U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2021–3045

August 2021

Hydrologic Conditions in Kansas, Water Year 2020

The U.S. Geological Survey 

(USGS), in cooperation with Federal, 

State, and local agencies, maintains a 

long-term network of hydrologic monitoring stations in Kansas. This network 

included 219 real-time streamgages, 

12 real-time reservoir-level monitoring 

stations, and 20 groundwater monitoring 

stations in water year (WY) 2020. A WY 

is a 12-month period from October 1 to 

September 30 and is designated by the 

calendar year in which it ends.

Real-time data are verified by 

USGS personnel throughout the year 

with regular measurements of streamflow, lake levels, and groundwater levels. 

Hydrologic data collected in real time 

aid in the understanding of, and decisions made involving, water resources 

of Kansas. Hydrologic conditions are 

assessed annually by comparing statistical analyses of current and past WY data 

for the period of record. The monitoring of hydrologic conditions in Kansas 

can provide critical information to meet 

several needs including water-resources 

management, protection of life and 

property, reservoir operations, agricultural practices, public supply, ecological 

assessments, and industrial and recreational purposes.

Preceding Conditions and 

Precipitation

WY 2019 was characterized by 

greater than normal precipitation across 

the State (fig. 1A; National Oceanic and 

Atmospheric Administration, 2020). This 

resulted in normal to much greater than 

normal runoff and streamflow (fig. 1B; 

U.S. Geological Survey, 2020b). Of the 

12 reservoirs monitored by the USGS in 

Kansas, 10 began WY 2020 with waterlevel elevations above their full conservation pool.

During WY 2020, some areas of 

Kansas received greater than normal 

annual precipitation, and some received 

less than normal precipitation (fig. 2; 

National Oceanic and Atmospheric 

Administration, 2020). All the major 

drainage basins in the State had areas 

with greater than normal, less than 

normal, and normal precipitation (fig. 3). 

There was however a pattern of predominantly greater than normal precipitation in north-central and northeastern 

Kansas and less than normal precipitation 

in extreme western and southeastern 

Kansas. Despite generally receiving 

a normal amount of precipitation in 

WY 2020, drought conditions intensified across much of the State (fig. 4A and 

B; National Drought Mitigation Center, 

2020).

Characteristically, Kansas is typified 

by a pronounced gradient of precipitation across the State, and WY 2020 was 

no different. The westernmost part of the 

State received 10–20 inches of precipitation, and the easternmost part received 

35–50 inches with small areas receiving as much as 50–60 inches (fig. 5; 

National Oceanic and Atmospheric 

Administration, 2020).

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 2018 2019 Last updated: 2021-04-07

EXPLANATION

Percentile class

Lowest — 

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

Much less than normal Less than 

normal Normal Greater 

than normal

Runoff

Much greater than normal

EXPLANATION

Water year 2019 percentage of

normal annual precipitation

(1981–2010)

A. Water year 2019 statewide percentage of normal precipitation B. Water year 2019 statewide monthly average runoff

Watershed boundaries

150 to 199.9

200 to 300

125 to 149.9

110 to 124.9

100 to 109.9

Osage

Republican

Smoky Hill

Neosho

Upper Arkansas

Middle Arkansas

Big Blue

Verdigris

Kansas

Upper Cimarron

Missouri

Upper Beaver

Arkansas

Lower Cimarron

Lower

Missouri

Blackwater

Republican

Arkansas

Osage

Republican

Smoky Hill

Neosho

Upper Arkansas

Middle Arkansas

Big Blue

Verdigris

Kansas

Upper Cimarron

Missouri

Upper Beaver

Arkansas

Lower Cimarron

Lower

Missouri

Blackwater

Republican

Arkansas

102° 101° 100° 99° 98° 97° 96° 95°

40°

39°

38°

37°

Base from U.S. Geological Survey digital data, 2020

North American Datum of 1983

0 50 10025 75 KILOMETERS

0 50 100 25 75 MILES

Figure 1. Water year 2019 precipitation in Kansas. A, water year 2019 statewide percentage of normal precipitation (1981–2010; National 

Oceanic and Atmospheric Administration, 2020); B, statewide monthly average runoff for Kansas during water year 2019 (U.S. Geological 

Survey, 2020b).
Arkansas

Republican

Osage

Republican

Smoky Hill

Neosho

Upper Arkansas

Middle Arkansas

Big Blue

Verdigris

Kansas

Upper Cimarron

Missouri

Upper Beaver

Arkansas

Lower Cimarron

Lower

Missouri

Blackwater

0 25 50 75 100 KILOMETERS

0 25 50 75 100 MILES

102° 101° 100° 99° 98° 97° 96° 95°

40°

39°

38°

37°

Base from U.S. Geological Survey digital data, 2020

North American Datum of 1983

EXPLANATION

Water year 2020

Less than 25

25 to 49.9

50 to 74.9

75 to 89.9

90 to 99.9

100 to 109.9

110 to 124.9

125 to 149.9

Water year 2020 percentage of normal 

annual precipitation (1981–2010)

Watershed boundaries

Figure 2. Comparison of water year 2020 statewide percentage of normal 

precipitation (1981–2010; National Oceanic and Atmospheric Administration, 2020).

