Karen R Ryberg, Ph.D.

Expertise/Projects/Research Interests

• Statistical analysis of hydrologic data, including parametric and nonparametric trend analysis and cluster analysis
• Concentration trend analysis for pesticides 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
• 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
• Course Coordinator and member of team teaching Statistical Methods for Environmental Data Analysis class at the USGS National Training Center
• Associate Editor, Hydrological Sciences Journal

Education

• Doctorate of Philosophy, Environmental and Conservation Sciences - Environmental Science Track, 2015
  North Dakota State University, Fargo, North Dakota
  • Dissertation: The impact of climate variability on streamflow and water quality in the North Central United States
     
• Graduate Certificate, Data Mining and Applications, 2008
  Stanford University, Stanford, California
   
• 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 September 2003
     
• Associate of Applied Science, Computer Support Specialist, 2003
  Bismarck State College, Bismarck, North Dakota
   
• Certificate, Management, 1996
  University of Mary, Bismarck, North Dakota
   
• Bachelor of Arts, Mathematics, 1995
  Luther College, Decorah, Iowa

Publications

Ryberg, K.R., Hodgkins, G.A., and Dudley, R.W., 2019, Change points in annual peak streamflows—Method comparisons and historical change points in the United States: Journal of Hydrology, 124307, https://doi.org/10.1016/j.jhydrol.2019.124307.

Ryberg, K.R., Blomquist, J.D., Sprague, L.A., Sekellick, A.J., and Keisman, J., 2018, Modeling drivers of phosphorus loads in Chesapeake Bay tributaries and inferences about long-term change: Science of The Total Environment, v. 616-617, p. 1423–1430, https://doi.org/10.1016/j.scitotenv.2017.10.173.

Dudley, R.W., Archfield, S.A., Hodgkins, G.A., Renard, B., and Ryberg, K.R., 2018, Basin characteristics and peak-streamflow trends and change-points for 2,683 USGS streamgages in the conterminous U.S.: U.S. Geological Survey data release, DOI: 10.5066/P9AEGXY0.

Ryberg, K.R., Hodgkins, G.A., Dudley, R., 2018, Flood-frequency analysis in a changing world: 2018 Western South Dakota Hydrology Conference Program and Abstracts, April 19, 2018, Rushmore Plaza Civic Center, Rapid City, S. Dak., p. 15.

Farmer, W.H., Murphy, J.C., Riskin, M.L., Ryberg, K.R., and Zuellig, R.E., 2017, 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: U.S. Geological Survey data release, DOI: 10.5066/F7D798JN.

Oelsner, G.P., Sprague, L.A., Murphy, J.C., Zuellig, R.E., Johnson, H.M., Ryberg, K.R., Falcone, J.A., Stets, E.G., Vecchia, A.V., Riskin, M.L., De Cicco, L.A., Mills, T.J., and Farmer, W.H., 2017, Water-quality trends in the Nation’s rivers and streams, 1972–2012—Data preparation, statistical methods, and trend results: U.S. Geological Survey Scientific Investigations Report 2017–5006, 136 p., https://doi.org/10.3133/sir20175006.

Ryberg, K.R., 2017, Flood-frequency analysis in a changing world: Program and Abstracts, 2017 Western South Dakota Hydrology Meeting, April 6, 2017, Rushmore Plaza Civic Center, Rapid City, S. Dak., p. 32.

Ryberg, K.R., 2017, Structural equation model for total phosphorus loads in the Red River of the North Basin: Journal of Environmental Quality, v. 46, no. 5, p. 1072-1080, https://dx.doi.org/10.2134/jeq2017.04.0131.

Ryberg, K.R., Goree, B.B., Williams-Sether, Tara, and Mason, R.R., Jr., 2017, The U.S. Geological Survey peak-flow file data verification project, 2008–16: U.S. Geological Survey Scientific Investigations Report 2017–5119, 61 p., https://doi.org/10.3133/sir20175119.

