Fact Sheet 2022–3071

August 2022

U.S. Department of the Interior

U.S. Geological Survey

Hydrologic Conditions in Kansas, Water Year 2021 Hydrologic Conditions in Kansas, Water Year 2021

The U.S. Geological Survey (USGS) maintains a network of hydrologic monitoring stations across Kansas 

in cooperation with Federal, State, Tribal, and local agencies. During water year (WY) 2021, this network 

included 230 real-time surface water data collection sites, referred to as “streamgages.” A WY is the 12-month 

period from October 1 through September 30 and is designated by the calendar year in which it ends. These 

real-time data are routinely collected and calibrated by USGS personnel via regular measurements of 

streamflow and water levels. Analyses of these data provide an understanding of hydrologic conditions in the 

State critical to the management of water resources, industrial and agricultural uses, protection of life and 

property during flooding, operation of reservoirs, recreation, and other activities.

Streamflow Conditions and 

Drainage Basin Runoff

Hydrologic conditions in Kansas for 

WY 2021 varied substantially across space 

and time. The year began with normal 

(25th–75th percentile class) streamflow 

over much of the State (based on the 

historical record of streamgages with more 

than 30 years of data); basins primarily 

in southern Kansas experienced less than 

normal (10th–24th percentile class) or low 

(lowest ever observed for the given time 

frame) flows, and a part of the Smoky 

Hill-Saline Basin experienced greater than 

normal (76th–90th percentile class) flow 

(fig. 1; U.S. Geological Survey, 2022b). 

Through February, less than normal to 

much less than normal (less than 10th 

percentile class) flows persisted in the 

northwestern and southwestern parts of 

the State, and the less than normal areas 

in east-central Kansas returned to normal 

flow by January. Late winter and spring 

precipitation events brought normal to 

high (highest observed for a given time 

frame) flows for most of the central and 

eastern parts of the State, which either persisted or returned to normal over the rest 

of the water year (fig. 2; National Weather 

Service, 2022). As summer progressed, 

flows in the southwestern and northwestern parts of the State decreased to be less 

or much less than normal, part of the 

Cimarron Basin dropped into low flow, 

and some central Kansas basins dropped 

to the less than normal percentile class. 

In the last quarter of WY 2021, flows 

increased in the western part of the State 

and primarily were within the less than 

normal and normal categories, whereas the 

eastern part of the State was mostly in the 

normal range but included areas ranging 

from less than normal to much greater 

than normal.

Runoff, or streamflow per unit 

area, can be used to characterize 

precipitation and streamflow across a 

given drainage basin. Monthly runoff 

in Kansas was in the normal percentile 

class for much of WY 2021 (fig. 3A), 

with the exceptions of January, March, 

and July, which fell into the greater 

than normal percentile class. The 

7-day average runoff

graph (fig. 3B) shows

seven instances of average runoff increasing

to the greater than

normal or much

greater than

normal percentile

classes, and a

peak in March was

greater than the 95th

percentile. The cumulative 7-day average

hydrograph for WY 2021

(based on data from WYs

1901 to 2021) was within the

25th–75th percentiles throughout

the WY (fig. 4). Overall, WY 2021

was in the 58th percentile and ranked

51st in computed runoff going back to

WY 1901 (U.S. Geological Survey,

2022b). The annual runoff for Kansas,

in millimeters, going back to WY

1946 is shown in figure 5.

View of the sunrise from the Topeka water plant site (06888990) 

on the Kansas River. Photograph by the U.S. Geological Survey.
October 2020 November 2020

December 2020

January 2021 February 2021

March 2021

April 2021

June 2021

May 2021

July 2021

September 2021

August 2021

EXPLANATION

[<, less than; >, greater than]

Percentile classes

Low

<10 10−24 25−75

76−90 >90

Much less 

than normal

Much greater

than normal

Greater than

normal

Normal

High No data

Less than

normal

Figure 1. Comparison of monthly streamflow conditions across 

Kansas throughout water year 2021 (U.S. Geological Survey, 

2022b). Clockwise from top left, October with subset November 

and December, 2020; January with subset February and March, 

2021; April with subset May and June, 2021; and July with subset 

August and September, 2021.

