Padraic S O'Shea
Padraic is a statistician at the Iowa City office of the Central Midwest Water Science Center. Since joining the USGS in February, 2014, he has been involved with a broad range of work. Presently, his research focuses on methods for estimating annual exceedance-probability discharges and selected low-flow frequency statistics.
Professional Experience
2014 - Present Statistician, USGS, Central Midwest Water Science Center, Iowa City, Iowa
Education and Certifications
2015 B.S. Statistics, University of Iowa
2010 B.A. Marketing, University of Iowa
Science and Products
Flood-Frequency Analysis in the Midwest: Addressing Potential Nonstationary Annual Peak-Flow Records
Period of Project: 2021 - Study Area: Midwest Cooperating Agency: Transportation Pooled Fund
Peak-Flow Frequency Analysis for 464 U.S. Geological Survey Streamgages in Illinois, Indiana, and Wisconsin, Based on Data Through Water Year 2017
The U.S. Geological Survey (USGS) Central Midwest Water Science Center (CMWSC) completed a report (Over and others, 2023) documenting methods for peak-flow frequency analysis in Illinois following Bulletin 17C guidelines. The 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) for selected USGS str
Data for Estimating Peak-Flow Quantiles for Selected Annual Exceedance Probabilities in Illinois
The U.S. Geological Survey Central Midwest Water Science Center completed a report (Over and others, 2023) documenting the methods, results, and applications of an updated flood-frequency study for the State of Illinois. This data release contains data related to the analysis completed to determine peak-flow quantiles (flood frequency estimates) at streamgages in Illinois for 50-, 20-, 10-, 4-, 2-
Peak-Flow Frequency Analysis for U.S. Geological Survey Streamgage 05481510 Bluff Creek at Pilot Mound, Iowa, in the Des Moines River Basin, Iowa, Based on Data Through Water Year 2021
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 s
Peak-flow frequency analysis for U.S. Geological Survey streamgage 05465500 Iowa River at Wapello, Iowa, based on data through water year 2021
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 fo
Peak-flow frequency analysis for seven selected U.S. Geological Survey streamgages in the Floyd and Little Sioux River Basins, Iowa, based on data through water year 2019
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 R
Peak-flow frequency analysis for U.S. Geological Survey streamgage 06810000 Nishnabotna River above Hamburg, Iowa, in the Nishnabotna River Basin, Iowa, based on data through water year 2020
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
Peak-flow frequency analysis for two selected streamgages in the Fourmile Creek Basin in central Iowa, based on data through water year 2018
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 proba
Peak-flow frequency analysis for three selected streamgages in the Cedar and Little Sioux River Basins, Iowa, based on data through water year 2019
This data release presents a peak-flow frequency analysis by the U.S. Geological Survey that was based 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
Multi-Agency Gage Height and Discharge Datasets for Selected Streamgages on the Missouri River from 10/01/1936 to 12/31/2018
This dataset includes data for 12 selected streamgages on the Missouri River from 10/01/1936 through 12/31/2018. The data include time series of gage height at the following U.S. Geological Survey (USGS) streamgages: 06601200 Missouri River at Decatur, Nebraska 06609100 Missouri River at Blair, Nebraska 06805600 Missouri River at Plattsmouth, Nebraska 06810070 Missouri River at Brownville, Nebrask
Introduction and methods of analysis for peak streamflow trends and their relation to changes in climate in Illinois, Iowa, Michigan, Minnesota, Missouri, Montana, North Dakota, South Dakota, and Wisconsin
Flood-frequency analysis, also called peak-flow frequency or flood-flow frequency analysis, is essential to water resources management applications including critical structure design and floodplain mapping. Federal guidelines for doing flood-frequency analyses are presented in a U.S. Geological Survey Techniques and Methods Report known as Bulletin 17C. A basic assumption within Bulletin 17C is t
Authors
