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Dr. Leonard Sklar, PhD

Emeritus Professor, Geography, Planning and Environment

Dr.  Leonard Sklar, PhD

Dr. Leonard Sklar is Emeritus Professor in the Department of Geography, Planning and Environment.  He earned a PhD in Geology and Geophysics and an MS in Water Resources Engineering at the University of California, Berkeley, as well as a BS in Applied Science from New York University and a BE in Civil Engineering from The Cooper Union of New York. Prior to coming to Concordia in 2017, Dr. Sklar served on the faculty of San Francisco State University for 14 years. 

Research Interests

  • Earth surface processes and landscape evolution

  • Sediment production and transport

  • Water resources management

  • Ecological and geomorphic process interactions

  • Global change and sustainability science

Teaching activities

GEOL 210: Introduction to the Earth

GEOG 298: From Source to Sea to Sustainability, Integrated Cycles in Wastewater and Nutrient Management

GEOG 475: Water Resources Management

GEOG 655: Environmental Modelling


Peer-Reviewed Journal Articles

65.  Verdian, J.P., L.S. Sklar, C.S.Riebe, and J.R. Moore (2021). Sedimentsize on talus slopes correlates with fracture spacing on bedrock cliffs:Implications for predicting initial sediment size distributions on hillslopes, Earth Surface Dynamics, 9:1073-1090, doi:10.5194/esurf-9-1073-2021.


64.  Li, T.,J.G. Venditti, and L.S. Sklar (2021). An analytical model for lateral erosion from saltatingbedload particle impacts, Journal ofGeophysical Research: Earth Surface, doi:10.1029/2020JF006061.

63.  Riebe, C.S., R.P. Callahan, S.B.M.Granke, B.J. Carr, J.L. Hayes, M.S. Schell, and L.S. Sklar (2021).Anisovolumetric weathering in granitic saprolite controlled by climate anderosion rates, Geology,49(5):551-555, doi:10.1130/G48191.1. 

62.  Callahan, R.P., C.S. Riebe, S. Pasquet,K.L. Ferrier, D. Grana, L.S. Sklar, N.J. Taylor, B.A. Flinchum, J.L.Hayes, B.J. Carr, P.C. Hartsough, A.T. O’Geen, and W.S. Holbrook (2020).Subsurface weathering revealed by hillslope-integrated porosity distributions, Geophysical Research Letters, doi:10.1029/2020GL088322.

 61.  Li, T., T.K. Fuller, L.S. Sklar,K.B. Gran, and J.G. Venditti (2020). A mechanistic model for lateralerosion of bedrock banks by bedload particle impacts, Journal of Geophysical Research: Earth Surface, doi:10.1029/2019JF005509.

60.  Sklar, L.S., C.S. Riebe, J. Genetti, S. Leclere, and C.E. Lukens, (2020). Downvalley fining of hillslope sediment in an alpine catchment: Implications for downstream fining of sediment flux in mountain rivers, Earth Surface Processes and Landforms, doi:10.1002/esp.4849.

59.  Lukens, C.E., C.S. Riebe, L.S. Sklar, and D.L. Shuster (2020). Sediment size and abrasion biases in detrital thermochronology, Earth and Planetary Science Letters, 531; doi:10.1016/j.epsl.2019.115929

58.  Tumolo, B., L. Albertson, W. Cross, M.Daniels, and L.S. Sklar (2019). Occupied and abandoned  structures from ecosystem engineering differentially facilitate stream community colonization, EcoSphere 10(5):e02734.10.1002/ecs2.2734.

57.  Albertson, L.K., L.S. Sklar, S.D. Cooper, and B.J. Cardinale (2019). Aquatic macro invertabrates stabilize gravel bed sediment: A test using silk net-spinning caddisflies in semi-natural river channels, PLoS ONE; doi:10.3071/journal.pone.0209087.

56.  Callahan, R.P., K.L. Ferrier, J. Dixon, A Dosseto, W.J. Hahm, B.S. Jessup, S.N. Miller, C.T. Hunsaker, D.W. Johnson, L.S. Sklar, and C.S.Riebe (2019). Arrested development: Erosional equilibrium in the southern Sierra Nevada, California, maintained by feedbacks between channel incision and hillslope sediment production, Geological Society of America Bulletin; doi:10.1130/B35006.1.

