Flood-frequency analysis provides information about the magnitude and frequency of floods based on records of annual maximum instantaneous peak discharges. Accurate flood-frequency estimates, created using consistent and uniformly applied methods, are a key component of any effective flood risk and management program. This is a list of current USGS flood frequency reports published by state.
NOTICE: Potential computational issues in the PeakFQ software continue to be investigated in collaboration with the U.S. Army Corps of Engineers (USACE). Refined user guidance and/or updated methodology documentation will be developed and made available, if needed.
For detailed information, please visit this page.
Flood Frequency Overview
Floods are dangerous natural hazards that can threaten lives, livelihoods, and property. Without information on flood risk, the planning, design, and management of infrastructure along rivers would be forced to proceed without quantitative scientific analysis. Flood-frequency analysis provides information about the magnitude and frequency of flood discharges based on records of annual maximum instantaneous peak discharges collected at streamgages. In essence, flood-frequency analysis is used to estimate the probability of flooding at specific river locations.
Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including most levels of government and the private sector.
To ensure consistency in flood-frequency analysis, multiple federal agencies have worked together to produce the Guidelines for Determining Flood Flow Frequency - Bulletin 17C, released in 2019. Updates include: adoption of a generalized representation of flood data that allows for interval and censored data types; a new method, called the Expected Moments Algorithm, which extends the method of moments so that it can accommodate interval data; a generalized approach to identification of low outliers in flood data; and an improved method for computing confidence intervals. Federal agencies are requested to use these Guidelines in all planning activities involving water and related land resources. State, local, and private organizations are encouraged to use these Guidelines to assure uniformity in the flood-frequency estimates that all agencies concerned with flood risk should use for Federal planning decisions.
For additional information on the basics of flood-frequency analysis, see also The 100-Year-Flood-It’s All About Chance (USGS General Information Product 106) and our 100-Year Flood webpage (USGS Water Science School).
USGS Reports: Flood Frequency and Regional Skew
Below is a list of the most recent flood frequency reports published by the USGS and organized by state. This list includes reports pertaining to regional skew, as well as regional annual exceedance probability equations for both peak flow and flood-duration flows. It will be updated as new reports are published.
As B17C recommends weighting the at-site skew with regional skew, this list provides the most current regional skew study for each state, which include both B17C recommended BGLS regional skew as well as other methodologies. If a B-GLS regional skew is not available, it is recommended that users consult with the USGS to determine the availability of alternate regional skew estimates. If no alternatives are available, then use the B17B map.
Reports which use the flood-frequency methods recommended in Bulletin 17C will be denoted with “B17C.”
For additional information, please contact your local Water Science Center or email gs_b17c@usgs.gov.
ALABAMA
Peak Flow
SIR 2007-5204, Magnitude and Frequency of Floods in Alabama, 2003
SIR 2010-2012, Magnitude and Frequency of Floods for Urban Streams in Alabama, 2007
B17C
SIR 2020-5032, Magnitude and Frequency of Floods in Alabama, 2015
ALASKA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5024, Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012
ARIZONA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2014-5211, Methods for estimating magnitude and frequency of floods in Arizona, developed with unregulated and rural peak-flow data through water year 2010
B17C Flood-Duration Flows with B17C B-GLS Regional Skews
SIR 2014-5109, Methods for estimating magnitude and frequency of 1-, 3-, 7-, 15-, and 30-day flood-duration flows in Arizona
ARKANSAS
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5081, Methods for estimating annual exceedance probability discharges for streams in Arkansas, based on data through water year 2013
B17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017
CALIFORNIA
B17C B-GLS Regional Skew
SIR 2010-5260, Regional skew for California, and flood frequency for selected sites in the Sacramento-San Joaquin River Basin, based on data through water year 2006
B17C Peak Flow
SIR 2012-5113, Methods for determining magnitude and frequency of floods in California, based on data through water year 2006
B17C Flood-Duration Flows with B17C B-GLS Regional Skews
SIR 2012-5130, Development of regional skews for selected flood durations for the Central Valley Region, California, based on data through water year 2008
COLORADO
B17C Peak Flow
SIR 2016-5099, Paleoflood investigations to improve peak-streamflow regional-regression equations for natural streamflow in eastern Colorado
Peak Flow
SIR 2009-5136, Regional Regression Equations for Estimation of Natural streamflow Statistics in Colorado
CONNECTICUT
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
Peak Flow
SIR 2020-5054, Estimating Flood Magnitude and Frequency on Streams and Rivers in Connecticut, Based on Data Through Water Year 2015
DELAWARE
Peak Flow
SIR 2006-5146, Magnitude and Frequency of Floods on Nontidal Streams in Delaware
B17C
SIR 2022-5005, Peak-Flow and Low-Flow Magnitude Estimates at Defined Frequencies and Durations for Nontidal Streams in Delaware
GEORGIA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5043, Magnitude and Frequency of Rural Floods in the Southeastern United States, 2006: Volume 1, Georgia.
SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011
Updated peakflows for GA/SC/ND coming soon...
HAWAII
Peak Flow
SIR 2010-5035, Flood-Frequency Estimates for Streams on Kaua'i, O'ahu, Moloka'i, Maui, and Hawai'i, State of Hawai'i
Update coming soon...
IDAHO
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5083, Estimating peak-flow frequency statistics for selected gaged and ungaged sites in naturally flowing streams and rivers in Idaho
ILLINOIS
Peak Flow
SIR 2004-5103, Estimating Flood-Peak Discharge Magnitudes and Frequencies for Rural Streams in Illinois
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
SIR 2016-5050, Estimation of Peak Discharge Quantiles for Selected Annual Exceedance Probabilities in Northeastern Illinois
INDIANA
Peak Flow
Rao, A. R. Flood Frequency Relationships for Indiana. Publication FHWA/IN/JTRP-2005/18. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2006.
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
IOWA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2013-5086, Methods for Estimating Annual Exceedance-Probability Discharges for Streams in Iowa, Based on Data through Water Year 2010
SIR 2015-5055, Comparisons of Estimates of Annual Exceedance-Probability Discharges for Small Drainage Basins in Iowa, Based on Data through Water Year 2013
KANSAS
Peak Flow & Regional Skew
WRIR 00-4079, Estimation of Peak Streamflows for Unregulated Streams in Kansas
SIR 2017-5063, Methods for estimating annual exceedance-probability streamflows for streams in Kansas based on data through water year 2015
KENTUCKY
Peak Flow & Regional Skew
WRIR 97-4219, Estimation of peak-discharge frequency of urban streams in Jefferson County, Kentucky
WRIR 03-4180, Estimating the Magnitude of Peak Flows for Streams in Kentucky for Selected Recurrence Intervals
LOUISIANA
Peak Flow
TR No. 60, (1998) Floods in Louisiana, Magnitude and Frequency, Fifth Edition. In progress (coming soon)
B17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017
A Coastal Plains peakflow report is coming soon...
B17C B-GLS Regional Skew
Appendix of: SIR 2016-5081, Methods for estimating annual exceedance probability discharges for streams in Arkansas, based on data through water year 2013
MAINE
Peak Flow & Regional Skew
WRIR 99-4008, Estimating the Magnitude of Peak Flows for Streams in Maine for Selected Recurrence Intervals
SIR 2015-5049, Peak flow regression equations For small, ungaged streams in Maine: Comparing map-based to field-based variables
SIR 2020-5092, Estimating Flood Magnitude and Frequency on Gaged and Ungaged Streams in Maine
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
MARYLAND
Peak Flow
WRIR 95-4154, Technique for Estimating Magnitude and Frequency of Peak Flows in Maryland
Application of Hydrologic Methods in Maryland
MASSACHUSETTS
B17C Peak Flow
SIR 2016-5156, Magnitude of flood flows at selected annual exceedance probabilities for streams in Massachusetts
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
MICHIGAN
Peak Flow
WRIR 84-4207, Statistical Models for Estimating Flow Characteristics of Michigan Streams, 1984
MINNESOTA
Peak Flow
SIR 2009-5250, Techniques for Estimating the Magnitude and Frequency of Peak Flows on Small Streams in Minnesota Based on Data through Water Year 2005
B17C
SIR 2019-5012, Techniques for Estimating the Magnitude and Frequency of Peak Flows on Small Streams in the Binational U.S. and Canadian Lake of the Woods–Rainy River Basin Upstream from Kenora, Ontario, Canada, Based on Data through Water Year 2013
Update coming soon...
