Nancy A Barth
Nancy is a hydrologist with the Wyoming-Montana Water Science Center in Helena, Montana. She specializes in statistical hydrology: peak-flow flood frequency analysis and regression, mixed population analysis, nonstationarity and changes in seasonality.
Nancy is currently a co-investigator on a multi-year, multi-phase regional study evaluating potential nonstationarity in annual peak flows and changes in seasonality related to hydroclimatic variability in the Midwest. And she is currently updating at-site peak-flow frequency analysis (FFA) in South Dakota. Previously she worked on studies to update FFA estimates at both gaged and ungaged sites in California and Alaska. She also worked with the USGS Office of Surface Water as a corresponding member of the Hydrologic Frequency Analysis Workgroup (HFAWG) under ACWI’s Subcommittee on Hydrology to update the Federal guidelines for determining flood frequency estimates in Bulletin 17C. In 2018, she completed her doctoral research at the University of Iowa in Civil and Environmental Engineering focused on improving flood frequency estimates based on the hydrometeorologic processes that drive much of the mixed populations of peak streamflows throughout the western United States. Her doctoral research built upon her work as a hydrologist with the USGS to better understand the complex process-driven flood hydrology found in the western United States.
Professional Experience
2022-Present Hydrologist, USGS Wyoming-Montana Water Science Center, Helena, Montana
2019-2022 Hydrologist, USGS Dakota Water Science Center, Bismarck, North Dakota
2008-2014 Hydrologist and Master of Science student, USGS California Water Science Center, Sacramento, California
Education and Certifications
Doctor of Philosophy, Civil and Environmental Engineering, University of Iowa, 2018.
Dissertation: Flood frequency and mixed populations in the western United States
Master of Science, Geology, California State University, Sacramento, 2010.
Thesis: Testing for Nonstationarity in the First Two Moments of Peak Flow Data in California
Bachelor of Science, Geophysics, University of California, Berkeley, 2001.
Science and Products
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
Simulation experiments comparing nonstationary design-flood adjustments based on observed annual peak flows in the conterminous United States
While nonstationary flood frequency analysis (NSFFA) methods have proliferated, few studies have rigorously compared them for modeling changes in both the central tendency and variability of annual peak-flow series, also known as the annual maximum series (AMS), in hydrologically diverse areas. Through Monte Carlo experiments, we appraise five methods for updating estimates of 10- and 100-year flo
Authors
Jory Seth Hecht, Nancy A. Barth, Karen R. Ryberg, Angela Gregory
Attribution of monotonic trends and change points in peak streamflow across the conterminous United States using a multiple working hypotheses framework, 1941–2015 and 1966–2015
The U.S. Geological Survey has a long history of leading flood-frequency analysis studies. These studies play a critical role in the assessment of risk, protection of lives, and planning and design of flood protection infrastructure. Standard flood-frequency analysis is based on the assumption of stationarity—that is, that the distribution of floods at a given site varies around a particular mean
Evaluation of recommended revisions to Bulletin 17B
For the past 36 years, Bulletin 17B, published by the Interagency Committee on Water Data in 1982, has guided flood-frequency analyses in the United States. During this period, much has been learned about both hydrology and statistical methods. In keeping with the tradition of periodically updating the Bulletin 17B guidelines in light of advances in our understanding and methods, the Hydrologic Fr
Authors
Timothy A. Cohn, Nancy A. Barth, John F. England, Beth A. Faber, Robert R. Mason,, Jery R. Stedinger
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
Estimates of the magnitude and frequency of floods are needed across Alaska for engineering design of transportation and water-conveyance structures, flood-insurance studies, flood-plain management, and other water-resource purposes. This report updates methods for estimating flood magnitude and frequency in Alaska and conterminous basins in Canada. Annual peak-flow data through water year 2012 we
Authors
Janet H. Curran, Nancy A. Barth, Andrea G. Veilleux, Robert T. Ourso
Methods for determining magnitude and frequency of floods in California, based on data through water year 2006
