Hall, B.M. Rus, D.L. Thomas, S.A. 2018 Reston, VA U.S. Geological Survey data release https://doi.org/10.5066/P9RBDQI5 David L. Rus Brent M. Hall Steven A. Thomas 2018 publication n/a US Geological Survey https://doi.org/10.3133/sir20185121 As a part of the statewide Public Beach Monitoring Program–Bacteria and Microcystin, the Lower Elkhorn Natural Resources District collected weekly samples at Willow Creek Lake to monitor microcystin concentrations. The monitoring generally followed the procedures described by Graham and others (2008) for recreational areas. Sampling occurred weekly during May through September, 2006 to 2014, though data provided in this Data Release are limited to 2012 to 2014. Grab samples were collected from the water surface by wading at the south-shore swimming beach. In the laboratory, the samples underwent three freeze-thaw cycles to lyse the cells prior to analysis using the enzyme-linked immunosorbent assay technique to measure total microcystin (MC) concentration (Metcalf and Codd, 2003). Sampled concentrations of the cyanotoxin microsystin were used to represent the cyanobacteria population in Willow Creek Lake and to characterize the algal response in the lake. 19890711 20141031 ground condition Complete None planned -97.608329999997 -97.552499999999 42.186111 42.16444 USGS Thesaurus nutrient content (water) harmful algal blooms USGS Metadata Identifier USGS:5af4477ce4b0da30c1b44822 Geographic Names Information System (GNIS) Willow Creek Lake Willow Creek none none Nebraska Water Science Center U.S. Geological Survey mailing and physical

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Lincoln NE 68512 USA 402-328-4100 bhall@usgs.gov Data were collected through a cooperative study between the U.S. Geological Survey, the Lower Elkhorn Natural Resources District, the Nebraska Department of Environmental Quality, the University of Nebraska, the Nebraska Department of Natural Resources, the Nebraska Game and Parks Commission, and the Nebraska Environmental Trust. Nebraska Department of Environmental Quality 2015 Lincoln, Nebr. Nebraska Department of Environmental Quality http://deq.ne.gov/NDEQProg.nsf/ Graham, J.L. Loftin, K.A. Ziegler, A.C. Meyer, M.T. 2008 Scientific Investigations Report 2008-5038 Reston, VA U.S. Geological Survey https://pubs.usgs.gov/sir/2008/5038/ Metcalf, J.S. Codd, G.A. 2003 Washington DC Chemical Research in Toxicology https://doi.org/10.1021/tx0200562 No formal attribute accuracy tests were conducted No formal logical accuracy tests were conducted Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted Grab samples were collected from the water surface by wading at the south-shore swimming beach. In the laboratory, the samples underwent three freeze-thaw cycles to lyse the cells prior to analysis using the enzyme-linked immunosorbent assay (ELISA) technique to measure total microcystin concentration. 2014 Microcystin.csv Recreational season weekly microcystin concentrations sampled at the Willow Creek Lake beach, 2012-2014 Dave Rus Date The date of sample collection Producer defined 20120507 20140929 Alert Status The microcystin alert status (Samples above a 20 microgram per liter threshold put the lake into alert status, and two consecutive samples below that threshold are required to remove it from alert status) Producer defined No The lake was not on alert for microcystin levels Producer defined Yes The lake was on alert for microcystin levels Producer defined Microcystin (µg/L) Microcystin level in micrograms per liter Producer defined 0.04 38.5 micrograms per liter >35 Microcystin levels exceeded 35 milligrams per liter Producer defined ScienceBase U.S. Geological Survey - ScienceBase mailing and physical

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Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. 20200824 Nebraska Water Science Center U.S. Geological Survey Hydrologist mailing and physical

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Lincoln NE 68512 USA 402-328-4100 bhall@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998