Figure 1. Map showing north part of Great Salt Lake and vicinity, Utah.

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2006–1359

December 2006

Calculation of Area and Volume for the 

North Part of Great Salt Lake, Utah

Prepared in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands

By Robert L. Baskin

Abstract

The U.S. Geological Survey, in cooperation with the 

Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data 

for the north part of Great Salt Lake during the spring 

and early summer of 2006 using a single-beam, highdefinition fathometer and real-time differential global 

positioning system. About 5.2 million depth measurements were collected along more than 765 miles (1,230

kilometers) of survey transects. Sound-velocity profiles 

were obtained in conjunction with the bathymetric data 

to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic 

software and exported into geographic information system 

(GIS) software for mapping and calculation of area and 

volume. Area and volume calculations show a maximum 

area of about 385,000 acres (1,560 square kilometers) and 

a maximum volume of about 5,693,000 acre-feet (about 7 

cubic kilometers) at a water-surface altitude of 4,200 feet 

(1,280 meters). Minimum natural water-surface altitude of 

the north part of Great Salt Lake is just below 4,167 feet 

(1,270 meters) in the area just north of the Union Pacific 

railroad causeway halfway between Saline and the western 

edge of the lake. The north part of Great Salt Lake generally grades gradually to the west and north and is bounded 

by steep scarps along its eastern border. Calculations 

for area and volume are based on a low altitude of 4,167 

feet (1,270 meters) to a high altitude of 4,200 feet (1,280 

meters).

Introduction

Prior to the 1980s, detailed information about many 

aspects of Great Salt Lake, including bathymetric data, 

was scarce. Flooding in the early 1980s increased concern for avian resources and the lake ecosystem, and the 

emergence of the brine shrimp industry created both public 

interest and management concern. To fill the need for a 

better understanding of the physical characteristics of the 

lake, the U.S. Geological Survey (USGS), in cooperation 

with the Utah Department of Natural Resources, Division 

of Forestry, Fire, and State Lands, collected bathymetric 

data for the north part of Great Salt Lake (fig. 1) during 

the spring and early summer of 2006 using a single-beam, 

high-definition fathometer and real-time differential global 

positioning system. These data were collected to better 

define the physical characteristics of the north part of the 

lake, provide data for improved calculations of area and 

volume, and provide lake-bottom contour information 

that could be used in future efforts to develop a general 

circulation model of the lake. Data-collection methods and 

quality-control restrictions were identical to those used 

for generation of the bathymetric map for the south part of 

Great Salt Lake (Baskin and Allen, 2005) and the resulting 

south part area/volume table (Baskin, 2005).

About 5.2 million depth measurements were collected 

along more than 765 miles (1,230 kilometers) of survey 

transects (fig. 2) during the data-collection phase of this study. Soundvelocity profiles were obtained in 

conjunction with the bathymetric 

data to provide time-of-travel 

corrections to the depth calculations. Data were processed 

with commercial hydrographic 

Gunnison

Island

Egg

Island

Gunnison Bay

Lakeside

Dolphin

Island

Black

Mountain

Locomotive Springs

Waterfowl

Management Area

Golden Spike

National Historic Site

Saline

41°15'

41°30' PROMONTORY MOUNTAINS

Gilbert Bay

Railroad causeway

113°00' 112°30'

HANSEL

MOUNTAINS

Base from U.S. Geological Survey digital data, 1:100,000, 1978, 1979, 1980, 1984

Universal Transverse Mercator projection, zone 12

0

0 10 20 KILOMETERS

10 20 MILES

MUD FLAT

MUD FLAT

MUD FLAT

U T A H

Great

 Salt

 Lake

Study

area
Lakeside

Dolphin

Island

Black

Mountain

Locomotive Springs

Waterfowl

Management Area

Golden Spike

National Historic

Site

Saline

41°15'

41°30' PROMONTORY MOUNTAINS

Gilbert Bay

Railroad causeway

113°00' 112°30'

