Results from stream quality assessments are summarized in the general categories of biological quality, suspended sediment, nutrients, bacteria, and organic compounds.
Biological assessments, or surveys of organisms living in aquatic environments, are crucial components of water-quality programs because they provide an indication of how well water bodies support aquatic life. Biological data that have been collected from Johnson County stream sites includes benthic macroinvertebrates, periphyton (algae), and riparian habitat information. The information is being used to better understand factors that affect stream health and to make more informed decisions regarding stream protection.
As impervious surface area (a general indication of urbanization) increased, biological quality generally decreased.
During 2003, 2004, and 2007 when biological samples were collected, one site in 2007 met State criteria for full support of aquatic life (Kansas Department of Health and Environment, 2006).
Important management practices for preserving streams include protecting stream corridors and reducing the effects of impervious surfaces associated with urbanization.
Suspended sediment in Johnson County streams
Sediment in streams can reduce light penetration, smother streambed habitat, and provide attachment sites for accumulation and transport of contaminants such as nutrients and bacteria. Suspended sediment was monitored in the five largest watersheds in Johnson County (Blue River, Indian Creek, Mill Creek, Cedar Creek, and Kill Creek). This information is being used to improve understanding of sediment transport and make more informed decisions regarding stream protection.
- Of the total suspended-sediment load transported in 2005-06, 90 percent or more occurred during less than 2 percent of the time (the equivalent of about 7 days per year), generally during large streamflows, at all five monitoring sites. Therefore, management practices designed to control sediment during large streamflows will substantially reduce annual loads.
- Sediment yields in the urban basins (Indian and Mill Creeks) were 50 percent larger than in rural basins (Cedar and Kill Creeks, Blue River) in 2005. See http://ks.water.usgs.gov/pages/mill-creek-sediment for additional information on effects of urbanization on sediment transport.
- In the Mill Creek watershed, stream sites downstream from construction activities had larger suspended sediment concentrations for longer periods of time, and increased deposition of fine sediment. See http://ks.water.usgs.gov/pages/mill-creek-sediment for additional information on effects of construction on sediment transport.
- Sediment transport in Johnson County streams and, therefore, management practices implemented to control sediment, are especially important because other contaminants such as nutrients and bacteria frequently are associated with sediment particles.
Nutrients and dissolved oxygen in Johnson County streams
Nutrients, including various forms of nitrogen and phosphorus, are essential for proper plant and animal growth but in excess can lead to eutrophication, algal blooms, fish kills, taste and odor problems, and other disruptions in aquatic ecosystems. Typical nutrient sources include fertilizers, and human and livestock wastewater discharges. Dissolved oxygen (DO) is an important factor for survival of aquatic organisms. The Kansas aquatic-life-support criterion requires that DO concentrations are not less than 5 milligrams per liter (Kansas Department of Health and Environment, 2006). This information is being used to improve understanding of nutrient sources and transport, and to make more informed decisions regarding stream protection.
- 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). In 2006, total annual rainfall was about 65 percent of the total rainfall that occurred in 2005 or 2007 resulting in less nonpoint-source nutrient load.
- From March 2004 through December 2007, dissolved oxygen was less than the minimum state criterion of 5 mg/L less than 5 percent of the time at the 5 continuous monitoring sites except Blue River (8 percent) and Indian Creek (15 percent) Low dissolved oxygen concentrations primarily occurred during the summer.
Indicator bacteria in Johnson County streams
Fecal indicator bacteria such as E. coli and fecal coliform are used as indicators of the sanitary quality of surface water
for public water supply and recreational activities. These bacteria are in human and animal waste and could be originating from
leaking septic systems or other infrastructure, untreated wastewater discharges, and pet and wildlife waste.
Kansas water-quality criteria require streams to be classified and regulated according to designated uses
(Kansas Department of Health and Environment, 2006). Information on bacteria is being used to improve understanding of sources
and transport, and to make more informed decisions regarding practices used to control bacteria in Johnson County streams.
Escherichia coli (E. coli) bacteria density at the Indian Creek site, located in the most urban basin, was nearly always largest with a median density more than double that of any other site. E. coli is used as an indicator of pathogens in streams that may cause illness in humans who come into contact with the water.
- During base flow, the largest bacteria densities occurred upstream from WWTFs indicating that wastewater discharges generally do not contribute substantially to bacteria densities in streams.
- During 2005-07, less than 3 percent of the total annual fecal coliform bacteria load in Indian Creek and the Blue River originated from WWTFs.
- Water-quality conditions in streams often change rapidly during storm runoff. For example, E. coli bacteria density in Kill Creek during May 2007 increased from about 180 colonies per 100 milliliters of water (col/100mL) to about 100,000 col/100mL during a 12-hour period.
