Jason Kean

My research focuses on the processes controlling debris-flow initiation and growth, particularly after wildfire, but also in unburned areas. This research includes a field component that obtains direct measurements of debris flows in natural settings, a modeling component that seeks to explain the observations, and an applied component that focuses on assessment of debris-flow hazards. My previous research at the USGS focused on river mechanics, including bank erosion and the development of model-based approaches to gage streams and rivers.

Education:

University of Colorado, Ph.D., 2003, Civil Engineering

University of Colorado, M.S., 1998, Civil Engineering

Cornell University, B.S., 1994, Civil Engineering

Publications

Kean, J.W., D.M. Staley, J.T. Lancaster, F.K. Rengers, B.J. Swanson, J.A. Coe, J.L. Hernandez, A.J. Sigman, K.E. Allstadt, D.N. Lindsay (2019), Inundation, flow dynamics, and damage in the 9 January 2018 Montecito debris-flow event, California, USA: Opportunities and challenges for post-wildfire risk assessment, Geosphere, doi: https://doi.org/10.1130/GES02048.

Kean, J.W., D.M. Staley, J.T. Lancaster, F.K. Rengers, B.J. Swanson, J.A. Coe, J.L. Hernandez, A.J. Sigman, K.E. Allstadt, D.N. Lindsay (2019), Debris-flow inundation and damage data from the 9 January 2018 Montecito debris-flow event, U.S. Geological Survey data release, http://doi.org/10.5066/P9JQJU0E.

Allstadt, K.E., Farin, M., Lockhart, A.B., McBride, S.K., Kean, J.W., Iverson, R.M., Logan, M., Smith, J.B., Tsai, V.C., and George, D. (2019), Overcoming barriers to progress in seismic monitoring and characterization of debris flows and lahars, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 77-84. [Link]

Barnhart, K.R., Rengers, F.K., Ghent, J.N., Tucker, G.E., Coe, J.A., Kean, J.W., Smith, J.B., Staley, D.M., Kleiber, W., Wiens, A.M. (2019), Topographic change detection at Chalk Cliffs, Colorado, USA, using Airborne LiDAR and UAS-based Structure-from-Motion photogrammetry, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 85-92. [Link]

Bessette-Kirton, E.K., Kean, J.W., Coe, J.A., Rengers, F.K., Staley, D.M. (2019), An evaluation of debris-flow runout model accuracy and complexity in Montecito, California:  Towards a framework for regional inundation-hazard forecasting, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 257-264. [Link]

Calhoun, N.C., Burns, W.J., Hay, S., Staley, D.M., and Kean, J.W. (2019), Post-fire rockfall and debris-flow hazard zonation in the Eagle Creek fire burn area, Columbia River Gorge, Oregon: A tool for emergency managers and first responders, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 581-588. [Link]

Coe, J.A., Bessette-Kirton, E.K., Slaughter, S.L., Rengers, F.K., Contreras, T.A., Mickelson, K.A., Taylor, E.M., Kean, J.W., Jacobacci, K.E., Hanson, M.A. (2019), A 4000-year history of debris flows in north-central Washington State, U.S.A.: Preliminary results from trenching and surficial geologic mapping at the Pope Creek fan, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 613-620. [Link]

McGuire, L.A., Rengers, F.K., Kean, J.W., Staley, D.M., Tang, H., and Youberg, A.M. (2019), Looking through the window of disturbance at post-wildfire debris-flow hazards, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 516-523. [Link]

Michel, A., Kean, J.W., Smith, J.B., Allstadt, K., and Coe, J.A. (2019), Taking the pulse of debris flows: extracting debris-flow dynamics from good vibrations in southern California and central Colorado, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 154-161. [Link]

Mirus, B.B., Staley, D.M., Kean, J.W., Smith, J.B., Wooten, R., McGuire, L.A., Ebel, B.A. (2019), Conceptual framework for assessing disturbance impacts on debris-flow initiation thresholds across hydroclimatic settings, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 524-531. [Link]

Rengers, F.K., Rapstine, T.D., Allstadt, K.E., Olsen, M., Bunn, M., Iverson, R.M., Kean, J.W., Leshchinsky, B., Logan, M., Sharif-Mood, M., Obryk, M., and Smith, J.B. (2019), Real-time monitoring of debris-flow velocity and mass deformation from field experiments with high sample rate lidar and video, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 192-198. [Link]