55.  Kui, L., J.C. Stella, R.M. Diehl, A.C.Wilcock, A. Lightbody, and L.S. Sklar (2018). Can environmental flows moderate riparian invasions? The influence of seedling morphology and density on scour losses in experimental floods, Freshwater Biology; doi:10.1111/fwb.13235.

54.  Wohl, E.E., G. Brierley, D. Cadol, T. Coulthard, T. Covino, K. Fryirs, G. Grant, R. Hilton, S. Lane, K. Meitzen, P. Passalacqua, R. Poppl, S. Rathburn, and L.S. Sklar (2018). Connectivity as an emergent property of geomorphic systems, Earth Surface Processes and Landforms; doi:10.1002/esp.4434.

53.  Bakke, P.D., L.S. Sklar, D.R. Dawdy, and W.C. Wang (2017). Design of a site-calibrated Parker-Klingeman gravel transport model, Water 9, 441; doi:10.3390/w9060441.

52.  Sklar, L.S., C.S. Riebe, C.E. Lukens, and D. Bellugi (2016). Catchment power and the joint distribution of elevation and travel distance to the outlet, Earth Surface Dynamics, doi:10.5194/esurf-2016-9.

51.  Diehl, R.M., A.C. Wilcox, J.C. Stella, L. Kui, L.S. Sklar, and A. Lightbody (2016). Fluvial sediment supply and pioneer woody seedlings as a control on bar surface topography, Earth Surface Processes and Landforms, doi: 10.1002/esp.4017.

50.  Goodfellow, B.W., G.E. Hilley, M.S. Schulz, S.M. Webb, L.S. Sklar, S. Moon, and C.Olson (2016). The chemical, mechanical, and hydrological evolution of a weathering granitoid, Journal of Geophysical Research – Earth Surface, doi: 10.1002/2016JF003822.

49.  Sklar, L.S., C.S. Riebe, J.A. Marshall, J. Genetti, S. Leclere, C.E.Lukens, and V. Merces (2016). The problem of predicting the particle size distribution of sediment supplied by hillslopes to rivers, Geomorphology, doi:10.1016/j.geomorph.2016.05.005

48.  Lukens, C.E., C.S. Riebe, L.S. Sklar, and D.L. Shuster (2016). Grain size bias in cosmogenic nuclide studies of stream sediment in steep terrain, Journal of Geophysical Research: Earth Surface 121, 978-999, doi:10.1002/2016JF003859.

47.  Fuller, T.K., K.B. Gran, L.S. Sklar, and C. Paola (2016). Lateral erosion in an experimental bedrock channel: the influence of bed roughness on erosion by bed-load impacts, Journal of Geophysical Research: Earth Surface, doi: 10.1002/2015JF003728.

46.  Murphy, B.P., J.P. Johnson, N.M. Gasparini and L.S. Sklar, (2016). A mechanism for the climatic control of bedrock river incision. Nature, doi: 10.1038/nature17449.

45.  Overstreet, B.T., C.S. Riebe, J.K. Wooster, L.S. Sklar, and D. Bellugi (2015). Gauging the capacity of salmon spawning substrates, Earth Surface Processes and Landforms, doi: 10.1002/esp.3831.

44.  Riebe, C.S., L.S. Sklar, C.E. Lukens, and D.L. Shuster (2015). Climate and topography control the size of sediment produced on mountain slopes, Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.1503567112.

43.  Manners, R.B., A.C. Wilcox, L. Kui, A. Lightbody, J.C. Stella and L.S. Sklar (2015). When do plants modify fluvial processes? Plant-hydraulic interactions under variable flow and sediment supply rates, Journal of Geophysical Research – Earth Surface, doi:10.1002/2014JF003265.

42.  Lamb M.P., N.J Finnegan, J.S. Scheingross and L.S. Sklar (2015). New insight into the mechanics of fluvial bedrock erosion through flume experiments and theory, Geomorphology, doi: 10.1016/j.geomorph.2015.03.003.

