Great Salt Lake Level and Volume Time Series
David Tarboton
Last updated 10/26/2026

Time series of level, area and volume in the Great Salt Lake from the earliest South Arm level record on 10/18/1847 to [LAST DATE]. Volume and area of the Great Salt Lake are derived from recorded levels and bathymetry. The bathymetry used is included. Bathymetry is adjusted for the presence or absence of Magnesium corps pond. The area of the evaporation pond is not regarded as part of the lake except prior to its construction and during the time it was overtopped.

Note that separate levels in the North Arm only started being recorded in 1966 so for dates prior to that the North Arm level is taken from the South Arm. The bathymetry was then used to compute area and volume in each arm separately and add them up. Headings in the data files should be obvious.

Measured data

GSL_north_arm.csv is measured data from the USGS station 10010100 GREAT SALT LAKE NEAR SALINE, UT
GSL_north_arm_2026-10-26.csv  Duplicate of above as run on 10/26/26
GSL_north_arm_2024-10-06.txt  Previous file from 10/6/24
GSL_north_arm_2023-10-07.txt  Previous file from 10/7/23

GSL_south_arm.csv is measured data from the USGS station 10010000 GREAT SALT LAKE AT SALTAIR BOAT HARBOR, UT
GSL_south_arm_2026-10-26.csv  Duplicate of above as run on 10/26/26
GSL_south_arm_2024-10-06.txt  Previous file from 10/6/24
GSL_south_arm_2023-10-07.txt  Previous file from 10/7/23

Derived data

GSLLAV.txt is time series of level, computed area and volume from level using bathymetry on the days of each observation
GSLLevelVol.csv is beginning of month time series of level and volume. This is interpolated when there is not an observation on the first day of the month.
GSLLevelVolAnn.csv is beginning of water year (October 1) time series of level and volume, subset from the monthly data. 
WyrAveLevels.csv is time series of average water year level
levstats.csv  Mean, median, and 16th and 84th percentiles of South Arm water year average level for the full record (from 10/1/1847) and for the period since 10/1/1949

Data behind figures (written by LevelVolPlots.R)

EndWYLevels.csv  South Arm and North Arm levels at the end of the latest water year (10/1/2026), with a text label for use in figures
RecentLevelPlot.csv  Daily South Arm and North Arm levels from a recent date
RecentLevelPlotMonthStep.csv  Beginning of month South Arm, North Arm and natural equivalent levels from a recent date
From1903NSmonths.csv  Beginning of month North Arm and South Arm levels from 10/1/1903 to 10/1/2024
recentNSmonths.csv  Beginning of month North Arm and South Arm levels from 10/1/2021 to 10/1/2024

Scripts

LevelVolWork.R is the R script used to process this data
LevelVolPlots.R is the R script used to make plots used to check and present this data. Plots are written as png files to the plots folder.
GSLFunctions.R  R functions used by the scripts

Figures

plots folder.  png figures produced by LevelVolPlots.R. File names begin with a number giving the order in which the plots are created.
GSLLevelRecord.pptx  PowerPoint file with some figures of this data

Bathymetry

Bathymetry folder.  Lake bathymetry used in these calculations. This data is also stored separately in https://www.hydroshare.org/resource/b26090299ec947c692d4ee4651815579/