydrophone buoy 

setup used in the study area

1 foot

Hydrophone buoy

Water surface

Hydrophone

Geophones 10 feet

Pond

Shore

10 feet Center line

100 feet

100 feet

EXPLANATION N

Approximate study area

Exclusion zone

Water gun

Geophone

Figure 5. Diagram of the equipment setup for the August 2014 study. Geophones are all the same 

type of instrument but color coded to distinguish among them (not to scale).
Methods for Collection of Seismic Data 7

May 2015 Study

During the May 2015 study, pressure data were collected 

from the firing of either one (single-gun shot) or two (doublegun shot) 100-in3

 water guns in order to map a simulated lock 

channel.

A passage was created using six 100-in3 water guns 

arranged in a three by two grid (fig. 4). Netting was secured 

around the north and south sides of the grid to create a channel 

roughly 110 ft wide and 52 ft long. This passage simulated the 

typical width of a lock channel in the CAWS (U.S. Army Corps 

of Engineers, 2016). The water guns were suspended 6 ft bws, 

with the ejection ports facing north-south. The water guns were 

approximately 132 ft from shore, separated by 26 ft east-west 

and 35 ft north-south. Data were collected for the center two 

water guns (fig. 4). The hydrophones were suspended at 1-ft 

increments from 1 to 12 ft bws. Winch measurements of depth 

to the bottom of the pond were made at each hydrophone group 

position. Based on the recorded winch-measurement depths, 

corrections to the pressure maps were made as needed. During 

data collection, hydrophones were moved to cover the area east 

of the water guns following an approximate 10-ft grid spacing. 

Measurements were made in a square-wave-type pattern, with 

the hydrophones advanced east-west across the eastern part of 

the simulated lock approach channel (fig. 6). The hydrophones 

were then moved approximately 10 ft south to establish a 

new east-west-trending sampling section. This pattern was 

repeated until the hydrophones reached the southern edge of 

the simulated lock channel. The water guns used in 2015 were 

larger than those used in 2014, so an exclusion zone had not 

yet been established. In order to prevent any damage to the 

hydrophones, and also owing to the inability to access the center 

channel area by boat because of steel support cabling, UBS 

were used to collect pressure measurements from a radius of 

26 ft inward. Three shots were recorded with the north gun and 

three shots with both guns at 2,000 lb/in2

. During hydrophone 

operation, the UBS were stationed approximately 40 ft north of 

the north gun and were not moved.

Profile view of hydrophone buoy 

setup used in the study area

1 foot

Hydrophone buoy

Water surface

Hydrophone

Profile view of blast sensor buoy 

setup used in the study

2 feet

Blast sensor buoy

Water surface

Blast sensor

52 feet

Center line

0 20 40 60 80 100 FEET

N

EXPLANATION

Approximate study area

Exclusion zone

Water gun

Blast sensor buoy

Net line

Figure 6. Diagram of the hydrophone setup for the May 2015 study.
8 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

After the completion of the hydrophone measurements, 

the UBS survey began. The UBS were used to map the rest 

of the pressure barrier on the eastern part of the simulated 

lock approach channel (from the centerline to 26 ft east of the 

centerline) (fig. 7). Three north-south lines were measured, 

one along the centerline, one 13 ft east of the centerline, and 

one 26 ft east of the centerline. Twelve shots were taken at an 

operating pressure of 2,000 lb/in2: six shots with the north gun 

(three with the UBS at 1, 3, and 5 ft bws and three with the UBS 

at 7, 9, and 11 ft bws) and then six shots with both guns firing 

simultaneously (three with the UBS at 1, 3, and 5 ft bws and 

three with the UBS at 7, 9, and 11 ft bws). Winch measurements 

were unable to be made at UBS group positions owing to the 

steel stabilizing cables surrounding the simulated lock channel, 

which prevented the boat from entering the grid. After each shot 

sequence, the UBS were moved approximately 13 ft along the 

survey line.

Equipment was located using RTK GPS. When GPS 

accuracy declined from insufficient satellites, equipment position 

was noted in relation to other geolocated equipment and recorded 

in a field notebook. A position was noted for each buoy supporting 

the hydrophone string and UBS string and a central point on 

the water gun barge. Position data were collected using UTM 

coordinates.

