In the world there is nothing more 

submissive and weak than water. Yet for 

attacking that which is hard and strong 

nothing can surpass it. 

Lao Tzu

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3085

May 2006

Flooding and streamflow in Utah during water year 2005

Introduction

 The 2004 and 2005 water years illustrate why water managers in Utah generally 

describe the water supply as ‘feast or famine.’ 

In September 2004, Utah was finishing 

its sixth year of drought. Most reservoirs 

were substantially drained and the soil was 

parched. In contrast, in September 2005 

Utah was finishing a water year that set new 

records for peak discharge and total annual 

streamflow. 

 The 2004 water year ended on September 

30, 2004. The 2005 water year brought with 

it a significant change in the weather, beginning with intense rainfall in the Virgin River 

basin of southwestern Utah. Only minor 

flooding resulted from this storm; however, it 

provided soil moisture that would contribute 

to severe flooding during January 2005 (figs. 

1 and 2).

Figure 1. Bridge washed out by the Santa 

Clara River in St. George, Utah, January 2005. 

(Photo by Trent Nelson, Salt Lake Tribune).

 In the high mountains and plateaus of 

Utah, these and subsequent storms built up a 

snowpack that reached record depths in some 

areas by the spring of 2005 (Julander and 

others, 2005). On April 28, 2005, heavy rain 

falling on snow in the Cache Valley area near 

Logan caused the next serious flood event. 

One month later, in late May and early June, 

the record snows began to melt and produced 

record runoff along the upper Sevier River in 

Figure 2. Virgin River near Washington, Utah, just upstream of the Santa Clara River. Discharge 

is approximately 12,000 cubic feet per second. View looking downstream on January 10, 2005. 

(Photo by D.E. Wilberg, U.S. Geological Survey).

Figure 3. Selected streamflow-gaging stations in Utah.

southern Utah and the Whiterocks River in 

northeastern Utah. 

 Eleven streamflow-gaging stations have 

been selected to highlight the flooding that 

occurred in Utah during water year 2005 

(fig. 3). Of the selected stations, five set new 

records for peak discharge. Eight stations 

set records for total annual streamflow. 

Additional data for these and other stations 

in Utah can be obtained from Wilberg and 

others (2006).

Bear

Lake Bear River

Logan

Salt Lake City 

Provo

Great

Salt

Lake

Lake

Powell

Flaming

Gorge

Reservoir

114° 42°

111°

37°

IDAHO 

WYOMING 

0

0

20

40

40

60 KILOMETERS 

60 MILES 

20

NEVADA

COLORADO

ARIZONA

St George Virgin River

Weber River

Utah

Lake 

Colorado 

River

Green River

Colorado 

River

Green River

Cedar City 

Ogden

Duchesne River near Randlett

North Fork Virgin River near Springdale

Little Bear River at Paradise Blacksmith Fork near Hyrum

Whiterocks River near Whiterocks

Coal Creek near Cedar City

Mammoth Creek

near Hatch

Santa Clara River Sevier River at Hatch

at St.George

Virgin River

near Bloomington

Virgin River

at Virgin

EXPLANATION

Streamflow-gaging

 station

Sevier River
Precipitation in Water Year 2005 

 Precipitation in Utah results from three 

general atmospheric conditions: Pacific frontal systems (late fall through early spring), 

cutoff low-pressure systems (late spring and 

fall), and monsoonal thunderstorms (summer). Frontal systems typically move westto-east across Utah and account for much 

of the mountain snowpack (U.S. Geological 

Survey, 1991). These systems can affect all or 

part of the state, depending on the prevailing jet stream (high-altitude winds). Cutoff 

low-pressure systems generally originate in 

the Pacific Ocean, are widespread and slow 

moving, and can produce large amounts of 

precipitation over an extended time (U.S. 

Geological Survey, 1991). These are typically dissipating tropical cyclones, including 

tropical storms and hurricanes. Monsoonal 

thunderstorms frequently occur during the 

summer months when high temperatures and 

heating of the Earth’s surface produce strong 

thermals. Subtropical moisture originating 

in the Gulf of Mexico and Gulf of California 

can combine with these thermals and produce 

locally intense thunderstorms.