Ryberg, K.R., Murphy, J.C., Falcone, J.A., Riskin, M.L., Wieben, C.M., and Vecchia, A.V., 2017, Pesticide concentration and streamflow datasets used to evaluate pesticide trends in the Nation’s rivers and streams, 1992–2012: U.S. Geological Survey data release, DOI: 10.5066/F7BC3WPC.

Ryberg, K.R., Sekellick, A.J., and Falcone, J.A., 2017, Ancillary data related to nutrients in the Chesapeake Bay—Data supporting structural equation modeling of nutrient loads: U.S. Geological Survey data release, DOI: 10.5066/F7NG4NQ4.

Williams-Sether, Tara, Ryberg, K.R., and Goree, B.B., 2017, Data documenting the U.S. Geological Survey peak-flow file data verification project, 2008-16: U.S. Geological Survey data release, https://doi.org/10.5066/F7GH9G3P.

Kolars, K.A., Vecchia, A.V., and Ryberg, K.R., 2016, Stochastic model for simulating Souris River Basin precipitation, evapotranspiration, and streamflow for 2014–2050: U.S. Geological Survey Scientific Investigations Report 2015–5185, 55 p., DOI: 10.3133/sir20155185.

Nustad, R.A., Kolars, K.A., Vecchia, A.V., and Ryberg, K.R., 2016, 2011 Souris River flood—Will it happen again?: U.S. Geological Survey Fact Sheet 2016–3073, 4 p., DOI: 10.3133/fs20163073.

Ryberg, K.R., Akyüz, F.A., Wiche, G.J., and Lin, W., 2016, Changes in seasonality and timing of peak streamflow in snow and semi-arid climates of the north central United States, 1910–2012: Hydrologic Processes, v. 30, p. 1208–1218, DOI: 10.1002/hyp.10693.

Ryberg, K.R., and Blomquist, J., May 5, 2016, Assessing the causes of changes in nutrient loading from major tributaries of Chesapeake Bay: Abstracts of the 10th National Monitoring Conference, May 2–6, 2016, Tampa, Florida, p. 61, http://acwi.gov/monitoring/conference/2016/2016-nmc-abstracts.pdf.

Ryberg, K.R., Falcone, J.A., and Kolars, K.A., 2016, Total phosphorus load and ancillary data related to sources of total phosphorus in the Red River of the North Basin—Data supporting structural equation modeling of total phosphorus loads: U.S. Geological Survey data release, DOI: 10.5066/F79G5JWD.

Ryberg, K.R., Hirsch, R.M., Helsel, D., Gilroy, E., and Archfield, S.A., May 4, 2016, Statistical methods in water resources—New edition, new methods, now using R: Abstracts of the 10th National Monitoring Conference, May 2–6, 2016, Tampa, Florida, p. 29, http://acwi.gov/monitoring/conference/2016/2016-nmc-abstracts.pdf.

Ryberg, K.R., Vecchia, A.V., Akyüz, F.A., Lin, W., 2016, Tree-ring based estimates of long-term seasonal precipitation in the Souris River Region of Saskatchewan, North Dakota, and Manitoba: Canadian Water Resources Journal / Revue canadienne des ressources hydriques, v. 41, no. 3, p. 412­–428, DOI: 10.1080/07011784.2016.1164627.

Ryberg, K.R., 2016, R vs. Python in Earth Sciences: Earth Science Women's Network newsletter, no. 11, Winter 2015-16, p. 8-9. [Link]

Ryberg, K.R, 2015, The impact of climate variability on streamflow and water quality in the North Central United States: Fargo, North Dakota State University, Ph.D. dissertation, 277 p.

Ryberg, K.R., Akyüz, F.A., and Lin, W., 2015, Changes in total phosphorus concentration in the Red River of the North Basin, 1970–2012: American Society of Agricultural and Biological Engineers ASABE/CSBE North Central Intersectional Meeting, Fargo, N. Dak., April 10–11, 2015, paper number RRV15-054, 9 p., DOI: 10.13031/rrv2015054.