Processed location data were integrated with the average 

maximum values obtained from each data point. These data 

were contoured by using Esri ArcMAP (ver. 10.3, http://

www.esri.com). A kernel smoothing with barriers algorithm 

was used to smooth the data and create pressure maps within 

the hydrophone and UBS boundaries on each side of the 

water gun. This kernel interpolation model fits a first order 

polynomial, within specified overlapping neighborhoods, 

to produce the mapping output, limiting instability by using 

methods similar to ridge regression to estimate the regression 

coefficients. Because this technique fits a surface to the 

majority of the data points, the surface does not always 

represent the exact values of the measured point data recorded 

by the hydrophones and UBS.

The hydrophone data closest to the gun were collected 

within a few feet of the UBS data farthest away from the gun. 

As the distance to the water guns became nearer, the equipment 

transitioned from hydrophone to UBS, locating the UBS and 

Profile view of blast sensor buoy 

setup used in the study area

2 feet

Blast sensor buoy

Water surface

Blast sensor

26 feet

35 feet

35 feet

35 feet

Center line

0 20 40 60 80 100 FEET

N

EXPLANATION

Approximate study area

Water gun

Net line

Figure 7. Diagram of the underwater blast sensor setup for the May 2015 study.
Water Pressure and Ground Vibrations Induced by Water Guns 9

hydrophones within a few feet of each other and allowing for 

comparison. However, the pressure values measured by these two 

sets of instruments were not consistent. An experiment was set up 

to create a side-by-side comparison. The hydrophones and UBS 

were both suspended next to each other at the northeast corner 

of the simulated lock channel in order to perform a comparison 

between the two types of instruments. Ten shots were recorded, 

with five measurements from the UBS at 1, 3, and 5 ft bws 

and five measurements from the UBS at 7, 9, and 11 ft bws. A 

comparison between the maximum recorded pressures at the 

various depths for the two instruments is displayed in figure 8. The 

hydrophones and UBS are better correlated at depths of 9 ft bws or 

greater, where they are located below the water gun.

The UBS are rated to 1,000 lb/in2, whereas the 

hydrophones are rated to 47 lb/in2. Pressures recorded during 

the surveys were on the lower end of the UBS recording 

spectrum, below the fifth percentile, so they are likely to be 

less reliable than the hydrophone data.

Water Pressure and Ground Vibrations 

Induced by Water Guns

The following sections of the report contain selected pressure 

maps and velocity graphs of the backwater pond, grouped by 

recording instrument. Pressure maps show data points that are 

derived from an arithmetic mean of the 3–5 maximum pressure 

values recorded at each position (appendix1, figs. 1–1 through 

1–8). The velocity graphs show the absolute maximum velocities 

of each component that were recorded. Signals from water gun 

firings were recorded by seismographs and datasets are cataloged 

as plan-view and cross-sectional maps in appendix1. Microsoft 

Excel files and raw digital data files are described in appendixes 

2 and 3, respectively. All data files are available at http://dx.doi.

org/10.3133/sir20165098.

August 2014 Study

Pressure Field

The August 2014 pressure field results for the hydrophones 

in figures 9 and 10 are presented as plan-view and vertical contour 

maps at increasing depths. Pressures in these plots range from 

less than 1 lb/in2 to approximately 13.7 lb/in2 25 ft away from the 

water guns. The 5-lb/in2 contour is noted in the figures as well as 

the location of the water guns and hydrophones.

Higher pressures are found closest to the water guns 

and decrease with increasing distance from the water guns 

(figs. 9, 10). The pressure value is maximized around a depth 

of 5 ft bws at 13.7 lb/in2, approximately 25 ft (horizontal 

distance) from the water guns. This depth also includes the 

greatest extent of the 5-lb/in2 target value (fig. 9C). The maps 

indicate that over the same distance from the water guns, 

there is a greater decrease in pressure below the water guns 

than above (figs. 9, 10B, C). The 1- and 2-ft-depth-bws plots 

0

2

4

6

8

10

12

14

16

1 3 5 7 9 11

Pressure, in pounds per square inch

Depth below water surface, in feet

Blast sensor

Hydrophone

Error bar

EXPLANATION

1 standard deviation

 above the mean

1 standard deviation

 below the mean

Figure 8. Comparison of 

the recorded pressures at 

various depths between 

blast sensors and 

hydrophones.
10 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

A B C D

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0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Pressure, in pounds per square inch

Water gun

Hydrophone group position

5 pounds per square inch contour line

EXPLANATION

Figure 9. Pressure map from two 80-in2 water guns fired at 1,550 lb/in2, for measurements at a depth of, A, 1 foot, B, 2 feet, C, 5 feet, 

and D, 8 feet.

