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Peter Griffiths

Supervisory Hydrologist

Contact Info


Short Biography

Professional Experience

U.S. Geological Survey, Denver, CO, 2009 to present. Assistant Chief, Central Branch of the National Research Program. The USGS National Research Program conducts a wide variety of basic research in the hydrologic sciences.

U.S. Geological Survey, Tucson, AZ, 2005 to 2009. Research Hydrologist, National Research Program. Conducted research focusing on mass-movement and sediment transport in the southwestern United States. Particular interests included the frequency, processes of initiation, and geomorphic impact of debris flows, especially in the canyons of the Colorado River system, and sediment yield and transport in small drainage basins in arid environments. Methods typically involve the collection and analysis of geospatial data and the modeling of landscape processes, and the use of naturally-occurring radioisotopes to track sediment movement and date sediment deposits.

U.S. Geological Survey, Tucson, AZ, 1991 to 2005. Hydrologist, National Research Program. Provided technical support in hydrologic and geomorphic fieldwork, field survey, GIS, sediment analysis, and statistics to the Landscape change in the Southwest research project.

Education

M.S., 1995, University of Ariziona, Geosciences (Minor in Hydrology)

B.A., 1987, Yale University, Archeological Studies





Publications

Magirl, C.S., Griffiths, P.G., and Webb, R.H., 2010, Analyzing debris flows with the statistically calibrated empirical model LAHARZ in southeastern Arizona, USA, Geomorphology, v. 119, p. 11-124.

Griffiths, P.G., Webb, R.H., Muth, A, Fisher, M., 2009, Plant and ventifacts delineate late Holocene wind vectors in the Coachella Valley, U.S.A., Aeolian Research, v. 1, p. 63-73

Griffiths, P.G., Magirl, C.S., Webb, R.H., Pytlak, E., Troch, P.A., Lyon, S.W., 2009, Spatial distribution and frequency of recipitation during an extreme event: the July 2006 mesoscale convective complexes and floods in southeastern Arizona, Water Resources Research, v. 45, W07419, doi:10.1029/2008WR007380, 14 p.

Webb, R.H., Magirl, C.S., Griffiths, P.G., Youberg, A., and Pearthree, P.A., 2008, Slopes fail, debris flows in extremis: Southwest Hydrology, v. 7, p. 8. [Link]

Webb, R.H., Griffiths, P.G., and Rudd, L.P., 2008, Occurrence of debris flows on the Colorado Plateau: the influence of clay mineralogy and chemistry, Geological Society of America Bulletin, vol. 120, No. 7/8, p. 1010-1020. [Link]

Magirl, C.S., Breedlove, M.J., Webb, R.H., and Griffiths, P.G., 2008, Modeling water-surface elevations and virtual shorelines for the Colorado River in Grand Canyon, Arizona: U.S. Geological Survey Scientific Investigation Report 2008-5075, 32 [Link]

Webb, R.H., Magirl, C.S., Griffiths, P.G., and Boyer, D.E., 2008, Debris flows and floods in southeastern Arizona from extreme recipitation in July 2006: magnitude, frequency, and sediment delivery: U.S. Geological Survey Open-File Report 2008-1274, 95 p. [Link]

Magirl, C.S., C. Shoemaker, R.H. Webb, M. Schaffner, P.G. Griffiths, E. Pytlak, 2007, “Debris flows and record floods from extreme mesoscale convective thunderstorms over the Santa Catalina Mountains, Arizona,” U.S. Geological Survey Open-File Report 2007-1108, 1 sheet. [Link]

Magirl, C.S., R.H. Webb, M. Schaffner, S.W. Lyon, P.G. Griffiths, C. Shoemaker, C.L. Unkrich, S. Yatheendradas, P.A. Troch, E. Pytlak, D.C. Goodrich, S.L.E. Desilets, A. Youberg, and P.A. Pearthree, 2007, “Impact of recent extreme Arizona storms,” Eos Transactions, American Geophysical Union, Vol. 88, No. 17, p. 191, 193. [Link]

Webb, R.H., Griffiths, P.G., Wallace, C.S.A., and Boyer, D.E., 2007, Channel response to low-elevation desert fire: the King Valley fire of 2005: U.S. Geological Survey Report Series Data-DS 275, 52 p. [Link]

Griffiths, P.G., Hereford, R., and Webb, R.H., 2006, Sediment yield and runoff frequency of small drainage basins in the Mojave Desert, California and Nevada: U.S. Geological Survey Fact Sheet 2006-3007, 4 p. [Link]

Magirl, C.S., Griffiths, P.G., and Webb R.H., 2006, “ADV point measurements within rapids of the Colorado River in Grand Canyon,” in Graham, R. (editor), Examining the Confluence of Environmental and Water Concerns, Proceedings of the 2006 World Environmental and Water Resources Congress, Omaha, Nebraska, May 21-25, 2006: Reston, Virginia, American Society of Civil Engineers Publication, 10 p.

Yanites, B.J., Webb, R.H., Griffiths, P.G., and Magirl, C.S., 2006, Debris-flow deposition and reworking by the Colorado River in Grand Canyon, Arizona, Water Resources Research, v. 42, W11411, doi:10.1029/2005WR004847, 16 p.

Webb, R.H., Griffiths, P.G., Magirl, C.S., and Hanks, T.C., 2005, Debris flows in Grand Canyon and the rapids of the Colorado River, in Gloss, S.P., Lovich, J.E., and Melis, T.S. (eds.), The State of the Colorado River Ecosystem in Grand Canyon: U.S. Geological Survey Circular 1282, p. 119-132. [Link]

Griffiths, P.G., Hereford, R., and Webb, R.H., 2005, Sediment yield and runoff frequency from small drainages in the Mojave Desert: Geomorphology, v. 74, p. 232-244.

