Linear regression model documentation for computing water-quality constituent concentrations or densities using continuous real-time water-quality data for the Kansas River above Topeka Weir at Topeka, Kansas, November 2018 through June 2021

First posted January 30, 2023 For additional information, contact: Director, Kansas Water Science CenterU.S. Geological Survey1217 Biltmore DriveLawrence, KS 66049Contact Pubs Warehouse The River and its associated alluvial aquifer provide drinking water to more than 950,000 people in northeastern Kansas. suppliers that rely on the as a water-supply source use physical chemical processes treat remove contaminants before public distribution. An early-notification system of changing water-quality conditions allows proactively make decisions affect treatment. U.S. Survey (USGS), cooperation with Office (funded part through Plan), Department Health Environment, Nature Conservancy, City Lawrence, Manhattan, Olathe, Topeka, WaterOne, Evergy, began collecting data at above Topeka Weir (USGS site 06888990, hereafter referred “Topeka site”), during November 2018 develop linear regression models relate continuous situ sensor measurements discretely sampled constituent concentrations or densities. addition expanded an existing monitoring network, which included upstream Wamego, Kans., downstream De Soto, sites. Linear analysis was used compute real-time densities for total dissolved solids, major ions, hardness calcium carbonate, nutrients (nitrogen phosphorus species), chlorophyll a, suspended sediment, Escherichia coli using collected June 2021. Water-quality computed from documented this report are available USGS National Real-Time Water-Quality website (https://nrtwq.usgs.gov), useful cultural recreational purposes, can be guide water-treatment processes, compare Federal State criteria, characterize changes time.