WSP00192

• File Number: 8220.101.10.A
• Description: Colorado River-Water Projects-Glen Canyon Dam/Lake Powel-Glen Canyon Adaptive Management-AMWG
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 8/13/2003
• Title: USGS - Drought Conditions in Utah During 1999 through 2002 - A Historical Perspective
• Water Supply Pro - Doc Type: Data

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Figure 7. Water levels in a well near Cedar City, Utah.

2002

Summary and Conclusions

Figure 6, Comparison of satellite images of Great Salt Lake, 1988-89 and 2002,

evidenced by the Green River near Green River,
UT, station (fig. 4 and table 2). Total annual
flow for water year 2002 is ranked in table 2.
The lowest total annual flow on record at the
Colorado River near Cisco, San Juan River near
B1ufT, and Virgin River at Virgin stations
occurred during 2002, as did the second lowest
total annual flow on record at the Whiterocks
River and Green River stations. The 2002
drought was not as severe at the northern stations;
however, 2002 was still one of the 10 driest
years on record for Smiths Fork and the Weber
and Beaver Rivers.

Effects of the Drought

Effects on Selected Reservoirs and
Great Salt Lake

The compounded effects of3 years of less-
than-nonnal precipitation include lowered water
levels of most major reservoirs in Utah. Releases
from darns on these reservoirs have been, and
most likely will continue to be, the minimum
releases required for downstream water users.
The level of Flaming Gorge Reservoir has
dropped by about 18 feet from its level during
years with average runoff. Recovery from this
deficit is expected to take about 2 years, assuming
that inflows return to nonnal by spring 2003
(Bureau of Reclamation, 2002).
According to the Bureau of Reclamation,
unregulated inflow to Lake Powell during water
year 2002 was only 3.06 million acre-feet, or
25 percent of the 30.year average, which is the
least amount of inflow to Lake Powell since the
completion of Glen Canyon Dam in 1963
(Bureau of Reclamation, 2002). Average
streamflow conditions during the past 4 years
in relation to historic maximum and minimum
flows at the Colorado River, Green River, and

San Juan River gaging stations are shown in
figure 5. These three rivers are the major intlows
to Lake Powell, and peak runofTtypically occurs
during May and June from snowmelt in the
mountain headwaters. All three stations recorded
streamflow near the historic mean during water
year 1999 a~ compared to 2002, when streamflow
at all three stations was at or near the historic
minimum. Essentially no spring peak runoff for
the Colorado River or San Juan River occurred
during 2002. After the spring runoff, summer
base-flow conditions also declined steadily (fig.
5). Lake Powell was filled to about 58 percent
of capacity as of November 2002.
Because Great Salt Lake is it ternlinallake
with no outlet to the sea, the water level fluctuates
continuously in response to climatic factors. As
surface-water inflows to the lake decreased
during 1999-2002, lake levels declined. The
water-surface altitude of Gre.lt Salt Lake during
November 2002 was about 4,197 feet, which is
slightly lower than the minimum altitude during
the 1974-78 and 1988-93 droughts. Since 1847
when record keeping began, the lake has been
lower than its current level only three times:
during approximately 1903-07, 1933-50, and
1956-72 (Hcrbert and othcn;, 200 I). Thc currcnt
level is about 6 feet above the historic low of
4.191.35 feet recorded doring the fall of 1963
and about 14 feet below the historic high of
4,211.6 feet recorded June 3, 1986. Recent
satellite imagery of Great Salt Lake shows the
2002 light-colored exposed shoreline in
comparison with an image obtained during 1988-
89 when the water level was 8 to 10 feet higher
(water-surface altitude of 4,205 to 4,207 feet,
fig, 6),

@ Printed on recycled paper

Effects on Ground Water

Utah has experienced drought conditions
statewide for the past 3 water years, and in the
southern part of the state for the past 4 water
years. In general, the drought has been more
severe in the southern parts of the state. Total
annual flow during water year 2002 at the
Colorado River near Cisco, Green River near
Green River, Virgin River near Virgin, and the
San Juan River near Bluff, was the lowest
recorded during approximately the past 100
years of record. During water year 2002.
streamflow conditions at streamflow-gaging
stations in southern Utah showed little to no
effect from spring runoff and approached or
exceeded the historic minimum flows.
Decreased flow from major rivers in Utah has
led to a decline in most reservoir levels and in
Great Salt Lake. Drought conditions in Utah are
common and nonnally last an average of about
4 years. The current drought is not unusual for
its length but rather for its severity, as water
year 2002 will be recorded as one of the driest
years on record for many parts of Utah.

