Post on 26-Dec-2015
Precipitation and the
Great Salt Lake
Patrick Loury and Eliana Manangòn
Precipitation and Lake Level of the Great Salt Lake (GSL)
Precipitation accounts for approximately 30% of the input to GSL (Lall and Mann, 1995)
This input has an important control on lake surface elevation (Stephens, 1990)
Since 1982, about 60% of elevation increase has resulted from greater than average precipitation and less than average evaporation rates
Snow is an important component of precipitation in the Great Basin, and accounts for about 85% of total precipitation input (Baskin, et al., 2002)
67%
30%
3%
Inputs Into the Great Salt LakeStream Flow Precipitation Groundwater
Precipitation Breakdown By Watershed*
Four watersheds comprise the Great Basin:
West desert
Largest area, least precipitation
Utah Lake
One of the largest freshwater lakes in the Western U.S.
Weber River
Smallest area, most precipitation
Bear River
Contains the largest tributary contributing to GSL (Bear River) *Data from http://www.greatsaltlakeinfo.org/Background
Watershed Area (mi2) Average Annual
Precipitation (in)
Minimum Recorded Precipitati
on (in)
Maximum Recorded Precipitati
on (in)
West Desert
18964 11 5 49
Utah Lake 3846 20 9 61
Weber River
2476 26 11 73
Bear River 7437 21 9 61
Total 32723 78
Historical Data*
*Data from http://www.prism.oregonstate.edu
189518961897189818991900190119021903190419051906190719081909191019111912191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939194019411942194319441945194619471948194919501951195219531954195519561957195819591960196119621963196419651966196719681969197019711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920100
5
10
15
20
25
30Annual Precipitation for Salt Lake
City
Time (years)
Pre
cip
itati
on
(i
nch
es)
Average Value: 14.98 inStandard Deviation: 3.44 inMinimum Value: 9.06 inMaximumValue: 26.64 in
Precipitation Trend Over Time*
On a decadal scale, the average annual precipitation in SLC seems to be increasing
If this trend continues, the lake surface elevation will rise in response
However, the data is not certain:
Weak correlation
Relatively short time period for data collection
Large variability in data
0
5
10
15
20
f(x) = 0.000931235 x³ − 0.0153974 x² + 0.4235058 x + 12.641576R² = 0.627789904636525
Average Annual Precipitation by Decade
Time (years)
Pre
cipit
ati
on (
in)
*Data from http://www.prism.oregonstate.edu
Note: For a full list of references, see handout