David R DeWalle, Ph.D.

David R DeWalle, Ph.D.

  • Professor Emeritus of Forest Hydrology
311 Forest Resources Building
University Park, PA 16802


  • B.S., University of Missouri (1964), Cum laude
  • M.S., University of Missouri (1966)
  • Ph.D., Colorado State University (1969)

Academic Interests:
Forest hydrology; forest microclimatology; isotope hydrology; snow hydrology; and impacts of ecosystem disturbances: atmospheric deposition, urbanization, and climate change

Affiliated Programs:
Penn State Institutes of the Environment; Pennsylvania Water Resources Research Center; Center for Watershed Stewardship.

Professional Affiliation:
American Water Resources Association, Fellow
American Geophysical Union
International Association of Hydrologic Sciences

Recent Research/Educational Projects:
Though I retired in 2007, I remain active as an environmental consultant and collaborator on analysis of the effects of 1990 Clean Air Act Amendments on forest stream chemistry in the Appalachians of Pennsylvania and West Virginia.  Key collaborators are Dr. Anthony Buda, USDA-Agricultural Research Service, Penn State; Dr. Elizabeth Boyer, Penn State, Ecosystem Science and Management; Dr. Christopher J. Grant, Biology Dept., Juniata College, Huntingdon, PA; and Dr. Pamela Edwards, USDA-Forest Service, Parsons, WV.  Major themes being pursued are: atmospheric deposition effects on watershed nitrogen retention efficiency, documentation of transient variations in atmospheric deposition and stream chemistry, and mercury bioaccumulation in forest aquatic ecosystems.

Selected Publications:

DeWalle, D R 2011. Benchmark Papers in Forest Hydrology, Introduction, Selection and Commentary. Int. Assoc. Hydrol. Sci., Benchmark Papers, no. 7, 474 p.

DeWalle, D R. 2010. Modeling stream shade: riparian buffer height and density as important as buffer width. J. Amer. Water Resourc. Assoc., vol 46(2):323-333.

O'Driscoll, M A, DeWalle D R. 2009. Seeps regulate stream nitrate concentration in a forest Appalachian catchment. J. Environ. Qual., vol 38:1-12.

Buda, A R, DeWalle D R. 2009. Dynamics of stream nitrate sources and flow pathways during stormflows on urban, forest and agricultural watersheds in central Pennsylvania, USA. Hydrological Processes, vol 23: 3292-3305.

DeWalle, D R, Rango, A. 2008. Principles of Snow Hydrology. Cambridge Univ. Press, 410 p.

MacDougall, S E, Carrick H J, DeWalle D R. 2008. Benthic algae in episodically-acidified Pennsylvania streams. Northeastern Naturalist, vol 15(2):189-208.

Adams, M B, DeWalle D R, Hom J L (eds). 2006. The Fernow Watershed Acidification Study. Environ. Pollution, vol. 11, Springer, 279 p.