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Karen R Ryberg, Ph.D.

Research Statistician for the Dakota Water Science Center

Expertise/Projects/Research Interests

  • Statistical analysis of hydrologic data, including parametric and nonparametric trend analysis and cluster analysis
  • Trend analysis for pesticide concentrations in surface water
  • Research related to the impact of climate variability on surface water
  • Data mining including automated data retrieval and analysis, outlier detection, and data cleaning
  • Machine learning
  • Graphical presentation of scientific data
  • R - Open Source Statistical Software
    • waterData package - Retrieval, analysis, and anomaly calculation of daily hydrologic time series data
    • seawaveQ package - A model and utilities for analyzing trends in chemical concentrations in streams with a seasonal wave (seawave) and adjustment for streamflow (Q) and other ancillary variables
  • Associate Editor, Hydrological Sciences Journal
  • Course Coordinator and member of team teaching Statistical Methods for Environmental Data Analysis at USGS National Training Center

Publications

Ryberg, K.R., 2021, The role of the U.S. Geological Survey in monitoring North Dakota’s environmental conditions: North Dakota Climate Bulletin, v. 15, no. 1, p. 11–14, https://www.ndsu.edu/ndsco/climatesummaries/quarterlyclimatebulletin/.

Helsel, D.R., Hirsch, R.M., Ryberg, K.R., Archfield, S.A., and Gilroy, E.J., 2020, Statistical methods in water resources: U.S. Geological Survey Techniques and Methods, book 4, chapter A3, 458 p., https://doi.org/10.3133/tm4a3. [Supersedes USGS Techniques of Water-Resources Investigat

Education and Certifications

  • Doctorate of Philosophy, Environmental and Conservation Sciences - Environmental Science Track, 2015 North Dakota State University, Fargo, North Dakota

    Dissertation: The impact of climate variability

  • Master of Science, Statistics, 2006, Colorado State University, Fort Collins, Colorado

    Masters Project: Water-quality trend analysis for the Devils Lake Basin, North Dakota, January 1965 through Sept

  • Associate of Applied Science, Computer Support Specialist, 2003 Bismarck State College, Bismarck, North Dakota

  • Bachelor of Arts, Mathematics, 1995 Luther College, Decorah, Iowa

  • Mathematics for Machine Learning Specialization Certificate— Imperial College London on Coursera, 2020

  • Facilitator Training—Learning to Lead Reflective Conversations, an educational program of Humanities North Dakota and Bismarck State College, Bismarck, ND., 2018

  • Specialization Certificate in Executive Data Science— Johns Hopkins University on Coursera, 2018

  • Graduate Certificate, Data Mining and Applications, 2008, Stanford University, Stanford, California

  • Management, 1996, University of Mary, Bismarck, North Dakota

Science and Products

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Flood-Frequency Analysis in the Midwest: Addressing Potential Nonstationary Annual Peak-Flow Records

Period of Project: 2021 -Study Area: MidwestCooperating Agency: Transportation Pooled Fund
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Dakota Water Science Center
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Flood-Frequency Analysis in the Midwest: Addressing Potential Nonstationary Annual Peak-Flow Records

Period of Project: 2021 -Study Area: MidwestCooperating Agency: Transportation Pooled Fund
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Data for simulation experiments comparing nonstationary design-flood adjustments based on observed annual peak flows in the conterminous United States

This dataset contains files used in this Monte Carlo simulation study comparing the performance of five statistical models for adjusting design floods for current conditions at sites with known trends. These files include (i) the observed annual peak-flow series in the conterminous US used to inform ranges of known moments and trends used in the simulation experiment, (ii) the 3,000 combinations o

Attributions for nonstationary peak streamflow records across the conterminous United States, 1941-2015 and 1966-2015

The U.S. Geological Survey Dakota Water Science Center, in cooperation with the Federal Highway Administration, analyzed annual peak-flow data to determine if trends are present and provide attribution of trends where possible. Work for the national trend attributions for nonstationary annual peak-flow records was broken into seven regions that are loosely based off of two-digit hydrologic unit wa
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Dakota Water Science Center

Peak-streamflow trends and change-points and basin characteristics for 2,683 U.S. Geological Survey streamgages in the conterminous U.S.