Figure 9. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for measurements recorded by 

hydrophones located at depths of 1 foot (A), 2 feet (B), 5 feet (C), and 8 feet (D) below the water surface of a backwater pond at Morris, 

Illinois, August 2014.
Water Pressure and Ground Vibrations Induced by Water Guns 11

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM),

Zone 16N, easting, in meters

A

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A

׳A

׳B

B

Depth, in feet

0

0

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-8

-8

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-12

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

B

C

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A A׳

B B׳

EXPLANATION

EXPLANATION

Pressure, in pounds per square inch

0

1

2

3

4

5

6

7

8

Water gun

Hydrophone

5 pounds per square inch contour line

Pond bottom

Cross-section profile line

 with profile identifier

Selected hydrophone group

 position for vertical profiling

Hydrophone group position

Water gun

A A׳

Figure 10. Plan-view map and cross-sectional pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square 

inch. Plan-view map (A) depicts the cross-section lines for the A–A’ (B) and B–B’ (C) cross-sectional pressure maps for the backwater 

pond study area at Morris, Illinois, August 2014.

(fig. 9A, B) have some of the lowest pressure values recorded. 

The 1-ft-depth-bws plot recorded slightly higher pressures 

because of interference from the water surface. The 5-lb/in2

target value pressure field is a roughly north-south-oriented 

elongated sphere with a segment of decreased diameter 

between the guns.

Relative standard deviations of the five-shot groupings at 

depths of 1, 5, and 12 ft bws for the August 2014 experiment 

are shown in figure 11. Standard deviations for this grouping 

decrease in close proximity to the water gun firing port. 

Variation is lower at the depths where the highest pressures 

were recorded (approximately 5 ft bws) and increases as 

horizontal and vertical distances from the water guns increase.

Ground Velocity

Geophone data were collected during a series of regular 

interval water gun shots (one shot every 10 s) with intermittent 

periods of no shots, over a period of 3 days. Ten velocity values 

were recorded every hour that personnel were present (usually 

10 hours per day) during water gun firing. Ground velocity was 

measured using three-component geophones mounted on the 
12 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

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A B C

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

EXPLANATION

Coefficient of variation (σ/μ)

Water gun

Hydrophone group position

Figure 11. Spatial distribution of the relative standard deviation for each five-shot grouping, measured at depths of 1 foot (A), 5 feet (B), 

and 12 feet (C) below the water surface for experiments in August 2014.

sandy shore of the pond. The geophones were deployed in a 

grid along the edge of the water and along the centerline, with 

10-ft grid spacing between each geophone, and oriented such 

that the longitudinal component of each geophone was pointing 

north. Each geophone was color coded with identifying tape for 

easier reference: red was northwest, orange was northeast, green 

was southwest, and white was southeast (fig. 5). The maximum 

velocities recorded for all geophones during the experiment were 

0.013 inches per second (in/s) of vertical velocity and 0.031 in/s of 

horizontal (longitudinal) velocity.

Some data points were removed from the dataset owing 

to aberrant sources. Suspicious points that did not fit in with the 

overall consistent velocity trend underwent a waveform analysis, 

comparing them to controls (those from shots within the trend), to 

determine any inconsistencies that would classify them as outliers 

and thus give reason for removal. A large group of outlying 

points were grouped together at shot number 106–112 owing 

to compressor failure because the compressor had to be shut 

down shortly after the recording of these values. Analysis of the 

waveforms of other points displayed high frequency noise from 

people walking or from boat motors nearing the geophones and 

causing constructive or destructive interference. The data point 

at shot 10 had an incomplete waveform owing to the recording 

starting too late and missing the peak velocity.
Water Pressure and Ground Vibrations Induced by Water Guns 13

Velocity values remained generally consistent as the shot 

number increased (fig. 12): 0.0067 in/s in the transverse direction, 

0.031 in/s in the longitudinal direction, and 0.013 in/s in the 

vertical direction. Air expelled by the water guns remained at a 

consistent pressure above 1,550 lb/in2; however, there appears to 

be a cyclic pattern to the horizontal component velocities recorded 

by the geophones. This cyclic pattern may be a result of the 

geophones picking up vibrations from the compressor as it turned 

on and off.

