Current Research Interests
Where does burned sediment comes from?
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 the vegetation that held the sediment in place on steep slopes before fire is incinerated, and that sediment is released downstream.
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? Do we see it more in hillslopes or valleys or channels? I study dry ravel because it can supply the ammo for postfire debris flows (see next section below).
Collaborators: Dr. Roman A. DiBiase *amazing advisor!
Figure Credit: BTF
How does burned sediment move?
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.
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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 landscapes evolve over geologic time?
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 compare two nearby canyons in Arizona with different rock types, and find that slot canyons form where vertical erosion is high and sediment input from hillsides is low. We suggest that soft, massive rock with few fractures allows rivers to cut deeply without widening the canyon.
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 do postfire erosion processes change over multiple storms?
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 where and 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 accurately do surface samples represent microplastic river transport?
Some microplastics float, some sink when moving through rivers and into oceans. We show that sampling the water’s surface doesn’t give an accurate picture of how much plastic is really flowing, as some plastics move differently depending on their size and buoyancy. Our results suggest using better sampling methods to measure plastic at different depths to get more accurate results.
Collaborators: Win C. Cowger, Dr. Andrew B. Gray, James J. Guilinger, & Dr. Kryss Waldschläger.
Figure Credit: WCC
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How do boulders move when it rains alot?
In December 2010, a big rainstorm produced multiple storms that saturated the Box Springs and Blue Mountains, California, and we observed large boulders move during shallow landslides in Southern California. Unlike rockfall where boulder size matters, we found that in shallow landslides, how far a boulder moves depends more on its location—especially if it's near where the slide started. Boulders at the top of the landslide traveled much farther than those farther downslope, which could be important for assessing landslide hazards.
Collaborators: James J. Guilinger, Dr. Andrew B. Gray, & Dr. Nicolas C. Barth
Figure Credit: BTF (mapping), Landsat Imagery 2009/2011 (aerial imagery)