HANSEL

MOUNTAINS

Base from U.S. Geological Survey digital data, 1:100,000, 1978, 1979, 1980, 1984

Universal Transverse Mercator projection, zone 12

0

0 10 20 KILOMETERS

10 20 MILES

MUD FLAT

MUD FLAT

MUD FLAT

Transect

Boundary of area used in area and volume calculations

Gunnison Bay

EXPLANATION

Gunnison

Island

Egg

Island

software and exported into geographic information system 

(GIS) software for mapping and calculation of area and 

volume. Because of the shallow nature of the lake and the 

limitations of the instrumentation, contours above an altitude of 4,194 feet (1,278 meters) were digitized from existing USGS 1:24,000-scale topographic maps. A triangulated 

irregular network generated from the bathymetric data and 

digitized contours was used for the calculations of area and 

volume. This report describes the methods and data used 

to calculate the area and volume of the north part of Great 

Salt Lake at 0.5-foot intervals from an altitude of 4,167 feet 

(1,270 meters) to 4,200 feet (1,280 meters).

Description of Study Area

Great Salt Lake is a terminal lake in the northwestern 

part of Utah; changes in water-surface altitude are determined by differences between net inflow and evaporation 

from the surface of the lake. Inflow to the lake is affected 

by impoundments on and diversions from streams that 

flow into the lake. At a water-surface altitude of 4,200 feet 

(1,280 meters), the lake has a surface area of about 1,660 

square miles (4,300 square kilometers) and an average 

depth of 14.6 feet (4.45 meters). In 1963, Great Salt Lake 

was at its lowest water-surface altitude in recent history 

(about 4,191 feet [1,277 meters]), covered about 950 square 

miles (2,460 square kilometers), and had a maximum depth 

of about 25 feet (7.6 meters). In 1986, Great Salt Lake was 

at its highest water-surface altitude in recent history (about 

4,212 feet [1,284 meters]), covered about 2,400 square 

miles (6,216 square kilometers), and had a maximum depth 

of about 45 feet (13.7 meters). The area of the lake surveyed and used for these calculations includes that part of 

the lake north of the Union Pacific railroad causeway and 

includes areas of impoundment near the southwest and 

southeast corners of the lake up to the 4,200-foot contour 

(fig. 2). Maximum altitude used in the calculation of area 

and volume in this report is 4,200 feet (1,280 meters).

Methods

Data Collection

Bathymetric data were collected over the navigable areas 

of the north part of Great Salt Lake during the spring and 

early summer of 2006. An automated system consisting 

of a digital and analog (paper chart) single-beam fathometer coupled to a real-time, differentially corrected global 

positioning system with the data logged into a navigational 

computer was used for the basic position/depth data collection. Depths were derived indirectly by measuring the time 

required for a sonar signal to travel from the transmitter 

to the bottom of the lake and back to a receiver. Measured 

sound velocities were used to calculate corrections to the 

basic time-of-travel data and provide a velocity-corrected 

distance between the transmitter and receiver. Distance 

from lake surface to the transceiver face was measured and 

added to the distance between the transducer and lake bottom to derive the calculated depth of the lake. Analog paper 

records were collected during the survey for all transects to 

cross-check digital readings and provide detail of bottom 

features during the collection of field data.

About 765 miles (1,230 kilometers) of transects 

were collected primarily on east-west transects 

spaced about 0.62 miles (1 kilometer) apart and 

included five north-south transects (fig. 2). Position data were recorded at about a 1-second rate 

and depth data at about 10 points per second. Vessel speed was limited to less than about 10 miles 

per hour (16 kilometers per hour) to maximize the 

number of depth measurements gathered during 

the data-collection phase. Quality-control considerations limited the periods of data collection to 

times when the lake surface had minimal swell and 

wave height generally was less than 6 inches (0.15 

meter). Because of the high sound velocity (a result 

of the higher-density water) and limitations in the 

instrumentation, data collection was limited to areas 

deeper than about 3 feet (1 meter).

