Todd Caldwell

Assistant Research Soil Scientist

Division of Earth and Ecosystem Sciences

Email: Todd.Caldwell@dri.edu

Right: Todd Caldwell standing beside a disc permeameter set-up used to measure hydraulic conductivity of soil surfaces

Education

Professional Interests

Mr. Caldwell is a hydrologist and soil scientist specializing in field investigations and numerical modeling associated with near-surface vadose zone hydrology, landscape restoration, and soil evolution. He is currently enrolled at the University of Nevada, Reno seeking his Ph. D. in the Hydrologic Sciences Program while continuing his professional career at the Desert Research Institute. His current research focuses on the ecohydrology and restoration of arid lands, the characterization and scaling of soils and hydraulic parameters, and soil moisture monitoring and data acquisition. He is also the Soil Characterization Laboratory supervisor and oversees its management.

Research

Areas of Interest and Expertise

• Transport of water, solute and heat through soils
• Soil hydraulic parameter characterization
• Numerical modeling of soil-atmosphere-plant systems
• Soil degradation and arid lands restoration
• Remote site instrumentation and data acquisition

Current Projects

• Catalina Island Automated Climate Network
• Master Environmental Reference Site (MERS): Deformation and recovery of desert pavements, U.S. Army Yuma Proving Ground.
• Measuring Heterogeneities of Soil Hydraulic Properties from Canopy to Interspace

Past Projects

• Integrated Site Design for the Restoration of Military Lands, Ft. Irwin, CA
• Seedbed Microclimate: Modeling and Monitoring Soil Moisture in Support of the Restoration of Military Lands
• Geochemical and Physical Characteristics of Iraqi Dust and Soil Samples
• Remote Sensing for Mapping Near-Surface Playa Moisture
• Geochemical and Physical Characteristics Of Vehicle Endurance and Dust Test Courses at U.S. Army Yuma Proving Ground
• Soil Evaluation in Support of Estimating Carrying Capacity and Landscape Degradation at the NTC – Fort Irwin, California
• Landscape Position and Hillslope Hydrology Associated with the Middle Ranch Hayfield Restoration, Catalina Island, CA
• Uranium Oxide Soil Stabilization Study, Yuma Proving Ground, AZ
• Analysis of Desert Shrubs Along First-order Channels on Desert Piedmonts: Possible Indicators of Ecosystem Health and Historic Variation
• Basic Research Linkages Among the Soil-Hydrologic-Biologic Systems Common to the Desert Piedmonts, U.S. Army Yuma Proving Grounds

Selected Publications

Peer Reviewed Journal Articles

Caldwell, T.G., M.H. Young, J. Zhu, and E.V. McDonald. 2008:

Spatial structure of hydraulic properties from canopy to interspace in the Mojave Desert. Geophys. Res. Lett. 35, L19406, doi:10.1029/2008GL035095.

Caldwell, T.G., E.V. McDonald, and M.H. Young. 2006:

Soil disturbance and hydrologic response at the National Training Center, Ft. Irwin, California. J. Arid Environs. 67:456-472.

Caldwell, T.G., E.V. McDonald, S.N. Bacon, and G. Stullenbarger:

The performance and sustainability of vehicle dust courses for military testing. J. Terramechanics. In press.

Caldwell, T.G., E.V. McDonald, and M.H. Young:

The seedbed microclimate and the active restoration of disturbed lands in the Mojave Desert. J. Arid Environs. In revision.

Caldwell, T.G, D.W. Johnson, W.W. Miller, and R.G. Qualls. 2002:

Forest floor carbon and nitrogen losses due to prescription fire. Soil Sci. Soc. Am. J. 66:262-267.

Gee, G.W., A.L. Ward, T.G. Caldwell, and J.C. Ritter. 2002:

A vadose zone water fluxmeter with divergence control. Water Resour. Res. 38(8), 10.1029/2001WR000816.

Johnson, D.W., R.B. Susfalk, R.A. Dahlgren, T.G. Caldwell, and W.W. Miller. 2001:

Nutrient fluxes in a snow-dominated, semi-arid forest: Spatial and temporal patterns. Biogeochem. 55(3): 219-245.

Johnson, D.W., R.B. Susfalk, T.G. Caldwell, J.D. Murphey, W.W. Miller, and R.F. Walker. 2004:

Fire effects on carbon and nitrogen budgets in forests. Water Air Soil Pollut. 4:263-275.

McDonald, E.V. and T.G. Caldwell, 2008:

Geochemical characteristics of Iraqi dust and soil samples and related impacts to weapon malfunctions, p. 258-265, In C.P. Nathanail, R.J. Abrahart, and R.P. Bradshaw (eds), Military Geography and Geology: History and Technology, Land Quality Press, Nottingham. 2008.

Sisson, J.B., W.L. Bratton, G.W. Gee, J M. Hubbell, J.C. Ritter, and T.G. Caldwell. 2002:

Advances in tensiometry for long-term monitoring of soil water pressures. Vadose Zone J. 1:310-315.

Shafer, D.S., M.H. Young, S.F. Zitzer, T.G. Caldwell and E.V. McDonald. 2007:

Interrelated pedogenic, hydraulic, biotic and abiotic processes during the past 125 000 years of landscape evolution in the northern Mojave Desert, Nevada, USA. J. Arid Environs. 69:633-657.

Stevenson, B.A., E.V. McDonald, T.G. Caldwell. 2009:

Root patterns for Larrea tridentata in relation to soil morphology in Mojave Desert soils of different ages. In R.H. Webb, L.F. Fenstermaker, J.S. Heaton, D.L. Hughson, E.V. McDonald, and D.M. Miller (eds.) Mojave Desert: Ecosystem Processes and Sustainability. University of Nevada Press. In Press.

Young, M.H., E.V. McDonald, T.G. Caldwell, S.G. Benner, and D.G. Meadows. 2004:

Hydraulic properties of a desert soil chronosequence in the Mojave Desert, USA. Vadose Zone J. 3: 956-963.