David J Topping, Ph.D.
My research is focused on sediment transport and sedimentology, and the physics linking sediment transport, sediment grain size, and channel morphology in rivers. Much of my work over the past two decades has been on developing new methods for making continuous measurements of suspended-sediment transport and grain size in rivers.
I received my Bachelor's degree from the Massachusetts Institute of Technology in 1988, my Master's degree from the University of Washington in 1991, and my doctorate from the University of Washington in 1997. I have authored or co-authored over 97 peer-reviewed publications in the scientific literature that have received over 2300 citations. I began my career with the USGS in 1993 in the National Research Program of the Water Resources Mission Area and, in 2007, moved my research project to the Southwest Biological Science Center's Grand Canyon Monitoring and Research Center.
Professional Experience
1993 - 2007: Water Resources Mission Area, National Research Program
2007 - present: Research Hydrologist, Southwest Biological Science Center's Grand Canyon Monitoring and Research Center
Education and Certifications
B.S., 1988: Massachusetts Institute of Technology
M.S., 1991: University of Washington
Ph.D., 1997: University of Washington
Science and Products
Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area
Underwater microscope for measuring spatial and temporal changes in bed-sediment grain size
The rate and pattern of bed incision and bank adjustment on the Colorado River in Glen Canyon downstream from Glen Canyon Dam, 1956-2000
Underwater Microscope for Measuring Spatial and Temporal Changes in Bed-Sediment Grain Size
Influence of a dam on fine-sediment storage in a canyon river
Sedimentology and stratigraphy of the Palisades, Lower Comanche, and Arroyo Grande areas of the Colorado River Corridor, Grand Canyon, Arizona
Application of wavelet analysis for monitoring the hydrologic effects of dam operation: Glen canyon dam and the Colorado River at lees ferry, Arizona
Regulation of sand transport in the Colorado River by changes in the surface grain size of eddy sandbars over multi-year timescales
U.S. Geological Survey research on surrogate measurements for suspended sediment
U.S. Geological Survey suspended-sediment surrogate research, Part II: Optic technologies
Testing laser-based sensors for continuous in situ monitoring of suspended sediment in the Colorado River, Arizona
Computation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona — May 8, 1921, through September 30, 2000
Science and Products
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Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area
Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inverselyAuthorsD.J. Topping, D. M. Rubin, T.S. MelisUnderwater microscope for measuring spatial and temporal changes in bed-sediment grain size
For more than a century, studies of sedimentology and sediment transport have measured bed-sediment grain size by collecting samples and transporting them back to the laboratory for grain-size analysis. This process is slow and expensive. Moreover, most sampling systems are not selective enough to sample only the surficial grains that interact with the flow; samples typically include sediment fromAuthorsDavid M. Rubin, Henry Chezar, Jodi N. Harney, David J. Topping, Theodore S. Melis, Christopher R. SherwoodThe rate and pattern of bed incision and bank adjustment on the Colorado River in Glen Canyon downstream from Glen Canyon Dam, 1956-2000
Closure of Glen Canyon Dam in 1963 transformed the Colorado River by reducing the magnitude and duration of spring floods, increasing the magnitude of base flows, and trapping fine sediment delivered from the upper watershed. These changes caused the channel downstream in Glen Canyon to incise, armor, and narrow. This study synthesizes over 45 yr of channel-change measurements and demonstrates thaAuthorsP.E. Grams, J. C. Schmidt, D.J. ToppingUnderwater Microscope for Measuring Spatial and Temporal Changes in Bed-Sediment Grain Size
For more than a century, studies of sedimentology and sediment transport have measured bed-sediment grain size by collecting samples and transporting them back to the lab for grain-size analysis. This process is slow and expensive. Moreover, most sampling systems are not selective enough to sample only the surficial grains that interact with the flow; samples typically include sediment from at leaAuthorsDavid M. Rubin, Henry Chezar, Jodi N. Harney, David J. Topping, Theodore S. Melis, Christopher R. SherwoodInfluence of a dam on fine-sediment storage in a canyon river