The geophones located along the edge of the water 

(orange and red) recorded larger horizontal velocities than 

their counterparts 10 ft from the edge of the water (white and 

green) (fig. 13). Geophones located in line with the water guns 

recorded larger velocities than their counterparts offset 10 ft 

from the centerline. The orange geophone, located at the edge 

of the water and along the water gun centerline, recorded the 

highest velocity (0.031 in/s in the longitudinal component) 

of the study. The component recording the highest velocity is 

Transverse

Longitudinal

Vertical

Geophone component

EXPLANATION

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0 20 40 60 80 100 120 140 160 180

Velocity, in inches per second

Shot number

Figure 12. Geophone 

component maximum velocity 

from each shot, recorded during 

water gun firing at Morris, 

Illinois, August 2014. Color 

designates which geophone the 

component was from (orange, 

northeast; green, southwest). 

EXPLANATION

Orange

White

Red

Green

Geophone

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

Transverse Longitudinal Vertical

Velocity, in inches per second

Geophone component

Figure 13. Maximum 

velocities recorded at each 

geophone, by component, 

during the August 2014 water 

gun firing at Morris, Illinois.
14 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

consistent between geophones: the longitudinal component 

recorded the fastest velocities whereas the transverse 

component recorded the slowest velocities.

May 2015 Study

Pressure Field—Single-Gun Shot

Based on hydrophone and UBS transects closest to the 

water guns (fig. 14), the May 2015 pressure field results for 

the hydrophones in figures 15 and 16 are presented as vertical 

and plan-view contour maps, at increasing depths. Pressures 

in these plots range from less than 1 lb/in2 to approximately 

56.7 lb/in2. The 5-lb/in2 contour, as well as the location of the 

guns and hydrophones, is noted in the figures.

Data next to the water gun at a depth of 5 ft bws showed 

both the highest pressure (approximately 56.7 lb/in2) and the 

greatest radial extent of the 5-lb/in2 target value, covering 

the entire north-south part and 80 percent of the east-west 

part of the study area (figs. 15A, 16). The 5-lb/in2 target 

value had a greater extent north-south than east-west owing 

to the orientation of the water gun ports. Pressure increases 

with depth to about 5 ft bws, where it begins to decrease 

with depth. Pressure then increases again around a depth of 

10 ft bws along the 5 lb/in2 contour line, possibly owing to 

the presence of the bottom of the pond (fig. 15A). Pressures 

are greatest next to the water gun and decrease farther away 

(figs. 15, 16). Data above and below a depth of 5 ft bws show 

smaller extents of the 5-lb/in2 target value. The overall shape 

of the 5-lb/in2 pressure field produced by a single water gun is 

that of an elongated sphere oriented north-south.

Pressure Field—Double-Gun Shot

The pressure field results for the hydrophones in figures 

17 and 18 are presented as vertical and plan-view contour 

maps at increasing depths. Pressures in these plots range from 

less than 1 lb/in2 to approximately 57.4 lb/in2. The 5-lb/in2

contour is noted in the figures as well as the location of the 

guns and hydrophones.

Data next to the water guns at a depth of 5 ft bws showed 

both thehighest pressure (approximately 57.4 lb/in2) and the 

greatest radial extent of the 5-lb/in2 target value, covering the 

entire north-south part and most of the east-west part of the study 

area (figs. 17A, 18). The 5-lb/in2 target value had a greater extent 

north-south than east-west owing to the orientation of the water 

gun ports. Pressure increases with depth to about 5 ft bws, where 

it begins to decrease with depth. Pressures are greatest next to 

the water guns and decrease farther away (figs. 17, 18). Data 

above and below a depth of 5 ft bws show smaller extents of the 

5-lb/in2 target value (fig. 18). The overall shape of the 5-lb/in2

pressure field produced by firing two water guns simultaneously 

is that of an elongated sphere oriented north-south. However, 

pressures at depths of 3, 5, 7, and 9 ft bws deviate from this 

overall pressure field shape (appendix 1, figs. 1–6B through 

׳B ׳A

A B

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Cross-section profile line

 with profile identifier

Water gun

Hydrophone

Underwater blast sensor

Underwater blast sensor group

 position used for vertical profiling

Hydrophone group position used

 for vertical profiling

EXPLANATION

A A׳

Figure 14. Location map of the underwater blast sensor (A–A’) 

and hydrophone (B–B’) lines chosen for vertical pressure map 

profiling, May 2015.

1–6E). A projection of higher pressure extends from between the 

two water guns eastward, as can be seen in the deviation of the 

5-lb/in2-target-value contour (fig. 18). This is most likely due to 

the interaction of each water gun’s pressure field as it expands. 