This data release contains drainage basin characteristics and peak-streamflow trend and change-point results for 2,683 U.S. Geological Survey (USGS) streamgages in the conterminous U.S. Data include streamgage identification number, name, drainage area, latitude, longitude, percent urban land use, dam storage, streamgage classification, record completeness status, lag-1 autocorrelation, trend slop
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New England Water Science Center

Daily streamflow datasets used to analyze trends in streamflow at sites also analyzed for trends in water quality and ecological condition in the Nation's rivers and streams

In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project of the National Water-Quality Program. One of the major goals of the NAWQA project is to determine how water-quality conditions change over time. To support that goal, long-term consistent and comparable monitoring has been c
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Water Resources, National Water Quality Program

Data Documenting the U.S. Geological Survey Peak-Flow File Data Verification Project, 2008-16

These data provide a public summary of the changes made to the U.S. Geological Survey peak-flow file since formal Nation-wide checking began in 2008. Coverage includes peak-flow sites in the United States and territories.
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Dakota Water Science Center

Total Phosphorus Load and Ancillary Data Related to Sources of Total Phosphorus in the Red River of the North Basin

The Red River of the North (Red River) transports phosphorus from North Dakota, Minnesota, and South Dakota, to Manitoba, Canada, and eventually into Lake Winnipeg. Phosphorus load (or flux) is the amount of total phosphorus (TP) transported by the Red River. The effect of TP load on water quality is a concern, especially with respect to downstream eutrophication issues in Lake Winnipeg, Manitob
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Dakota Water Science Center
Interview at 2018 South Dakota Hydrology Conference
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Karen Ryberg
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Image: Mud Lake Channel Arrowwood National Wildlife Refuge
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Image: The James River
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Image: Jim Lake Drawdown Channel Arrowwood National Wildlife Refuge
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Image: Jim Lake Drawdown Channel Arrowwood National Wildlife Refuge
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Filter Total Items: 45

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
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Water Resources

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
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Water Resources, New England Water Science Center

Projecting flood frequency curves under near-term climate change

Flood-frequency curves, critical for water infrastructure design, are typically developed based on a stationary climate assumption. However, climate changes are expected to violate this assumption. Here, we propose a new, climate-informed methodology for estimating flood-frequency curves under non-stationary future climate conditions. The methodology develops an asynchronous, semiparametric local-
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Water Resources, Dakota Water Science Center

Assessment of streamflow trends in the eastern Dakotas, water years 1960–2019

Hydrologic extremes, whether periods of drought or flooding, are occurring more frequently with greater severity and can have substantial economic impacts. Along with flooding, the timing and volume of streamflow also is changing across the United States. The focus of this report is to characterize a unique trend in mean annual streamflow occurring in eastern North and South Dakota, hereafter refe
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Dakota Water Science Center

Historical and paleoflood analyses for probabilistic flood-hazard assessments—Approaches and review guidelines

Paleoflood studies are an effective means of providing specific information on the recurrence and magnitude of rare and large floods. Such information can be combined with systematic flood measurements to better assess the frequency of large floods. Paleoflood data also provide valuable information about the linkages among climate, land use, flood-hazard assessments, and channel morphology. This d
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Ecosystems, Water Resources, Fort Collins Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Dakota Water Science Center, Oregon Water Science Center

Climate extremes as drivers of surface-water-quality trends in the United States

Surface-water quality can change in response to climate perturbations, such as changes in the frequency of heavy precipitation or droughts, through direct effects, such as dilution and concentration, and through physical processes, such as bank scour. Water quality might also change through indirect mechanisms, such as changing water demand or changes in runoff interaction with organic matter on t
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Water Resources, Virginia and West Virginia Water Science Center, Dakota Water Science Center

