Current Research Interests
How does sediment move after a wildfire? Where is dry sediment more abundant?
Wildfires enhance sediment transport, especially in steep (slopes > 30 degrees) mountainous terrain such as the San Gabriel Mountains in Southern California. We focus on the mountains in Southern California because they are on fire very often, are home to alot of people, and because we have a lot of data there. A lot of sediment moves from the hillslopes to the channels as dry ravel - a process where sediment rolls, bounces, or slides downhill. Dry ravel (often called dry sediment too) occurs because vegetation held that sediment in place on steep slopes but that sediment is released downstream. I study dry ravel because it can supply postfire debris flows (see next section below).
Im my work, I am focusing on where we see dry ravel: is it on steep slopes, where more shrubs burned, or on specific types of rock?
Collaborators: Dr. Roman A. DiBiase *amazing advisor!
Figure Credit: BTF
What happens to "burned" sediment after it rains?
Wildfires leave the ground scorched and devoid of vegetation, which reduces the ability of soil to absorb water. When it rains alot, this can increase the risk of flash flooding and post-fire debris flows (top figure). Post-fire debris flows are slurries of sediment and water that can move fast (>20 mph in the video on the bottom right), cause millions in damages to infrastructure, and threaten human lives. In Southern California, we look at how sediment stored in the channels as dry ravel (bottom left figure with red arrows) relates to how debris flows (bottom right video) occur.
In my research, we find that in the San Gabriel Mountains, areas with a lot of dry ravel also had postfire debris flows that occurred. But in the San Bernardino Mountains, we find that debris flows happen in areas that had a lot of rain and the amount of dry ravel was not as important..​
Collaborators: Dr. Roman A. DiBiase
Figure (top) Credit: National Weather Service; Figure (bottom left) Credit: RAD, Video (bottom right) Credit: San Bernardino County Public Works
How do slot canyons form? Why are they deep and not wide like "normal" rivers?
Slot canyons, bedrock rivers that are deeper than they are wide, are often found in massive sandstones in arid climates with highly variable precipitation (think Arizona and Utah). Why are they deep and U-shaped instead of the V-shape seen in hillslopes globally? We use field observations and modelling to explain how slot canyons form and why they deep and not wide like normal rivers.
Collaborators: Michael J. Robinson, Maryn A. Sanders (these folks are amazing! check our their awesome research!!!)
With Advising and Input from: Dr. Joel S. Scheingross, Dr. Roman A. DiBiase, Dr. Joshua A. Roering.
Previous Research Interests
How does sediment move out of a burned mountain?
Wildfires adversely affect the landscape especially in semi-arid, steep mountainous terrain, leading to landslides and debris flows. We have studied the hydrological and sedimentological response of a small watershed after the 2018 Holy Fire in the Santa Ana Mountains, California and determined how the amount of sediment changes over time. Check out the article below!
Collaborators: Dr. James J. Guilinger, Dr. Andrew B. Gray, & Dr. Nicolas C. Barth.
Figure Credit: JJG
How do microplastics float or sink in streams and rivers?
The current approach to assessing and modeling the fluvial transport of microplastics in riverine systems is limited to surface sampling. This approach does not account for all microplastics, some of which are neutral or negatively buoyant. Here, we modified the Rouse profile to account for all microplastics and use this adaptation to estimate the bias and uncertainty from from the use of surface samples compared to depth stratified sampling in estimating depth-averaged concentrations. Check out the article below!
Collaborators: Win C. Cowger, Dr. Andrew B. Gray, James J. Guilinger, & Dr. Kryss Waldschläger.
Figure Credit: WCC
_edited.jpg)
When it rains enough to trigger landslides how do boulders move?
In December 2010, a big rainstorm produced multiple storms that saturated the Box Springs and Blue Mountains, California, leading to soil slips and the transport of boulders along the hillslope and channels. The main objective of this project was to track boulders displaced from landslides from source to sink and quantify boulder movement. Further analyses were done to understand the process of landform remodeling and determine the topographic controls on total boulder runout distance.
Collaborators: James J. Guilinger, Dr. Andrew B. Gray, & Dr. Nicolas C. Barth
Figure Credit: BTF (mapping), Landsat Imagery 2009/2011 (aerial imagery)