Prolonged droughts have a primary and
secondary effect on ground-water resources.
First, decreased precipitation leads to decreased
recharge to aquifers. Second, decreased surface-
water resources generally lead to increased
ground-water withdrawals, a'i well as to increa..ro
requests for water-well construction pcnnits
(Gates and Allen, 1996).
Aquifers in arid to semiarid regions arc
typically recharged from higher-altitude areas
that receive more precipitation. Decreased
precipitation and snowpack runotT in these areas
leads 10 a decrease in aquifer recharge. In
addition, dry conditions deplete soil moisture.
This moisture needs to be replaced before
recharge conditions can return to nonnal.
Aquifers also can be recharged by seepage from
lakes and streams. As these surface-water
sources of recharge dry up during a drought.
recharge to aquifers is again decreased.
As surface-water sources diminish during
a drought, irrigators and public-supply systems
withdraw more ground water. During the
droughts of 1974-77 and 1988.93. the number
of well pennits granted rose sharply (Gates and
Allen. 1996). This increased demand for h'TOund
water increased the stress on an already depleted
aquifer. In general, ground-water levels in Utah
have declined during the current drought years
(Burden and others, 2002). The corrclation
between droughts and low water levels is shown
in a well in Cedar Valley, near Cedar City, Utah
(fig. 7). Lower ground-water levels are the
result of both decrea'icd recharge and increased
withdrawals; however, it is diflicult to detcnnine
which causes the greater effect.

U.S. Geological Survey Streamflow-
Monitoring Program

For more than 100 years, the USGS has
been collecting water data in Utah with support
from Federal, State, and local cooperators. The
USGS investigates the occurrence, quantity.
quality. and movement of surface and ground
water and disseminates the data to the public
and to Federal. State, and local agencies and
govemmcnts involved with managing the water
resources of Utah. In cooperation with the State
of Utah. the USGS measures water levels on a
yearly basis in more than 1,000 water wells
throughout Utah. The USGS also operates more
than 150 streamflow-gaging stations in Utah.
Real-time data from most of these stations are
available on the Utah District website at
http://ut.water.usgs.govorfrom the National
USGS website at
http://waterdata.usgs.gov/ut/nwis.

'tt u.s. GOVUNMfNT PRINTING OFFICE; ZOO) - SlHI81/460Z6 Region No.8

For more infonnation contact:
U.S. Geological Survey
2329 West Orton Circle
Salt Lake City. UT 84119
801.908.5000
http://ut.water.usgs.gov

By Chris D. Wilkowske. David V. Allen,
and JeffV. Phillips

References

Burden, C.B., and others, 2002, Ground-
water conditions in Utah, Spring of 2002: Utah
Division of Water Resources Cooperative
Investigations Report No. 43, 120 p.

Bureau of Reclamation, 2002, Upper
Colorado Region Water Resources Infonnation
Center. accessed November 27. 2002, at
http://www.uc.usbr.gov/wrg/index.html

Bu'ler. E.. and Man;ell, R.E., 1972.
Cloudbun;, tl<xxls in Utah. 1939-69: Utah
Division of Water Resources Cooperative
Investigations Report II, 103 p.

Gates. J .5.. and Allen. D. V.. 1996. Ground-
water development in Utah and effects on
ground-water levels and chemical quality, Utah
Department of Natural Resources Cooperative
Investigations Report 37, 19 p.

Hayes. MJ.. 2002, Drought indices, in
What is Drought?: National Drought Mitigation
Center. University of Nebraska, Lincoln.
accessed September 26, 2002. at
http://www.drought.uni.edulwhatis/indices.hunl

Herbert. L.R.. Wilberg, D.E.. and Tibbetts.
J.R., 200 I, Water resources data. Utah. water
year 2001. U.S. Geological Survey Water.Data
Report UT-O I-I. 440 p.