Standard deviation values for the May 2015 study were not 

calculated because only three shots were recorded at each point.
Water Pressure and Ground Vibrations Induced by Water Guns 15

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

A A׳

A

B

Depth, in feet

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

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B B׳

56

EXPLANATION

Pressure, in pounds

 per square inch

0

4

8

12

16

20

24

28

32

36

40

44

48

52

5 pounds per square

 inch contour line

Pond bottom

Water gun

Underwater blast

 sensor

Hydrophone Figure 15. Cross-sectional pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per 

square inch, for measurements from underwater blast sensor (A) and hydrophone (B) profile lines. 

Water gun marked was the one fired.

56.74

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Universal Transverse Mercator (UTM), Zone 16N, easting, in meters

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EXPLANATION

Pressure, in pounds

 per square inch

5 pounds per square

 inch contour line

Water gun

Hydrophone

Underwater blast sensor

Pressure reading that 

 exceeds maximum 

 contoured pressure

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36 and greater

56.74

Figure 16. Pressure map from 

a 100- cubic-inch water gun 

fired at 2,000 pounds per square 

inch, for measurements at a 

depth of 5 feet below the water 

surface of a backwater pond at 

Morris, Illinois, May 2015.
16 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

57.43

53.00 57.43

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

A A׳

A

B

Depth, in feet

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

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B B׳

EXPLANATION

Pressure, in pounds

 per square inch

44 and greater

40

36

32

28

24

20

16

12

8

4

0

5 pounds per square

 inch contour line

Pond bottom

Water gun

Underwater blast

 sensor

Hydrophone

Pressure reading that 

 exceeds maximum 

 contoured pressure

Figure 17. Cross-sectional pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds per 

square inch, for measurements from underwater blast sensor (A) and hydrophone (B) lines closest to the 

water guns, May 2015.

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM), Zone 16N, easting, in meters

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EXPLANATION

Pressure, in pounds

 per square inch

53.00

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36 and greater

5 pounds per square

 inch contour line

Water gun

Hydrophone

Underwater blast sensor

Pressure reading that 

 exceeds maximum 

 contoured pressure

57.43

57.43

Figure 18. Pressure map from 

two 100-cubic-inch water guns 

fired at 2,000 pounds per square 

inch, for measurements at a depth 

of 5 feet below the water surface 

of a backwater pond at Morris, 

Illinois, May 2015.
References Cited 17

Summary

Two studies, one each in August 2014 and May 2015, 

were performed to evaluate the physical characteristics of the 

pressure field in the water and the ground velocity on land 

created by water guns fired in a backwater pond of the Illinois 

River at a quarry near Morris, Illinois. Pressure data were 

collected by using blast-rated hydrophones in 2014, whereas 

both hydrophones and underwater blast sensors (UBS) were 

used to evaluate pressure in 2015. Geophones were used to 

collect ground velocity data in 2014.

The purpose of the August 2014 study was to measure 

and map the pressure field created by two 80-in3 water guns 

fired simultaneously every 10 s. The recorded ground velocities 

remained consistent over time, were greater at the edge of 

the water and decreased farther from the water’s edge, and 

produced a maximum recorded horizontal velocity of 0.031 in/s. 

The magnitude of the pressure field produced by an 80-in3

 water 

gun was greatest at a depth of 5 ft bws, producing a pressure 

field shaped like an elongated sphere, with the greatest extent 

of the 5-lb/in2 target value extending across the majority of the 

study area.

The May 2015 study measured and mapped the pressure 

field created by one and two simultaneously fired 100-in3 water 

guns. Pressures were recorded both inside and outside of the 

constructed simulated lock approach channel. The magnitude of 

the pressure field was the greatest at a depth of 5 ft bws with the 

greatest extent of the 5-lb/in2 target value extending across the 

majority of the study area. The shape of the pressure field was 

more consistent with depth during double-gun shots, however, 

the 5-lb/in2 target value contour was not as smooth as compared 

to the single-gun shots, producing a projection of higher 

pressure between the two guns.

Despite the two surveys having different water output 

volumes, separation distances, and firing pressures—80-in3,100 ft, 

and 1,550 lb/in2 compared to 100-in3, 26 ft, and 2,000 lb/in2—the 

greatest pressures and extent of the 5-lb/in2 target value were 

both recorded at a depth of 5 ft bws. At this 5-ft depth, maximum 

recorded pressure was 13.7 lb/in2

 (by a hydrophone) in 2014 

and 57.4 lb/in2 (by a UBS) in 2015 from firing two water guns 

simultaneously. The extent of the 5-lb/in2 target value covered the 

majority of the study area. The overall shape of the pressure fields 

produced right next to the water guns by firing two water guns 

simultaneously were north-south-oriented elongated spheres.

