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U.S. Geological Survey scientists and partners will inject a harmless, bright red fluorescent dye into the Kansas River at numerous locations beginning the evening of April 5, river flows permitting. 

The study is being done by USGS in cooperation with the City of Lawrence, City of Manhattan, City of Olathe, City of Topeka, Kansas Department of Health and Environment, Kansas Water Office, the Nature Conservancy and WaterOne to improve understanding of streamflow velocities and travel times in the Kansas River.  


The Kansas River provides drinking water for multiple cities in northeastern Kansas and is used for recreational activities. This dye-tracing study will provide a better understanding of how quickly water flows from one location to another. Water-resource managers use this information to effectively respond to potential critical events such as harmful algal blooms or contaminant spills that may make the water unsafe for the public to use. Several dye-tracing experiments have been conducted along the Kansas River as part of this study starting in September of 2020.  


“Recent events with spills above intakes in rivers have pointed out the need for travel-time data to monitor and respond appropriately,” said Tom Stiles, Bureau of Water Director at the Kansas Department of Health and Environment. “With so many people dependent upon surface water supplies in Kansas, understanding how those rivers move is critical to proper water management.”  


The red-hued dye will be measured using instruments in the stream and compared with laboratory analyses. The study will consist of multiple experimental runs to optimize time-of-travel data collection by injecting non-toxic rhodamine water-tracing dye into the Kansas River during low, medium and high flow conditions at Manhattan, Topeka and Eudora.  


The primary purpose of performing a dye-tracer study on the Kansas River is to calibrate a time-of-travel model used for estimating streamflow velocities and travel times, which can be used by the public as well as drinking-water suppliers to protect water resources and public-water supplies.