Water depth was measured with a survey-grade 

Reson, Inc.1, model 210, single-beam echosounder 

using a 2.7-degree beam width, 200-kilohertz 

transducer. Manufacturer specifications for this 

echosounder indicate that the depth of operation is 

from 0.2 to 600 meters (0.7 to 1,969 feet) and that 

the depth-measurement accuracy is 1 centimeter (0.4 

inch) at depths of less than 100 meters. Speed of 

Figure 2. Map showing location of survey transects and boundary of area 

used in area and volume calculations for north part of Great Salt Lake, Utah.

1

 Use of trade names in this report is for identification purposes only 

and does not constitute endorsement by the U.S Geological Survey.
sound for the data-collection segment of this survey was 

set at a constant 1,600 meters per second (5,250 feet per 

second). Speed-of-sound corrections were subsequently 

applied during data processing.

Sound-velocity profiles were collected at several times 

and locations throughout the survey at 1-meter (3.28-foot) 

vertical intervals with a direct “time-of-flight” soundvelocity sensor. The sound-velocity sensor used during this 

investigation was accurate to plus or minus 0.25 meter per 

second (0.8-foot-per-second) in water with a 0.2-meter-persecond (0.7-foot-per-second) resolution. Measured sound 

velocities ranged from 1,788 meters per second to 1,804 

meters per second. These data were written into soundvelocity correction files and used during data processing.

Horizontal position data (latitude and longitude) were 

obtained with a Trimble AG132 integrated Global Positioning System (GPS)/ Differential Global Positioning 

System (DGPS) coupled with an OmniSTAR Wide Area 

DGPS Solution. The integrated GPS/DGPS is capable of 

improving regular GPS accuracies to submeter accuracy 

by solving for atmospheric delays and weighting of distant 

base stations. Data were collected and processed while 

surveying and recorded with the unprocessed depth data 

while in the field. Position data were collected only during times of good satellite visibility and when OmniSTAR 

Wide Area DGPS Solution differential corrections were 

available. Differentially corrected data were acquired for all 

data obtained during this study and positional accuracy is 

estimated to be 1 meter (3.28 feet) or less.

The PC-based Windows navigational and bathymetric 

mapping software, Hypack Max, by Coastal Oceanographics, Inc., was used to plan and manage the hydrographic 

surveys and edit and manage the bathymetric data collected 

at each lake transect. This software was installed on a 

portable computer interfaced with the DGPS and surveygrade depth sounder for navigational use. Hypack Max was 

configured to display and track the vessel position against a 

background of survey control lines (fig. 3) and later used in 

the office for processing of the bathymetric data.

Data Processing

Strict controls on data quality were enforced and no data 

were included in the final processing that showed systematic roll or vertical boat movement. Relative positions 

of the DGPS antenna and echosounder transducer were 

fixed during the survey period to assure accurate horizontal control. Depth to transducer was physically measured, 

recorded in the field, and used in processing of the data. 

Raw data were processed in Hypack Max and exported into 

an X-Y-Z (latitude-longitude-depth) format for importing 

into a GIS.

Initial processing of the data included the manual 

removal of spurious data points (outliers) such as singlepoint depths located substantially above or below the 

general lake-bottom trend, zero depths, or data that showed 

roll or vertical boat movement (fig. 4). Outliers were generally the result of submerged debris or gas bubbles in the 

water column. Outliers were visually identified, tagged for 

deletion, and removed before additional data processing. 

The resultant data were then corrected for sound velocity 

by applying the profile data to the raw depth data collected 

during the survey. Depth from the lake surface to the active 

face of the transducer was added to the sound-velocity-corrected depths to calculate depth below water surface.

Figure 3. Navigation screen used in survey control of north part of Great Salt Lake, Utah.
Figure 4. Example survey transect before (A) and after (B) removal of outliers, north part of Great Salt Lake, Utah.