41.  Gaeuman, D., L.S. Sklar, and Y. Lai (2014). Experiments to constrain bedload adaptation length, Journal of Hydrologic Engineering, doi: 10.1061/(ASCE)HE.1943-5584.0001067.

40.  Albertson, L.K., L.S. Sklar, P. Pontau, M. Dow and B.J. Cardinale (2014). A mechanistic model linking insect (Hydropsychidae) silk nets to incipient sediment motion in gravel-bedded streams, Journal of Geophysical Research – Earth Surface, 110, 1833-1852, doi:10.1002/2013JF003024.

39.  Sklar,L.S.  (2014). An ephemeral gorge: News & Views, Nature Geoscience 7, 624-625, doi:10.1038/ngeo2235.

38.  Albertson, L.K., B.J. Cardinale and L.S. Sklar (2014). Non-additive species interactions produce synergistic effects on sediment stability in streams, PLoS ONE, doi:10.1371/journal.pone.0103417.g005.

37.  Hsu, L., W.E. Dietrich and L.S. Sklar (2014). Mean and fluctuating basal forces generated by granular flows: laboratory observations in a large vertically rotating drum, Journal of Geophysical Research – Earth Surface, doi: 10.1002/2013JF003078.

36.  Newcomer, M.E., J.J. Gurdak, L.S. Sklar, and L. Nanus (2014). Urban recharge beneath low impact development and effects of climate variability and change, Water Resources Research 50, doi:10.1002/2013WR014282.

35.  Riebe, C.S., L.S. Sklar, B.T. Overstreet, and J.K. Wooster (2014). Optimal reproduction in salmon spawning substrates linked to grain size and fish length, Water Resources Research 50, doi:10.1002/2013WR014231.

34.  Luers, A.L. and L.S. Sklar (2013). The difficult, the dangerous, and the catastrophic: Managing the spectrum of climate risks, Earth’s Future 2, doi:10.1002/2013EF000192.

33.  Burr, D.M., J.T. Perron, M.P. Lamb, R.P.Irwin, A.D. Howard, G.C. Collins, L.S. Sklar, J.M Moore, M. Adamkovics, V.R. Baker, S.A. Drummond, B.A. Black (2012). Fluvial features on Titan: Insights from morphology and modeling, Geological Society of America Bulletin, doi: 10.1130/B30612.2.

32.  Litwin, K.L., B.R. Zygielbaum, P.J. Polito, L.S. Sklar, and G.C.Collins, (2012). Influence of temperature, composition and grain size on tensile failure of water ice: implications for erosion on Titan, Journal of Geophysical Research – Planets; doi:10.1029/2012JE004101.

31.  Marshall, J.A. and L.S. Sklar (2012). Mining soil databases for patterns in the abundance and size distribution of rock fragments, Earth Surface Processes and Landforms, 37(3): 287-300; doi:10.1002/esp.2241.

30.  Humphries, R., J.G. Venditti, L.S. Sklar, J.K. Wooster (2012). Experimental evidence for the effect of hydrographs on sediment pulse dynamics in gravel-bedded rivers, Water Resources Research 48, W01533, doi: 10.1029/2011WR010419.

29.  Hodge, R., T. Hoey, and L.S. Sklar (2011). Bedload transport in bedrock rivers: the role of sediment cover in grain entrainment, translation and deposition, Journal of Geophyscial Research – Earth Surface, doi: 10.1029/2011JF002032.

28.  Fuller. B.M., L.S. Sklar, Z.G. Compson, K.J. Adams, J.C. Marks, and A.C. Wilcox (2011).  Ecogeomorphic feedbacks in regrowth of travertine step-pool morphology after dam decommissioning, Fossil Creek, Arizona, Geomorphology,126: 314-322; doi: 10.1016/j.geomorph.2010.05.010.

27.  Grove, K., L.S. Sklar, A.M. Scherer, G. Lee, and J. Davis (2010).  Accelerating and spatially-varying rock uplift and its geomorphic expression, San Andreas fault zone north of San Francisco, California, Tectonophysics, 495:256-268, doi: 10.1016/j.tecto.2010.09.034.