Missouri

Republican

Arkansas

Osage

Republican

Smoky Hill

Neosho

Upper Arkansas

Middle Arkansas

Big Blue

Verdigris

Kansas

Upper Cimarron

Missouri

Upper Beaver

Arkansas

Lower Cimarron

Lower

Missouri

Blackwater

Republican

Arkansas

0 25 50 75 100 KILOMETERS

0 25 50 75 100 MILES

102° 101° 100° 99° 98° 97° 96° 95°

40°

39°

38°

37°

EXPLANATION

Departure from normal precipitation,

in inches

Watershed boundaries

Base from U.S. Geological Survey digital data, 2020

North American Datum of 1983

Water year 2020

−12 to −8.1

−8 to −6.1

−6 to −4.1

−4 to −2.1

−2 to 1.9

2 to 3.9

4 to 5.9

6 to 7.9

8 to 11.9

12 to 16

Figure 3. Observed statewide departure from normal precipitation, in inches (1981–

2010; National Oceanic and Atmospheric Administration, 2020), for water year 2020.

Abnormally dry

Moderate 

Severe 

Extreme

Exceptional

EXPLANATION

Drought intensity

A. October 1, 2019

B. September 29, 2020

Figure 4. Comparison of drought conditions in 

Kansas (National Drought Mitigation Center, 2020). 

A, at the beginning of water year 2020; B, at the end 

of water year 2020.
Figure 5. Observed statewide precipitation, in inches (1981–2010; National Oceanic and 

Atmospheric Administration, 2020), water year 2020.

Drainage Basin Runoff and 

Streamflow Conditions

Estimated runoff (flow per unit area) 

based on available streamflow data at 

gaged locations can be used to characterize streamflow over large areas such 

as drainage basins or States (Brakebill 

and others, 2011). In WY 2020, Kansas 

was characterized by normal to much 

greater than normal runoff (fig. 6A and 

B; U.S. Geological Survey, 2020b). 

WY 2020 began with statewide runoff 

much greater than the normal level, but 

by summer, runoff was in the normal 

range, approaching slightly less than 

the normal level in September (fig. 6B; 

U.S. Geological Survey, 2020b). The less 

than normal runoff condition corresponds 

to the mostly less than normal precipitation across most of the State from May 

to the end of the WY (fig. 7A–J). This 

condition resulted in increased drought 

conditions across much of the State by 

the end of September 2020, in comparison with drought conditions at the 

beginning of the WY (fig. 4A; National 

Drought Mitigation Center, 2020).

Streamflow conditions across 

the State ranged from extremely low 

to extremely high percentiles during WY 2020 (fig. 8; U.S. Geological 

Survey, 2020b). The southwestern part 

of the State remained at less than normal 

to much less than normal through the 

entirety of the WY. In the rest of the 

State, a wide range of streamflow conditions was observed.

B. Water year 2020 monthly average runoff

EXPLANATION

Percentile class

Lowest — 

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

Much less than normal Less than 

normal Normal Greater 

than normal

Runoff

Much greater than normal

Cumulative runoff between daily 25th and 75th percentiles

Cumulative runoff of daily median

Lowest observed cumulative runoff (1956)

Highest observed cumulative runoff (1993)

Observed cumlative runoff (2020)

A. Water year 2020 cumulative runoff 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

0.01

2019 2020 Last updated: 2021-04-07

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

2019 2020 Last updated: 2021-10-27

Figure 6. Statewide runoff for Kansas during water year 2020 

(U.S. Geological Survey, 2020b). A, cumulative runoff; B, monthly 

average runoff.
E. July 28, 2020

A. May 26, 2020

C. June 30, 2020

F. July 2020 

B. May 2020 

D. June 2020 

Abnormally dry

Moderate 

Severe 

Extreme

Exceptional

EXPLANATION

Drought intensity

Figure 7. Comparison of drought conditions in Kansas (National Drought Mitigation Center, 2020) and observed statewide departure 

from normal precipitation, in inches (1981–2010; National Oceanic and Atmospheric Administration, 2020). A, at the end of May 2020; 

B, the month of May 2020; C, at the end of June 2020; D, the month of June 2020; E, at the end of July 2020; F, the month of July 2020; 

G, at the end of August 2020; H, the month of August 2020; I, at the end of September 2020; J, the month of September 2020.
Abnormally dry

Moderate 

Severe 

Extreme

Exceptional

EXPLANATION

Drought intensity

G. August 25, 2020

I. September 29, 2020

H. August 2020 

J. September 2020 

Figure 7. Comparison of drought conditions in Kansas (National Drought Mitigation Center, 2020) and observed statewide departure 

from normal precipitation, in inches (1981–2010; National Oceanic and Atmospheric Administration, 2020). A, at the end of May 2020; 