References Cited

Adams, R.F., and Morrow, W.S., 2015, Geophysical 

investigation of the pressure field produced by water guns 

at a pond site in La Crosse, Wisconsin: U.S. Geological 

Survey Open-File Report 2015–1130, 24 p., 1 app., 

http://dx.doi.org/10.3133/ofr20151130. 

Boeger, W.A., Pie, M.R., Ostrensky, A., and Cardoso, M.F., 

2006, The effect of exposure to seismic prospecting on 

coral reef fishes: Brazilian Journal of Oceanography, v. 54, 

no. 4, p. 235–239.

Ellefsen, K.J., 2003, seg2_edit: A Program for Editing and 

Manipulating SEG-2 Files: U.S. Geological Survey OpenFile Report 03–141, 11 p., http://pubs.usgs.gov/of/2003/

ofr-03-141/ofr_03_141_508.pdf.

Gordon, J., Gillespie, D., Potter, J., Frantzis, A., Simmonds, 

M.P., Swift, R., and Thompson, D., 2003, A review of the 

effects of seismic survey on marine mammals: Marine 

Technology Society Journal, v. 37, no. 4, p. 16–34.

Gross, J.A., Irvine, K.M., Wilmoth, S., Wagner, T.L., Shields, 

P.A., and Fox, J.R., 2013, The effects of pulse pressure 

from seismic water gun technology on Northern Pike: 

Transactions of the American Fisheries Society, no. 142, 

no. 5, p. 1335–1346.

Hirst, A.G., and Rodhouse, P.G., 2000, Impacts of 

geophysical surveying on fishing success: Reviews in Fish 

Biology and Fisheries, v. 10, p. 113–118.

Layhee, M.J., Gross, J.A., Parsley, M.J., Romine, J.G., 

Glover, D.C., Suski, C.D., Wagner, T.L., Sepulveda, 

A.J., and Gresswell, R.E., 2013, Asian carp behavior in 

response to static water gun firing: U.S. Geological Survey 

Fact Sheet 2013–3098, 4 p., http://dx.doi.org/10.3133/

fs20133098.

Romine, J.G., Jensen, N.R., Parsley, M.J., Gaugush, R.F., 

Severson, T.J., Hatton, T.W., Adams, R.F., and Gaikowski, 

M.P., 2015, Response of Bighead Carp and Silver Carp to 

repeated water gun operation in an enclosed shallow pond: 

North American Journal of Fisheries Management, v. 35, 

no. 3, p. 440–453, http://dx.doi.org/10.1080/02755947.20

15.1012279.

Turnpenny, A.W.H., and Nedwell, J.R., 1994, The effects 

on marine fish, diving mammals and birds of underwater 

sound generated by seismic surveys: Southampton, United 

Kingdom, Fawley Aquatic Research Laboratories, Ltd., 

Report no. FCR 089/94, 50 p.

U.S. Army Corps of Engineers, 2016, Illinois Waterway 

Locks & Dams: U.S. Army Corps of Engineers Fact 

Sheet, 17 p., available at http://www.mvr.usace.army.mil/

Portals/48/docs/CC/FactSheets/IL/IWW%20Locks%20

&%20Dams%20-%202016.pdf. 

Wardle, C.S., Carter, T.J., Urquhart, G.G., Johnstone, A.D.F., 

Ziolkowski, A.M., Hampson, G., and Mackie, D., 2001, 

Effects of seismic air guns on marine fish: Continental 

Shelf Research, v. 21, p. 1005–1027.
18 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

These pressure maps are provided in sequential order by 

depth of water gun placement to facilitate comparison between 

the different studies.

Appendix 1. Pressure Maps Produced During All Experiments
A B C D

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0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Pressure, in pounds per square inch

Water gun

Hydrophone group position

5 pounds per square inch contour line

EXPLANATION

Appendix 1A-D. Pressure map from two 80-in2 water guns fired at 1,550 lb/in2, for measurements at a depth of, A, 1 foot, B, 2 feet, C, 3 feet, 

and D, 4 feet.

Figure 1–1. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for 

measurements at depths of 1 foot (A), 2 feet (B), 3 feet (C), and 4 feet (D) below the water surface of a backwater 

pond at Morris, Illinois, August 2014.