Karen R. Ryberg, Thomas M. Over, Sara B. Levin, David C. Heimann, Nancy A. Barth, Mackenzie K. Marti, Padraic S. O'Shea, Christopher A. Sanocki, Tara J. Williams-Sether, Harper N. Wavra, T. Roy Sando, Steven K. Sando, Milan S. Liu
Estimating peak-flow quantiles for selected annual exceedance probabilities in Illinois
This report presents the methods, results, and applications of an updated flood-frequency study for the State of Illinois. This study, which uses data through September 2017, updates two previous studies that used data through 1999 and 2009, respectively. Flood-frequency estimates are used for a variety of land-use planning and infrastructure design purposes, including for the hydraulic design of
Authors
Thomas M. Over, Mackenzie K. Marti, Padraic S. O'Shea, Jennifer B. Sharpe
Floods of June 21–July 1, 2018, in the Floyd River and Little Sioux River Basins, northwestern Iowa
The Floyd River and Little Sioux River Basins in northwestern Iowa flooded on June 21–July 1, 2018, after sustained rainfall on June 14–27, 2018. Within the Floyd River Basin, rainfall totals from June 14 to 21 preceding flooding were 3.01 inches (in.) at Le Mars, 4.50 in. at Orange City, and 7.44 in. at Sheldon. Within the Little Sioux River Basin, rainfall amounts for the 2-week period from June
Authors
Padraic S. O'Shea, Jordan L. Wilson, Jared C. Vegrzyn, Kimberlee K. Barnes
Flood of June 30–July 1, 2018, in the Fourmile Creek Basin, near Ankeny, Iowa
Major flooding occurred June 30–July 1, 2018, in the Fourmile Creek Basin in central Iowa after thunderstorm activity over the region. The largest recorded 24-hour precipitation total at a National Oceanic and Atmospheric Administration weather station was 8.72 inches in Ankeny, Iowa, and 7.54 inches in Des Moines, Iowa. A maximum peak-of-record discharge of 10,000 cubic feet per second was record
Authors
Padraic S. O'Shea, Jared C. Vegrzyn, Kimberlee K. Barnes
Stream-channel and watershed delineations and basin-characteristic measurements using lidar elevation data for small drainage basins within the Des Moines Lobe landform region in Iowa
Basin-characteristic measurements related to stream length, stream slope, stream density, and stream order have been identified as significant variables for estimation of flood, flow-duration, and low-flow discharges in Iowa. The placement of channel initiation points, however, has always been a matter of individual interpretation, leading to differences in stream definitions between analysts.This
Authors
David A. Eash, Kimberlee K. Barnes, Padraic S. O'Shea, Brian K. Gelder
Flood of August 24–25, 2016, Upper Iowa River and Turkey River, northeastern Iowa
Major flooding occurred August 24–25, 2016, in the Upper Iowa River Basin and Turkey River Basin in northeastern Iowa following severe thunderstorm activity over the region. About 8 inches of rain were recorded for the 24-hour period ending at 4 p.m., August 24, at Decorah, Iowa, and about 6 inches of rain were recorded for the 24-hour period ending at 7 a.m., August 24, at Cresco, Iowa, about 14
Authors
S. Mike Linhart, Padraic S. O'Shea
Methods for estimating selected spring and fall low-flow frequency statistics for ungaged stream sites in Iowa, based on data through June 2014
A statewide study was led to develop regression equations for estimating three selected spring and three selected fall low-flow frequency statistics for ungaged stream sites in Iowa. The estimation equations developed for the six low-flow frequency statistics include spring (April through June) 1-, 7-, and 30-day mean low flows for a recurrence interval of 10 years and fall (October through Decemb
Authors
David A. Eash, Kimberlee K. Barnes, Padraic S. O'Shea
Estimation of peak discharge quantiles for selected annual exceedance probabilities in northeastern Illinois
This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set of
Authors
Thomas M. Over, Riki J. Saito, Andrea G. Veilleux, Padraic S. O'Shea, Jennifer B. Sharpe, David T. Soong, Audrey L. Ishii
Statistical summaries of selected Iowa streamflow data through September 2013
Statistical summaries of streamflow data collected at 184 streamgages in Iowa are presented in this report. All streamgages included for analysis have at least 10 years of continuous record collected before or through September 2013. This report is an update to two previously published reports that presented statistical summaries of selected Iowa streamflow data through September 1988 and Septembe
