U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2008–3007

March 2008

Prepared in cooperation with the Johnson County Stormwater Management Program

Continuous Water-Quality Monitoring of Streams in Johnson 

County, Kansas, 2002−06

Teresa J. Rasmussen, Casey J. Lee, and Andrew C. Ziegler

Printed on recycled paper

Introduction

Water quality in Johnson County, 

Kansas was characterized on the basis 

of continuous, in-stream monitoring. The 

results summarized in this fact sheet may 

be used to better understand concentration and load variability during changing seasonal and streamflow conditions 

and to assess water-quality conditions 

relative to water-quality standards and 

management goals. The baseline information also will be useful for evaluating 

future changes in land use and effectiveness of implemented best management 

practices.

Population growth and expanding urban land use in Johnson County, 

northeast Kansas, affect the quality of 

streams, which are important for human 

and environmental health, water supply, 

recreation, and aesthetic value. Johnson County is one of the most rapidly 

developing counties in Kansas, with a 

population increase of about 90 percent 

in the last 25 years, from 270,269 in 

1980 (University of Kansas, 2006) to an 

estimated 516,731 in 2006 (U.S. Census 

Bureau, 2007). Urbanization generally 

affects streams by altering hydrology, 

geomorphology, chemistry, and biology 

(Paul and Meyer, 2001). The implementation of total maximum daily loads 

(TMDLs) and the National Pollutant 

Discharge Elimination System (NPDES), 

both required by the Federal Clean Water 

Act to address water-quality impairments, makes it increasingly necessary 

to document and monitor water-quality 

conditions. In addition, as urban areas 

expand and municipalities including 

those in Johnson County expend increasing funds on management practices 

designed to improve water quality, it is 

necessary to monitor changes in water 

quality over time. Figure 1. Location of monitoring sites, watershed boundaries, and land use, Johnson County, 

northeast Kansas.

50’

38°45’

39°

95° 55’

50’

45’ 94°40’

55’

MISSOURI

KANSAS

Kansas River

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

Base map from U.S. Geological Survey digital data, 1:2,000,000, 1994

Albers Conic Equal-Area Projection,

Standard parallels 29°30' and 45°30', central meridian 96°

Horizontal coordinate information is referenced to the

North American Datum of 1983 (NAD 83)

Land use from Johnson County Automated Information 

Mapping System (written commun., 2003)

Mill Creek

watershed

Indian Creek

watershed

Brush Creek

watershed

Rock Creek

watershed

Turkey

Creek

watershed

Kill Creek

watershed

Cedar Creek

watershed

Blue River

watershed

Big Bull Creek

watershed

Little Bull Creek

watershed

Tomahawk

Creek

watershed

Captain

Creek

watershed

Dykes Branch

watershed

Kill Creek at 95th

Street (06892360)

Cedar Creek near

DeSoto (06892495)

Mill Creek at Johnson

Drive (06892513)

Captain Creek

Kill Creek

Big Bull Creek

Little Bull Creek

Mill Creek

Turkey Creek

Brush Cree

Ro

k

ck Creek

Dykes

Branch

Indian Creek

Tomahawk Creek

Blue River

Lake

Olathe

Cedar

Lake

Coffee Creek

Wolf Creek

Camp Branch

Kansas City metropolitan area

Johnson County

Index map

KANSAS MISSOURI

EXPLANATION

Commercial

Industrial

Parks

Residential

Land use

Surface water

Nonurban land use

No data (government 

 property, public roads)

Watershed boundary

U.S. Geological Survey streamflow-gaging 

 station and number

Water-quality monitoring site

Municipal wastewater-treatment facility—

 Capacity more than 1 million gallons per day

Municipal wastewater-treatment facility—

 Capacity less than 1 million gallons per day

Indian Creek

at State Line

Road 

(06893390)

Indian Creek

at Overland

Park

(06893300)

Blue River at

Kenneth Road 

(06893100)

Blue River 

at Stanley

(06893080)
sas. Constituent concentrations, loads, and yields are described 

for five major watersheds of Johnson County using continuous 

in-stream sensor measurements. Load is the amount of constituent transported in the stream over a specified period of time. 