October 2020 November 2020

December 2020

January 2021 February 2021

March 2021

April 2021

June 2021

May 2021

July 2021

September 2021

August 2021

EXPLANATION

Precipitation, in percent

600

400

300

200

150

125

110

100

90

75

50

25

10

5

0

Figure 2. Statewide percentage of normal precipitation 

in Kansas throughout water year 2021 (National Weather 

Service, 2022). Clockwise from top left, October with subset 

November and December, 2020; January with subset 

February and March, 2021; April with subset May and June, 

2021; and July with subset August and September, 2021.
Duration hydrograph of monthly runoff for Kansas

Monthly runoff, in millimeters

90

10

1

0.1

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

2020 2021 Last updated: 2022-02-16

EXPLANATION

Percentile class

10th percentile 

— lowest 5 10–24 25–75 76–90 95 90th percentile — highest

Much less 

than normal

Less than

normal Normal Greater 

than normal

Runoff

Much greater 

than normal

A. Monthly runoff

EXPLANATION

Percentile class

10th percentile 

— lowest 5 10–24 25–75 76–90 95 90th percentile — highest

Much less 

than normal

Less than 

normal Normal Greater 

than normal

Runoff

Much greater 

than normal

Duration hydrograph of 7-day average runoff for Kansas

Monthly runoff, in millimeters

7

1

0.1

0.01

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

2020 2021 Last updated: 2022-02-16

B. 7-day average runoff

Figure 3. Statewide (A) monthly and (B) 7-day average runoff for 

Kansas during water year 2021 (U.S. Geological Survey, 2022b).

EXPLANATION

Cumulative runoff between daily 25th and 75th percentiles 

based on data from WYs 1901 to 2021

Cumulative runoff of daily median based on data 

from WYs 1901 to 2021

Lowest observed cumulative runoff (WY 1956)

Highest observed cumulative runoff (WY 1993)

Observed cumulative runoff (WY 2021)

[WY, water year]

Cumulative runoff, in millimeters

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

Hydrograph of cumulative daily runoff for Kansas

100

10

300

1

0.1

2020 2021 Last updated: 2021-11-30

Figure 4. Statewide cumulative 7-day average runoff for 

Kansas during water year 2021 (U.S. Geological Survey, 2022b).

1950 1960 1970 1980 1990 2000 2010 2020

Water year

Runoff, in millimeters

0

50

100

150

200

250

Figure 5. Annual runoff for Kansas, in millimeters, from water 

years 1946 to 2021 (U.S. Geological Survey, 2022b).
Statewide Precipitation 

and Drought Conditions

Annual precipitation for 

WY 2021 was typical in that it demonstrated a gradient increasing from 

west to east (figs. 6A–D; National 

Weather Service, 2022). Parts of 

western Kansas, along with an area 

in east-central Kansas, experienced 

higher than average rainfall, but much 

of the rest of the State experienced 

average to less than average rainfall 

amounts.

In early October, drought conditions were prevalent across the State, 

and about 80 percent of land area was 

categorized as abnormally dry; the 

remaining land area was categorized 

as experiencing moderate, severe, or 

extreme drought conditions (fig. 7; 

National Drought Mitigation Center, 

2022). By the end of October, dry 

conditions began to intensify in the 

northwestern part of the State (fig. 8; 

National Drought Mitigation Center, 

2022). National Drought Mitigation 

Center data in figures 7 and 8 indicate 

dry conditions subsided in the far 

southern reaches of the State around 

early November. These data also 

indicate dry conditions in the western 

reaches persisted through the end of 

April. In May and June, much of the 

State did not fall into any drought 

category, except for two clusters 

in north-central and south-central 

Kansas, which were categorized as 

abnormally dry (fig. 8). After June, 

dry conditions returned and were 

somewhat localized to the northwestern corner and central corridor. About 

50 percent of Kansas was under some 

level of the drought monitor categories by the end of WY 2021 (fig. 7).

Reservoirs

The USGS monitors real-time 

water levels and storage for 

12 reservoirs in Kansas. At the 

beginning of WY 2021, five of these 

reservoirs, Milford Lake (06857050), 

Tuttle Creek Lake (06886900), Perry 

Lake (06890898), Clinton Lake 

(06891478), and Hillsdale Lake 

(06914995) had 100 percent of their 

conservation-pool capacity filled 

when comparing daily mean storage values with reservoir capacity 

tables (fig. 9; U.S. Geological Survey, 

2022a). Of the seven reservoirs below 

full conservation-pool capacity, Cedar 

Bluff Reservoir (06861500), at 

63 percent of conservation-pool 

capacity, had the smallest percentage 

of conservation-pool capacity filled. 

By the end of WY 2021, nine reservoirs were filled to their conservationpool capacities; those with less than 

100 percent storage in the conservation pool included Cedar Bluff 

Reservoir (06861500) at 59 percent, 

HorseThief Reservoir (07140885) 

at 95 percent, and Cheney Reservoir 

(07144790) at 90 percent. Five 

reservoirs exceeded 150 percent 

of conservation-pool capacity at 

some point in WY 2021 including 

Kanopolis Lake (06865000), Tuttle 

Creek Lake (06886900), Clinton 

Lake (06891478), Melvern Lake 

(06910997), and Pomona Lake 

(06912490). Pomona Lake demonstrated the greatest storage in relation 

to conservation-pool capacity during 

WY 2021 with a peak daily mean 

storage of 289 percent of the conservation pool.