MISSISSIPPI
Peak Flow & Regional Skew (combined report)
WRIR 91-4037, Flood Characteristics of Mississippi Streams
B17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017
MISSOURI
B17C Peak Flow & B17C Regional Skew (combined report)
SIR 2014-5165, Methods for Estimating Annual Exceedance-Probability Discharges and Largest Recorded Floods for Unregulated Streams in Rural Missouri
SIR 2010-5073, Estimation of the Magnitude and Frequency of Floods in Urban Basins in Missouri
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017
MONTANA
Peak Flow & Regional skew (combined report)
WRIR 2015-5019, Montana StreamStats
SIR 2020-5142, Regional Regression Equations Based on Channel-Width Characteristics to Estimate Peak-Flow Frequencies at Ungaged Sites in Montana Using Peak-Flow Frequency Data through Water Year 2011
NEBRASKA
Peak Flow & Regional skew (combined report)
WRIR 99-4032, Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in Nebraska
NEVADA
Peak Flow & Regional skew (combined report)
WSP 2433 (1997), Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States
Update coming soon...
NEW HAMPSHIRE
Peak Flow
SIR 2008-5206, Estimation of Flood Discharges at Selected Recurrence Intervals for Streams in New Hampshire
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
NEW JERSEY
Peak Flow & Regional skew (combined report)
SIR 2009-5167, Methodology for Estimation of Flood Magnitude and Frequency for New Jersey Streams
NEW MEXICO
Peak Flow & Regional skew (combined report)
SIR 2008-5119, Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak Discharge in New Mexico and Surrounding Areas
WSP 2433, Methods for estimating magnitude and frequency of floods in the southwestern United States
SIR 2006-5306, Analysis of the Magnitude and Frequency of Peak Discharges for the Navajo Nation in Arizona, Utah, Colorado, and New Mexico
NEW YORK
Peak Flow
SIR 2006-5112, Magnitude and Frequency of Floods in New York
Regional Skew
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
Report for eastern region in progress (coming soon)
WRIR 00-4022, Development of a Contour Map Showing Generalized Skew Coefficients of Annual Peak Discharges of Rural, Unregulated streams in New York, Excluding Long Island
NORTH CAROLINA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5158, Magnitude and Frequency of Rural Floods in the Southeastern United States, through 2006: Volume 2, North Carolina. Update in progress (coming soon)
NORTH DAKOTA
Peak Flow & Regional skew (combined report)
SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011. Update in progress (coming soon)
SIR 2015-5096, Regional regression equations to estimate peak-flow frequency at sites in North Dakota using data through 2009
OHIO
Peak Flow
WSP 2432, Estimation of peak-frequency relations, flood hydrographs, and volume-duration-frequency relations of ungaged small urban streams in Ohio
B17C
SIR 2019-5018, Flood-Frequency Estimates for Ohio Streamgages Based on Data through Water Year 2015 and Techniques for Estimating Flood-Frequency Characteristics of Rural, Unregulated Ohio Streams
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
OKLAHOMA
Peak Flow
SIR 2010-5137, Methods for Estimating the Magnitude and Frequency of Peak Streamflows for Unregulated Streams in Oklahoma
SIR 2015-5134, Methods for estimating the magnitude and frequency of peak streamflows at ungaged sites in and near the Oklahoma Panhandle
B17C
SIR 2019-5043, Methods for Estimating the Magnitude and Frequency of Peak Streamflows for Unregulated Streams in Oklahoma Developed by Using Streamflow Data Through 2017
Regional Skew
SIR 2009-5135, Statistical Summaries of Streamflow in and near Oklahoma Through 2007
OREGON
Peak Flow & Regional skew (combined report)
SIR 2005-5116, Estimation of Peak Discharges for Rural, Unregulated Streams in Western Oregon
WSP 2433 (1997), Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States
B17C B-GLS Regional Skew
Appendix of: SIR 2016-5118, Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (ver 1.1, October 2016)
PENNSYLVANIA
Peak Flow
SIR 2008-5102, Regression Equations for Estimating Flood Flows at Selected Recurrence Intervals for Ungaged Streams in Pennsylvania
B17C
SIR 2019-5094, Development of Regression Equations for the Estimation of Flood Flows at Ungaged Streams in Pennsylvania