To maximize the amount of depth information acquired 

during this investigation, depth data were recorded at a 

frequency of 10 hertz. Differentially corrected positional 

data were recorded at a frequency of 1 hertz. As a result, 

about three to five depth measurements were recorded 

for every meter of survey line depending on actual vessel speed. About 5.2 million discrete depth measurements 

were initially collected along more than 765 miles (1,230 

kilometers) of survey transects and processed during this 

survey. To remove minor bottom-surface variations, an 

average depth for the lake bottom was calculated every 16 

feet (5 meters) along each processed survey line, and the 

averaged depth below lake surface was used in defining 

the bathymetric surface of the lake. The Behrens Trench 

(Baskin and Turner, 2006) and other small bottom features 

were excluded from the map and subsequent calculations 

of area and volume due to the amount of data necessary to 

adequately define their structure. Approximately 240,000 

averaged depth measurements were calculated and used in 

the final data analysis.

Depth and location data in an X-Y-Z format were 

imported into the ArcGIS GIS software package for additional processing. Daily average water-surface altitude data 

(based on the USGS recorded water-surface altitude) were 

used to adjust the processed depth-below-water-surface 

values to altitude. Corrected depth was subtracted from the 

daily average water-surface altitude for the day the original 

data were collected to provide lake-bottom altitude along 

the surveyed transects.

Areas of the lake unavailable for survey because of 

physical barriers or shallow conditions were digitized 

from USGS 1:24,000 digital line graphs at a scale of 

about 1:5,000. These contours ranged from the 4,194-foot 

(1,278-meter) contour through the 4,200-foot (1,280-

meter) contour and included all areas of Great Salt Lake 

north of the Union Pacific railroad causeway. These digitized contours were incorporated into the bathymetric data 

set as fixed data contours and used in the calculation of 

area and volume.

Generation of Bathymetric Surface

The data points defining the bottom surface of the 

lake were compiled into a single data file, combined with 

the digitized contours, and processed into a triangulated 

irregular network for contour generation and subsequent 

calculations of area and volume. A triangulated irregular 

network is defined as a set of adjacent, nonoverlapping 

triangles computed from irregularly spaced points with 

x, y coordinates and z values. The triangulated-irregularnetwork model stores the topological relations between 

triangles and their adjacent neighbors; for example, which 

points define each triangle and which triangles are adjacent 

to each other (Environmental Systems Research Institute, 

Inc., 2004). Each of these triangles has a surface area 

and an average depth. The triangulated-irregular-network 

contouring function interpolates straight lines across each 

triangle that span the contour value by using linear interpolation between the edge endpoints to determine where the 

contour crosses the face.

The contoured lake-bottom surface for Great Salt Lake 

was originally computed in 0.5-foot intervals from altitudes of 4,167 feet (1,270 meters) to 4,200 feet (1,280 

meters) and subsequently used as a guide for contouring 

of the lake-bottom bathymetric surface. As a result of 

the spacing and orientation of the survey transects, the 

computer-interpolated contour lines were problematic in 

areas of high relief. The computer-contoured data were 

examined and manually recontoured in areas of high relief, 

primarily those areas bordering the east edge of the basin. 

The resultant contours were mapped and published in 

Baskin and Turner (2006) (fig. 5). The interpreted contour 

data from Baskin and Turner (2006) are used as the basis 

for the calculation of area and volume in 

this report.

Calculations of Area and Volume

Area and volume were calculated with 

the 3-D surface analysis package in ArcGIS 9.1 (Environmental Systems Research 

Institute, Inc., 2004). For each altitude, the 

triangulated irregular network is examined 

to determine the area and volume of each 

triangle contained within the limits of 

that particular altitude. The sum of these 

triangles is used for the output of area and 

volume. Output from the calculations of 

area and volume was tabled and converted 

to acres and acre-feet for use in this report 

(table 1).