Appendix 1 19
20 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

A B C D

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0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Pressure, in pounds per square inch

Water gun

Hydrophone group position

5 pounds per square inch contour line

EXPLANATION

Appendix 1E-H. Pressure map from two 80-in2 water guns fired at 1,550 lb/in2, for measurements at a depth of, E, 5 feet, F, 6 feet, G, 7 feet,

and H, 8 feet. Figure 1–2. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, 

for measurements at depths of 5 feet (A), 6 feet (B), 7 feet (C), and 8 feet (D) below the water surface of a 

backwater pond at Morris, Illinois, August 2014.
A B C D

374420 374430

4576440

4576450

4576460

4576470

4576480

4576490

4576500

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM), Zone 16N, easting, in meters

374420 374430 374420 374430 374420 374430

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Pressure, in pounds per square inch

Water gun

Hydrophone group position

5 pounds per square inch contour line

EXPLANATION

Appendix 1I-L. Pressure map from two 80-in2 water guns fired at 1,550 lb/in2, for measurements at a depth of, I, 9 feet, J, 10 feet, K, 11 feet,

and L, 12 feet. Figure 1–3. Pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per square inch, for 

measurements at depths of 9 feet (A), 10 feet (B), 11 feet (C), and 12 feet (D) below the water surface of a backwater 

pond at Morris, Illinois, August 2014.

Appendix 1 21
22 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM),

Zone 16N, easting, in meters

A

374420 374434

4576440

4576450

4576460

4576470

4576480

4576490

4576500

A

׳A

׳B

B

Depth, in feet

0

0

-2

-2

-4

-4

-6

-6

-8

-8

-10

-10

-12

-12

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

B

C

4576440 4576450 4576460 4576470 4576480 4576490 4576500

A A׳

B B׳

EXPLANATION

EXPLANATION

Pressure, in pounds per square inch

0

1

2

3

4

5

6

7

8

Water gun

Hydrophone

5 pounds per square inch contour line

Pond bottom

Cross-section profile line

 with profile identifier

Selected hydrophone group

 position for vertical profiling

Hydrophone group position

Water gun

A A׳

Figure 1–4. Plan-view map and cross-sectional pressure maps from two 80-cubic-inch water guns fired at 1,550 pounds per 

square inch. Plan-view map (A) depicts the cross-section lines for the A–A’ (B) and B–B’ (C) cross-sectional pressure maps.
4576455

4576460

4576465

4576470

4576475

4576480

4576485

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM), Zone 16N, easting, in meters

374420 374425 374430 374435

4576455

4576460

4576465

4576470

4576475

4576480

4576485

374420 374425 374430 374435 374420 374425 374430 374435

A B C

D E F

EXPLANATION

Pressure, in pounds per square inch

0 4 8 12 16 20 24 28 32 >36

5 pounds per square inch contour line

Water gun

Hydrophone

Underwater blast sensor

Figure 1–5. Pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per square inch, for measurements at 

depths of 1 foot (A), 3 feet (B), 5 feet (C), 7 feet (D), 9 feet (E), and 11 feet (F) below the water surface of a backwater pond at 

Morris, Illinois, May 2015.

Appendix 1 23
24 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

4576455

4576460

4576465

4576470

4576475

4576480

4576485

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

Universal Transverse Mercator (UTM), Zone 16N, easting, in meters

374420 374425 374430 374435

4576455

4576460

4576465

4576470

4576475

4576480

4576485

374420 374425 374430 374435 374420 374425 374430 374435

A B C

D E F

EXPLANATION

Pressure, in pounds per square inch

0 4 8 12 16 20 24 28 32 >36

5 pounds per square inch contour line

Water gun

Hydrophone

Underwater blast sensor

Figure 1–6. Pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds per square inch, for measurements 

at depths of 1 foot (A), 3 feet (B), 5 feet (C), 7 feet (D), 9 feet (E), and 11 feet (F) below the water surface of a backwater pond 

at Morris, Illinois, May 2015.
-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

A A׳

A

B

Depth, in feet

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

4576455 4576460 4576465 4576470 4576475 4576480 4576485

B B׳

56

EXPLANATION

Pressure, in pounds

 per square inch

0

4

8

12

16

20

24

28

32

36

40

44

48

52

5 pounds per square

 inch contour line

Pond bottom

Water gun

Underwater blast

 sensor

Hydrophone

Appendix 1 25

Figure 1–7. Cross-sectional pressure maps from a 100-cubic-inch water gun fired at 2,000 pounds per 

square inch, for measurements from underwater blast sensor (A–A’, A) and hydrophone (B–B’, B) profile 

lines. Water gun marked was the one fired. See figure 14 of main text for locations of cross sections.
26 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

