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Gerard McMahon

Research Geographer
U.S. Geological Survey
Water Resources Discipline

North Carolina Water Science Center
3916 Sunset Ridge Rd
Raleigh, NC 26707

(919) 571-4068 Voice
(919) 571-4041 FAX
gmcmahon@usgs.gov

Education · Research · Publications

Educational Background

Doctor of Philosophy, City and Regional Planning (1995) The University of North Carolina at Chapel Hill

Master of City and Regional Planning (1985) The University of North Carolina at Chapel Hill

Master of Science, Agricultural Economics (1976) University of Missouri at Columbia

Bachelor of Arts, (June 1974) Johns Hopkins University

Recent Research Projects

Effects of urbanization. Activities include the design and implementation of multiple National Water-Quality Assessment (NAWQA) projects to study the interrelation of urbanization and physical, chemical, and biological water-quality responses. Responsible for GIS-based characterization of physical and socioeconomic descriptors for study watersheds; development of metrics for hydrologic variability based on continuous stage data; and analysis of the relation between basin characteristics and hydrologic variability.

Nutrient fate and transport modeling. Activities include calibrating a spatially referenced regression model (SPARROW) for three major coastal North Carolina drainage basins to estimate the effects of nutrient sources, landscape characteristics, and in-stream processes on nutrient loading. Responsible for developing spatial and tabular data and for model calibration.

Landscape regionalization. Activities include participating in Federal interagency committee for developing a map of commonly used ecological regions, developing spatial environmental frameworks for local and national NAWQA Program use, and participation in the USGS ecoregionalization science plan development.

Selected Publications

McMahon, Gerard, 2007, Consequences of land-cover misclassification in models of impervious surface: Photogrammetric Engineering and Remote Sensing, v. 73, no. 12, p. 1343-1353.

McMahon, Gerard, Benjamin, S.P., Clarke, K., Findley, J.E., Fisher, R.N., Graf, W.L., Gundersen, L.C., Jones. J.W., Loveland, T.R., Roth K.S., Usery, E.L., and Wood, N.J., 2005, Geography for a changing world: A science strategy for the geographic research of the U.S. Geological Survey, 2005-2015. U.S. Geological Survey, Circular 1281.

McMahon, Gerard, Wiken, E.B., and Gautier, D.A. 2004. Toward a scientifically rigorous basis for developing mapped ecological regions: Environmental Management, v. 34, suppl. 1, p. S111-S124.

McMahon, Gerard, Alexander, R.B., and Qian, S., 2003, Support of TMDL programs using spatially referenced regression models, American Society of Civil Engineers Journal of Water Resources Planning and Management, v. 129, no. 4, p. 315-329.

McMahon, Gerard, Bales, J.D., Coles, J.F., Giddings, E.M.P., and Zappia, Humbert, 2003, Use of stage data to characterize hydrologic conditions in an urbanizing environment: Journal of the American Water Resources Association, v. 39, no.6, p. 1529-1546.