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
Report for eastern region in progress (coming soon)
PUERTO RICO
Peak Flow & B17C Regional skew (combined report)
SIR 2021-5062, Development of Regression Equations for the Estimation of the Magnitude and Frequency of Floods at Rural, Unregulated Gaged and Ungaged Streams in Puerto Rico Through Water Year 2017
RHODE ISLAND
Peak Flow & Regional skew (combined report)
SIR 2012-5109, Magnitude of Flood Flows for Selected Annual-Exceedance Probabilities in Rhode Island, through 2010, Version 1.1
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
SOUTH CAROLINA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5156, Magnitude and Frequency of Rural Floods in the Southeastern United States, 2006: Volume 3, South Carolina. Update in progress (coming soon)
SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011
SOUTH DAKOTA
Peak Flow
WRIR 98-4055, A Method for Estimating Magnitude and Frequency of Floods in South Dakota
TENNESSEE
Peak Flow
WRIR 84-4110, Flood Frequency and Storm Runoff of Urban Areas of Memphis and Shelby County, Tennessee
WRIR 84-4182, Synthesized flood frequency for small urban streams in Tennessee
WRIR 03-4176, Flood-Frequency Prediction Methods for Unregulated Streams of Tennessee, 2000
TEXAS
Peak Flow
SIR 2009-5087, Regression Equations for Estimation of Annual Peak-Streamflow Frequency for Undeveloped Watersheds in Texas Using an L-moment-Based, PRESS-Minimized, Residual-Adjusted Approach
UTAH
Peak Flow & Regional Skew (combined report)
SIR 2006-5306, Analysis of the Magnitude and Frequency of Peak Discharges for the Navajo Nation in Arizona, Utah, Colorado, and New Mexico
SIR 2007-5158, Methods for Estimating Magnitude and Frequency of Peak Flows for Natural Streams in Utah
VERMONT
Peak Flow
SIR 2014-5078, Estimation of Flood Discharges at Selected Annual Exceedance Probabilities for Unregulated, Rural Streams in Vermont
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New England
VIRGINIA
Peak Flow
SIR 2011-5144, Peak-Flow Characteristics of Virginia Streams
WASHINGTON
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5118, Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (ver 1.1, October 2016)
WEST VIRGINIA
Peak Flow
SIR 2010-5033, Estimation of Flood-Frequency Discharges for Rural, Unregulated Streams in West Virginia
Regional Skew
OFR 2008-1304, Generalized Skew Coefficients of Annual Peak Flows for Rural, Unregulated Streams in West Virginia
WISCONSIN
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013
SIR 2022-5118, Estimating Flood Magnitude and Frequency for Unregulated Streams in Wisconsin
WYOMING
Peak Flow & Regional Skew (combined report)
WRIR 03-4107, Peak-Flow Characteristics of Wyoming Streams
Below are other science projects associated with flood frequency.
The 100-Year Flood
StreamStats: Streamflow Statistics and Spatial Analysis Tools for Water-Resources Applications
Flood Inundation Mapping (FIM) Program
- Overview
Flood-frequency analysis provides information about the magnitude and frequency of floods based on records of annual maximum instantaneous peak discharges. Accurate flood-frequency estimates, created using consistent and uniformly applied methods, are a key component of any effective flood risk and management program. This is a list of current USGS flood frequency reports published by state.
NOTICE: Potential computational issues in the PeakFQ software continue to be investigated in collaboration with the U.S. Army Corps of Engineers (USACE). Refined user guidance and/or updated methodology documentation will be developed and made available, if needed.
For detailed information, please visit this page.
Flood Frequency Overview
Floods are dangerous natural hazards that can threaten lives, livelihoods, and property. Without information on flood risk, the planning, design, and management of infrastructure along rivers would be forced to proceed without quantitative scientific analysis. Flood-frequency analysis provides information about the magnitude and frequency of flood discharges based on records of annual maximum instantaneous peak discharges collected at streamgages. In essence, flood-frequency analysis is used to estimate the probability of flooding at specific river locations.
Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including most levels of government and the private sector.
To ensure consistency in flood-frequency analysis, multiple federal agencies have worked together to produce the Guidelines for Determining Flood Flow Frequency - Bulletin 17C, released in 2019. Updates include: adoption of a generalized representation of flood data that allows for interval and censored data types; a new method, called the Expected Moments Algorithm, which extends the method of moments so that it can accommodate interval data; a generalized approach to identification of low outliers in flood data; and an improved method for computing confidence intervals. Federal agencies are requested to use these Guidelines in all planning activities involving water and related land resources. State, local, and private organizations are encouraged to use these Guidelines to assure uniformity in the flood-frequency estimates that all agencies concerned with flood risk should use for Federal planning decisions.
For additional information on the basics of flood-frequency analysis, see also The 100-Year-Flood-It’s All About Chance (USGS General Information Product 106) and our 100-Year Flood webpage (USGS Water Science School).
Sources/Usage: Public Domain.USGS Reports: Flood Frequency and Regional Skew
Below is a list of the most recent flood frequency reports published by the USGS and organized by state. This list includes reports pertaining to regional skew, as well as regional annual exceedance probability equations for both peak flow and flood-duration flows. It will be updated as new reports are published.
As B17C recommends weighting the at-site skew with regional skew, this list provides the most current regional skew study for each state, which include both B17C recommended BGLS regional skew as well as other methodologies. If a B-GLS regional skew is not available, it is recommended that users consult with the USGS to determine the availability of alternate regional skew estimates. If no alternatives are available, then use the B17B map.
Reports which use the flood-frequency methods recommended in Bulletin 17C will be denoted with “B17C.”
For additional information, please contact your local Water Science Center or email gs_b17c@usgs.gov.
ALABAMA
Peak Flow
SIR 2007-5204, Magnitude and Frequency of Floods in Alabama, 2003SIR 2010-2012, Magnitude and Frequency of Floods for Urban Streams in Alabama, 2007
B17C
SIR 2020-5032, Magnitude and Frequency of Floods in Alabama, 2015ALASKA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5024, Estimating flood magnitude and frequency at gaged and ungaged sites on streams in Alaska and conterminous basins in Canada, based on data through water year 2012ARIZONA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2014-5211, Methods for estimating magnitude and frequency of floods in Arizona, developed with unregulated and rural peak-flow data through water year 2010B17C Flood-Duration Flows with B17C B-GLS Regional Skews
SIR 2014-5109, Methods for estimating magnitude and frequency of 1-, 3-, 7-, 15-, and 30-day flood-duration flows in ArizonaARKANSAS
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5081, Methods for estimating annual exceedance probability discharges for streams in Arkansas, based on data through water year 2013B17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017CALIFORNIA
B17C B-GLS Regional Skew
SIR 2010-5260, Regional skew for California, and flood frequency for selected sites in the Sacramento-San Joaquin River Basin, based on data through water year 2006B17C Peak Flow
SIR 2012-5113, Methods for determining magnitude and frequency of floods in California, based on data through water year 2006B17C Flood-Duration Flows with B17C B-GLS Regional Skews
SIR 2012-5130, Development of regional skews for selected flood durations for the Central Valley Region, California, based on data through water year 2008COLORADO
B17C Peak Flow
SIR 2016-5099, Paleoflood investigations to improve peak-streamflow regional-regression equations for natural streamflow in eastern ColoradoPeak Flow
SIR 2009-5136, Regional Regression Equations for Estimation of Natural streamflow Statistics in ColoradoCONNECTICUT
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandPeak Flow
SIR 2020-5054, Estimating Flood Magnitude and Frequency on Streams and Rivers in Connecticut, Based on Data Through Water Year 2015DELAWARE
Peak Flow
SIR 2006-5146, Magnitude and Frequency of Floods on Nontidal Streams in DelawareB17C
SIR 2022-5005, Peak-Flow and Low-Flow Magnitude Estimates at Defined Frequencies and Durations for Nontidal Streams in DelawareGEORGIA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5043, Magnitude and Frequency of Rural Floods in the Southeastern United States, 2006: Volume 1, Georgia.SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011
Updated peakflows for GA/SC/ND coming soon...