57.43

53.00 57.43

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

A A׳

A

B

Depth, in feet

Universal Transverse Mercator (UTM), Zone 16N, northing, in meters

4576455 4576460 4576465 4576470 4576475 4576480 4576485

B B׳

EXPLANATION

Pressure, in pounds

 per square inch

44 and greater

40

36

32

28

24

20

16

12

8

4

0

5 pounds per square

 inch contour line

Pond bottom

Water gun

Underwater blast

 sensor

Hydrophone

Pressure reading that 

 exceeds maximum 

 contoured pressure

Figure 1–8. Cross-sectional pressure maps from two 100-cubic-inch water guns fired at 2,000 pounds 

per square inch, for measurements from underwater blast sensor (A–A’, A) and hydrophone (B–B’, B) 

profile lines closest to the water guns. See figure 14 of main text for locations of cross sections.
Pressure Data

Seismic pressure data in this report are formatted as 

Microsoft Excel files and are available online at http://dx.doi.

org/10.3133/sir20165098. All files are arranged by year and 

sensor in the sir20165098_Morris_Seismic_Data zip folder. 

Consult the metadata file (.xml) for complete descriptions of 

column data.

Appendix 2. Underwater Pressure Data and Data-collection Equipment

Appendix 2 27

Equipment

Data were collected by using Instantel Blastware 

seismographs and a National Instruments data acquisition 

system linked to a personal computer. Two types of sensors 

were deployed: OYO Geospace Hydrophones with a 

sensitivity of 0.0237 lb/in2 and PCB Piezotronics Underwater 

Blast Sensors with a sensitivity of 0.02 lb/in2.
28 Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River

Appendix 3. Ground Velocity Data and Data-collection Equipment

Ground Velocity Data

Seismic ground velocity data in this report are online in 

the SEG-2 format at http://dx.doi.org/10.3133/sir20165098. 

Seismic data can be accessed through standard geophysical 

software that is capable of reading SEG-2 files. Software 

capable of reading SEG-2 format is available and documented 

in U.S. Geological Survey Open-File Report 03–141 (Ellefsen, 

2003), available at http://pubs.usgs.gov/of/2003/ofr-03-141/. 

Other open-source software, such as Geopsy (available at 

http://www.geopsy.org/), is available to read SEG-2 formatted 

data. These files are arranged in the sir20165098_Morris_

Seismic_Data zip folder.

Equipent

Data were collected by using Geometrics Geode 

seismographs and on personal computers with Single Geode 

Operating System (SGOS) and Multiple Geode Operating System 

(MGOS) software.

One type of three-component (3C) sensors was deployed: 

RTClark 10-hertz (Hz) surface geophones. Each of the three 

components corresponds to channels as shown below:

10-Hz surface geophones

• Channel 1: transverse component

• Channel 2: longitudinal component

• Channel 3: vertical component

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch water 

gun)—August 12, 2014

Files 81201.dat through 81276.dat

[ft, feet; lb/in2, pounds per square inch; 3C, three-component]

Seismograph channels Sensor location

1–3 At the edge of the water and aligned with the water guns, surface 3C geophone

4–6 10 ft from the edge of the water and aligned with the water guns, surface 3C geophone

7–9 At the edge of the water and 10 ft west of the water guns, surface 3C geophone

10–12 10 ft from the edge of the water and 10 ft west of the water guns, surface 3C geophone

File Water gun pressure (lb/in2

) or noise source Gun distance from canal wall (ft)

81201.dat-81276.dat 1,550 100/200
Appendix 3 29

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch water 

gun)—August 13, 2014

Files 81277.dat through 81310.dat

[ft, feet; lb/in2, pounds per square inch]

File Water gun pressure (lb/in2

) or noise source Gun distance from canal wall (ft)

81277.dat-81310.dat 1,550 100/200

Morris Sand and Gravel Pond Sensor Configurations and Shot Information (80-cubic-inch 

water gun)—August 14, 2014

Files 81311.dat through 81356.dat

[ft, feet; lb/in2, pounds per square inch]

File Water gun pressure (lb/in2

) or noise source Gun distance from canal wall (ft)

81311.dat-81356.dat 1,550 100/200

Menlo Park Publishing Service Center, California

Manuscript approval date June 27, 2016

Edited by Regan Austin

Design and layout by Cory Hurd
Koebel and Egly—Water Pressure and Ground Vibrations Induced by Water Guns at a Backwater Pond on the Illinois River—Scientific Investigations Report 2016–5098

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20165098