- Contact with stream water during storm runoff is likely to result in exposure to high levels of bacteria. Management practices targeting runoff during large storms should be most effective in controlling excessive bacteria in urban areas.
Organic compounds in Johnson County streams
Organic compounds include pesticides, petroleum products, and many household chemicals. They originate from commercial, industrial, agricultural, and residential sources. Many organic compounds are known to be toxic to aquatic life. Additional study is needed to better understand the long-term effects of these compounds in very small concentrations. Information on organic compounds is being used to improve understanding of chemicals that affect stream quality, and to make more informed decisions regarding stream protection.
- Atrazine (an herbicide commonly used on corn crops) was detected in nearly all water samples, including base flow samples, and had the largest concentrations of all pesticides sampled. Atrazine concentrations, however, did not exceed the state chronic aquatic-life criterion of 3.0 micrograms per liter as an annual average.
- During baseflow, water samples from urban stream sites had the largest number of pesticide compounds detected, and water samples from rural sites had the largest total concentration of pesticides.
- The largest total concentrations of organic wastewater compounds occurred in base-flow samples from sites at or immediately downstream from WWTFs. The most common compounds were AHTN (acetyl-hexamethyl-tetrahydro-napthalene, a musk fragrance), caffeine, DEET (mosquito repellant), a detergent surfactant (nonylphenol-diethoxylate), and a flame retardant and plasticizer (tris(2-butoxyethyl) phosphate), which together comprised more than one-half of the total organic wastewater compound concentrations in 80 percent of the base flow samples.
- In streambed sediment samples, the largest organic compound concentrations included chlordane (an insecticide banned in 1988), dichloro-diphenyl-trichloroethane (DDT, a pesticide banned in 1972), and polyaromatic hydrocarbons (PAHs, likely carcinogens that originate from combustion of fossil fuels and are used as an ingredient in asphalt), and were present in urban basins but were not closely linked to WWTF discharges.
- Many organic compounds have been shown to persist following wastewater treatment processes in small concentrations and discharge into streams. Some wastewater treatment processes are more effective at removing organic compounds than others. For example, in Johnson County activated sludge treatment was found to be more effective at removing some organic compounds than trickling filter treatment.
Additional factors affecting the quality of Johnson County streams
- Water contaminants including sediment, total nitrogen, total phosphorus, bacteria, and pesticides (particularly during spring) at urban and rural sites originated primarily from nonpoint sources during storm runoff. As a consequence, climate (precipitation and resulting runoff) had a substantial effect on water quality, and larger amounts of rainfall resulted in larger amounts of contaminants. In addition, the probability that water-quality criteria are exceeded is substantially larger during storm runoff.
- About 10 percent of the time chloride concentrations in Indian and Mill Creeks were elevated as a result of runoff from road salt application; however, the acute aquatic life criterion of 860 milligrams per liter (mg/L) was exceeded less than 1 percent of the time.
Ongoing studies in Johnson County
Stream monitoring in Johnson County has continued with the following projects:
- In 2010, biological and chemical data were collected at 20 streams sites for evaluation of changing stream quality. Results will be published late in 2011.
- Streamflow data are being collected at 5 stream sites and continuous water quality data are being collected at 2 sites,
Indian Creek at State Line and
Blue River at Kenneth Road.
- A cooperative study with Johnson County Wastewater evaluating the effects of wastewater discharge on the upper Blue River will be published early in 2011.
- Water-quality monitors were installed on Big Bull and Little Bull Creeks in the fall of 2010 to monitor sediment in Hillsdale Lake as part of a reservoir sustainability study with the Kansas Water Office.
- The USGS Missouri Water Science Center has conducted several studies in the Blue River watershed. Reports can be accessed at http://mo.water.usgs.gov/.
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, various 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
Paul, M.J., and Meyer, J.L., 2001, Streams in the urban landscape: Annual Review of Ecological Systems, v. 32, p. 333-365.
Current river stage and water-quality conditions:
Blue River at Kenneth Road
Indian Creek at State Line Road
Cedar Creek near DeSoto
Mill Creek at Johnson Drive
Kill Creek at 95th Street
Blue River at Blue Ridge Extension, Missouri
Kansas River at DeSoto
Indian Creek at Overland Park
Big Bull Creek nr Edgerton
Little Bull Creek nr Spring Hill
Mill Creek Sediment Source Project
Lake Olathe Watershed Study
Johnson County Stormwater Management Program
Overland Park ALERT Flood Warning System
For additional information, please write or call:
U.S. Geological Survey
4821 Quail Crest Place
Lawrence, KS 66049-3839
Telephone: (785) 832-3576
Fax: (785) 832-3500