HAWAII
Peak Flow
SIR 2010-5035, Flood-Frequency Estimates for Streams on Kaua'i, O'ahu, Moloka'i, Maui, and Hawai'i, State of Hawai'iUpdate coming soon...
IDAHO
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5083, Estimating peak-flow frequency statistics for selected gaged and ungaged sites in naturally flowing streams and rivers in IdahoILLINOIS
Peak Flow
SIR 2004-5103, Estimating Flood-Peak Discharge Magnitudes and Frequencies for Rural Streams in IllinoisB17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013SIR 2016-5050, Estimation of Peak Discharge Quantiles for Selected Annual Exceedance Probabilities in Northeastern Illinois
INDIANA
Peak Flow
Rao, A. R. Flood Frequency Relationships for Indiana. Publication FHWA/IN/JTRP-2005/18. Joint Transportation Research Program, Indiana Department of Transportation and Purdue University, West Lafayette, Indiana, 2006.B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013IOWA
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2013-5086, Methods for Estimating Annual Exceedance-Probability Discharges for Streams in Iowa, Based on Data through Water Year 2010SIR 2015-5055, Comparisons of Estimates of Annual Exceedance-Probability Discharges for Small Drainage Basins in Iowa, Based on Data through Water Year 2013
KANSAS
Peak Flow & Regional Skew
WRIR 00-4079, Estimation of Peak Streamflows for Unregulated Streams in KansasSIR 2017-5063, Methods for estimating annual exceedance-probability streamflows for streams in Kansas based on data through water year 2015
KENTUCKY
Peak Flow & Regional Skew
WRIR 97-4219, Estimation of peak-discharge frequency of urban streams in Jefferson County, KentuckyWRIR 03-4180, Estimating the Magnitude of Peak Flows for Streams in Kentucky for Selected Recurrence Intervals
LOUISIANA
Peak Flow
TR No. 60, (1998) Floods in Louisiana, Magnitude and Frequency, Fifth Edition. In progress (coming soon)B17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017A Coastal Plains peakflow report is coming soon...
B17C B-GLS Regional Skew
Appendix of: SIR 2016-5081, Methods for estimating annual exceedance probability discharges for streams in Arkansas, based on data through water year 2013MAINE
Peak Flow & Regional Skew
WRIR 99-4008, Estimating the Magnitude of Peak Flows for Streams in Maine for Selected Recurrence IntervalsSIR 2015-5049, Peak flow regression equations For small, ungaged streams in Maine: Comparing map-based to field-based variables
SIR 2020-5092, Estimating Flood Magnitude and Frequency on Gaged and Ungaged Streams in Maine
B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandMARYLAND
Peak Flow
WRIR 95-4154, Technique for Estimating Magnitude and Frequency of Peak Flows in MarylandApplication of Hydrologic Methods in Maryland
MASSACHUSETTS
B17C Peak Flow
SIR 2016-5156, Magnitude of flood flows at selected annual exceedance probabilities for streams in MassachusettsB17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandMICHIGAN
Peak Flow
WRIR 84-4207, Statistical Models for Estimating Flow Characteristics of Michigan Streams, 1984MINNESOTA
Peak Flow
SIR 2009-5250, Techniques for Estimating the Magnitude and Frequency of Peak Flows on Small Streams in Minnesota Based on Data through Water Year 2005B17C
SIR 2019-5012, Techniques for Estimating the Magnitude and Frequency of Peak Flows on Small Streams in the Binational U.S. and Canadian Lake of the Woods–Rainy River Basin Upstream from Kenora, Ontario, Canada, Based on Data through Water Year 2013Update coming soon...