Smith, J.B., Kean, J.W., and Coe, J.A. (2019), Exploring controls on debris-flow surge velocity and peak discharge at Chalk cliffs, Colorado, USA, in Debris-Flow Hazards Mitigation: Mechanics, Monitoring, Modeling, and Assessment, edited by Kean, J.W., Coe, J.A., Santi, P.M., and Guillen, B.K., Association of Environmental and Engineering Geologists, Special Publication #28,  p. 199-206. [Link]

Tang, H., L.A. McGuire, F.K. Rengers, J.W. Kean, D.M. Staley, and J.B. Smith (2019), Evolution of debris-flow intiation mechanisms and sediment sources during a sequence of post-wildfire rainstorms, J. Geophys. Res. Earth Surf., doi:10.1029/2018JF004837. [Link]

Kean, J.W., J.B. Smith, F.K. Rengers, L.A. McGuire, and D.M. Staley (2019), Post-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017: U.S. Geological Survey data release, https://doi.org/10.5066/P9F3YTBP.

Bessette-Kirton, E.K., C. Cerovski-Darriau, W.H. Schulz, J.A. Coe, J.W. Kean, J.W. Godt, M.A. Thomas, and K.S. Hughes (2019), Landslides triggered by Hurrican Maria: Assessment of an extreme event in Puerto Rico, GSA Today, doi:10.1130/GSATG383A.1. [Link]

Smith, J.B., and J.W. Kean (2018), Long-term soil-water tension measurements in semiarid environments: A method for automated tensiometer refilling, Vadose Zone Journal, 17:180070. doi:10.2136/vzj2018.04.0070. [Link]

Staley, D.M., A.C. Tillery, J.W. Kean, L.A. McGuire, H.E. Pauling, F.K. Rengers, J.B. Smith (2018), Estimating post-fire debris-flow hazards prior to wildfire using a statistical analysis of historical distributions of fire severity from remote sensing data, International Journal of Wildland Fire, doi:10.1071/WF17122. [Link]

McGuire, L. A., F. K. Rengers, J. W. Kean, D. M. Staley, and B.B. Mirus (2018), Incorporating spatially heterogeneous infiltration capacity into hydrologic models with applications for simulating post-wildfire debris flow initiation, Hydrological Processes, doi:10.1002/hyp.11458. [Link]

Kean, J.W., D.M. Staley, F.K. Rengers, L.A. McGuire, J.B. Smith, and B.B. Mirus (2018), Post-wildfire debris-flow monitoring data, 2014 Silverado Fire, Orange County, California, November 2014 to January 2016: U.S. Geological Survey data release, [Link]. 

Bessette-Kirton, E.K., J.A. Coe, J.W. Godt, J.W. Kean, F.K. Rengers, W.H. Schulz, R.L. Baum, E.S. Jones, and D.M. Staley (2017), Map data showing concentration of landslides caused by Hurricane Maria in Puerto Rico: U.S. Geological Survey data release, https://doi.org/10.5066/F7JD4VRF

McGuire, L. A., F. K. Rengers, J. W. Kean, and D. M. Staley (2017), Debris flow initiation by runoff in a recently burned basin: Is grain-by-grain sediment bulking or en masse failure to blame?, Geophysical Research Letters, 44, doi:10.1002/2017GL074243. [Link]

Kean, J.W., D.M. Staley, and S.H. Cannon (2017), Post-wildfire debris-flow monitoring data, Arroyo Seco, 2009 Station Fire, Los Angeles County, California, November 2009 to March 2010: U.S. Geological Survey data release, [Link]. 

Staley, D.M., Negri, J.A., Kean, J.W., Laber, J.L., Tillery, A.C., and Youberg, A.M. (2017), Prediction of spatially explicit rainfall intensity-duration thresholds for post-fire debris-flow generation in the western United States, Geomorphology, doi:10.1016/j.geomorph.2016.10.019. [Link]

McGuire, L.A., J.W. Kean, D.M. Staley, F.K. Rengers, and T.A. Wasklewicz (2016), Constraining the relative importance of raindrop- and flow-driven sediment transport mechanisms in post-wildfire environments and implications for recovery time scales, J. Geophys. Res. Earth Surf., 121, doi:10.1002/2016JF003867. [Link]

McGuire, L.A., Rengers, F.K., Kean, J.W., Coe, J.A., Mirus, B.B., Baum R.L., and Godt, J.W. (2016), Elucidating the role of vegetation in the initiation of rainfall-induced shallow landslides: Insights from an extreme rainfall event in the Colorado Front Range, Geophysical Research Letters, doi:10.1002/2016GL070741. [Link]

Kean, J.W., McGuire, L.A., Rengers, F.K., Smith, J.B., and Staley, D.M. (2016), Amplification of postwildfire peak flow by debris, Geophysical Research Letters, doi:10.1002/2016GL069661. [Link]