A. Normal precipitation B. Observed precipitation

EXPLANATION

Normal precipitation, in inches

100

80

70

60

50

40

35

30

25

20

15

10

5

2.5

0.01

EXPLANATION

Observed precipitation, in inches

100

80

70

60

50

40

35

30

25

20

15

10

5

2.5

0.01

C. Percentage of normal precipitation

EXPLANATION

Percentage of normal precipitation

600

400

300

200

150

125

110

100

90

75

50

25

5

2.5

0.01

D. Departure from normal precipitation 

EXPLANATION

Departure from normal precipitation, in inches

20

16

12

8

6

4

2

−2

−4

−6

−8

−12

−16

−20

−24

Figure 6. Statewide (A) normal precipitation, in inches, based on data from 1981 to 2010; (B) 

observed precipitation, in inches; (C) percentage of normal precipitation; and (D) departure 

from normal precipitation, in inches, for water year 2021 (National Weather Service, 2022).
EXPLANATION

Drought intensity

Abnormally dry

Moderate 

Severe 

Extreme

Exceptional

Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov.

2020 2021

Land area, in percent

100

80

60

40

20

0

Figure 7. Statewide land area in U.S. drought monitor categories, in percent (National Drought Mitigation Center, 2022).

October 31, 2020 November 30, 2020

December 31, 2020

January 31, 2021 February 28, 2021

March 31, 2021

April 30, 2021

June 30, 2021

May 31, 2021

July 31, 2021

September 30, 2021

August 31, 2021

EXPLANATION

Drought intensity

Abnormally dry Moderate Severe Extreme Exceptional

Figure 8. Comparison of drought conditions in Kansas during water year 2021 (National Drought Mitigation Center, 2022). Clockwise 

from top left, October 31 with subset November 30 and December 31, 2020; January 31 with subset February 28 and March 31, 2021; 

April 30 with subset May 31 and June 30, 2021; and July 31 with subset August 31 and September 30, 2021.
0

100

200

300

Conservation-pool storage, in percent

Reservoirs in Kansas, water year (WY) 2021

06857050 

Milford Lake 

near Junction 

City, Kansas

06861500 

Cedar Bluff

Reservoir 

near Ellis,

Kansas

06865000 

Kanopolis 

Lake near

Kanopolis, 

Kansas

06868100

Wilson 

Lake near

Wilson,

Kansas

06886900 

Tuttle Creak 

Lake near 

Manhattan, 

Kansas

06890898 

Perry Lake 

near Perry, 

Kansas

06891478 

Clinton 

Lake near 

Lawrence,

Kansas

06910997

Melvern 

Lake near

Melvern, 

Kansas

06912490

Pomona

Lake near

Quenemo,

Kansas

06914995

Hillsdale

Lake near

Hillsdale,

Kansas

07140885

HorseThief

Reservoir

near 

Jetmore,

Kansas

07144790

Cheney 

Reservoir

near Cheney, 

Kansas

U.S. Geological Survey monitored reservoirs

Peak daily storage during WY 2021 

Storage at beginning of WY 2021 

Storage at end of WY 2021

EXPLANATION

Figure 9. Conservation-pool storage, in percent, in reservoirs monitored by the U.S. Geological Survey as daily 

mean values at the beginning and end of water year 2021 and the peak daily value during that time frame 

(U.S. Geological Survey, 2022a).

Summary

Hydrologic conditions in Kansas during water year 

2021 were generally normal, although seasonal variation 

in precipitation and runoff was observed in different parts 

of the State. Drought conditions were most severe in 

western Kansas from October to December, whereas 

precipitation and flows were highest in east-central 

Kansas from March to July. Despite spatial and temporal 

variability in precipitation and runoff, hydrologic conditions were sufficient to maintain reservoir conservationpool storage in most reservoirs across the State.

References Cited

National Drought Mitigation Center, 2022, U.S. Drought 

Monitor—Kansas: National Drought Mitigation Center web 

page, accessed February 16, 2022, at https://

droughtmonitor.unl.edu/.

National Weather Service, 2022, Advanced Hydrologic 

Prediction Service: National Weather Service digital data, 

accessed January 27, 2022, at https://water.

weather.gov/precip/.

U.S. Geological Survey, 2022a, USGS water data for the Nation: 

U.S. Geological Survey National Water Information System 

database, accessed March 16, 2022, at https://doi.org/10.5066/

F7P55KJN.

U.S. Geological Survey, 2022b, WaterWatch: U.S. Geological 

Survey digital data, accessed January 27, 2022, at https://

waterwatch.usgs.gov/.

By Kyle A. Puls

For more information about this publication, contact:

Director, USGS Kansas Water Science Center

1217 Biltmore Drive

Lawrence, KS 66049

785–842–9909

For additional information, visit: 

https://www.usgs.gov/centers/kswsc

Publishing support provided by the Rolla Publishing Service Center

SSN 2327-6916 (print)

ISSN 2327-6932 (online)

https://doi.org/10.3133/fs20223071