 The greatest percentage of flow for most 

streams in Utah comes from melting mountain snowpack that generally occurs in May 

and June. This runoff may produce some 

flooding along lower reaches of rivers, but 

damage from these type of flows is generally 

small (Western Regional Climate Center, 

2006). The most common flooding in Utah 

comes from flash floods that occur as a result 

of a locally heavy precipitation event. Flash 

floods can occur throughout the year and 

across the state. A combination of intense 

rain on top of melting snow generally produce 

the largest and most damaging floods in the 

state. 

 During water year 2005, the flooding and 

high spring runoff was the direct result of a 

wet, southerly Pacific storm track that was 

attributed to a weak El Niño event (Brian 

McInerney, National Weather Service, oral 

commun., 2006). Starting in October 2004, 

this storm track produced heavy snows in 

the mountains and plateaus of southwestern 

Utah and along the south slope of the Uinta 

Mountains. It also produced several large 

rainfall events that occurred during October, 

January, and April. During this time, adjacent areas of the southwestern United States, 

including southern California, Arizona, New 

Mexico, and southern Colorado also experienced greater-than-normal precipitation. 

The Pacific Northwest, Montana, and areas 

of Wyoming, however, received substantially 

less-than-normal precipitation.

 Snowpack in Utah on April 1, 2005, is 

shown in table 1. Snowpack ranged from 

102 percent of average in the Bear River 

basin (north) to 234 percent of average in the 

southwestern mountains (Julander and others, 

2005). Average soil-moisture conditions 

throughout Utah as of April 1, 2005, also are 

shown in table 1. Soil-moisture conditions 

can play an important role in the degree of 

Table 1. Snowpack and soil moisture in 

selected areas in Utah on April 1, 2005

Snowpack,

in percent of

average

Soil moisture,

in percent of

saturation

Bear River basin 102 71

Weber and Ogden 

River basins

121 72

Jordan River and 

Tooele Valley 

basins

133 68

Uinta Mountains 154 64

Southeastern Utah 139 70

Table 2. Maximum discharge data from 11 streamflow-gaging stations in Utah that were affected by flooding during water year 2005

[ft3/s, cubic feet per second; -, no data; >, greater than]

Station name Period of record

2005 maximum instantaneous discharge 

(ft3/s)

Date of 2005 

maximum instantaneous 

discharge 

2005 percentile of 

yearly maximum 

instantaneous 

discharge

Recurrence interval 

of 2005 maximum 

instantaneous 

discharge

Maximum 

instantaneous 

discharge for 

period of record 

(ft3/s)

Date of maximum 

instantaneous 

discharge for period 

of record

Virgin River Basin

North Fork Virgin River near Springdale, Utah 1925-2005 5,450 1/11/2005 94 10-25 years1 9,150 12/6/1966

Virgin River at Virgin, Utah 1910-1971, 1978-2005 9,840 1/11/2005 82 10-25 years1 22,800 12/6/1966

Santa Clara River at St. George, Utah 1950-1956, 1984-2005 6,200 1/11/2005 100 25-50 years1 6,200 1/11/2005

Virgin River near Bloomington, Utah 1978-2005 19,600 1/11/2005 1002 >100 years1 19,6002 1/11/2005

Cache Valley

Little Bear River at Paradise, Utah 1993-2005 4,800 4/28/2005 100 >100 years 3 4,800 4/28/2005

Little Bear River near Paradise, Utah 1937-1986 - - - - 2,250 2/19/1986

Blacksmith Fork near Hyrum, Utah 1915-1917, 1919-1996, 

2001-2005 1,570 4/28/2005 97 25-50 years 3 1,650 5/14/1984

Sevier River Basin

Mammoth Creek near Hatch, Utah 1965-2005 1,390 6/3/2005 100 >100 years 3 1,390 6/3/2005

Sevier River at Hatch, Utah 1915-1928, 1940-2005 1,990 6/3/2005 100 >100 years 3 1,990 6/3/2005

Coal Creek near Cedar City, Utah 1939-2005 1,690 6/3/2005 74 5-10 years 3 4,620 7/23/1969

Duchesne River Basin

Whiterocks River near Whiterocks, Utah 1930-2005 1,920 5/23/2005 81 5-10 years 3 4,640 6/22/1983

Duchesne River near Randlett, Utah 1943-2005 7,570 5/26/2005 92 5-10 years 3 11,500 6/20/1983

1 Weighted estimates using regional regression equations (Thomas and others, 1997) and guidelines outlined in Bulletin 17B.