Ryberg, K.R., Akyüz, F.A., Wiche, G.J., and Lin, W., April 15, 2015, Changes in seasonality and timing of peak streamflow in the north-central United States, 1910–2012: Program and Abstracts, Western South Dakota Hydrology Meeting, April 15–16­, 2015, Rushmore Plaza Civic Center, Rapid City, S. Dak., p. 16.

Ryberg, K.R., Gilliom, R.J., 2015, Trends in pesticide concentrations and use for major rivers of the United States: Science of the Total Environment, v. 538, p. 431–444, DOI: 10.1016/j.scitotenv.2015.06.095.

Ryberg, K.R., Lin, W., Vecchia, A.V., 2014, Impact of climate variability on runoff in the north-central United States: Journal of Hydrologic Engineering, v. 19, no. 1, p. 148–158, DOI: 10.1061/(ASCE)HE.1943-5584.0000775.

Ryberg, K.R., Vecchia, A.V., Gilliom, R.J., Martin, J.D., 2014, Pesticide trends in major rivers of the United States, 1992–2010: U.S. Geological Survey Scientific Investigations Report 2014–5135 63 p., DOI: 10.3133/sir20145135.

Stone, W.W., Gilliom, R.J., and Ryberg, K.R., 2014, Pesticides in U.S. streams and rivers—occurrence and trends during 1992–2011: Environmental Science & Technology, v. 48, no. 19, p. 11025–11030, DOI: 10.1021/es5025367.

Ryberg, K.R., and Vecchia, A.V., 2013, 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: U.S. Geological Survey Open-File Report 2013–1255, 13 p., DOI: 10.3133/ofr20131255.

Peterson, T.C., Heim, R., Hirsch, R.M., Kaiser, D., Brooks, H., Diffenbaugh, N.S., Dole, R., Giovannettone, J., Guiguis, K., Karl, T.R., Katz, R.W., Kunkel, K., Lettenmaier, D., McCabe, G.J., Paciorek, C.J., Ryberg, K.R., Schubert, S., Silva, V.B.S., Stewart, B., Vecchia, A.V., Villarini, G., Vose, R.S., Walsh, J., Wolock, D., Wolter, K., Woodhouse, C.A., Wehner, M., and Wuebbles, D., 2013, Monitoring and understanding changes in heatwaves, coldwaves, floods and droughts in the United States—State of knowledge: Bulletin of the American Meteorological Society, v. 94, no. 6, 821–834, DOI: 10.1175/BAMS-D-12-00066.1.

Ryberg, K.R., and Vecchia, A.V., 2012, waterData—An R package for retrieval, analysis, and anomaly calculation of daily hydrologic time series data, version 1.0: U.S. Geological Survey Open-File Report 2012–1168, 8 p., http://pubs.usgs.gov/of/2012/1168/.

Hirsch, R.M., and Ryberg, K.R., 2012, Has the magnitude of floods across the USA changed with global CO₂ levels? Hydrological Sciences Journal, v. 57, no. 1, p. 1–9, DOI: 10.1080/02626667.2011.621895.

Ryberg, K.R., Hirsch, R.M., and Wiche, G.J., June 29, 2011, Trends in flood magnitude in the United States, with emphasis on the Red River of the North Basin: Proceedings of the 64th Canadian Water Resources Association National Conference, June 27–30, 2011, St. John’s, Newfoundland and Labrador, Canada, p. 92.

Wiche, G.J., Ryberg, K.R., Vecchia, A.V., June 29, 2011, Implications of increased risk of extreme flooding in the northern Great Plains since 1993, with emphasis on the Red River of the North: Proceedings of the 64th Canadian Water Resources Association National Conference, June 27–30, 2011, St. John’s, Newfoundland and Labrador, Canada, p. 91.