Authors
David A. Eash, Padraic S. O'Shea, Jared R. Weber, Kevin T. Nguyen, Nicholas L. Montgomery, Adrian J. Simonson
Science and Products
- Science
Flood-Frequency Analysis in the Midwest: Addressing Potential Nonstationary Annual Peak-Flow Records
Period of Project: 2021 - Study Area: Midwest Cooperating Agency: Transportation Pooled Fund - Data
Peak-Flow Frequency Analysis for 464 U.S. Geological Survey Streamgages in Illinois, Indiana, and Wisconsin, Based on Data Through Water Year 2017
The U.S. Geological Survey (USGS) Central Midwest Water Science Center (CMWSC) completed a report (Over and others, 2023) documenting methods for peak-flow frequency analysis in Illinois following Bulletin 17C guidelines. The 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) for selected USGS strData for Estimating Peak-Flow Quantiles for Selected Annual Exceedance Probabilities in Illinois
The U.S. Geological Survey Central Midwest Water Science Center completed a report (Over and others, 2023) documenting the methods, results, and applications of an updated flood-frequency study for the State of Illinois. This data release contains data related to the analysis completed to determine peak-flow quantiles (flood frequency estimates) at streamgages in Illinois for 50-, 20-, 10-, 4-, 2-Peak-Flow Frequency Analysis for U.S. Geological Survey Streamgage 05481510 Bluff Creek at Pilot Mound, Iowa, in the Des Moines River Basin, Iowa, Based on Data Through Water Year 2021
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 sPeak-flow frequency analysis for U.S. Geological Survey streamgage 05465500 Iowa River at Wapello, Iowa, based on data through water year 2021
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 foPeak-flow frequency analysis for seven selected U.S. Geological Survey streamgages in the Floyd and Little Sioux River Basins, Iowa, based on data through water year 2019
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 RPeak-flow frequency analysis for U.S. Geological Survey streamgage 06810000 Nishnabotna River above Hamburg, Iowa, in the Nishnabotna River Basin, Iowa, based on data through water year 2020
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 thisPeak-flow frequency analysis for two selected streamgages in the Fourmile Creek Basin in central Iowa, based on data through water year 2018
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 probaPeak-flow frequency analysis for three selected streamgages in the Cedar and Little Sioux River Basins, Iowa, based on data through water year 2019
This data release presents a peak-flow frequency analysis by the U.S. Geological Survey that was based 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-, 1Multi-Agency Gage Height and Discharge Datasets for Selected Streamgages on the Missouri River from 10/01/1936 to 12/31/2018
This dataset includes data for 12 selected streamgages on the Missouri River from 10/01/1936 through 12/31/2018. The data include time series of gage height at the following U.S. Geological Survey (USGS) streamgages: 06601200 Missouri River at Decatur, Nebraska 06609100 Missouri River at Blair, Nebraska 06805600 Missouri River at Plattsmouth, Nebraska 06810070 Missouri River at Brownville, Nebrask - Publications
Introduction and methods of analysis for peak streamflow trends and their relation to changes in climate in Illinois, Iowa, Michigan, Minnesota, Missouri, Montana, North Dakota, South Dakota, and Wisconsin
Flood-frequency analysis, also called peak-flow frequency or flood-flow frequency analysis, is essential to water resources management applications including critical structure design and floodplain mapping. Federal guidelines for doing flood-frequency analyses are presented in a U.S. Geological Survey Techniques and Methods Report known as Bulletin 17C. A basic assumption within Bulletin 17C is tAuthorsKaren R. Ryberg, Thomas M. Over, Sara B. Levin, David C. Heimann, Nancy A. Barth, Mackenzie K. Marti, Padraic S. O'Shea, Christopher A. Sanocki, Tara J. Williams-Sether, Harper N. Wavra, T. Roy Sando, Steven K. Sando, Milan S. LiuEstimating peak-flow quantiles for selected annual exceedance probabilities in Illinois