Values contained in table 1 are for areas 

of Great Salt Lake north of the Union 

Pacific railroad causeway, including areas 

of impoundment near the southwest and 
MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

MUD FLAT

G I L B E R T

B A Y

G U N N I S O N

B A Y

Coyote

Ponds

East

Lake

4210

Little Valley

Harbor

BAY

SPRING

West

Lake

Indian Cove

Clyman Bay

Spring

Bay

4209

4265

4232

4921

5577

4593

4265

4593

4921

4265

4921

4593 4265

4593

4265

4593

4921

5741

4921

4921

4593

4265

4921

4921

4921

4921

4921

5741

4921

4921

4249

5577

5577

6234

4593

5249

4265

4921

4265

4265

4921

4921

6234

4265

36 31

36

6 1

36 31

6

T 9 N

T 8 N

36

6 1

31

31 36 36 31

R 6 W

R 5 W

31

T 10 N

T 9 N

36 31

1 6

36 31

1 6

T 11 N

T 10 N

36 31

1 6

35 31

2 6

36 31

1 6

31

6

36

1

31

6

36

1

T 6 N

R 10 W R 9 W R 6 W

T 8 N

T 9 N

T 10 N

T 11 N

T 12 N

T 7 N

31

6

31

6

36 31

1 6

36 31

1 6

36 31

1 6

36 31

1 6

36 31

1 6

36 31

R 12 W R 11 W

36 31

1 6

36 31

1 6

36 31

1 6

36 31

1 6

36

31

1 6

36 31

1 6

R 8 W R 7 W R 5 W

R 11 W R 10 W R 9 W R 8 W R 7 W R 6 W R 5 W

T 6 N

T 8 N

T 9 N

T 10 N

T 11 N

T 12 N

T 7 N

Teal Slough

Sparks Slough

Baker Slough

Slough

Locomotive

West

Big

Wash

Slough

Off Slough

Bar M

Aquaduct

Pothole

Springs

Sparks

Spring

Teal

Spring

West

Chokecherry

Spring

Mountain

Springs

Wild Horse

Spring

Rose

Spring

Springs

West Locomotive

Spring

Bar M Spring

Hereford

Spring

Spring

Cedar

Spring

Spring

Springs

Engineer

Spring

Mud

Springs

Spring

(salt)

Spring

(salt)

Springs

(salt)

Mineral

Springs

Mineral

Spring

Chokecherry

Spring

Owen

Spring

Miller

Spring

Henry

Spring

4195

4190

4185

4180

4175

4170

4195

4170

4175

4180 4190

4185

No data

No data No data

4195

4195

4190

4190

4185

4185

4180

4180

4175

4175

4170

4195

4195

4190

4185

4180

4175

4170

4170

4170

4190

4170

Solar

evaporation

ponds

Solar

evaporation

pond

Solar

evaporation

pond

Solar

evaporation

pond

4200

4200

4200

4200

4200

4200 10010100

10172968

10172965

10172964

10172967

10172963

10010050

41°15'N

113°00'W 112°52'30"W 112°45'W 112°37'30"W 112°30'W

41°30'N

41°22'30"N

113°07'30"W

41°37'30"N

113°07'30"W 113°00'W 112°52'30"W 112°45'W 112°37'30"W 112°30'W

41°15'N

41°30'N

41°22'30"N

41°37'30"N

Lake Ridge

Sunset

Pass

Hollow

Strongs Knob

1464

Pacific Union

Twin

Hills

4984

Lakeside

Butte

Lakeside (Lucin Cutoff)

Little Valley

Death Ridge

TheGillespies

4665

4567

Maple Canyon

Hills

Rozel Flat

Rozel

Point

Rozel

7372 Messix

Peak

Messix

Canyon

Dolphin

Island

Lead

Mountain

5823

Saline

Black Mountain

Spiral

Jetty

Lone

Rock

Monument

Point

Broadmouth

Canyon

Indian

Caves

Miller

Canyon

Squaw

Flat

North Canyon

South Canyon

Brushy Canyon

Indian

Hill 4344

4272

Salt Wells Flat

6368

South Cold Water

Promontory Hollow

Pipeline

Point

Canyon

North Cold Water Canyon

South

Canyon

North

Canyon

Antelope Flat

NORTH PROMONTORY

MOUNTAINS

PROMONTORY MOUNTAINS

Promontory

Sand

Engineer Mountain

Big Canyon

Mount Tarpey 6978

Big

Pass

Broom Mountain

Hogup

Base from U.S. Geological Survey digital line graph data, 1:24,000, and 1:100,000 scales, 1968–99