 (U.S. Interagency Advisory Committee on Water Data, 1982).

2

 Does not include failure of Quail Creek Reservoir dike in 1989 (60,000 ft3/s).

3

 Estimate computed following guidelines outlined in Bulletin 17B (U.S. Interagency Advisory Committee on Water Data, 1982).

flooding in an area. If soil-moisture conditions are low, much of the melting snow or 

falling rain will enter the ground. If soils are 

saturated, or if rain falls on an impermeable 

surface such as exposed bedrock, a much 

higher percentage of the precipitation will 

become streamflow. Soil moisture in Utah on 

April 1, 2005, ranged from 64 to 74 percent 

of saturation as measured in the upper 2 feet 

of soil (Julander and others, 2005). Soilmoisture in this range is considered adequate 

for an efficient runoff.

Flood Events in Water Year 2005

 Maximum instantaneous discharge 

recorded during the 2005 water year is shown 

in table 2 for 11 selected streamflow-gaging 

stations in Utah. Several of these stations 
set new maximum instantaneous discharge 

records in 2005. All of the stations in table 2 

had a maximum instantaneous discharge that 

exceeded the 70th percentile. 

Virgin River Basin

 Streamflow in the Virgin River at the start 

of water year 2005 was below average baseflow conditions. Monthly mean discharges 

for June through September 2004 at U.S. 

Geological Survey (USGS) streamflow-gaging station Virgin River at Virgin, Utah, 

averaged more than 50 percent less than 

the monthly mean discharge for these same 

months during the 89-year period of record. 

 In southwestern Utah, soil moisture in the 

upper 2 feet of soil on October 1, 2004, was 

estimated at about 30 percent of saturation 

by the Utah Snow Survey Program of the 

Natural Resources Conservation Service 

(NRCS) (Randall Julander, written commun., 

2005). During October 18-22, 2004, a Pacific 

frontal moisture system delivered between 

1.5 and 9.4 inches of rain in the Virgin River 

basin above the confluence with the Santa 

Clara River (fig. 4). The precipitation data 

shown in figure 4 is an estimate produced 

by the National Weather Service from Next 

Generation Weather Radar, or NEXRAD 

(National Oceanic and Atmospheric Administration, 2006). The apparent total volume 

of water that fell as precipitation from this 

storm was 493,000 acre-feet, as calculated 

from the NEXRAD data. The resultant peak 

discharge that occurred on October 21 on the 

Virgin River near Bloomington, Utah, was 

about 11,000 cubic feet per second (ft3/s) (fig. 

5). Peak discharge on the Santa Clara River 

at St. George, Utah, was 1,190 ft3/s (fig. 5). 

These peaks correspond to about a 5- to 10-

year flow recurrence interval. Minor damage 

was reported along Ash Creek and the upper 

reaches of the Santa Clara River in the Pine 

Valley area.

 During January 8-12, 2005, another large, 

wet Pacific frontal system moved into the 

Virgin River basin in Utah. This system 

delivered between 0.7 and 7.7 inches of rain 

(fig. 6). The total apparent volume of precipitation from the January storm was about 

half as much as the October event, or 264,000 

acre-feet. However, as a result of the October 

storm, the soil-moisture at the time was estimated to be 70 percent of saturation (Julander 

and others, 2005).

 On the evening of January 8, 2005, light 

rain began to fall in the Virgin River basin. 