Yield is the load divided by the drainage area and is a meaningful way to compare different watersheds. Specific conductance, 

pH, water temperature, turbidity, and dissolved oxygen were 

monitored in Cedar and Mill Creeks from October 2002 through 

December 2006, and in Blue River, Kill and Indian Creeks 

from March 2004 through December 2006 (fig. 2). Continuous 

in-stream measurements were used in conjunction with discrete 

water samples and watershed information to develop regression 

models for estimating concentrations of selected constituents. 

Continuous regression-based concentrations were estimated for 

suspended sediment, dissolved solids and selected major ions, 

nutrients (nitrogen and phosphorus species), and fecal-indicator 

bacteria. The complete report from which this information was 

summarized (Rasmussen and others, 2008) is available on the 

Web at http://pubs.er.usgs.gov/usgspubs/.

Water Quality in Johnson 

County Streams

Water quality at the five monitoring sites varied according 

to hydrologic conditions, contributing drainage area, land use, 

degree of urbanization, relative contributions from point and 

nonpoint constituent sources, and human activity within each 

watershed. Many water contaminants in Johnson County, at both 

urban and nonurban sites, originated primarily from nonpoint 

sources during storm-runoff periods. Therefore, climate (precipitation and resulting runoff) had a substantial effect on water 

quality, and larger amounts of rainfall resulted in larger amounts 

of many contaminants like sediment, nutrients, and bacteria in 

streams. In addition, the probability that water-quality criteria 

are exceeded is substantially greater during storm runoff. Sediment yields in the urban watersheds (Indian and Mill Creeks) 

were larger than in nonurban watersheds. Both urban nonpoint 

sources of Escherichia coli (E. coli) bacteria (leaking sewer 

lines, wastewater, wildlife, and pet waste) and nonurban sources 

(wildlife, septic systems, and livestock) were shown to be important contributors to large bacteria densities in Johnson County 

streams. Nearly all bacteria originated from nonpoint sources. 

Urban sources of chloride (primarily road salt but also possibly 

wastewater and industrial runoff) contributed more contaminants 

than nonurban sources (geology). 

Annual yields for suspended sediment and total suspended 

solids, dissolved solids and selected major ions, nutrients 

(nitrogen and phosphorus species), and fecal-indicator bacteria 

were at least five times larger in 2005 than 2006 at the least 

urban site, Kill Creek (fig. 3). In Indian Creek, the most urban 

site, yields in 2005 generally were about 25 percent larger than 

yields in 2006. The annual differences resulted from differences 

in annual precipitation and subsequent runoff to streams. Loads 

for all constituents were larger during 2005, when rainfall was 

about normal, than in 2006 when rainfall was 15 to 30 percent 

less than normal in each watershed (2005 and 2006 precipitation 

data obtained from http://www.stormwatch.com). In the Blue 

In 2002, the U.S. Geological Survey (USGS), in cooperation with the Johnson County Stormwater Management 

Program, began an investigation to characterize the water quality of Johnson County streams and to provide comprehensive 

information for municipalities to help in developing effective 

water-quality management plans. Initial study efforts described 

the effects of nonpoint and selected point contaminant sources 

on stream-water quality and their relation to land use (Lee and 

others, 2005). Also, baseline biological conditions were evaluated to characterize stream biology relative to urban development (Poulton and others, 2007). Throughout these studies, 

water quality was monitored continuously at five sites (fig. 1), 

each on streams identified as water-quality impaired (Kansas 

Department of Health and Environment, 2006). The streams 

were monitored over several years to develop concentration 

estimation models that were used to characterize variability in 

constituent concentrations, loads, and yields. 

This fact sheet characterizes transport and general sources 

of selected water-quality constituents in Johnson County, KanFigure 2. (A) Kill Creek at 95th Street, one of five continuous 

water-quality monitoring sites in Johnson County, Kansas. The 

water-quality monitor is placed beneath the water surface next 

to the streambank. (B) Monitor used to measure continuous, 

in-stream specific conductance, pH, water temperature, turbidity, 

and dissolved oxygen. The fluorescence sensor is pictured, but 

fluorescence was not monitored continuously during this study.

(A) Kill Creek at 95th Street

(B) Continuous water-quality monitor

Location of waterquality monitor

Specific conductance

Temperature

Fluorescence

Turbidity Dissolved oxygen

pH
River and Indian Creek watersheds, nonpoint storm runoff was 

the primary source of fecal coliform bacteria, and wastewatertreatment facilities were a substantial source of nutrients.