This report presents the methods, results, and applications of an updated flood-frequency study for the State of Illinois. This study, which uses data through September 2017, updates two previous studies that used data through 1999 and 2009, respectively. Flood-frequency estimates are used for a variety of land-use planning and infrastructure design purposes, including for the hydraulic design ofAuthorsThomas M. Over, Mackenzie K. Marti, Padraic S. O'Shea, Jennifer B. SharpeFloods of June 21–July 1, 2018, in the Floyd River and Little Sioux River Basins, northwestern Iowa
The Floyd River and Little Sioux River Basins in northwestern Iowa flooded on June 21–July 1, 2018, after sustained rainfall on June 14–27, 2018. Within the Floyd River Basin, rainfall totals from June 14 to 21 preceding flooding were 3.01 inches (in.) at Le Mars, 4.50 in. at Orange City, and 7.44 in. at Sheldon. Within the Little Sioux River Basin, rainfall amounts for the 2-week period from JuneAuthorsPadraic S. O'Shea, Jordan L. Wilson, Jared C. Vegrzyn, Kimberlee K. BarnesFlood of June 30–July 1, 2018, in the Fourmile Creek Basin, near Ankeny, Iowa
Major flooding occurred June 30–July 1, 2018, in the Fourmile Creek Basin in central Iowa after thunderstorm activity over the region. The largest recorded 24-hour precipitation total at a National Oceanic and Atmospheric Administration weather station was 8.72 inches in Ankeny, Iowa, and 7.54 inches in Des Moines, Iowa. A maximum peak-of-record discharge of 10,000 cubic feet per second was recordAuthorsPadraic S. O'Shea, Jared C. Vegrzyn, Kimberlee K. BarnesStream-channel and watershed delineations and basin-characteristic measurements using lidar elevation data for small drainage basins within the Des Moines Lobe landform region in Iowa
Basin-characteristic measurements related to stream length, stream slope, stream density, and stream order have been identified as significant variables for estimation of flood, flow-duration, and low-flow discharges in Iowa. The placement of channel initiation points, however, has always been a matter of individual interpretation, leading to differences in stream definitions between analysts.ThisAuthorsDavid A. Eash, Kimberlee K. Barnes, Padraic S. O'Shea, Brian K. GelderFlood of August 24–25, 2016, Upper Iowa River and Turkey River, northeastern Iowa
Major flooding occurred August 24–25, 2016, in the Upper Iowa River Basin and Turkey River Basin in northeastern Iowa following severe thunderstorm activity over the region. About 8 inches of rain were recorded for the 24-hour period ending at 4 p.m., August 24, at Decorah, Iowa, and about 6 inches of rain were recorded for the 24-hour period ending at 7 a.m., August 24, at Cresco, Iowa, about 14AuthorsS. Mike Linhart, Padraic S. O'SheaMethods for estimating selected spring and fall low-flow frequency statistics for ungaged stream sites in Iowa, based on data through June 2014
A statewide study was led to develop regression equations for estimating three selected spring and three selected fall low-flow frequency statistics for ungaged stream sites in Iowa. The estimation equations developed for the six low-flow frequency statistics include spring (April through June) 1-, 7-, and 30-day mean low flows for a recurrence interval of 10 years and fall (October through DecembAuthorsDavid A. Eash, Kimberlee K. Barnes, Padraic S. O'SheaEstimation of peak discharge quantiles for selected annual exceedance probabilities in northeastern Illinois
This report provides two sets of equations for estimating peak discharge quantiles at annual exceedance probabilities (AEPs) of 0.50, 0.20, 0.10, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years, respectively) for watersheds in Illinois based on annual maximum peak discharge data from 117 watersheds in and near northeastern Illinois. One set ofAuthorsThomas M. Over, Riki J. Saito, Andrea G. Veilleux, Padraic S. O'Shea, Jennifer B. Sharpe, David T. Soong, Audrey L. IshiiStatistical summaries of selected Iowa streamflow data through September 2013
Statistical summaries of streamflow data collected at 184 streamgages in Iowa are presented in this report. All streamgages included for analysis have at least 10 years of continuous record collected before or through September 2013. This report is an update to two previously published reports that presented statistical summaries of selected Iowa streamflow data through September 1988 and SeptembeAuthorsDavid A. Eash, Padraic S. O'Shea, Jared R. Weber, Kevin T. Nguyen, Nicholas L. Montgomery, Adrian J. Simonson