The highest-intensity precipitation of the 

event occurred on January 9th, and streamflow rose rapidly in response (fig. 7). Initial 

peaks of 4,890 ft3/s on the Santa Clara River 

at St. George, and 19,000 ft3/s at the Virgin 

River near Bloomington occurred on the 

morning of the 10th. At this time, numerous 

roads were closed and a State of Emergency 

5-7

Washington

ARIZONA

UTAH

Virgin River

Gunlock Reservoir

Saint George

Kanab

Hurricane

NORTH FORK VIRGIN RIVER 

NEAR SPRINGDALE, UT

VIRGIN RIVER NEAR 

BLOOMINGTON, UT

SANTA CLARA RIVER 

AT ST. GEORGE, UT 

VIRGIN RIVER AT 

VIRGIN, UT 

Virgin River

La Verkin Creek

Deep Creek

Santa Clara River

Moody Wash

East Fork Virgin River

Ash Creek

North Fork Virgin R.

EXPLANATION

Precipitation, in inches Streamflow-gaging station

5-7

7-9

3-5 Greater than 9

1-3

3-5

Washington

ARIZONA

UTAH

Virgin River

Gunlock Reservoir

Saint George

Kanab

Hurricane

NORTH FORK VIRGIN RIVER 

NEAR SPRINGDALE, UT

VIRGIN RIVER NEAR 

BLOOMINGTON, UT

SANTA CLARA RIVER 

AT ST. GEORGE, UT 

VIRGIN RIVER AT 

VIRGIN, UT 

Virgin River

La Verkin Creek

Deep Creek

Santa Clara River

Moody Wash

East Fork Virgin River

Ash Creek

North Fork Virgin R.

113°30' 113°0'

37°0' 37°20'

0 5 10 Miles

0 5 10 Kilometers

Figure 4. Storm-total precipitation calculated from National Weather Service Next 

Generation Radar data for the Virgin River basin, Utah, October 18-22, 2004.

was declared. Flows began to recede by the 

late afternoon on the 10th. Additional rain 

on January 11, however, brought discharge to 

record levels in the Santa Clara River at St. 

George, and the Virgin River near Bloomington. The peak discharge for the Santa Clara 

River on January 11, 2005, was 6,200 ft3/s 

(table 2), resulting in the collapse of several 

houses into the Santa Clara River as the river 

shifted its course. The peak discharge on 

January 11, 2005, for the Virgin River near 

Bloomington was 19,600 ft3/s (table 2).

 The floods along the Santa Clara River 

caused 28 homes to be destroyed or damaged, resulting in an estimated $85 million 

in personal property damage. The floods 

caused an additional $140 million in damage 

to local infrastructure (Ryan Pietramali, Utah 

Department of Public Safety, written commun., 2006).

Cache Valley

 On April 28, 2005, heavy localized precipitation, believed to be in part a rain-on-snow 

event, caused flooding in Cache Valley in 

northern Utah. Peak discharge at streamflow-gaging station Little Bear River at 

Paradise, Utah, for this event was 4,800 ft3/s 

(table 2), or more than 3,500 ft3/s more than 

the previous recorded maximum discharge. 

From 1937 to 1986 a station was operated at a 

location 1 mile downstream from the present 

site. When compared to this record, the peak 

from April 28, 2005, was nearly twice as 

large as any previously recorded discharge. 

Peak discharge on the nearby Blacksmith 

Fork River did not break a record for the 87-

year history of the gage; however, discharge 

was at the 97th percentile during the flood 

event (table 2).

Figure 5. Discharge at selected streamflow-gaging stations in the Virgin River basin for 

October 19-25, 2004.

10/19/2004 10/20/2004 10/21/2004 10/22/2004 10/23/2004 10/24/2004 10/25/2004

2,000

0

4,000

6,000

8,000

10,000

12,000

DISCHARGE, IN CUBIC FEET

PER SECOND

 North Fork Virgin River near Springdale, UT

 Virgin River at Bloomington, UT

 Santa Clara River at St. George, UT

EXPLANATION

 Virgin River at Virgin, UT
Figure 6. Storm-total precipitation calculated from National Weather Service Next Generation 

Radar data for the Virgin River basin, Utah, January 8-12, 2005.

Figure 7. Discharge at selected streamflow-gaging stations in the Virgin River basin for January 

8-14, 2005.