Updates to base data from U.S. Geological Survey digital orthophoto quadrangles, 1:24,000-scale, 1993–99

Additional base data from Great Salt Lake Minerals Corporation

Bathymetric contours below 4,194 feet from U.S. Geological Survey single beam, high definition fathometer data, collected 2002–06

Bathymetric contours between 4,194 and 4,200 feet (NVGD 1929) from U.S. Geological Survey digital line graph data, 1:24,000-scale, 1968–99

Cartography by Joseph F. Gardner, U.S. Geological Survey Utah Water Science Center

PREPARED by the U.S. GEOLOGICAL SURVEY

IN COOPERATION WITH THE

UTAH DEPARTMENT OF NATURAL RESOURCES, DIVISION OF FORESTRY, FIRE, AND STATE LANDS

Scientific Investigations Map 2954 U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Bathymetric Map of the North Part of Great Salt Lake, Utah, 2006 By

Robert L. Baskin and Jane Turner 2006

G R E A T S A L T

L A K E

G U N N I S O N

B A Y

Altitude 4,200 feet

Delle

Hasings

Pass

MUD FLATS

SKULL

Study area

UTAH

1 .5 0 1 2 3 4 5

KILOMETERS

1 .5 0 1 2 3

MILES

0 5,000 10,000

FEET

6 7 8 9 10

15,000

M N

G N

UTM grid and 1991 Magnetic North

(Approximate)

141/2°

258 MILS 1°07'

20 MILS

Universal Transverse Mercator projection, Zone 12, NAD83

Vertical datum referenced to NGVD of 1929

EXPLANATION

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands,

collected bathymetric data for the north part of Great Salt Lake during the spring and early summer of 2006 using a single beam, high-definition

fathometer and real-time differential global positioning system. Approximately 5.2 million depth readings were collected along more than 765

miles of survey transects for construction of this map. Sound velocities were obtained in conjunction with the bathymetric data to provide timeof-travel corrections to the depth calculations. Data were processed using commercial hydrographic software and exported into a geographic

information system (GIS) software for mapping. Due to the shallow nature of the lake and the limitations of the instrumentation, contours above

an altitude of 4,194 feet were digitized from existing USGS 1:24,000 source-scale digital line graph data. The Behrens Trench is approximately

located.

For additional information on methods used to derive the bathymetric contours for this map, please see Baskin, Robert L., 2006, Calculation

of area and volume for the North Part of Great Salt Lake, Utah, U.S. Geological Survey Open-File Report OFR–2006–1359.

NOT FOR NAVIGATIONAL USE Manuscript approved for publication November, 2006

For sale by U.S. Geological Survey, Branch of Information Services, Box 25286, Federal Center, Denver, CO 80225, 1-888-ASK-USGS

Available on the World Wide Web at http://pubs.usgs.gov/sim/2006/2954

4 5

10172968

4275

Crocodile Mountain

Hogup Bar

4222

Locomotive

Springs

State

Waterfowl

Management

Area

Table

Mtn

Peplin Flats

Little Valley Gravel Pit

Gravel Pits

Gravel Pits

Chockecherry

Canyon

Coyote

Point

Hogup Ridge

Gunnison

Island

Egg

Island

Behrens Trench

Behrens Trench

Perennial water body

Solar evaporation pond or other ephemeral water body

Wetland

Mud flat

Waterfowl Management Area

Golden Spike National Historic Site

Bathymetric contour—Shows altitude of bottom of lake.

Dashed where approximately located. Contour interval 1 foot.

Hachures show area of depression

Bathymetric contour—Shows altitude of bottom of lake.

Dashed where approximately located. Contour interval 5 feet.

Hachures show area of depression

Land-surface contour—Shows altitude of surface of land.

