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Karl Williard

Karl Williard, Professor and Director

Forestry, School of Forestry and Horticulture

Karl W.J. Williard is a Professor of Forest Hydrology and Watershed Management in the Forestry Program at Southern Illinois University Carbondale (SIU).

Dr. Williard teaches undergraduate and graduate courses in Watershed Management and Hydrology at SIUC. His current research interests include nitrogen, phosphorus, and sediment attenuation in riparian buffers; and agricultural land management impacts on soil and water quality. Since 1999, he has been awarded over $13.1 million in federal, state, and foundation grants to support his research program. This research has been disseminated in 54 peer-reviewed journal articles. A total of 25 M.S. students and 2 Ph.D. students have completed their Master's theses and Ph.D. dissertations under Dr. Williard's direction, as of the fall of 2020. From 2014-2023, Dr. Williard served as Executive Director of the Universities Council on Water Resources (UCOWR), a national professional water organization with its home office at SIU. Dr. Williard currently serves as the Director of the School of Forestry and Horticulture.

Research Interests and Specialities

  • Agricultural land management impacts on soil and water quality
  • Quantifying the water quality benefits of riparian buffers in agricultural watersheds
  • Impacts of forest management on hydrology, erosion, and sedimentation
  • Watershed management and planning.
Karl Williard
Office: Agriculture Building, Room 184-A
Phone: 618-453-7478


  • FOR 430 Wildland Watershed Management
  • FOR 502 Advanced Watershed Hydrology Management

Descriptions available for each of these classes in course listings for Forestry [FOR].


  • Pennsylvania State University, Forest Hydrology [Ph.D. 1999]
  • Pennsylvania State University, Environmental Pollution Control [M.S. 1996]
  • Lehigh University, Biology [B.A. 1994]

Recent Publications

(Articles where the senior author was a M.S. or Ph.D. student advisee are indicated with an asterisk) 

  • *Singh, G. *A.D. Thilakarathne*, K.W.J. Williard, J.E. Schoonover, R.L. Cook, K.L. Gage, and R. McElroy. 2020. Tillage and legume non-legume cover cropping effects on corn-soybean production. Agronomy Journal 112:2636-2648. doi 10.1002/agj2.20221
  • *Singh, G., G. Kaur, K. Williard, J. Schoonover, and K.A. Nelson. 2020. Managing phosphorus loss from agroecosystems of the Midwestern United States: A review. Agronomy 10, 561 doi:10.3390/agronomy10040561
  • *Singh, G. A.D., M. Dhakal, L. Yang, G. Kaur, K.W.J. Williard, J.E. Schoonover, and A. Sadeghpour. 2020. Decomposition and nitrogen release of cover crops in reduced- and no-tillage systems. Agronomy Journal 112:3605–3618. doi: 10.1002/agj2.20268
  • *Singh, G., K. Williard, J. Schoonover, K.A. Nelson, and G. Kaur. 2019. Cover crops and landscape position effects on nitrogen dynamics in plant-soil-water pools. Water 11, 513 doi:10.3390/w11030513
  • *Singh, G., *N.M.M. Mejia, K.W.J. Williard, J.E. Schoonover, J.W. Groninger. 2019. Watershed Vulnerability to Invasive N2-Fixing Autumn Olive and Consequences for Stream Nitrogen Concentrations. Journal of Environmental Quality 48:614-623.
  • Sebestyen, S.D., D.S. Ross, J.B. Shanley, K.W.J. Williard, + 26 additional authors. 2019.  Unprocessed Atmospheric Nitrate in Waters of the Northern Forest Region in the U.S. and Canada. Environmental Science & Technology 53:3620-3633.
  • *Singh, G., G. Kaur, K.W.J. Williard, K. Nelson, and J.E. Schoonover. 2019. Cover crops and topography differentially impacts weeds at a watershed scale. Weed Technology.
  • *Singh, G., J.E. Schoonover, K.W.J. Williard, G. Kaur, and J. Crim. 2018. Carbon and Nitrogen Pools in Deep Soil Horizons at Different Landscape Positions. Soil Science Society of America Journal 82:1512-1525. doi 10.2136/sssaj2018.03.0092
  • *Singh, G., D. Goble, J.E. Schoonover, K.W.J. Williard, and J.J. Zaczek. 2018. Allometry, Morphometry, and Soil Characterization of Giant Cane (Arundinaria gigantea) Stands. Ecological Restoration. 36. 314. 10.3368/er.36.4.315.
  • *Singh, G., K.W.J. Williard, and J.E. Schoonover. 2018. Cover Crops and Tillage Influence on Nitrogen Dynamics in Plant-Soil-Water Pools. Soil Science Society of America Journal. 82. 10.2136/sssaj2018.03.0111.
  • *Shrestha, P., K.W.J. Williard, J.E. Schoonover, and L. Park. 2018. Prevalence of Concentrated Flow Paths in Agricultural Fields in Southern Illinois. Water, Air, & Soil Pollution. 229. 10.1007/s11270-018-3841-y.
  • Eade, A., *G. Singh, J.E. Schoonover, K.W.J. Williard, and J.J. Zaczek. 2018. Innovative Sandbag Propagation Method for Giant Cane (Arundinaria gigantea (Walter) Muhl.). Castanea. 83. 10.2179/17-142.
  • *Singh, G., J.E. Schoonover, and K.W.J. Williard. 2018. Cover Crops for Managing Stream Water Quantity and Improving Stream Water Quality of Non-Tile Drained Paired Watersheds. Water. 10. 10.3390/w10040521.
  • Google Scholar profile

Honors and Awards

  • Chair, American Water Resources Association Agricultural Hydrology and Water Quality Conference (international conference). St. Louis, MO. Mar. 25-27, 2013
  • Outstanding Scholar, College of Agricultural Sciences, SIUC, 2012.
  • Board of Directors, American Water Resources Association. Term 2009 – 2011.
  • Outstanding Scholar, College of Agricultural Sciences, SIUC, 2009
  • Technical Program Chair, 2007 Annual American Water Resources Association Conference. Responsible for conducting and coordinating abstract review (420 abstracts) and creating the technical program (81 oral sessions and 6 poster sessions).
  • Pyramid Award, American Water Resources Association. This national award recognizes a young professional who has demonstrated outstanding achievements, talents, and leadership potential through their professional activities in water resources.