Rengers, F.K., McGuire, L.A., Coe, J.A., Kean, J.W., Baum, R.L., Staley, D.M., and Godt, J.W. (2016), The influence of vegetation on debris-flow initiation during extreme rainfall in the northern Colorado Front Range, Geology, doi:10.1130/G38096.1. [Link]

Lam, N., Kean, J.W., and Lyon, S.W. (2016), Modeling streamflow from coupled airborne laser scanning and acoustic Doppler current profiler data, Hydrology Research, doi:10.2166/nh.2016.257. [Link]

Staley, D.M., and Kean, J.W. (2016), Post-Fire Debris Flows in Southern California: Science, Prediction, and Implications for Practitioners, in Applied Geology in California, edited by R. Anderson and H. Ferriz, Association of Environmental and Engineering Geologists, Special Publication #26.

Rengers F.K., McGuire, L.A., Kean, J.W., Staley, D.M., Hobley, D.E.J. (2016), Model simulations of flood and debris-flow timing in steep catchments after wildfire, Water Resources Research, doi:10.1002/2015WR018176. [Link]

Staley, D.M., Negri, J.A., Kean, J.W., Laber, J.M., Tillery, A.C., and Youberg, A.M. (2016), Updated Logistic Regression Equations for the Calculation of Post-Fire Debris-Flow Likelihood in the western United States, U.S. Geological Survey Open-File Report, 2016-1106, 13 p. doi.org/ofr20161106. [Link]

Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Schmitt, R.G., Morgan, M.L., White, J.L.,  Stratton, B. Hayashi, T.A., and Kean, J.W. (2016), Rock avalanche dynamics revealed by large-scale field mapping and seismic signals at a highly mobile avalanche in the West Salt Creek Valley, western Colorado: Geosphere, v. 12, no. 2, p. 607-631, doi:10.1130/GES01265.1. [Link]

Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Schmitt, R.G., Morgan, M.L., White, J.L., Stratton, B.T., Hayashi, T.A., and Kean, J.W. (2016), Map data and unmanned aircraft system imagery from the May 25, 2014 West Salt Creek rock avalanche in western Colorado: U.S. Geological Survey data release, doi.org/10.5066/F74J0C55. [Link]

Staley, D.M., Gartner, J.E., Kean, J.W. (2015), Objective Definition of Rainfall Intensity-Duration Thresholds for Post-fire Flash Floods and Debris Flows in the Area Burned by the Waldo Canyon Fire, Colorado, USA. in Engineering Geology for Society and Territory - Volume 2., edited by G. Lollino, D. Giordan, G. B. Crosta, J. Corominas, R. Azzam, J. Wasowski, and N. Sciarra, Springer International Publishing: 621-624. DOI: 10.1007/978-3-319-09057-3_10. [Link]

Lyon, S.W., Nathanson, M., Lam, N., Dahlke, H., Rutzinger, M., Kean, J.W., Laudon, H. (2015), Can low-resolution airborne laser scanning data be used to model stream rating curves?, Water, 7, 1324-1339, doi:10.3390/w7041324. [Link]

Kean, J. W., J. A. Coe, V. Coviello, J. B. Smith, S. W. McCoy, and M. Arattano (2015), Estimating rates of debris-flow entrainment from ground vibrations, Geophysical Research Letters, 42, doi:10.1002/2015GL064811. [Link]

Staley, D.M., Wasklewicz, T.A., and Kean, J.W. (2014), Characterizing the primary material sources and dominant erosional processes for post-fire debris-flow initiation in a headwater basin using multi-temporal terrestrial laser scanning data, Geomorphology, 214, 324-338, doi:10.1016/j.geomorph.2014.02.015. [Link]

Godt, J.W., Coe, J. A., Kean J.W., Baum, R.L., Jones, E.S., Harp E.L., Staley, D.M., and Barnhart, W.D. (2014), Landslides in the Northern Colorado Front Range Caused by Rainfall, September 11–13, 2013, U.S. Geological Survey Fact Sheet 2013-3114, 3 p., doi:10.3133/fs20133114. [Link]

Coe, J.A., Kean, J.W., Godt, J.W., Baum, R.L., Jones, E.S., Gochis, D.J., and Anderson, G.S. (2014), New insights into debris-flow hazards from an extraordinary event in the Colorado Front Range: GSA Today, v. 24, no. 10, p. 4-10. doi:10.1130/GSATG214A.1. [Link]

