Drainage basin evolution models strive to understand geomorphological process operation over extended scales of space and time. A primary focus of this part of my research is to further refine geomorphic transport processes invoked in LandMod. LandMod is a numerical model of drainage basin evolution that considers both hillslope and fluvial systems. Field studies are integral to this work, and complement this modelling effort by contributing to the development, calibration and testing of model equations.

I am particularly interested in using LandMod to evaluate sediment transport rates and sediment routing patterns in previously glacierized drainage basins in British Columbia over Holocene time scales. The long-term objective of the research program is to improve our understanding of sediment transport rates and sediment routing patterns during interglacial periods. The numerical model of hillslope/channel processes can eventually be combined with tectonic, climate and glacial models to simulate landscape evolution during both nonglacial and glacial episodes.

Increasingly, it is being realized that critical links between geomorphology and vegetation may affect patterns of sediment movement and drainage basin evolution. Hence, I have several developing several research projects that begin to explore these linkages in more detail. Results of these studies will eventually be incorporated in LandMod to better represent geomorphic processes involved in drainage basin evolution.

Wildfire Impacts on Geomorphology

Wildfire occurrence affects the operation of geomorphological processes in several ways. The loss of vegetation due to wildfire disturbance may affect soil erosion, mass wasting, and fluvial processes. My research projects related to this theme cover both field and modelling studies, and a range of spatial and temporal scales. Recent research has explored impacts of wildfire on shallow landsliding over millenial time scales using a numerical modelling approach. In addition, several field projects have been initiated at the Kootenay wildfire site as part of research for the G8 Legacy Chair in Wildlife Ecology. The three projects falling under this initiative are: (i) effects of post-fire tree toppling on sediment supply and hillslope erosion; (ii) post-fire losses in tree root strength and impacts on hillslope stability; and (iii) woody debris supply to streams following wildfire and effects on channel morphology and aquatic habitat

              first visit to Kootenay burn site 2004    Kootenay National Park study site
    Kootenay National Park burn site, March 2004     Kootenay National Park burn site, October 2004
              Josh Roering (Prof., Univ. of Oregon), Yvonne Martin,                         Joan Gallaway (M.Sc. candidate, Dr. Ed Johnson
                      Joan Gallaway (M.Sc. candidate, U of C)                                        (Prof. Biol., U of C), Reid Van Brabant (Ph.D.
                                                                                                                               candidate, U of C)

Interactions Between Geomorphology and Ecology

It is becoming increasingly clear that there are critical links and feedbacks between geomorphology and landscape ecology. Since water flow paths are directed down slopes, processes determining hillslope morphology and arrangement play an essential role in plant community organization and dynamics. Hillslope morphology, substrate characteristics and climate determine flow routing and water budgets along slopes. Wetness is a function of transmissivity, contributing area and slope gradient. Movement of nutrients along hillslopes generally follows wetness values, and is affected by soil type. Plant species have different tolerances to wetness and nutrients; hillslope length and slope angle determine the moisture-nutrient gradient, and in turn the shape of plant tolerance curves. This research attempts to better understand the critical linkages between topography and plant communities.

Fluvial Geomorphology

My research interests in fluvial geomorphology include topics such as:

bed load transport and formulae for its predictions
sediment budgets analysis to unravel transport patterns at a variety of time scales
developing models of sediment transport for both low-gradient and high-gradient channels

Hillslope Geomorphology

My research interests in hillslope geomorphology include topics such as:

analyzing large data bases of landsliding in mountainous regions
magnitude-frequency analysis of landsliding
constructing equations for landsliding transport at large scales
remote sensing technology for landsliding identification