Magirl, C.S., Webb, R.H., and Griffiths, P.G., 2005, Long-term change in the water-surface profile of the Colorado River in Grand Canyon, Arizona: Water Resources Research, v. 41, W05021, doi:10.1029/2003WR002519, 10 p.

Webb, R.H., Griffiths, P.G., and Melis, T.S., 2004, Debris flows and rapids in Grand Canyon: Implications for erosion rates and evacuation of sediment from tributary canyons, in Young, R.A., and Spamer, E.E. (eds.), 2001, The Colorado River: Origin and evolution: Grand Canyon, Arizona, Grand Canyon Association Monograph 12, p. 183-188.

Griffiths, P.G., Webb, R.H., and Melis, T.S., 2004, Initiation and frequency of debris flows in Grand Canyon, Arizona: Journal of Geophysical Research, Earth Surface, v. 109, F04002, doi:10.1029/2003JF000077, 14 p.

Webb, R.H., Melis, T.S., and Griffiths, P.G., 2003, Debris flows and the Colorado River, in Beus, S.S., and Morales, M., Grand Canyon Geology, 2nd edition: New York, Oxford University Press, p. 371-390.

Griffiths, P.G., Webb, R.H., Lancaster, N., Kaehler, C.A., and Lundstrom, S.C., 2002, Long-term sand supply to Coachella Valley fringe-toed lizard (Uma inornata) habitat in the northern Coachella Valley, California: U.S. Geological Survey Water-Resources Investigations Report 02-4013, 49 p. [Link]

Webb, R.H., and Griffiths, P.G., 2001, Sediment delivery by ungaged tributaries of the Colorado River in Grand Canyon: U.S. Geological Survey Fact Sheet FS-018-01, 4 p. [Link]

Webb, R.H., Griffiths, P.G., and Hartley, D.R., 2001, Techniques for estimating sediment yield of ungaged tributaries on the southern Colorado Plateau: Reno, Nevada, Proceedings of the Seventh Federal Interagency Sedimentation Conference, p. I-24 to I-31.

Webb, R.H., and Griffiths, P.G., 2001, Monitoring of coarse sediment inputs to the Colorado River in Grand Canyon: U.S. Geological Survey Fact Sheet FS-019-01, 4 p. [Link]

Webb, R.H., Griffiths, P.G., Melis, T.S., and Hartley, D.R., 2000, Sediment delivery by ungaged tributaries of the Colorado River in Grand Canyon: U.S. Geological Survey Water Resources Investigations Report 00-4055, 67 p [Link]

Pizzuto, J.E., Webb, R.H., Griffiths, P.G., Elliott, J.G, and Melis, T.S., 1999, Entrainment and transport of cobbles and boulders from debris fans, in Webb, R.H., Schmidt, J.C., Marzolf, G.R., and Valdez, R.A., The controlled flood in Grand Canyon: Scientific experiment and management demonstration: Washington, D.C. American Geophysical Union, Geophysical Monograph 110, p. 53-70.

Webb, R.H., Griffiths, P.G., Melis, T.S., Elliott, J.G., and Pizzuto, J.E., 1999, Reworking of debris fans by the 1996 controlled flood in Grand Canyon, in Webb, R.H., Schmidt, J.C., Valdez, R.A., and Marzolf, G.R., The 1996 flood in Grand Canyon: Scientific experiment and management demonstration: Washington, D.C. American Geophysical Union, Geophysical Monograph, p. 37-51.

Webb, R.H., Melis, T.S., Griffiths, P.G., Elliott, J.G., Cerling, T.E., Poreda, R.J, Wise, T.W., and Pizzuto, J.E., 1999, Lava Falls Rapid in Grand Canyon, Effects of late Holocene debris flows on the Colorado River: U.S. Geological Survey Professional Paper 1591, 90 p. [Link]

Griffiths, P.G., Webb, R.H., and Melis, T.S., 1997, Initiation of debris flows in bedrock canyons of the Colorado River, USA, in Chen, Cheng-lung (editor), Debris-flow hazards mitigation: Mechanics, prediction, and assessment: New York, American Society of Civil Engineers, p. 12-20.

Webb, R.H., Melis, T.S., Griffiths, P.G., and Elliott, J.G., 1997, Reworking of aggraded debris fans by the 1996 controlled flood on the Colorado River in Grand Canyon National Park, Arizona: U.S. Geological Survey Open-file Report 97-16, 40 p. [Link]

Melis, T.S., Webb, R.H., and Griffiths, P.G., 1997, Debris flows in Grand Canyon National Park: Peak discharges, flow transformations, and hydrographs, in Chen, Cheng-lung (editor), Debris-flow hazards mitigation: Mechanics, prediction, and assessment: New York, American Society of Civil Engineers, p. 727-736.

Griffiths, P.G., Webb, R.H., and Melis, T.S., 1996, Initiation and frequency of debris flows in Grand Canyon, Arizona: U.S. Geological Survey Open-File Report 96-491, 35 p. [Link]

Melis, T.S., Webb, R.H., Griffiths, P.G., and Wise, T.J., 1994, Magnitude and frequency data for historic debris flows in Grand Canyon National Park and vicinity, Arizona: U.S. Geological Survey Water Resources Investigations Report 94-4214, 285 p. [Link]






                           

My Science Topics


Science Topic
Subtopic
Hydrologic Processessediment transport
Natural Hazardslandslides
Water Resourcessediment transport



My USGS Science Strategy Areas

A Water Census of the United States

A National Hazard, Risk, and Resilience Assessment Program

Contact Information

Peter Griffiths
West 6th Ave. & Kipling St., DFC Bldg. 53
Lakewood, CO 80225-0046
pggriffi@usgs.gov
303-236-5023
303-236-5034 - Fax
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