Washington

ARIZONA

UTAH

Virgin River

Gunlock Reservoir

Saint George

Kanab

Hurricane

NORTH FORK VIRGIN RIVER 

NEAR SPRINGDALE, UT

VIRGIN RIVER NEAR 

BLOOMINGTON, UT

SANTA CLARA RIVER 

AT ST. GEORGE, UT 

VIRGIN RIVER AT 

VIRGIN, UT 

Virgin River

La Verkin Creek

Deep Creek

Santa Clara River

Moody Wash

East Fork Virgin River

Ash Creek

North Fork Virgin R.

EXPLANATION

7-9

5-7

3-5

1-3

3-5

Less than 1

Washington

ARIZONA

UTAH

Virgin River

Gunlock Reservoir

Saint George

Kanab

Hurricane

NORTH FORK VIRGIN RIVER 

NEAR SPRINGDALE, UT

VIRGIN RIVER NEAR 

BLOOMINGTON, UT

SANTA CLARA RIVER 

AT ST. GEORGE, UT 

VIRGIN RIVER AT 

VIRGIN, UT 

Virgin River

La Verkin Creek

Deep Creek

Santa Clara River

Moody Wash

East Fork Virgin River

Ash Creek

North Fork Virgin R.

113°30' 113°0'

37°0' 37°20'

0 5 10 Miles

0 5 10 Kilometers Precipitation, in inches Streamflow-gaging station

1/8/2005 1/9/2005 1/10/2005 1/11/2005 1/12/2005 1/13/2005 1/14/2005

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

DISCHARGE, IN CUBIC FEET PER SECOND

0

 Estimated daily mean discharge at Virgin River near 

 Bloomington, UT

 North Fork Virgin River near Springdale, UT

 Virgin River at Virgin, UT

 Virgin River at Bloomington, UT

 Santa Clara River at St. George, UT

EXPLANATION

Sevier River Basin

 The April 1, 2005, snowpack for the 

upper Sevier River basin was 225 percent of 

normal. The April 1, 2005, snowpack in the 

Coal Creek drainage basin was 242 percent 

of normal. Melt of this massive snowpack 

created new maximum discharge records for 

gages on the Sevier River at Hatch, Utah, 

and on Mammoth Creek near Hatch, Utah, a 

tributary of the Sevier River (table 2). Both 

of these peaks had a recurrence interval of 

greater than 100 years.

 The 2005 peak discharge for Coal Creek 

near Cedar City, Utah, was 1,690 ft3/s, which 

ranks at the 74th percentile. The recurrence 

interval for this peak was between 5 and 

10 years. The maximum discharge for the 

period of record on Coal Creek near Cedar 

City was 4,620 ft3/s (table 2). This peak, 

along with most of the large peaks that have 

occurred on this stream, happened in the 

summer as the result of heavy monsoonal 

rains. For comparison, the spring runoff 

peak of 1983, a very wet year, was 1,480 ft3/s 

(ReMillard and others, 1984).

 The 2005 peak discharge for the Sevier 

River at Hatch, Utah, was 1,990 ft3/s. Peak 

discharge was 1,390 ft3/s on Mammoth Creek 

near Hatch (table 2). Both peaks for the 

2005 water year were maximum discharges 

for the period of record at these stations. 

Some flooding of cabins and road closures 

occurred along Mammoth Creek as a result 

of the spring flood peak. The reaches of the 

lower Sevier River were spared flood damage 

because reservoirs located downstream of 

Hatch captured a substantial amount of the 

runoff. 

Duchesne River Basin

 The April 1, 2005, snowpack for the entire 

Duchesne River basin was 164 percent of 

normal (Julander and others, 2005). For 

the Whiterocks River in the upper part 

of the Duchesne River basin, the April 1, 

2005, snowpack was 226 percent of normal 

(Julander and others, 2005). This greaterthan-normal snowpack caused some concern 

during the spring of 2005, raising fears that a 

rapid temperature increase or a rain-on-snow 

event in late spring would cause flooding on 

the Whiterocks or Duchesne Rivers. Daily 

mean discharge for the Whiterocks River near 

Whiterocks in relation to daily snow-water 

equivalent measured at the NRCS Chepeta 

SNOTEL site is shown in figure 8. The 

maximum recorded discharge for Whiterocks River near Whiterocks during the 2005 

water year was 1,920 ft3/s. The maximum 

discharge for the period of record was 4,640 

ft3/s and occurred June 22, 1983 (table 2). 

