This data release presents peak-flow frequency analyses by the U.S. Geological Survey that were based on methods described by Eash and others (2013) for streamgages 05485605 Fourmile Creek near Ankeny, Iowa, and 05485640 Fourmile Creek at Des Moines, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for these streamgages were retrieved from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (fourmile_ffa_2018_WATSTORE.txt), PeakFQ specifications (fourmile_ffa_2018.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (fourmile_ffa_2018.xlsx). 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/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 20, 2020, 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://dx.doi.org/10.3133/fs20133108.

This data release presents peak-flow frequency analyses by the U.S. Geological Survey based on methods described by Eash and others (2013) for streamgages 06600100, Floyd River at Alton, Iowa; 06600300, West Branch Floyd River near Struble, Iowa; 06600500, Floyd River near James, Iowa; 06605000, Ocheyedan River near Spencer, Iowa; 06605850, Little Sioux River at Linn Grove, Iowa; 06607200, Maple River at Mapleton, Iowa; and 06607500, Little Sioux River near Turin, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analyses for these streamgages were retrieved from the U.S. Geological Survey National Water Information System webpage (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (floyd_ffa_2019_WATSTORE.txt), PeakFQ specifications (floyd_ffa_2019.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (floyd_ffa_2019.xlsx). 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/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 25, 2020, 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://dx.doi.org/10.3133/fs20133108.

This data release presents peak-flow frequency analyses by the U.S. Geological Survey based on methods described by Eash and others (2013) for streamgages 06600100, Floyd River at Alton, Iowa; 06600300, West Branch Floyd River near Struble, Iowa; 06600500, Floyd River near James, Iowa; 06605000, Ocheyedan River near Spencer, Iowa; 06605850, Little Sioux River at Linn Grove, Iowa; 06607200, Maple River at Mapleton, Iowa; and 06607500, Little Sioux River near Turin, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analyses for these streamgages were retrieved from the U.S. Geological Survey National Water Information System webpage (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (floyd_ffa_2019_WATSTORE.txt), PeakFQ specifications (floyd_ffa_2019.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (floyd_ffa_2019.xlsx). 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/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 25, 2020, 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://dx.doi.org/10.3133/fs20133108.

This data release presents a peak-flow frequency analysis (Eash and others, 2013) for U.S. Geological Survey streamgage 05465500 Iowa River at Wapello, Iowa. These methods are used to provide estimates of peak-flow quantiles corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for this streamgage was retrieved from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2022) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (05465500_ffa_2022_WATSTORE.txt), PeakFQ specifications (05465500_ffa_2022.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (Wapello_ffa_2022.xlsx)

This data release presents a peak-flow frequency analysis (Eash and others, 2013) for U.S. Geological Survey streamgage 05465500 Iowa River at Wapello, Iowa. These methods are used to provide estimates of peak-flow quantiles corresponding to the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for this streamgage was retrieved from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2022) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (05465500_ffa_2022_WATSTORE.txt), PeakFQ specifications (05465500_ffa_2022.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (Wapello_ffa_2022.xlsx)

This data release presents a peak-flow frequency analysis by the U.S. Geological Survey that was based on on methods described by Eash and others (2013) for streamgages 05458300 Cedar River at Waverly, Iowa; 05458500 Cedar River at Janesville, Iowa; and 06606600 Little Sioux River at Correctionville, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for these streamgages were retrieved from the U.S. Geological Survey National Water Information System webpage (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (Iowa_ffa_2019_WATSTORE.txt), PeakFQ specifications (Iowa_ffa_2019.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (Iowa_ffa_2019.xlsx). 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/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 25, 2020, accessed June 25, 2020, 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://dx.doi.org/10.3133/fs20133108.

This data release presents a peak-flow frequency analysis by the U.S. Geological Survey that was based on on methods described by Eash and others (2013) for streamgages 05458300 Cedar River at Waverly, Iowa; 05458500 Cedar River at Janesville, Iowa; and 06606600 Little Sioux River at Correctionville, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for these streamgages were retrieved from the U.S. Geological Survey National Water Information System webpage (U.S. Geological Survey, 2020) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (Iowa_ffa_2019_WATSTORE.txt), PeakFQ specifications (Iowa_ffa_2019.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (Iowa_ffa_2019.xlsx). 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/. U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed June 25, 2020, accessed June 25, 2020, 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://dx.doi.org/10.3133/fs20133108.

This data release presents a peak-flow frequency analysis for U.S. Geological Survey streamgage 05481510 Bluff Creek at Pilot Mound, Iowa. The annual peak-flow record at this streamgage consists of both a discrete crest-stage period and a continuous partial-record period. The streamgage, which is in the Des Moines River Basin, is located on 130th Street in Pilot Mound, Iowa. Drainage area at the streamgage is 23.5 square miles. Annual peak-flow data are available for the period 1966-2021. The peak of record, 1,290 cubic feet per second, occurred on June 16, 1990. The annual peak-flow data used in the frequency analysis were downloaded from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2022) and the procedures for the flood frequency analyses are described in Eash and others (2013). The program PeakFQ version 7.4 was used for these analyses, a description of this program can be found in Flynn and others (2006) and Veilleux and others (2014). 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, 2022, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed September 12, 2022, https://doi.org/10.5066/F7P55KJN. [Site information directly accessible at https://waterdata.usgs.gov/nwis/inventory/?site_no=05481510&agency_cd=USGS&]. 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.

This data release presents a peak-flow frequency analysis for U.S. Geological Survey streamgage 05481510 Bluff Creek at Pilot Mound, Iowa. The annual peak-flow record at this streamgage consists of both a discrete crest-stage period and a continuous partial-record period. The streamgage, which is in the Des Moines River Basin, is located on 130th Street in Pilot Mound, Iowa. Drainage area at the streamgage is 23.5 square miles. Annual peak-flow data are available for the period 1966-2021. The peak of record, 1,290 cubic feet per second, occurred on June 16, 1990. The annual peak-flow data used in the frequency analysis were downloaded from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2022) and the procedures for the flood frequency analyses are described in Eash and others (2013). The program PeakFQ version 7.4 was used for these analyses, a description of this program can be found in Flynn and others (2006) and Veilleux and others (2014). 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, 2022, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed September 12, 2022, https://doi.org/10.5066/F7P55KJN. [Site information directly accessible at https://waterdata.usgs.gov/nwis/inventory/?site_no=05481510&agency_cd=USGS&]. 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.

This data release presents a peak-flow frequency analysis (Eash and others, 2013) for U.S. Geological Survey streamgage 06810000 Nishnabotna River above Hamburg, Iowa. These methods are used to provide estimates of peak-flow quantiles for 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs). Annual peak-flow data used in the peak-flow frequency analysis for this streamgage was retrieved from the U.S. Geological Survey National Water Information System database (U.S. Geological Survey, 2021) and used with USGS flood-frequency analysis software PeakFQ (Veilleux and others, 2014). This data release contains annual peak-flow data (nishnabotna_2020_WATSTORE.txt), PeakFQ specifications (nishnabotna_ffa_2020.psf), and a series of tables describing the methods and results of the peak-flow frequency analysis (nishnabotna_ffa_2020.xlsx). 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/. U.S. Geological Survey, 2021, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed March 10, 2021, 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://dx.doi.org/10.3133/fs20133108.