Methods for estimating the magnitude and frequency of floods in California that are not substantially affected by regulation or diversions have been updated. Annual peak-flow data through water year 2006 were analyzed for 771 streamflow-gaging stations (streamgages) in California having 10 or more years of data. Flood-frequency estimates were computed for the streamgages by using the expected mome
Authors
Anthony J. Gotvald, Nancy A. Barth, Andrea G. Veilleux, Charles Parrett
Regional skew for California, and flood frequency for selected sites in the Sacramento-San Joaquin River Basin, based on data through water year 2006
Improved flood-frequency information is important throughout California in general and in the Sacramento-San Joaquin River Basin in particular, because of an extensive network of flood-control levees and the risk of catastrophic flooding. A key first step in updating flood-frequency information is determining regional skew. A Bayesian generalized least squares (GLS) regression method was used to d
Authors
Charles Parrett, Andrea Veilleux, J.R. Stedinger, N.A. Barth, Donna L. Knifong, J.C. Ferris
Science and Products
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
Simulation experiments comparing nonstationary design-flood adjustments based on observed annual peak flows in the conterminous United States
While nonstationary flood frequency analysis (NSFFA) methods have proliferated, few studies have rigorously compared them for modeling changes in both the central tendency and variability of annual peak-flow series, also known as the annual maximum series (AMS), in hydrologically diverse areas. Through Monte Carlo experiments, we appraise five methods for updating estimates of 10- and 100-year flo
Authors
Jory Seth Hecht, Nancy A. Barth, Karen R. Ryberg, Angela Gregory
Attribution of monotonic trends and change points in peak streamflow across the conterminous United States using a multiple working hypotheses framework, 1941–2015 and 1966–2015
The U.S. Geological Survey has a long history of leading flood-frequency analysis studies. These studies play a critical role in the assessment of risk, protection of lives, and planning and design of flood protection infrastructure. Standard flood-frequency analysis is based on the assumption of stationarity—that is, that the distribution of floods at a given site varies around a particular mean
Evaluation of recommended revisions to Bulletin 17B
For the past 36 years, Bulletin 17B, published by the Interagency Committee on Water Data in 1982, has guided flood-frequency analyses in the United States. During this period, much has been learned about both hydrology and statistical methods. In keeping with the tradition of periodically updating the Bulletin 17B guidelines in light of advances in our understanding and methods, the Hydrologic Fr
Authors
Timothy A. Cohn, Nancy A. Barth, John F. England, Beth A. Faber, Robert R. Mason,, Jery R. Stedinger
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
Estimates of the magnitude and frequency of floods are needed across Alaska for engineering design of transportation and water-conveyance structures, flood-insurance studies, flood-plain management, and other water-resource purposes. This report updates methods for estimating flood magnitude and frequency in Alaska and conterminous basins in Canada. Annual peak-flow data through water year 2012 we
Authors
Janet H. Curran, Nancy A. Barth, Andrea G. Veilleux, Robert T. Ourso
Methods for determining magnitude and frequency of floods in California, based on data through water year 2006
Methods for estimating the magnitude and frequency of floods in California that are not substantially affected by regulation or diversions have been updated. Annual peak-flow data through water year 2006 were analyzed for 771 streamflow-gaging stations (streamgages) in California having 10 or more years of data. Flood-frequency estimates were computed for the streamgages by using the expected mome
Authors
Anthony J. Gotvald, Nancy A. Barth, Andrea G. Veilleux, Charles Parrett
Regional skew for California, and flood frequency for selected sites in the Sacramento-San Joaquin River Basin, based on data through water year 2006
Improved flood-frequency information is important throughout California in general and in the Sacramento-San Joaquin River Basin in particular, because of an extensive network of flood-control levees and the risk of catastrophic flooding. A key first step in updating flood-frequency information is determining regional skew. A Bayesian generalized least squares (GLS) regression method was used to d
Authors
Charles Parrett, Andrea Veilleux, J.R. Stedinger, N.A. Barth, Donna L. Knifong, J.C. Ferris