B, the month of May 2020; C, at the end of June 2020; D, the month of June 2020; E, at the end of July 2020; F, the month of July 2020; 

G, at the end of August 2020; H, the month of August 2020; I, at the end of September 2020; J, the month of September 2020.—

Continued

Reservoirs

The USGS monitors the water 

level and contents of 12 reservoirs 

in Kansas. Some of these reservoirs began WY 2020 more than 

100 percent above their conservation pools because of the greater than 

normal precipitation received during WY 2019. These reservoirs (and 

their real-time monitoring stations) 

included Milford Lake (06857050), 

Kanopolis Lake (06865000), Tuttle 

Creek Lake (06886900), Perry Lake 

(06890898), Clinton Lake (06891478), 

and Pomona Lake (06912490) (fig. 9; 

U.S. Geological Survey, 2020a). 

Additional reservoirs above their conservation pool at the beginning of the 

WY, but at less than 120 percent of their 

conservation pool, were Wilson Lake 

(06868100), Melvern Lake (06910997), 

and Hillsdale Lake (06914995). The 

remaining reservoirs, Cedar Bluff 

(06861500), HorseThief (07140885), and 

Cheney (07144790), began the WY with 

less than 100 percent of their conservation 

pool full.

Except for Milford Lake, Tuttle 

Creek Lake, Perry Lake, and Hillsdale 

Lake, reservoir storage was below the 

conservation pool at the eight reservoirs 

by the end of WY 2020. Four of the 

reservoirs with larger storage capacity 

(Milford Lake, Tuttle Creek Lake, Perry 

Lake, and Clinton Lake) ended the WY, 

still above a 100-percent full conservation pool, with greater than 40 percent less than the volume with which 

they began the WY. Only HorseThief 

Reservoir indicated an increase in storage 

at the end of the WY compared to the 

beginning.

Cedar Bluff Reservoir indicated 

lower storage conditions from the other 

11 reservoirs monitored by the USGS. 

Cedar Bluff has little inflow, which 

results in relying heavily on precipitation. 

As a result, Cedar Bluff has minimal outflow, except during heavy precipitation 

conditions; thus, this reservoir is not as 

sensitive to storage changes as the other 

11 reservoirs monitored.
Low

Greater than No data

normal

Normal

<10 10–24 25–75

76–90 >90

Less than

normal

High

Much less 

than normal

Much greater 

than normal

Percentile classes

[<, less than; >, greater than]

EXPLANATION

2020

October through December 2019

January through March 2020

July through September 2020

April through June 2020

Figure 8. Comparison of monthly streamflow 

conditions across Kansas throughout water 

year 2020 (U.S. Geological Survey, 2020b).

0

100

200

300

400

500

600

Conservation pool storage, in percent

Reservoirs in Kansas water year (WY) 2020

06857050 

Milford Lake 

nearJunction 

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 storage during WY 2020 (percent)

Storage at beginning of WY 2020 (percent)

Storage at end of WY 2020 (percent)

EXPLANATION

year 2020 (U.S. Geological Survey, 2020a).

Figure 9. Contents of reservoirs in Kansas monitored by the U.S. Geological Survey in water 

Summary

At the beginning of water year 

(WY) 2020, streamflow in Kansas was 

generally greater than normal in response 

to greater than normal precipitation in 

WY 2019. By the end of WY 2020, 

streamflow was generally at normal levels throughout the State, in response to a 

year with near normal precipitation.

References Cited

Brakebill, J.W., Wolock, D.M., and Terziotti, 

S.E., 2011, Digital hydrologic networks 

supporting applications related to spatially referenced regression modeling: 

Journal of the American Water Resources 

Association, v. 47, no. 5, p. 916–932. 

[Also available at https://doi.org/10.1111/

j.1752-1688.2011.00578.x.]

National Drought Mitigation Center, 2020, 

U.S. Drought Monitor—Kansas: National 

Drought Mitigation Center web page, 

accessed October 27, 2020, at 

https://droughtmonitor.unl.edu/.

National Oceanic and Atmospheric 

Administration, 2020, Advanced 

Hydrologic Prediction Service—2020 

precipitation maps for Kansas: National 

Oceanic and Atmospheric Administration, 

National Weather Service web page, 

accessed October 27, 2020, at 

https://water.weather.gov/precip/.

U.S. Geological Survey, 2020a, USGS water 

data for the Nation: U.S. Geological 

Survey National Water Information 

System database, accessed October 27, 

2020, at https://doi.org/10.5066/

F7P55KJN.

U.S. Geological Survey, 2020b, 

WaterWatch—Current water resources 

in Kansas: U.S. Geological Survey web 

page, accessed October 27, 2020, at 

https://waterwatch.usgs.gov/.

—By Chantelle Davis

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

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

https://doi.org/10.3133/fs20213045