Ryberg, K.R., Vecchia, A.V., Martin, J.D., and Gilliom, R.J., 2010, Trends in pesticide concentrations in urban streams in the United States, 1992–2008: U.S. Geological Survey Scientific Investigations Report 2010–5139, 42 p., http://pubs.usgs.gov/sir/2010/5139/.

Ryberg, K.R., Emerson, D.G., and Macek-Rowland, K.M., 2009, Solid precipitation measurement intercomparison in Bismarck, North Dakota, from 1988 through 1997: U.S. Geological Survey Scientific Investigations Report 2009–5180, 24 p., http://pubs.usgs.gov/sir/2009/5180/.

Ryberg, K.R., and Hiemenz, G., 2009, Summary and analysis of water-quality data for the Arrowwood National Wildlife Refuge, east-central North Dakota, 1987–2004: U.S. Geological Survey Scientific Investigations Report 2009–5017, 92 p., http://pubs.usgs.gov/sir/2009/5017/.

Ryberg, K.R., 2008, PFReports: A program for systematic checking of annual peaks in NWISWeb, U.S. Geological Survey Open-File Report 2008–1284, 18 p., http://pubs.usgs.gov/of/2008/1284/.

Ryberg, K.R., Macek-Rowland, K.M., Wiche, G.J., and Klapprodt, L.A., 2007, 10th Anniversary of the 1997 Red River flood: U.S. Geological Survey General Information Publication 49, http://pubs.usgs.gov/gip/2007/49/.

Ryberg, K.R., Macek-Rowland, K.M., Banse, T.A., and Wiche, G.J., 2007, A history of flooding in the Red River Basin: U.S. Geological Survey General Information Publication 55, http://pubs.usgs.gov/gip/2007/55/.

Ryberg, K.R., 2007, Summary and trend analysis of water-quality data for the Oakes Test Area, southeastern North Dakota, 1984–2004: U.S. Geological Survey Scientific Investigations Report 2007–5056, 118 p., http://pubs.usgs.gov/sir/2007/5056/.

Ryberg, K.R., 2007, Continuous water-quality monitoring and regression analysis to estimate constituent concentrations and loads in the Sheyenne River, North Dakota, 1980–2006: U.S. Geological Survey Scientific Investigations Report 2007–5153, 22 p., http://pubs.usgs.gov/sir/2007/5153/.

Ryberg, K.R., and Vecchia, A.V., 2006, Water-quality trend analysis and sampling design for the Devils Lake Basin, North Dakota, January 1965 through September 2003: U.S. Geological Survey Scientific Investigations Report 2006–5238, 64 p., http://pubs.usgs.gov/sir/2006/5238/.

Ryberg, K.R., 2006, Continuous water-quality monitoring and regression analysis to estimate constituent concentrations and loads in the Red River of the North, Fargo, North Dakota, 2003–05: U.S. Geological Survey Scientific Investigations Report 2006–5241, 35 p., http://pubs.usgs.gov/sir/2006/5241/.

Ryberg, K.R., 2006, Cluster analysis of water-quality data for Lake Sakakawea, Audubon Lake, and McClusky Canal, central North Dakota, 1990–2003: U.S. Geological Survey Scientific Investigations Report 2006–5202, 38 p., http://pubs.usgs.gov/sir/2006/5202/.

Ryberg, K.R., Damschen, W.C., and Vecchia, A.V., 2005, Graphical user interface for accessing water-quality data for the Devils Lake Basin, North Dakota: U.S. Geological Survey Open-File Report 2005–1419, 15 p., http://pubs.usgs.gov/of/2005/1419/.

Macek-Rowland, K.M., Arntson, A.D., Ryberg, K.R., Dahl, A. L., Lieb, A., 2004, Water-use data for the Red River of the North Basin, North Dakota, Minnesota, and South Dakota, 1979–2001: U.S. Geological Survey Open-File Report 2004–1308, 260 p., http://pubs.water.usgs.gov/ofr2004-1308/.