Dashed where approximately located. Contour interval variable

Highway

Paved road

Other road

Railroad

U.S. Geological Survey streamflow

gaging station and site number—Period

of record variable

Ship channel

Pacific Union Railroad Causeway

Culvert

Culvert

Breach

Indian

Cove

Pump

station

THE FINGERPOINT

HOGUP MOUNTAINS

HOGUP MOUNTAINS

Deadman

Knoll

Rozel

Kings

Pass

Little Valley Harbor Little Valley

Harbor

Clyman Bay

southeast corners of the lake up to the 4,200-foot contour 

(fig. 2). The 4,200-foot (1,280-meter) contour digitized 

from USGS 1:24,000-scale topographic maps was used 

to limit the north part of the Great Salt Lake triangulated 

irregular network such that interpolation could not occur 

outside of that contour. The triangulated irregular network 

incorporated the vertices of the 4,194 to 4,200-foot (1,278 

to 1,280-meter) contours as additional points.

Calculations of area and volume for the north part of 

Great Salt Lake show a maximum area of about 385,000 

acres (1,560 square kilometers) and a maximum volume 

of about 5,693,000 acre-feet (about 7 cubic kilometers) at 

a water-surface altitude of 4,200 feet (1,280 meters). The 

minimum natural water-surface altitude of the north part of 

Great Salt Lake is just below 4,167 feet (1,270 meters) in 

the area just north of the Union Pacific railroad causeway 

halfway between Saline and the western edge of the lake. 

The north part of Great Salt Lake generally grades gradually to the west and north and is bounded by steep scarps 

along its eastern border. Calculations for area and volume 

Figure 5. Bathymetric map of the north part of Great Salt Lake, Utah (Baskin and Turner, 2006).

are based on a low altitude of 4,167 feet (1,270 meters) to a 

high altitude of 4,200 feet (1,280 meters).

Summary

The U.S. Geological Survey, in cooperation with the 

Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data 

for the north part of Great Salt Lake during the spring and 

early summer of 2006 using a single-beam, high-definition 

fathometer and real-time differential global positioning system. About 5.2 million depth measurements were collected 

along more than 765 miles (1,230 kilometers) of survey 

transects. Sound-velocity profiles were obtained in conjunction with the bathymetric data to provide time-of-travel 

corrections to the depth calculations. Data were processed 

with commercial hydrographic software and exported into 

geographic information system (GIS) software for mapping 

and calculation of area and volume. Data collection methods and quality-control restrictions were identical to those 

used for generation of the bathymetric map for the south 
part of Great Salt Lake (Baskin and Allen, 2005) and the 

resulting south part area/volume table (Baskin, 2005).

Area and volume values were calculated for areas of 

Great Salt Lake north of the Union Pacific railroad causeway, including areas of impoundment near the southwest 

and southeast corners of the lake up to the 4,200-foot 

contour (fig. 2). The Behrens Trench and other small bottom features were excluded from the map and subsequent 

calculation of area and volume due to the amount of data 

necessary to adequately define their structure. The 4,200-

foot (1,280-meter) contour digitized from USGS 1:24,000-

scale quadrangle maps was used to limit the north part of 

the Great Salt Lake triangulated irregular network such that 

interpolation could not occur outside of that contour. The 

triangulated irregular network incorporated the vertices of 

the 4,194 to 4,200-foot (1,278 to 1,280-meter) contours as 

additional points.

Area and volume calculations show a maximum area of 

about 385,000 acres (1,560 square kilometers) and a maximum volume of about 5,693,000 acre-feet (about 7 cubic 

kilometers) at a water-surface altitude of 4,200 feet (1,280 

meters). Minimum natural water-surface altitude of the 

north part of Great Salt Lake is just below 4,167 feet (1,270 

meters) in the area just north of the Union Pacific railroad 

causeway halfway between Saline and the western edge of 

the lake.