MISSISSIPPI
Peak Flow & Regional Skew (combined report)
WRIR 91-4037, Flood Characteristics of Mississippi StreamsB17C
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017MISSOURI
B17C Peak Flow & B17C Regional Skew (combined report)
SIR 2014-5165, Methods for Estimating Annual Exceedance-Probability Discharges and Largest Recorded Floods for Unregulated Streams in Rural MissouriSIR 2010-5073, Estimation of the Magnitude and Frequency of Floods in Urban Basins in Missouri
SIR 2021-5046, Magnitude and Frequency of Floods in the Alluvial Plain of the Lower Mississippi River, 2017
MONTANA
Peak Flow & Regional skew (combined report)
WRIR 2015-5019, Montana StreamStatsSIR 2020-5142, Regional Regression Equations Based on Channel-Width Characteristics to Estimate Peak-Flow Frequencies at Ungaged Sites in Montana Using Peak-Flow Frequency Data through Water Year 2011
NEBRASKA
Peak Flow & Regional skew (combined report)
WRIR 99-4032, Peak-Flow Frequency Relations and Evaluation of the Peak-Flow Gaging Network in NebraskaNEVADA
Peak Flow & Regional skew (combined report)
WSP 2433 (1997), Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United StatesUpdate coming soon...
NEW HAMPSHIRE
Peak Flow
SIR 2008-5206, Estimation of Flood Discharges at Selected Recurrence Intervals for Streams in New HampshireB17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandNEW JERSEY
Peak Flow & Regional skew (combined report)
SIR 2009-5167, Methodology for Estimation of Flood Magnitude and Frequency for New Jersey StreamsNEW MEXICO
Peak Flow & Regional skew (combined report)
SIR 2008-5119, Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak Discharge in New Mexico and Surrounding AreasWSP 2433, Methods for estimating magnitude and frequency of floods in the southwestern United States
SIR 2006-5306, Analysis of the Magnitude and Frequency of Peak Discharges for the Navajo Nation in Arizona, Utah, Colorado, and New Mexico
NEW YORK
Peak Flow
SIR 2006-5112, Magnitude and Frequency of Floods in New YorkRegional Skew
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013Report for eastern region in progress (coming soon)
WRIR 00-4022, Development of a Contour Map Showing Generalized Skew Coefficients of Annual Peak Discharges of Rural, Unregulated streams in New York, Excluding Long Island
NORTH CAROLINA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5158, Magnitude and Frequency of Rural Floods in the Southeastern United States, through 2006: Volume 2, North Carolina. Update in progress (coming soon)NORTH DAKOTA
Peak Flow & Regional skew (combined report)
SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011. Update in progress (coming soon)SIR 2015-5096, Regional regression equations to estimate peak-flow frequency at sites in North Dakota using data through 2009
OHIO
Peak Flow
WSP 2432, Estimation of peak-frequency relations, flood hydrographs, and volume-duration-frequency relations of ungaged small urban streams in OhioB17C
SIR 2019-5018, Flood-Frequency Estimates for Ohio Streamgages Based on Data through Water Year 2015 and Techniques for Estimating Flood-Frequency Characteristics of Rural, Unregulated Ohio StreamsB17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013OKLAHOMA
Peak Flow
SIR 2010-5137, Methods for Estimating the Magnitude and Frequency of Peak Streamflows for Unregulated Streams in OklahomaSIR 2015-5134, Methods for estimating the magnitude and frequency of peak streamflows at ungaged sites in and near the Oklahoma Panhandle
B17C
SIR 2019-5043, Methods for Estimating the Magnitude and Frequency of Peak Streamflows for Unregulated Streams in Oklahoma Developed by Using Streamflow Data Through 2017Regional Skew
SIR 2009-5135, Statistical Summaries of Streamflow in and near Oklahoma Through 2007OREGON
Peak Flow & Regional skew (combined report)
SIR 2005-5116, Estimation of Peak Discharges for Rural, Unregulated Streams in Western OregonWSP 2433 (1997), Methods for Estimating Magnitude and Frequency of Floods in the Southwestern United States
B17C B-GLS Regional Skew
Appendix of: SIR 2016-5118, Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (ver 1.1, October 2016)PENNSYLVANIA
Peak Flow
SIR 2008-5102, Regression Equations for Estimating Flood Flows at Selected Recurrence Intervals for Ungaged Streams in PennsylvaniaB17C