McCoy, S.W., G.E. Tucker, J.W. Kean, and J.A. Coe (2013), Field measurement of basal forces generated by erosive debris flows, Journal of Geophysical Research, 118, doi:10.1002/jgrf.20041. [Link]

Staley, D.M., Kean, J.W., Cannon, S.H., Schmidt, K.M., and Laber, J.L. (2013), Objective definition of rainfall intensity-duration thresholds for the initiation of post-fire debris flows in southern California,Landslides, doi: 10.1007/s10346-012-0341-9. [Link]

Kean, J.W., S.W. McCoy, G.E. Tucker, D.M. Staley, and J.A. Coe (2013), Runoff-generated debris flows: Observations and modeling of surge initiation, magnitude and frequency, Journal of Geophysical Research, 118, doi:10.1002/jgrf.20148. [Link]

Kean, J.W., D.M. Staley, R.J. Leeper, K.M. Schmidt, and J.E. Gartner (2012), A low-cost method to measure the timing of postfire flash floods and debris flows relative to rainfall, Water Resources Research, 48, W05516, doi:10.1029/2011WR011460. [Link]

Nathanson, M., Kean, J.W., Grabs, T.J., Seibert, J., Laudon, H., and S.W. Lyon (2012), Modeling rating curves using remotely sensed LiDAR data, Hydrological Processes, doi:10.1002/hyp.9225. [Link]

Reid, M.E., LaHusen, R.G., Baum, R.L., Kean, J.W., Schulz W.H., and L.M. Highland (2012), Real-time monitoring of landslides, U.S. Geological Survey Fact Sheet 2012-3008, 4 p. [Link]

McCoy, S.W., Kean, J.W., Coe, J.A., Tucker, G.E., Staley, D.M., Wasklewicz, T.A. (2012), Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment, Journal of Geophysical Research, 117, F03016, doi:10.1029/2011JF002278. [Link]

Kean, J. W., Staley, D.M., and Cannon, S.H. (2011), In situ measurements of post‐fire debris flows in southern California: Comparisons of the timing and magnitude of 24 debris‐flow events with rainfall and soil moisture conditions, Journal of Geophysical Research, 116, F04019, doi:10.1029/2011JF002005. [Link]

Jorgensen, D.P., Hanshaw, M.N., Schmidt, K.M., Laber, J.L., Staley, D.M., Kean, J.W., and Restrepo, P.J. (2011), Value of a dual-polarized gap-filling radar in support of southern California post-fire debris-flow warnings, Journal of Hydrometeorology, 1581-1595, doi:10:.1175/JHM-D-11-05.1. [Link]

Gomberg, J., Schulz, W., Bodin, P. , and Kean, J. (2011), Seismic and geodetic signatures of fault slip at the Slumgullion Landslide Natural Laboratory, Journal of Geophysical Research, 116, B09404, doi:10.1029/2011JB008304. [Link]

Cannon, S.H., Boldt, E.M., Laber, J.L., Kean, J.W., Staley, D.M., (2011), Rainfall intensity–duration thresholds for postfire debris-flow emergency-response planning, Natural Hazards, 59:209–236, doi:10.1007/s11069-011-9747-2. [Link]

Kean, J.W. and Staley, D.M. (2011), Direct measurements of the hydrologic conditions leading up to and during post-fire debris flow in southern California, U.S.A., Debris-flow Hazards Mitigation, Mechanics, Prediction, and Assessment, R. Genevois, D. L. Hamilton, A. Prestininzi, eds., Casa Editrice Universita La Sapienza, Rome, 685-694, doi:10.4408/IJEGE.2011-03.B-075. [Link]

Schmidt K.M., Hanshaw, M.N., Howle, J.F., Kean, J.W., Staley, D.M., Stock, J.D., and Bawden G.W. (2011), Hydrologic conditions and terrestrial laser scanning of post-fire debris flows in the San Gabriel Mountains, CA, U.S.A., Debris-flow Hazards Mitigation, Mechanics, Prediction, and Assessment, R. Genevois, D. L. Hamilton, A. Prestininzi, eds., Casa Editrice Universita La Sapienza, Rome, 583-593, doi:10.4408/IJEGE.2011-03.B-064.