References Cited

Baskin, R.L., 2005, Calculation of area and volume for the south 

part of Great Salt Lake, Utah: U.S. Geological Survey OpenFile Report 2005–1327, accessed 08/16/06 at http://pubs.usgs.

gov/of/2005/1327/

Baskin, R.L., and Allen, D.V., 2005, Bathymetric map of the 

south part of Great Salt Lake, Utah: U.S. Geological Survey 

Scientific Investigations Map 2894, accessed 08/16/06 at 

http://pubs.usgs.gov/sim/2005/2894/

Baskin, R.L., and Turner, J., 2006, Bathymetric map of the north 

part of Great Salt Lake, Utah: U.S. Geological Survey Scientific Investigations Map 2006–2954.

Environmental Systems Research Institute, Inc., 2004, ArcToolbox: About surfaces and surface models: ArcGIS 9.0 Desktop 

Help, accessed June 2005 at 

http://webhelp.esri.com/arcgisdesktop/ 9.1

Table 1. Water-surface altitude, area, and volume of north part of Great Salt Lake, Utah

[Values calculated for the area of Great Salt Lake north of the Union Pacific railroad causeway]

Water-surface

altitude

(in feet)1

Area

(acres)

Volume

(acre-feet)

4,167.0 2,141 1

4,167.5 4,658 1,658

4,168.0 8,546 4,827

4,168.5 11,891 9,906

4,169.0 19,698 16,837

4,169.5 24,685 27,891

4,170.0 33,316 41,687

4,170.5 38,786 59,708

4,171.0 44,522 80,518

4,171.5 49,697 104,298

4,172.0 54,068 130,234

4,172.5 58,839 158,588

4,173.0 63,216 189,095

4,173.5 68,795 222,170

4,174.0 74,243 257,922

4,174.5 80,060 296,521

4,175.0 86,040 338,033

4,175.5 91,396 382,420

4,176.0 96,949 429,491

4,176.5 102,195 479,375

4,177.0 107,263 531,729

4,177.5 111,222 586,350

4,178.0 116,640 643,012

Water-surface

altitude

(in feet)1

Area

(acres)

Volume

(acre-feet)

4,178.5 121,381 702,497

4,179.0 127,179 764,476

4,179.5 132,215 829,308

4,180.0 138,428 896,759

4,180.5 143,029 967,108

4,181.0 150,430 1,039,843

4,181.5 154,836 1,116,148

4,182.0 159,824 1,194,723

4,182.5 164,868 1,282,671

4,183.0 171,609 1,359,241

4,183.5 175,809 1,446,093

4,184.0 180,028 1,535,052

4,184.5 184,657 1,626,337

4,185.0 188,996 1,719,742

4,185.5 193,547 1,815,544

4,186.0 197,773 1,913,357

4,186.5 202,476 2,013,589

4,187.0 206,743 2,115,881

4,187.5 210,552 2,220,286

4,188.0 214,171 2,326,460

4,188.5 217,374 2,434,351

4,189.0 220,662 2,543,854

4,189.5 224,044 2,655,035

Water-surface

altitude

(in feet)1

Area

(acres)

Volume

(acre-feet)

4,190.0 227,516 2,767,920

4,190.5 231,043 2,882,582

4,191.0 234,973 2,998,990

4,191.5 239,695 3,117,654

4,192.0 245,098 3,238,699

4,192.5 249,516 3,362,349

4,193.0 255,045 3,488,231

4,193.5 259,429 3,616,850

4,194.0 264,597 3,747,660

4,194.5 269,214 3,881,097

4,195.0 285,934 4,016,938

4,195.5 292,701 4,161,596

4,196.0 306,649 4,309,643

4,196.5 313,915 4,464,768

4,197.0 321,569 4,623,623

4,197.5 335,497 4,789,829

4,198.0 341,895 4,959,165

4,198.5 356,685 5,135,356

4,199.0 365,556 5,315,903

4,199.5 377,427 5,502,856

4,200.0 384,580 5,693,352

1

Altitude referenced to National Geodetic 

Vertical Datum of 1929 (NGVD 29).