Gregory B. Pasternack, Brett Valle, Joshua Wyrick
The interaction between flow, sediment transport, and channel morphology is very poorly known for bedrock rivers. A key foci for channel change in such rivers is the bed step. Despite their prevalence, the role of bed steps on river flow mechanics, sediment transport, channel change, and basin evolution has been hardly investigated at all, primarily because of adverse site conditions that previously limited field data collection. The overall goal of this line of research has been to overcome past constraints on investigating the fluid mechanics in the vicinity of waterfalls of all sizes and its relevance to fluvial geomorphology. This is being done with the aid of new technologies that enable precise in situ measurement for the first time. New technologies developed and tested at UC Davis include a patented River Truss system, an air content sensor for studying the hydraulic jump at the base of falls, a 3D force sensor, and differential pressure transducers with high-frequency response. These new technologies are being used to address hypotheses regarding bedrock river morphology, universal waterfalls systematics, the dynamics associated with individual types of bed steps. A better understanding of the role of waterfalls in channel change is very important to science because it would improve the physics of landscape evolution models, provide needed guidance for including in-stream features in river restoration, and make interdisciplinary contributions to ecology and aquatic geochemistry. In future research, other scientists will be able to apply the newly proven field technologies and resulting models to better understand the complex flow mechanics and channels interactions occurring in mountain rivers.
Please select specific topical areas from the list below to learn more about the specific research activities that have been done as part of this program.
Internal structure of air in natural hydraulic jumps.
Maping and digital elevation modeling of small natural steps.
What are the relations between spatial transcritical flow structures and localized topographic heterogeneities in bedrock channels?
- Valle, B. and Pasternack, G. B. 2002. TDR Measurements of Hydraulic Jump Aeration in the South Fork of the American River, CA. Geomorphology 42:153-165.
- Valle, B. and Pasternack, G. B. 2006. Field mapping and digital elevation modelling of submerged and unsubmerged hydraulic jump regions in a bedrock step-pool channel. Earth Surface Processes and Landforms 31:6:646-664.
- Valle, B. L. and Pasternack, G. B. 2006. Air concentrations of submerged and unsubmerged hydraulic jumps in a bedrock step-pool channel, Journal of Geophysical Research 111:F03016:1-12, doi:10.1029/2004JF000140.
- Valle, B. and Pasternack, G. B. 2006. Submerged and unsubmerged natural hydraulic jumps in a bedrock step-pool mountain channel. Geomorphology 82:146-159.
- Pasternack, G.B., Ellis, C. Leier, K.A., Valle, B.L., Marr, J.D. 2006. Convergent hydraulics at horseshoe steps in bedrock rivers. Geomorphology 82:126-145.
- Pasternack, G. B., Ellis, C. R. and Marr, J. D. 2007. Jet and hydraulic jump near-bed stresses below a horseshoe waterfall, Water Resources Research 43, W07449, doi:10.1029/2006WR005774.
- Wyrick, J. R. and Pasternack, G. B. 2008. Modeling energy dissipation and hydraulic jump regime responses to channel nonuniformity at river steps. Journal of Geophysical Research 113, F03003, doi:10.1029/2007JF000873.
NSF Funding Notification
The information on this web page and those linked under it is based on work supported in part by the STC Program of the National Science Foundation under Agreement number EAR-0120914, in part by the Hydrology Program of the National Science Foundation under Agreement number EAR-0207713, in part by the UC Center for Water Resources under project W-944, in part by UC Davis, and in part by direct financial contributions by Prof. Greg Pasternack.