David J Dean

Hydrology, geomorphology, and sediment transport of rivers in arid and semi-arid ecosystems. 

Biography

As a research hydrologist with the GCMRC and SBSC, I conduct original research linking hydrology and sediment transport to fluvial geomorphic processes.  My research is conducted in the Rio Grande in the Big Bend region of far west Texas, the Green and Yampa Rivers in Dinosaur National Monument, the Green and Colorado Rivers in Canyonlands National Park, the Little Colorado River and its tributaries in northern Arizona, and the Colorado River in Grand Canyon National Park. My research aims to quantify how hydrologic and geomorphic processes respond to factors such as climate change, large-scale water development and management, the widespread establishment of non-native riparian plants, and anthropogenic modifications to fluvial bottomlands. All of these perturbations directly affect how water and sediment are routed through fluvial drainage networks, which controls the geomorphic behavior, and biologic processes of these river systems. 

Much of my work incorporates the use of acoustic instrumentation to passively monitor suspended-sediment transport processes on rivers with high suspended-sediment loads.  This work is paired with measurements of geomorphic change using a variety of data and techniques including: high-resolution topographic data collected with real-time-kinematic GPS and LIDAR, aerial imagery, and analysis of historical hydrologic and geomorphic data. My work is directly relevant to the primary scientific understanding of the hydrologic and geomorphic behavior of these rivers, as well as the management actions that may help mitigate fluvial perturbations that have occurred.  My work also focuses on the biogeomorphic interactions between stream flow, sediment transport, and riparian vegetation, and how those interactions can result in negative and/or positive feedbacks of geomorphic change. 

Selected Publications:

Topping, D.J., Mueller, E.R., Schmidt, J.C., Griffiths, R.E., Dean, D.J., Grams, P.E., 2018, Long-term evolution of sand transport through a river network: Relative influences of a dam versus natural changes in grain size from sand waves. Journal of Geophysical Research: Earth Surface, 123, https://doi.org/10.1029/2017JF004534. p. 1-30.

Dean, D.J., Bennett, J., Sirotnak, J., 2017, Parsing out the effects of non-native vegetation management on channel form and riparian and aquatic habitat. In: Ralston and Sarr (Ed.) Case Studies of Riparian and Watershed Restoration in the Southwestern United States – Principles, Challenges, and Successes, USGS Open-File Report 2017-1091, p. 59-66

Norman, L.M., Sankey, J.B., Dean, D., Caster, J., Delong, S., Delong, W., Pelletier, J.D., 2017, Quantifying geomorphic change at ephemeral stream restoration sites using a coupled-model approach: Geomorphology, 283, p. 1-16. http://dx.doi.org/10.1016/j.geomorph.2017.01.017

Dean, D.J., Topping, D.J., Schmidt, J.C., Griffiths, R.E., Sabol, T.A., 2016. Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads. Journal of Geophysical Research: Earth Surface, 121.1, 82-110.

Dean, D.J., Topping, D.J., Griffiths, R.E., Sabol, T.A., Schmidt, J.C., and Bennett, J., 2015, Using 15-minute acoustic data to analyze suspended-sediment dynamics in the Rio Grande in the Big Bend Region, in Proceedings of the 3rd Joint Federal Interagency Conference (10th Federal Interagency Sedimentation Conference and 5th Federal Interagency Hydrologic Modeling Conference), Reno, Nev., April 19-23, 2015: p. 1234-1245, http://acwi.gov/sos/pubs/3rdJFIC/Proceedings.pdf.

Topping, D.J., Wright, S.A., Griffiths, R.E., and Dean, D.J., 2015, Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of single-frequency acoustic-doppler profilers, in Proceedings of the 3rd Joint Federal Interagency Conference (10th Federal Interagency Sedimentation Conference and 5th Federal Interagency Hydrologic Modeling Conference), Reno, Nev., April 19-23, 2015: p. 883-846, http://acwi.gov/sos/pubs/3rdJFIC/Proceedings.pdf.

Keller, D.L, Laub, B.G., Birdsey, P., Dean, D.J., 2014, Effects of flooding and tamarisk removal on habitat for sensitive fish species in the San Rafael River, Utah—implications for fish habitat and enhancement and future restoration efforts:  Environmental Management, v. 54.3, p. 465–478. doi: 10.1007/s00267-014-0318-7.

Dean, D.J., and Schmidt, J.C., 2013, The geomorphic effectiveness of a large flood on the Rio Grande in the Big Bend Region—insights on geomorphic controls and post-flood geomorphic response: Geomorphology v. 201, p. 183–198, doi:10.1016/j.geomorph.2013.06.020.

Dean, D.J., Scott, M.L., Shafroth, P.B., Schmidt, J.C., 2011, Stratigraphic, sedimentologic, and dendrogeomorphic analyses of rapid floodplain formation along the Rio Grande in Big Bend National Park, Texas: Geological Society of America Bulletin, v. 123 no. 9-10, p. 1908–1925, doi:10.1130/B30379.1.

Dean, D.J., Schmidt, J.C., 2011, The role of feedback mechanisms in historic channel changes of the Lower Rio Grande in the Big Bend Region: Geomorphology, v. 126, no. 3-4, p. 333–349, doi:10.1016/j.geomorph.2010.03.009.

News and Multimedia

Film:

Confluence: The Big Bend Reach of the Rio Grande

https://www.youtube.com/watch?v=flb_1JGUrvA

News: 

USU Watershed Sciences Student Excels at Geomorphology Gathering

http://www.usu.edu/today/index.cfm?id=31304