26.  Venditti, J.G., W.E. Dietrich, P.A. NelsonM.A. Wydzga, J. Fadde, and L.S. Sklar (2010). Effect of sediment pulse grain size on sediment transport rates and bed mobility in gravel bedded rivers, Journal of Geophysical Research-Earth Surface, 115: F03039.  doi:10.1029/2009JF001418.

25.  Venditti, J.G., W.E. Dietrich, P.A. NelsonM.A. Wydzga, J. Fadde and L.S. Sklar (2010). Mobilization of coarse surface layers in gravel-bedded rivers by finer gravel bedload, Water Resources Research, doi:10.1029/2009WR008329.

24.  Johnson, J.P., K.X. Whipple, and L.S. Sklar (2010). Contrasting bedrock incision rates from snowmelt and flash floods in the Henry Mountains, Utah, Geological Society of America Bulletin, 122(9/10):1600-1615, doi: 10.1130/B30126.1.

23.  Downs, P.W., Y. Cui, J.K. Wooster, S.R. Dusterhoff, D.B. Booth, W.E. Dietrich, and L.S. Sklar (2009). Managing sediment release in dam removal projects: an approach informed by physical and numerical modeling of non-cohesive sediment, International Journal of River Basin Management,7(4): 433-452.

22.  Braudrick, C.A., W.E. Dietrich, G.T. Leverich, and L.S. Sklar (2009).  Experimental evidence for the conditions necessary to sustain meandering in coarse-bedded rivers, Proc. of the National Academy of Science, 106(40), 16936-16941,doi: 10.1073/pnas.0909417106.

21.  Sklar, L.S., J. Fadde, J.G. Venditti, A. Wyzdga, P. Nelson,Y. Cui, and W.E. Dietrich (2009). Translation and dispersion of sediment pulses in flume experiments simulating gravel augmentation below dams, Water Resources Research, 45, doi:10.1029/2008WR007346.

20.  Johnson, J.P., K.X. Whipple, L.S. Sklar, and T. Hanks (2009).  Transport slopes, sediment cover and bedrock channel incision in the Henry Mountains, Utah, Journal of Geophysical Research-Earth Surface, 114, F02014,doi:10.1029/2007JF000862.

19.  Nelson, P.A., J.G. Venditti, W.E. Dietrich, J.W. Kirchner, H. Ikeda, F. Iseya and L.S. Sklar (2009).  Response of bed surface patchiness to reductions in sediment supply, Journal of Geophysical Research-Earth Surface, 114, F02005, doi:10.1029/2008JF001144.

18.  Lamb, M.P., W.E. Dietrich, and L.S. Sklar (2008).  A model for fluvial bedrock incision by impacting suspended and bed load sediment, Journal of Geophysical Research-Earth Surface, 113, F03025, doi:10.1029/2007JF000915.

17.  Cui, Y., P. Baker, J. Wooster, S. Dusterhoff, L.S. Sklar, and W.E. Dietrich (2008). Theory of fine sediment infiltration into immobile gravel bed, Journal of Hydraulic Engineering, 134(10):1421-1429, doi:10.1061/(ASCE)134:10(1421).

16.  Sas, R.J., L.S. Sklar, L.S. Eaton, and J. Davis (2008).  A method for developing regional, road-fill failure hazard assessments using GIS and virtual fieldwork, Environmental and Engineering Geosciences 14(3):221-229,doi: 10.2113/gseegeosci.14.3.221.

15.  Sklar, L.S. and W.E. Dietrich (2008). Implications of the saltation-abrasion bedrock incision model for steady state river longitudinal profile relief and concavity, Earth Surface Processes and Landforms, doi: 10.1002/esp.1689.

14.  Hsu, L., W.E. Dietrich, and L.S. Sklar (2008).  Experimental study of bedrock incision by granular flows, Journal of Geophysical Research-Earth Surface, 113, F02001, doi:10.1029/2007JF000778.