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Natural Resources Conservation Service.
2002, National Water and Climate Center
SNOTEL data. accessed January 2, 2003, at
hup://www.wcc.nrcs.usda.gov/water/
w _data.html

U.S. Geological Survey, 1991. National
water summary. 1988-89: U.S. Geological
Survey Water-Supply Paper 2375. 591 p,

Yevjevich. y, Hall. W.A.. and Salas, J.D.
cds., 1977, Drought research needs. in
Proceedings of the Conference on Drought
Research Needs. December 12-15, 1977:
Colorado State University, Fort Collins,
Colorado, 276 p., accessed January 17,2003. at
http://md.usgs.gov/droughtldefine,html

Drought Conditions in Utah During 1999-2002:
A Historical Perspective .73 (

Introduction

"When the well is dry, we learn
the worlh of water" - Ben Franklin,
from Poor Richard's Almanac, 1733

Utah's weather is prone to extremes-from
severe flooding to multiyear droughts. Five
major tloods occurred during 1952, 1965, 1966.
1983, and 1984, and six multiyear droughts
occurred during 1896-1905,1930-36. 1953-65,
1974-78 (U.S. Gcological Survey. 1991). and
more reccntly during 1988-93 and 1999-2002.
The areal extent of floods generally is limited
in size from one to several watersheds, whereas
droughts generally affect most or all of the state.
Southern Utah, in particular Ihe Virgin River
drainage basin, began experiencing drought
conditions during the winter of 1998-99. By
2000, drought conditions were evident
throughout all of Utah. The current drought
(1999-2002) is comparablc in length and
magnitude to previous droughts; however, with
population growth and increased demand for
water in Utah, the general effect is more severe.
During 2002, the fourth straight year of
nearly statewide drought conditions, some areas
of Utah experienced record-low stream flows.
Several record-low stream flows occurred in
streams with records dating back to the 19005.
The V,S. Geulogical Survcy (USGS) uscs
streamflow data from eight long-term

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200 I, to September 30. 2002): Colorado River
near Cisco, San Juan River near BlufT, and
Virgin River at Virgin. At two other gages in
eastern Utah, Whitcrocks River near Whiterocks
and Green River near Green River, 2002 was
the second driest year on record. Streamflow
in the Upper Colorado River Basin has been so
low that the water surface of Lake Powell is
predicted to be 80 feet below the fill level by
January 2003 (Bureau of Reclamatioll, 2002).
The water level of Lake Powell is currently
(2003) low enough near Ilite Marina (at the
upstream end of the lake) that much of the
riverbed of the Colorado and Dirty Devil Rivers
is exposed, a<i are the deltaic scdimenl'i that have
been deposited since the Jake began filling in
1963 (fig. 2).
The adjacent states of Colorado. Arizona,
and New Mexico also have been experiencing
extreme drought conditions and the negative
impacts that result. Record-sized forest fires
during the summer of 2002 in Arizona and
Colorado were directly related to the extremely
dry conditions.

Precipitation
Precipitation directly affects streamflow.
Under nonnal precipitation conditions. Utah
receives less precipitation than every other state
except Nevada. Average annual precipitation at
Salt Lake City is about 16.5 inches, and
precipitation statewide ranges from about 5

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Figure 1. Location of selected streamflow-
gaging stations in Utah and Wyoming,

streamflow-gaging stations for comparison of
hydrologic conditions in Utah (fig. I). Three of
these gages registered new record-low annual
strcamtlows for water year 2002 (October I,

Figure 2. Lake Powell near Hite, Utah, showing exposed channel of the Colorado and Dirty Devil Rivers, which are normally flooded by
the lake, as well as the deltaiC sediments that are depOSited at the upper end of the lake; view to east in October 2002.

u.s. Department 01 the Interior
U.S. Geological Survey

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\?CP1 0 A

USGS Fact Sheet 037-03
April 2003

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