McCoy, S.W., Coe, J.A., Kean, J.W., Tucker, G.E., Staley, D.M., and Wasklewicz, T.A. (2011), Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, In situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009, Italian Journal of Engineering Geology and Environment, 1, doi:10.4408/IJEGE.2011-03.B-078. [Link]

Staley, D.M., Wasklewicz, T.A., Coe J.A., Kean, J.W., McCoy, S.W., and Tucker, G.E. (2011), Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 2, Changes in surface morphometry from terrestrial laser scanning in the summer of 2009, Debris-flow Hazards Mitigation, Mechanics, Prediction, and Assessment, R. Genevois, D. L. Hamilton, A. Prestininzi, eds., Casa Editrice Universita La Sapienza, Rome, 759-768, doi:10.4408/IJEGE.2011-03.B-083. [Link]

Cannon, S.H., Boldt, E.M., Kean, J.W., Laber, J., Staley, D. M. (2010), Relations Between Rainfall and Postfire Debris-Flow and Flood Magnitudes for Emergency-Response Planning, San Gabriel Mountains, Southern California. U.S. Geological Survey Open-File Report 2010-1039, 31 p. [Link]

Coe, J.A., Kean, J.W., McCoy, S.W., Staley, D.M., and Wasklewicz, T.A. (2010), Chalk Creek Valley: Colorado’s natural debris-flow laboratory, in Morgan, L.A., and Quane, S.L., eds., Through the Generations: Geologic and Anthropogenic Field Excursions in the Rocky Mountains from Modern to Ancient: Geological Society of America Field Guide 18, p. 95–117, doi: 10.1130/2010.0018(05). [Link]

Clayton, J.A., and Kean, J.W., (2010), Establishing a multi-scale stream gaging network in the Whitewater River basin, Kansas, USA, Water Resources Management, DOI 10.1007/s11269-010-9624-x

Kean, J.W., and Smith, J.D. (2010), Calculation of stage-discharge relations for gravel bedded channels, Journal of Geophysical Research, 115, F03020, doi:10.1029/2009JF001398. [Link]

McCoy, S.W., Kean, J.W., Coe, J.A., Staley, D.M., Wasklewicz, T.A., and Tucker, G.E. (2010), Evolution of a natural debris flow: in situ measurements of flow dynamics, video imagery, and terrestrial laser scanning, Geology, 38, 8, p. 735-738, doi:10.1130/G30928.1. [Link]

Kean, J.W., Kuhnle, R.A., Smith, J.D., Alonso, C.V., and Langendoen, E.J. (2009), Test of a method to calculate near-bank velocity and boundary shear stress, Journal of Hydraulic Engineering, 135, 7, doi: 10.1061/_ASCE_HY.1943-7900.0000049. [Link]

Schulz, W.H., Kean, J.W., and Wang, G. (2009), Landslide movement in southwest Colorado triggered by atmospheric tides, Nature Geoscience, doi:10.1038/NGEO659. [Link]

Wobus, C.W., Kean, J.W., Tucker, G.E., Anderson, R.S. (2008), Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity, Journal of Geophysical Research, 113, F02004, doi:10.1029/2007JF000914. [Link]

Coe, J.A.; Godt, J.W.; Wait, T.C.; Kean, J.W., 2007. Field Reconnaissance of Debris Flows Triggered by a July 21, 2007, Thunderstorm in Alpine, Colorado, and Vicinity. Geological Survey (U.S.) Open-File Report 2007-1237, iii, 25 p. [Link]

Kean, J.W., and Smith, J.D. (2006), Calculation of suspended sediment at gaging stations, in Proceedings of the Eighth Federal Interagency Sedimentation Conference, April 2-6, 2006, Reno, Nevada, USA.

Kean, J.W., and Smith, J.D. (2006). Form drag on small-scale natural topographic features: 2. Irregular Sequences., Journal of Geophysical Research, 111, F04010, doi:10.1029/2006JF000490. [Link]

Kean, J.W., and Smith, J.D. (2006), Form drag on small-scale natural topographic features: 1. Regular Sequences. Journal of Geophysical Research, 111, F04009, doi:10.1029/2006JF000467. [Link]

Kean, J.W., and Smith, J.D. (2005), Generation and verification of theoretical rating curves in the Whitewater River Basin, KS, Journal of Geophysical Research, 110, F04012, doi:10.1029/2004JF000250.[Link]

Griffin E.R., Kean, J.W., Vincent, K.R., Smith, J.D., and Friedman, J.M. (2005), Modeling effects of bank friction and woody bank vegetation on channel flow and boundary shear stress in the Rio Puerco, New Mexico, Journal of Geophysical Research, 110, F04023, doi:10.1029/2005JF000322. [Link]

Kean, J.W., and Smith, J.D. (2004), Flow and boundary shear stress in channels with woody bank vegetation, in Riparian Vegetation and Fluvial Geomorphology, AGU Water Science and Application Series 8, edited by S.J. Bennett and A. Simon, pp. 237-252, AGU, Washington, D.C.