Glen Canyon Dam has caused a fundamental change in the distribution of fine sediment storage in the 99-km reach of the Colorado River in Marble Canyon, Grand Canyon National Park, Arizona. The two major storage sites for fine sediment (i.e., sand and finer material) in this canyon river are lateral recirculation eddies and the main-channel bed. We use a combination of methods, including direct meaAuthorsJ.E. Hazel, D.J. Topping, J. C. Schmidt, M. KaplinskiSedimentology and stratigraphy of the Palisades, Lower Comanche, and Arroyo Grande areas of the Colorado River Corridor, Grand Canyon, Arizona
This report analyzes various depositional environments in three archaeologically significant areas of the Colorado River corridor in Grand Canyon. Archaeological features are built on and buried by fluvial, aeolian, and locally derived sediment, representing a complex interaction between geologic and cultural history. These analyses provide a basis for determining the potential influence of GlAuthorsAmy E. Draut, David M. Rubin, Jennifer L. Dierker, Helen C. Fairley, Ronald E. Griffiths, Joseph E. Hazel, Ralph E. Hunter, Keith Kohl, Lisa M. Leap, Fred L. Nials, David J. Topping, Michael YeattsApplication of wavelet analysis for monitoring the hydrologic effects of dam operation: Glen canyon dam and the Colorado River at lees ferry, Arizona
Wavelet analysis is a powerful tool with which to analyse the hydrologic effects of dam construction and operation on river systems. Using continuous records of instantaneous discharge from the Lees Ferry gauging station and records of daily mean discharge from upstream tributaries, we conducted wavelet analyses of the hydrologic structure of the Colorado River in Grand Canyon. The wavelet power sAuthorsM.A. White, J. C. Schmidt, D.J. ToppingRegulation of sand transport in the Colorado River by changes in the surface grain size of eddy sandbars over multi-year timescales
In settings where the transport of sand is partially or fully supply limited, changes in the upstream supply of sand are coupled to changes in the grain size of sand on the bed. In this manner, the transport of sand under the supply-limited case is 'grain-size regulated'. Since the closure of Glen Canyon Dam in 1963, the downstream reach of the Colorado River in Marble and Grand Canyons has exhibiAuthorsD.J. Topping, D. M. Rubin, J. C. SchmidtU.S. Geological Survey research on surrogate measurements for suspended sediment
The U.S. Geological Survey is evaluating potentially useful surrogate instruments and methods for inferring the physical characteristics of suspended sediments. Instruments operating on bulk acoustic, bulk and digital optic, laser, and pressure-differential technologies are being tested in riverine and laboratory settings for their usefulness to Federal agencies toward providing quantifiably reliaAuthorsJohn R. Gray, Theodore S. Melis, Eduardo Patiño, Matthew C. Larsen, David J. Topping, Patrick P. Rasmussen, Carlos Figueroa-AlamoU.S. Geological Survey suspended-sediment surrogate research, Part II: Optic technologies
No abstract available.AuthorsJohn R. Gray, Daniel J. Gooding, Theodore S. Melis, David J. Topping, Patrick P. RasmussenTesting laser-based sensors for continuous in situ monitoring of suspended sediment in the Colorado River, Arizona
High-resolution monitoring of sand mass balance in the Colorado River below Glen Canyon Dam, Arizona, USA, is needed for environmental management. In the Grand Canyon, frequent collection of suspended-sediment samples from cableways is logistically complicated, costly and provides limited spatial and temporal resolution. In situ laser sensors were tested in the Colorado River as an alternative metAuthorsT.S. Melis, D.J. Topping, D. M. RubinComputation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona — May 8, 1921, through September 30, 2000
A gaging station has been operated by the U.S. Geological Survey at Lees Ferry, Arizona, since May 8, 1921. In March 1963, Glen Canyon Dam was closed 15.5 miles upstream, cutting off the upstream sediment supply and regulating the discharge of the Colorado River at Lees Ferry for the first time in history. To evaluate the pre-dam variability in the hydrology of the Colorado River, and to determineAuthorsDavid J. Topping, John C. Schmidt, L. E. Vierra - News