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Graphs showing percent low and moderate oxygen tolerant diatoms, oligosaprobic and beta-mesosaprobic diatoms, eutrophic diatoms, nitrogenheterotrophic diatoms, and Bahls Index values at each biological sampling site on the upper Blue River during April

Multiply By To obtain acre-foot (acre-ft) 1,233 cubic meter (m 3) acre-foot per square mile per year [(acre-ft/mi 2)/yr] Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µg/L). Densities of fecal-indicator bacteria are given in colonies per 100 milliliters of water (col/100 mL).

The population of Johnson County, Kansas increased by about 24 percent between 2000 and 2012, making it one of the most rapidly developing areas of Kansas. The U.S. Geological Survey, in cooperation with the Johnson County Stormwater Management Program, began a comprehensive study of Johnson County streams in 2002 to evaluate and monitor changes in stream quality. The purpose of this report is to describe water-quality variability and constituent transport for streams representing the five largest watersheds in Johnson County, Kansas during 2003 through 2011. The watersheds ranged in urban development from 98.3 percent urban (Indian Creek) to 16.7 percent urban (Kill Creek). Water-quality conditions are quantified among the watersheds of similar size (50.1 square miles to 65.7 square miles) using continuous, in-stream measurements, and using regression models developed from continuous and discrete data. These data are used to quantify variability in concentrations and loads during changing streamflow and seasonal conditions, describe differences among sites, and assess water quality relative to water-quality standards and stream management goals. Water quality varied relative to streamflow conditions, urbanization in the upstream watershed, and contributions from wastewater treatment facilities and storm runoff. Generally, as percent impervious surface (a measure of urbanization) increased, streamflow yield increased. Water temperature of Indian Creek, the most urban site which is also downstream from wastewater facility discharges, was higher than the other sites about 50 percent of the time, particularly during winter months. Dissolved oxygen concentrations were less than the Kansas Department of Health and Environment minimum criterion of 5 milligrams per liter about 15 percent of the time at the Indian Creek site. Dissolved oxygen concentrations were less than the criterion about 10 percent of the time at the rural Blue River and Kill Creek sites, and less than 5 percent of the time at the other sites. Low dissolved oxygen at all sites generally coincided with lowest streamflow and warmer water temperatures. Hourly dissolved oxygen concentrations less does the ability to monitor additional constituents of interest, with smaller measurement error, and at lower operational cost. Continuous water-quality data including model information and computed concentrations and loads during the study period are available at http://nrtwq.usgs.gov/ks/. national studies (Coles and others, 2012). The U.S. Geological Survey (USGS), in cooperation with the Johnson County Stormwater Management Program, began a comprehensive study of Johnson County streams in 2002. Previous reports published as part of that study have described water quality of streams throughout the County during baseflow conditions (Lee and others, 2005), biological conditions in streams (Poulton and others, 2007), and relations between

For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation:Rasmussen, T.J., Ziegler, A.C., and Rasmussen, P.P., 2005, Estimation of constituent concentrations, densities, loads, and yields in lower Kansas River, northeast Kansas, using regression models and continuous water-quality monitoring, DefinitionsAltitude, as used in this report, refers to distance above the vertical datum. Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µg/L).Diurnal, as used in this report, means having a daily cycle.Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C).Water year is the 12-month period beginning October 1 and ending September 30. The water year is designated by the year in which it ends. For example, the year ending September 30, 1999, is called the "1999 water year." Calculation of Loads AbstractThe lower Kansas River is an important source of drinking water for hundreds of thousands of people in northeast Kansas. Constituents of concern identified by the Kansas Department of Health and Environment (KDHE) for streams in the lower Kansas River Basin include sulfate, chloride, nutrients, atrazine, bacteria, and sediment. Real-time continuous water-quality monitors were operated at three locations along the lower Kansas River from July 1999 through September 2004 to provide in-stream measurements of specific conductance, pH, water temperature, turbidity, and dissolved oxygen and to estimate concentrations for constituents of concern. Estimates of concentration and densities were combined with streamflow to calculate constituent loads and yields from January 2000 through December 2003. The Wamego monitoring site is located 44 river miles upstream from the Topeka monitoring site, which is 65 river miles upstream from the DeSoto monitoring site, which is 18 river miles upstream from where the Kansas River flows into the Missouri River. Land use in the Kansas River Basin is dominated by grassland and cropland, and streamflow is affected substantially by reservoirs.Water quality at the three monitoring sites varied with hydrologic conditions, season, and proximity to constituent sources. Nutrient and sediment concentrations and bacteria densities were substantially larger during periods of increased streamflow, indicating important contributions from nonpoint sources in the drainage basin.During the study period, pH remained well above the KDHE lower criterion of 6.5 standard units at all sites in all years, but exceeded the upper criterion of 8.5 standard units annually between 2 percent of the time (Wamego...