Peak-flow frequency analysis for U.S. Geological Survey streamgage, USGS 06897858 Sevenmile Creek near Thayer, IA, in the Thompson River Basin, based on data through water year 2025

This data release presents a peak-flow frequency analysis for U.S. Geological Survey (USGS) streamgage, USGS 06897858 Sevenmile Creek near Thayer, IA, in the Thompson River Basin, based on annual peak streamflow data from water year 1991 (WY91; a water year is the 12-month period, October 1 through September 30, in which it ends) through WY25. The annual peak-streamflow data were downloaded from the USGS National Water Information System database (U.S. Geological Survey, 2026), and used in the peak-flow frequency analyses (Eash and others, 2013). The USGS computer program PeakFQ, version 7.5.1 was used for this analysis. The description of this program can be found in Flynn and others (2006) and Veilleux and others (2014).

This data release includes four comma-separated values files (.csv):

"Table_DR-1_streamgage_info.csv" contains the streamgage information used in analysis;
"Table_DR-2_analytical_results.csv" contains the analytical methods used for peak-flow frequency analysis;
"Table_DR-3_peak_flow_frequency_results.csv" contains the peak-flow frequency results, including at-site, regional-regression, and weighted estimates; and
"Table_DR-4_variance.csv" contains the variance of prediction for all estimate types. 

It also includes a zip file, "PeakFQ_Data.zip", which contains two folders: (1) "PeakFQ_Input" and (2) "PeakFQ_Output." The "PeakFQ_Input" folder contains a text file of annual peak streamflow data, "06897858.txt" and a specification file for PeakFQ, "06897858.psf." The "PeakFQ_Output" folder includes tabular output files from PeakFQ, "06897858.PRT" and "06897858.EXP." Input and output data file formats are described in the PeakFQ user's manual (Flynn and others, 2006).

References Cited:

Eash, D.A., Barnes, K.K., and Veilleux, A.G., 2013, Methods for estimating annual exceedance-probability discharges for streams in Iowa, based on data through water year 2010: U.S. Geological Survey Scientific Investigations Report 2013-5086, 63 p. with appendix., http://pubs.usgs.gov/sir/2013/5086/.

Flynn, K.M., Kirby, W.H., and Hummel, P.R., 2006, User’s Manual for Program PeakFQ Annual Flood-Frequency Analysis Using Bulletin 17B Guidelines: U.S. Geological Survey, Techniques and Methods Book 4, Chapter B4; 42 pgs., accessed on July 1, 2022, at https://pubs.usgs.gov/tm/2006/tm4b4/tm4b4.pdf.

U.S. Geological Survey, 2026, USGS Water Data for the Nation: U.S. Geological Survey National Water Information System database, accessed July 6, 2026, at https://doi.org/10.5066/F7P55KJN.

Veilleux, A.G., Cohn, T.A., Flynn, K.M., Mason, R.R., Jr., and Hummel, P.R., 2014, Estimating magnitude and frequency of floods using the PeakFQ 7.0 program: U.S. Geological Survey Fact Sheet 2013–3108, 2 p., https://doi.org/10.3133/fs20133108.