News Release

Ongoing Studies Identify Negative Effects of Urbanization on Stream Water Quality in Johnson County, Kansas

A summary of results from studies of the water quality of streams in Johnson County, Kansas has been released.  The water quality in Johnson County streams was evaluated from October 2002 through December 2007 in a cooperative study between the U.S. Geological Survey, and the Johnson County Stormwater Management Program.  Studies identified sources of water-quality contaminants throughout the county in relation to urban and rural land uses.   Stream quality was then evaluated on the basis of biological conditions.  Results from continuous monitoring provided additional information about water quality by documenting changing conditions - hourly, daily, weekly, seasonally, and in response to different storm events.  Ongoing monitoring of water quality and stream biologic health will provide information about trends with time and effectiveness of management plans to improve water quality.

Biological conditions in Johnson County streams generally reflected the amount of upstream urbanization.  As urban land use increased, biological quality of streams decreased.  Many rural stream sites in the southern and western part of the county contained a diversity of insects generally associated with healthy streams including mayflies, stoneflies, caddisflies, and dragonflies.  Most urban sites, such as sites along Indian Creek, had few of these insects and were dominated by pollution-tolerant species.

Sediment and bacteria in streams originated primarily from stormwater runoff.  Therefore, increasing rainfall resulted in larger concentrations of these constituents and an increased risk of exceeding water-quality criteria and management goals.  In Johnson County stream reaches during 2005 and 2007, about two-thirds of the Indian Creek total nitrogen load and one-third of the Blue River total nitrogen load originated from wastewater treatment facilities (WWTFs), primarily occurring in the form of nitrates.  Wastewater treatment facilities on Indian Creek and the Blue River were a substantial source of nutrients to streams.  The facilities are undergoing major upgrades to increase capacity and reduce nutrients in discharges to streams.

Information from these studies is being used by municipal and county officials to address water-quality concerns, particularly those related to expected increases in population and urban land use which generally lead to additional stress on streams.

“The studies have helped us to understand that everything we do in a watershed affects the water quality of our streams. Our goal is to use this information to educate our citizens and develop management practices that everyone can use to minimize the impacts of stormwater runoff and protect our streams,” said Lee Kellenberger, Johnson County Stormwater Management Program. 

Ongoing and new USGS studies funded by the Johnson County Stormwater Management Program and the USGS include biological and water-quality monitoring of streams throughout the County and sediment modeling in the Indian Creek watershed.  In addition, the USGS began a study in 2008, in cooperation with Johnson County Wastewater, to evaluate the effects of the wastewater treatment facility improvements on water quality and biological communities in the Blue River. 

More information about the Johnson County studies can be found at:

http://ks.water.usgs.gov/Kansas/studies/qw/joco/

The fact sheet summarizing the results of the studies is now available online at:

 http://pubs.usgs.gov/fs/2008/3090/