James Lynch, Ph.D.

James Lynch, Ph.D.

  • Professor Emeritus of Forest Hydrology
University Park, PA 16802


  • B.S., The Pennsylvania State University (1966)
  • M.S., The Pennsylvania State University (1969)
  • Ph.D., The Pennsylvania State University (1974)

Academic Interests

Effects of forest management and atmospheric deposition on water resources; forest hydrology; spatial and temporal variations in wet deposition; water quality

Professional Affiliation:

Chair, National Atmospheric Deposition Program/National Trends Network; Member, Science and Technical Advisory Committee, Chesapeake Bay Program

Recent Research/Educational Projects

Modeling Changes in the Chemical Climate Related to Atmospheric Deposition Effective linkages between global change parameters and environmental effects require detailed spatial patterns in deposition of toxic substances. Current monitoring programs are spatially limited and extrapolation of point estimates to unmonitored regions results in errors that often limit cause-effect assessments. To alleviate this problem, a 3-dimensional precipitation model was developed using elevation, topographic features, and existing precipitation data to estimate precipitation in unmonitored regions on a 100 m grid scale. Combining model output with concentration estimates yields wet deposition estimates at a spatial scale that permits meaningful environmental assessments.

The Leading Ridge Experimental Watersheds The Leading Ridge Experimental Watersheds were established in 1958 as a cooperative project between the School of Forest Resources, the Pennsylvania Bureau of Forestry, and the U.S. Forest Service, Northeastern Forest Experiment Station. The purpose of this cooperative project was to study the effects of forest management activities on water resources and to support a graduate research program in forest hydrology and watershed management. The watersheds have been a focal point for many studies dealing with such diverse topics as the effects of acid rain on episodic and long-term changes in stream chemistry and acidity, the effects of gypsy moth defoliation on water quality, and the potential effect of climate change on water supply. The watersheds were also used to develop and evaluate the effectiveness of Best Management Practices (BMPs) for controlling water pollution during the following forest harvesting. The long-term implication of forest harvesting on both water quality and quantity are still under investigation as are changes in stream chemistry associated with implementation of the Clean Air Act Amendments, Title IV to reduce acidic deposition in the Eastern U.S.

Evaluating the Effectiveness of the Clean Air Act Amendments in Reducing Acidic Deposition in the USA Phase I of the Title IV of the Clean Air Act Amendments of 1990 (CAAA) was implemented on 1 January 1995 to reduce acidic deposition in the Eastern U.S. On that date, limitations were imposed on sulfur dioxide emissions from 110 coal-fired electric utility plants in 21 states of which 17 are east of the Mississippi River. Sulfur dioxide emissions at these plants dropped an average 2.86 million tons (39%) from 1995 through 1997, when compared to mean 1993-1994 emissions from these plants. Further reductions in emission are scheduled under Phase II of Title IV, which will be implemented on 1 January 2000. The purpose of this study is to determine the effectiveness o the reductions in emission on precipitation chemistry and atmospheric deposition throughout the USA.

Assessing Atmospheric Deposition Trends in Pennsylvania and Their Impact on Stream Chemistry Pennsylvania receives the most acidic deposition in North America. Because of the impact of atmospheric deposition on sensitive ecosystems in the state, a monitoring network was established in the state in 1980 to determine the spatial and temporal variations in deposition. The long-term objective of the project is to determine the effectiveness of national and state regulations designed to reduce acidic deposition in the state in reversing the long-term acidification of streams draining forested watersheds. In addition, nitrogen deposition contributions to nitrate export from both harvested and non-harvested watershed are also being investigated. Nitrogen deposition and export from forested watersheds has been identified as a significant source of nitrate export to the Chesapeake Bay. This research is being conducted on the Leading Ridge Watersheds. Wet deposition data from a nearby acid rain monitoring site will be analyzed along with stream water chemistry data from the Leading Ridge Watersheds from the late 1970s to the present.

Selected Publications

Dietterick, B.C., J.A. Lynch, and e.S. Corbett. 1999. A calibration procedure using TOPMODEL to determine suitability for evaluating potential climate change effect on water yield, J. of the american Water Resources Assoc, 35(2):457-468.