The cooler temperatures at the end of May 

2005 most likely prevented a peak of similar 

magnitude to 1983.

 The maximum discharge recorded on the 

Duchesne River near Randlett during water 

year 2005 was 7,570 ft3/s (table 2). This 

peak was greater than the 90th percentile of 

recorded discharge for this station.

Total Annual Discharge for 

Water Year 2005

 Total annual discharge at 11 streamflowgaging stations in Utah is shown in table 

3. At the selected stations, total annual 

discharge ranged from 98 percent of average at Blacksmith Fork near Hyrum to 773 

percent of average on the Santa Clara River at 

St. George. 

 Record total annual discharge was measured at stations on the North Fork of the Virgin River near Springdale; the Virgin River at 

Virgin; the Santa Clara River at St. George; 
the Virgin River near Bloomington; Coal 

Creek near Cedar City; the Sevier River at 

Hatch, and Mammoth Creek near Hatch. The 

record total annual discharge at these stations 

was produced by snowpacks that were also 

near or above historic maximums (Julander 

and others, 2005). In contrast, the Little Bear 

River and Blacksmith Fork River experienced 

localized flooding on April 28, 2005, but had 

near average total annual discharge (table 3).

 Total annual discharge for stations in the 

Virgin River basin ranged from 261 percent 

of average for the Virgin River at Virgin to 

773 percent of average for the Santa Clara 

River at St. George. A hydrograph with daily 

mean discharge for the 2005 water year along 

with the historic daily median discharges is 

shown in figure 9. The hydrograph shows 

that daily mean discharges were greater than 

the median discharges for nearly the entire 

water year. These sustained above-normal 

discharges combined with the flash flooding 

in October and January caused the exceedingly high total annual runoff on the Santa 

Clara River (table 3).

 The total annual discharge for Whiterocks 

River near Whiterocks, Utah, which is a 

tributary of the Duchesne River, set a new 

record during water year 2005 and was nearly 

twice the average amount (table 3). The 

snowpack in the sub-basin directly above this 

station, measured at the Chepeta SNOTEL 

site was 226 percent of normal. Snowpack 

for the entire Duchesne River basin was 164 

percent of normal; however, total annual discharge for the station on the Duchesne River 

near Randlett was only at the 79th percentile, 

which is considered slightly above normal. 

Summary

 During water year 2005, new historic maximum discharge records were set at streamflow-gaging stations on the Santa Clara River 

at St. George; Virgin River near Bloomington; Little Bear River at Paradise; Mammoth 

Creek near Hatch; and Sevier River at Hatch. 

4/1/2005 4/22/2005 5/13/2005 6/3/2005 6/24/2005 7/15/2005 8/5/2005

0

500

1,000

1,500

2,000

2,500

 Daily mean discharge - Whiterocks River near 

 Whiterocks, Utah

 Daily snow-water equivalent - Chepeta SNOTEL site

DISCHARGE, IN CUBIC FEET

 PER SECOND

0

5

10

15

20

25

30

35

40

SNOW-WATER EQUIVALENT, 

IN INCHES

Figure 8. Relation of daily mean discharge for Whiterocks River near Whiterocks, Utah, to snowwater equivalent measured at the Chepeta SNOTEL site during the spring of 2005.

Table 3. Annual streamflow data from 11 streamflow-gaging stations in Utah that were affected by flooding during water year 2005

[kac-ft, thousands of acre-feet]

Station name Period of record

Average total annual 

discharge for period 

of record (kac-ft)

2005 total annual 

discharge (kac-ft)