13.  Wooster, J., S. Dusterhoff, Y. Cui, L.S. Sklar, W.E. Dietrich, and M. Malko (2008).  Sediment supply and relative grain size distribution effects on fine sediment infiltration into immobile gravels, Water Resources Research, 44, W03424, doi: 10.1029/2006WR005815.

12.  Cui, Y., J. Wooster, J.G. Venditti, S. Dusterhoff, W.E. Dietrich, and L.S. Sklar (2008).  Simulating sediment transport in a highly two-dimensional flume: examinations of two one-dimensional numerical models, Journal of Hydraulic Engineering, 134(7), 892-904, doi:10.1061/(ASCE)0733-9429(2008)134:7(892).

11.  Finnegan, N.J., Sklar, L.S. and T.K. Fuller (2007). The interplay of sediment supply, river incision and bedrock channel morphology revealed by the transient evolution of an experimental bedrock channel, Journal of Geophysical Research-Earth Surface, 112, F03S11, doi:10.1029/2006JF000569.

10. Sklar, L.S., W.E. Dietrich, E. Foufoula-Georgiou, B. Lashermes and D. Bellugi (2006). Do gravel-bed river size distributions record channel network structure?  Water Resources Research, Vol. 42, No. 6, W06D18, doi:10.1029/2006wr005035.

9.   Sklar, L.S. and W.E. Dietrich (2006). The role of sediment in controlling bedrock channel slope: Implications of the saltation-abrasion incision model, Geomorphology, Vol. 82, No. 1-2, p.58-83, doi: 10.1016/j.geomorph.2005.08.019.

8.   Stock, J.D., D.R. Montgomery, B. Collins, W.E. Dietrich, and L.S. Sklar (2005). Field measurements of incision rates following bedrock exposure: Implications for process controls on the long-profiles of valleys cut by rivers and debris flows, Geological Society of America Bulletin, Vol. 117, No. 11/12, p. 174-195, doi:10.1130/B25560.1.

7.   Sklar, L.S. and W. E. Dietrich (2004).  A mechanistic model for river incision into bedrock by saltating bedload, Water Resources Research, Vol. 40,W06301, doi:10.1029/2003WR002496. PDF

6.   Luers, A.L,, D.B. Lobell, L.S. Sklar, C.L. Adams and P. Matson (2003).  A method for quantifying vulnerability, applied to the agricultural system of the Yaqui Valley, Mexico, Global Environmental Change, Vol. 13, No. 4, p. 255-267.

5.   Dietrich, W.E., D. Bellugi, L.S. Sklar, J.D. Stock, A.M. Heimsath, and J.J. Roering (2003). Geomorphic transport laws for predicting landscape form and dynamics, in Prediction in Geomorphology,  P. Wilcock and R. Iverson, eds., Geophysical Monograph Series, Vol. 135, p. 103-132, American Geophysical Union, Washington DC.

4.   Sklar, L.S. and W.E. Dietrich (2001). Sediment and rock strength controls on river incision into bedrock, Geology, Vol. 29, No. 12, p. 1087-1090.

3b. Roering, J.J., J.W. Kirchner, L.S. Sklar and W.E. Dietrich (2002). Hillslope evolution by nonlinear creep and landsliding: An experimental study: Reply, Geology, Vol. 30, No.5, p. 482.

3a. Roering, J.J., J.W. Kirchner, L.S. Sklar and W.E. Dietrich (2001). Hillslope evolution by nonlinear creep and landsliding: An experimental study, Geology, Vol. 29, No. 2, p.143-146.

2.   Sklar, L.S. and W.E. Dietrich (1998). River longitudinal profiles and bedrock incision models: Stream power and the influence of sediment supply, in Tinkler, K.J. and E.E. Wohl, eds., Rivers Over Rock: Fluvial Processes in Bedrock Channels, Geophysical Monograph Series,Vol. 107, p. 237-260, American Geophysical Union, Washington DC.

1.   Moore, D. and L.S. Sklar (1998).  Reforming the World Bank's lending for water: The process and outcome of developing a water resources management policy, in Fox, J., ed., The Struggle for Accountability, Institute for Development Research Press, Boston, p. 345-390.

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