The role of the U.S. Geological Survey in monitoring North Dakota’s environmental conditions

No abstract available. 
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Dakota Water Science Center

Statistical methods in water resources

This text began as a collection of class notes for a course on applied statistical methods for hydrologists taught at the U.S. Geological Survey (USGS) National Training Center. Course material was formalized and organized into a textbook, first published in 1992 by Elsevier as part of their Studies in Environmental Science series. In 2002, the work was made available online as a USGS report.The t
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Water Resources

Flood-frequency estimation for very low annual exceedance probabilities using historical, paleoflood, and regional information with consideration of nonstationarity

Streamflow estimates for floods with an annual exceedance probability of 0.001 or lower are needed to accurately portray risks to critical infrastructure, such as nuclear powerplants and large dams. However, extrapolating flood-frequency curves developed from at-site systematic streamflow records to very low annual exceedance probabilities (less than 0.001) results in large uncertainties in the st
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Water Resources

seawaveQ—An R package providing a model and utilities for analyzing trends in chemical concentrations in streams with a seasonal wave (seawave) and adjustment for streamflow (Q) and other ancillary variables, version 2.0.0

The seawaveQ R package provides functionality and help to fit a parametric regression model, SEAWAVE-Q, to pesticide concentration data from stream-water samples to assess trends. The model incorporates the strong seasonality and high degree of censoring common in pesticide data, and users can incorporate numerous ancillary variables such as streamflow anomalies. The model is fitted to pesticide d
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Water Resources

Landscape drivers of dynamic change in water quality of US rivers

Water security is a top concern for social well-being and dramatic changes in the availability of freshwater have occurred as a result of human uses and landscape management. Elevated nutrient loading and perturbations to major ion composition have resulted from human activities and have degraded freshwater resources. This study addresses the emerging nature of stream water quality in the 21st ce
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Water Resources, New Jersey Water Science Center

Causal effect of impervious cover on annual flood magnitude for the United States

Despite consensus that impervious surfaces increase flooding, the magnitude of the increase remains uncertain. This uncertainty largely stems from the challenge of isolating the effect of changes in impervious cover separate from other factors that also affect flooding. To control for these factors, prior study designs rely on either temporal or spatial variation in impervious cover. We leverage b
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Water Resources, Pennsylvania Water Science Center
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Atrazine concentrations have decreased in streams and rivers across the United States

From 2002 to 2012, concentrations of atrazine decreased in more than one-half of 60 U.S. streams and rivers studied and increased in only about one...

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First-of-its-kind Interactive Map Brings Together 40 Years of Water-Quality Data

USGS provides a long-term look at changes in the quality of our nation’s rivers and streams

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Exhibit Fusing Art and Science Coming to Bismarck

Earth as Art, a U.S. Geological Survey traveling exhibit that merges art with dramatic Landsat imagery of the earth’s surface, is coming to Bismarck...

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The Scientific Story of the Souris: Could the 2011 Flood Happen Again?

   

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Modeling the Mouse: Future Flood Risk for the Souris River

The Souris, or Mouse, River Basin is currently in a wet climate period and will be at high flood risk for some time, according to a scientific model...

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Trends in River Pesticide Levels Echo Pesticide Use

Trends in pesticide concentrations in 38 major rivers in the U.S. during 1992-2010 reflect large-scale trends in pesticide use and regulatory changes...
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Local Scientist Receives Prestigious Mentoring Award

Aldo V. (Skip) Vecchia, a U.S. Geological Survey scientist, will be awarded the 2015 Jeanne E. Griffith Mentoring Award for his outstanding efforts...
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20-Year Study Shows Levels of Pesticides Still a Concern for Aquatic Life in U.S. Rivers and Streams

Levels of pesticides continue to be a concern for aquatic life in many of the Nation’s rivers and streams in agricultural and urban areas, according...

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