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FACTSHEET - Monitoring the Water Quality of Lake Olathe, Johnson County, KansasBackground of Lake Olathe Watershed ProjectLake Olathe, Olathe, Kansas, located in northeast Kansas, is an important recreational resource for the city of Olathe, providing boating and fishing throughout the year. The lake also serves as a drinking-water supply, contributing about 10 percent of the city's water needs, with the remaining supply coming from wells in the Kansas River alluvium near DeSoto, Kansas. The reservoir was built in 1956 in response to the increased sediment deposition occurring in an upstream lake, Cedar Lake. Following completion of Lake Olathe, Cedar Lake was removed from service as a water supply, but it still remains as a recreational lake.  Location of Lake Olathe and Cedar Lake, Kansas Taste-and-odor occurrences in the drinking water obtained from Lake Olathe have happened periodically during the past 20 years. These occurrences are probably a result of algal blooms that occur during the fall of the year but also may be derived from algal conditions in the shallow water of Cedar Lake that is water discharged during storm runoff to Lake Olathe via Cedar Creek. In addition, increased residential and commercial development in the watershed have created sources of potential contaminants, especially nutrients, that can migrate by surface-water or ground-water flow to either Cedar Lake or Lake Olathe. Nutrients serve as a food source to algae and bacteria, but an increase in nutrient concentrations in water can shift the balance from stable algae and bacteria populations to an enriched environment that leads to algal blooms and a reduction in the dissolved oxygen concentration. This condition, known as eutrophication, causes many problems in lakes and reservoirs, from taste-and-odor occurrences in the water supply, to the reduction in fish populations, to the elimination of the water body as a resource to the community. ApproachIn response to these concerns, the U.S. Geological Survey, in cooperation with the city of Olathe, Kansas, and with support from the Kansas Department of Health and Environment and the U.S. Environmental Protection Agency, began a study in June 2000 to evaluate the water quality, sediment, and chemical transport through the Lake Olathe watershed and at Lake Olathe. The study includes analysis of water samples collected from an inflow site on Cedar Creek, upstream from Lake Olathe, and at Lake Olathe. The water samples will be analyzed for trace elements and selected organic compounds, as well as for indicators of biologic activity that contribute to algal blooms such as chlorophyll a, b, c, and phytoplankton species. In conjunction with a full mapping of the lake bottom at both lakes, known as bathymetric surveys, historic sediment and nutrient transport are evaluated by analyzing lake bottom sediment from both Lake Olathe and Cedar Lake. A sediment core from each reservoir will be divided into 10 sub-intervals, and each interval will be analyzed for selected chemical constituents. Results from the analysis will provide information on trends in deposition of metals and organic compounds and historical chemical loads.
A monitoring station using an automated vertical profiling water-quality monitor that measure specific conductance, pH, water temperature, turbidity, dissolved oxygen, chlorophyll, and PAR (photosynthetically-active radiation) is installed at Lake Olathe. The water-quality monitor makes continuous measurements of water conditions and relays this information via satellite to the internet so that water-treatment managers can use the information to make adjustments to water-treatment operations at Lake Olathe.
BenefitsThis study provides a comprehensive assessment for the city of Olathe with which to help manage development and water quality in the Lake Olathe watershed and reservoir. Historical changes in nutrient and sediment loads can be evaluated from the results of the bathymetric surveys and can be used to evaluate the effects of changes in land and chemical use in the watershed. Additionally, results of chemical analyses indicate whether there is cause for concern for selected organic compounds in the sediment that may bioaccumulate in the biota and cause human health concerns through the consumption of fish. Results of the study can be used by the city of Olathe to alter their supply source or treatment strategies using measured data for taste-and-odor problems. The measured changes in water quality will allow the city to provide improved drinking-water. Results from this study benefit Federal interest by developing tools and approaches that can be applied throughout the Nation for small watershed water-supply reservoirs and the effects of urbanization on these water bodies. Eutrophication of lakes and taste-and-odor problems are national problems that can be addressed through information on the watershed in addition to the use of engineering approaches. Results of this study have broad application in eastern Kansas and the Midwest where there are a large number of small impoundments with similar concerns and problems. Real-Time Water Quality
For more information on real-time water-quality. Publications
Related LinksFor additional information, please write or call: For additional information, please write or call:
Patrick Rasmussen |
U.S. Department of the Interior |
U.S. Geological Survey
URL: /studies/qw/olathe/index.html
Page Contact Information: GS-W-KS_info@usgs.gov
Page Last Modified:Wednesday, 17-Sep-2008 12:26:21 CDT
Color Contour Plots of Various Water-Quality Parameters at Lake Olathe, Kansas