SIR 2019-5094, Development of Regression Equations for the Estimation of Flood Flows at Ungaged Streams in PennsylvaniaB17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013Report for eastern region in progress (coming soon)
PUERTO RICO
Peak Flow & B17C Regional skew (combined report)
SIR 2021-5062, Development of Regression Equations for the Estimation of the Magnitude and Frequency of Floods at Rural, Unregulated Gaged and Ungaged Streams in Puerto Rico Through Water Year 2017RHODE ISLAND
Peak Flow & Regional skew (combined report)
SIR 2012-5109, Magnitude of Flood Flows for Selected Annual-Exceedance Probabilities in Rhode Island, through 2010, Version 1.1B17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandSOUTH CAROLINA
Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2009-5156, Magnitude and Frequency of Rural Floods in the Southeastern United States, 2006: Volume 3, South Carolina. Update in progress (coming soon)SIR 2014-5030, Methods for Estimating the Magnitude and Frequency of Floods for Urban and Small, Rural Streams in Georgia, South Carolina, and North Carolina, 2011
SOUTH DAKOTA
Peak Flow
WRIR 98-4055, A Method for Estimating Magnitude and Frequency of Floods in South DakotaTENNESSEE
Peak Flow
WRIR 84-4110, Flood Frequency and Storm Runoff of Urban Areas of Memphis and Shelby County, TennesseeWRIR 84-4182, Synthesized flood frequency for small urban streams in Tennessee
WRIR 03-4176, Flood-Frequency Prediction Methods for Unregulated Streams of Tennessee, 2000
TEXAS
Peak Flow
SIR 2009-5087, Regression Equations for Estimation of Annual Peak-Streamflow Frequency for Undeveloped Watersheds in Texas Using an L-moment-Based, PRESS-Minimized, Residual-Adjusted ApproachUTAH
Peak Flow & Regional Skew (combined report)
SIR 2006-5306, Analysis of the Magnitude and Frequency of Peak Discharges for the Navajo Nation in Arizona, Utah, Colorado, and New MexicoSIR 2007-5158, Methods for Estimating Magnitude and Frequency of Peak Flows for Natural Streams in Utah
VERMONT
Peak Flow
SIR 2014-5078, Estimation of Flood Discharges at Selected Annual Exceedance Probabilities for Unregulated, Rural Streams in VermontB17C B-GLS Regional Skew
SIR 2017-5037, Methods for estimating regional coefficient of skewness for unregulated streams in New EnglandVIRGINIA
Peak Flow
SIR 2011-5144, Peak-Flow Characteristics of Virginia StreamsWASHINGTON
B17C Peak Flow & B17C B-GLS Regional Skew (combined report)
SIR 2016-5118, Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014 (ver 1.1, October 2016)WEST VIRGINIA
Peak Flow
SIR 2010-5033, Estimation of Flood-Frequency Discharges for Rural, Unregulated Streams in West VirginiaRegional Skew
OFR 2008-1304, Generalized Skew Coefficients of Annual Peak Flows for Rural, Unregulated Streams in West VirginiaWISCONSIN
B17C B-GLS Regional Skew
SIR 2019-5105, Methods for Estimating Regional Skewness of Annual Peak Flows in Parts of the Great Lakes and Ohio River Basins, Based on Data Through Water Year 2013SIR 2022-5118, Estimating Flood Magnitude and Frequency for Unregulated Streams in Wisconsin
WYOMING
Peak Flow & Regional Skew (combined report)
WRIR 03-4107, Peak-Flow Characteristics of Wyoming Streams - Science
Below are other science projects associated with flood frequency.
The 100-Year Flood
A 100-year flood happened last year so it won't happen for another 99 years, right? Not exactly. Misinterpretation of terminology often leads to confusion about flood recurrence intervals. Read on to learn more.StreamStats: Streamflow Statistics and Spatial Analysis Tools for Water-Resources Applications
StreamStats provides access to spatial analytical tools that are useful for water-resources planning and management, and for engineering and design purposes. The map-based user interface can be used to delineate drainage areas, get basin characteristics and estimates of flow statistics, and more. Available information varies from state to state.Flood Inundation Mapping (FIM) Program
Floods are the leading cause of natural-disaster losses in the U.S. More than 75 percent of declared Federal disasters are related to floods, and annual flood losses average almost $8 billion with over 90 fatalities per year. Although the amount of fatalities has declined due to improved early warning systems, economic losses continue to rise with increased urbanization in flood-hazard areas. - Publications
- Web Tools