Suspended Sediment

Sediment transport in Johnson County streams and, therefore, management practices implemented to control sediment 

are especially important because of the implications for other 

contaminants such as nutrients and bacteria that are associated with sediment particles. Most of the time (except during 

substantial storm runoff), suspended-sediment concentrations 

in Indian Creek were smallest in part because of the large 

contribution of treated water discharged from the wastewatertreatment facility just upstream from the monitoring site (fig. 1). 

However, total annual sediment load and yield in Indian Creek 

were largest because of the disproportional loading that occurs 

during high streamflow compared to base flow. In June 2005, a 

single period of runoff on the Blue River lasted about 3 days but 

contributed more than 50 percent of the total annual sediment 

load. Suspended-sediment concentration was nearly always 

largest in Mill Creek, a watershed that is undergoing rapid 

development that likely is contributing to larger suspendedsediment concentrations. In 2005–06, 90 percent or more of the 

total suspended-sediment load occurred in less than 2 percent of 

the time at all five monitoring sites indicating that management 

practices designed to control sediment during small or medium 

streamflows will not have a substantial effect on annual loads. 

Indicator Bacteria

From March 2004 through December 2006, E. coli density 

at the Indian Creek site was nearly always largest with a median 

density more than double that of any other site. The annual E. 

coli bacteria load in Indian Creek also was at least double that 

of other sites. The primary contact criterion for E. coli

(262 colonies per 100 milliliters of water; Kansas Department 

of Health and Environment, 2005) was exceeded about 65 percent of the time at the Indian Creek site and 8 to 25 percent of 

the time at the other four monitoring sites. More than 97 percent 

of the fecal coliform bacteria load in the Blue River and Indian 

Creek originated from nonpoint sources in 2005 and 2006 

(fig. 4; calculated from data provided by Johnson County 

Wastewater, written commun., September 2007). The primary 

nonpoint sources of fecal-indicator bacteria may include leaking sewer lines, wastewater, wildlife, livestock, and pet waste. 

Indicator bacteria are used to evaluate the sanitary quality of 

water and its use as a public-water supply and for recreational 

activities such as swimming, wading, boating, and fishing. The 

presence of indicator bacteria indicates the possible presence of 

pathogens that may cause illness.

Nutrients

Wastewater-treatment facilities were a primary source of 

nutrients in the Blue River and Indian Creek. Wastewater-treatment facility nutrient loads were calculated from data provided 

by Johnson County Wastewater (written commun., September 

2007). On the Blue River about 40 percent of the total nitroFigure 3. Estimated annual yields for suspended sediment, chloride, 

and Escherichia coli bacteria at five monitoring sites in Johnson 

County, Kansas, 2005−06.

Figure 4. Total annual estimated fecal coliform bacteria loads 

and loads originating from wastewater-treatment-facility (WWTF) 

discharges to the Blue River and Indian Creek, Johnson County, 

Kansas, 2005−06. (Loads from waste-water-treatment facility 

discharges calculated from data provided by Johnson County 

Wastewater, written commun., September 2007).

0

100

200

300

400

500

600

700

800

Suspended-sediment yield, in

tons per square mile per year

0

20

40

60

80

100

120

140

160

180

Chloride yield, in tons per

square mile per year

0

50,000

100,000

150,000

200,000

250,000

Escherichia coli bacteria yield,

in billion colonies per square

mile per year 

Blue River

at Kenneth

Road

Cedar Creek

near DeSoto

Indian Creek

at State Line

Road

Kill Creek

at 95th

Street

Mill Creek

at Johnson

Drive

2005

2006

2005

2006

2005

2006

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

2005 2006 2005 2006

Blue River Indian Creek

Fecal coliform bacteria load,

in billions of colonies

WWTF discharge 

 load

Total downstream 

 load

12,000

6,500,000

2,780

3,410,000

130,000

20,300,000

478,000

15,100,000
gen load in 2005 and 70 percent of the total nitrogen load in 

2006 originated from wastewater-treatment discharge (fig. 5). 

One-fourth (in 2005) to one-half (in 2006) of the downstream 

total phosphorus load in the Blue River originated from WWTF 

discharges. Total nitrogen discharged from the two Indian Creek 

wastewater-treatment facilities accounted for at least two-thirds 

of the estimated total nitrogen load at the downstream Indian 

Creek monitoring site in 2005 and 2006 (fig. 5). Total phosphorus load from the Indian Creek wastewater-treatment facilities 

was 90 percent of the total phosphorus load at the downstream 

monitoring site in 2005 and 120 percent of the downstream total 

phosphorus load in 2006. 