2005 percent of 

average total annual 

discharge

2005 percentile of total 

annual discharge

Virgin River Basin

North Fork Virgin River near Springdale, Utah 1926, 1928-2005 75 232 309 100

Virgin River at Virgin, Utah 1910-1971, 1978-2005 145 379 261 100

Santa Clara River at St. George, Utah 1950-1956, 1984-2005 11 85 773 100

Virgin River near Bloomington, Utah 1978-2005 172 549 319 100

Cache Valley

Little Bear River at Paradise, Utah 1993-2005 65 86 132 75

Blacksmith Fork near Hyrum, Utah 1915-1917, 1919-1996, 

2001-2005

91 89 98 56

Sevier River Basin

Mammoth Creek near Hatch, Utah 1965-2005 36 115 319 100

Sevier River at Hatch, Utah 1915-1928, 1940-2005 87 245 282 100

Coal Creek near Cedar City, Utah 1939-2005 25 84 336 100

Duchesne River Basin

Whiterocks River near Whiterocks, Utah 1930-2005 82 158 193 100

Duchesne River near Randlett, Utah 1943-2005 388 578 149 79
New total annual discharge records were set 

at Whiterocks River near Whiterocks; North 

Fork of the Virgin River near Springdale; 

Virgin River at Virgin; Santa Clara River at 

St. George; Virgin River near Bloomington; 

Mammoth Creek near Hatch; Sevier River 

at Hatch; and Coal Creek near Cedar City. 

New peak instantaneous discharge records 

were set on the Santa Clara, Virgin, and Little 

Bear Rivers as a result of locally intense rainfall events. The record peak discharges set on 

Mammoth Creek and the Sevier River were 

the result of snowpacks that were substantially greater than normal. The total annual 

discharge records for all of the stations were 

the result of greater-than-normal precipitation 

during the winter of 2005 caused by a weak 

El Niño event.

USGS Streamflow-Monitoring 

Program

 For more than 100 years, the USGS Utah 

Water Science Center has been collecting 

streamflow data in Utah with support from 

Federal, State, and local cooperators. The 

USGS operates more than 150 streamflowgaging stations in Utah. Real-time data from 

most of these stations are available on the 

Utah Water Science Center website at http://

ut.water.usgs.gov.

For more information contact:

U.S. Geological Survey

2329 West Orton Circle

Salt Lake City, Utah 84119

801.908.5000

http://ut.water.usgs.gov

By C.D. Wilkowske, T.A. Kenney, and

T.S. McKinney

10/1/2004 1/1/2005 4/1/2005 7/1/2005 10/1/2005

1

10

100

1,000

10,000

 2005 DAILY MEAN

 HISTORIC MEDIAN

DISCHARGE, IN CUBIC 

FEET PER SECOND

Figure 9. Hydrograph for Santa Clara River at St. George, Utah.

Climate is what we expect, 

weather is what we get.

Mark Twain

References

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 M., and Nault, B., 2005, Utah water

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 February 23, 2006, at http://www.ut.nrcs.

 usda.gov/snow/watersupply/wsor/

 2005/wsor_0405.pdf

National Oceanic and Atmospheric 

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 National Center for Environmental 

 Prediction, Precipitation 4KM stage IV

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 www.emc.ncep.noaa.gov/mmb/ylin/ 

 pcpanl/stage4/

ReMillard, M.D., Birdwell, G.A., Garrett,

 R.B., and Sandberg, G.W., 1984, Water

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 1983, U.S. Geological Survey Water-Data

 Report UT-83-1, 489 p.

Thomas, B.E., Hjalmarson, H.W., and 

 Waltemeyer, S.D., 1997, Methods for esti-

 mating magnitude and frequency of floods

 in the southwestern United States, U.S.

 Geological Survey Water-Supply Paper

 2433, 195 p.

U.S. Geological Survey, 1991, National water

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 Survey Water-Supply Paper 2375, 591 p.

U.S. Interagency Advisory Committee on

 Water Data, 1982, Guidelines for detemin-

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 of the Hydrology Subcommittee: Reston,

 Virginia, U.S. Geological Survey, Office

 of Water Data Coordination, 183 p.

Western Regional Climate Center, 2006, 

 Climate of Utah, accessed February 23,

 2006, at http://www.wrcc.dri.edu/

 narratives/UTAH.htm 

Wilberg, D.E., Tibbetts, J.R., Enright,

 Michael, Burden, C.B., Smith, Cynthia,

 and Angeroth, C.E., 2006, Water resources

 data, Utah, water year 2005, U.S. 

 Geological Survey Water-Data Report 

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