Nutrient loads from wastewater-treatment facilities were 

nearly the same in 2005 and 2006. However, because less 

precipitation occurred in 2006, nutrient loads originating from 

runoff were smaller compared to 2005. In Indian Creek, the 

total phosphorus load from wastewater-treatment facilities 

exceeded the downstream total phosphorus load in 2006 primarily because of additional settling of nutrients along with sediment that occurred within the distance between the wastewatertreatment discharges and the monitoring site, with less flushing 

from stormwater runoff.

Chloride

During 2005–06, about 10 percent of the time, all during 

the winter (November–February), chloride concentrations in 

Indian and Mill Creeks were elevated as a result of runoff from 

road-salt application. Generally, the chloride concentration from 

March 2004 through 2006 at the Indian Creek monitoring site 

was about four times the median at the Kill Creek site, a nonurban site that was not affected by road salt. Two chloride 

runoff occurrences in January–February 2005 accounted for 

19 percent of the total chloride load in Indian Creek in 2005. 

The effect of accumulated road salt on ground water and base 

flow is unknown.

References

Kansas Department of Health and Environment, 2005, Kansas 

Administrative Regulations (KAR), Title 28, Article 16, Surface water quality standards 2005: Topeka, Kansas, Secretary 

of State, multiple pagination.

Kansas Department of Health and Environment, 2006, Kansas 

section (303(d) list of impaired surface waters: Information 

available on Web, accessed April 2007 at http://www.kdheks.

gov/tmdl/methodology.htm

Lee, C.J., Mau, D.P., and Rasmussen, T.J., 2005, Effects of 

point and nonpoint sources on water quality and relation to 

land use in Johnson County, northeastern Kansas, October 

2002 through June 2004: U.S. Geological Survey Scientific 

Investigations Report 2005–5144, 104 p.

Paul, M.J., and Meyer, J.L., 2001, Streams in the urban landscape: Annual Review of Ecological Systems, v. 32, 

p. 333–65.

Poulton, B.C., Rasmussen, T.J., and Lee, C.J., 2007, Assessment of biological conditions at selected stream sites in 

Johnson County, Kansas, and Cass and Jackson Counties, 

Missouri, 2003 and 2004: U.S. Geological Survey Scientific 

Investigations Report 2007–5108, 68 p.

Rasmussen, T.J., Lee, C.J., and Ziegler, A.C., 2008, Estimation 

of constituent concentrations, loads, and yields in streams of 

Johnson County, northeast Kansas, using continuous waterquality monitoring and regression models, October 2002 

through December 2006: U.S. Geological Survey Scientific 

Investigations Report 2008–5014, 105 p. 

University of Kansas, 2006, Kansas statistical abstract 2005 

(40th ed.): Lawrence, Kansas, Institute for Policy and Social 

Research, available on Web accessed June 18, 2007, at 

http://www.ipsr.ku.edu/ksdata/ksah/

U.S. Census Bureau, 2007, State and county quickfacts: Information available on Web accessed June 18, 2007, at 

http://quickfacts.census.gov/qfd/states/20000.html

Publishing support provided by:

Rolla Publishing Service Center

For more information concerning this publication, contact:

Director, USGS Kansas Water Science Center

4821 Quail Crest Place

Lawrence, KS 66049

(785) 842–9909

Visit the Kansas Water Science Center web site at:

http://ks.water.usgs.gov

Or visit the Johnson County Stormwater Management 

web site at:

http://stormwater.jocogov.org

0

100

200

300

400

500

600

2005 2006 2005 2006 2005 2006 2005 2006

Total nitrogen Total phosphorus Total nitrogen Total phosphorus

Nutrient load, in tons

Blue River Indian Creek

WWTF discharge load

Total downstream load

Figure 5. Annual estimated total nitrogen and total phosphorus 

loads and loads originating from wastewater-treatment-facility 

(WWTF) discharges to the Blue River and Indian Creek, Johnson 

County, northeast Kansas, 2005–06. (Loads from waste-watertreatment facility discharges calculated from data provided by 

Johnson County Wastewater, written commun., September 2007).