INCREASED ANGULARITY OF SAND-SIZED GRAINS REFLECTING FLUVIAL PROCESSES OF TRABUCO CREEK, ORANGE COUNTY, CA: PRELIMINARY RESULTS FROM A COMMUNITY COLLEGE RESEARCH EXPERIENCE
We formulated several working hypotheses in response to this unexpected trend in angularity: 1. Short, steep tributaries contribute sediment which has undergone less transport and is more angular into Trabuco Creek. We excluded a section of Trabuco Creek in our stream profiling and sampling due to lack of accessibility to the site. Renewed efforts to sample this area and conduct roundness studies for the 2.00mm to 63μm fraction will provide insight into the importance of tributary contribution. 2. Alternatively, expected trends of increasing roundedness downstream have been modified in Trabuco Creek because the system is susceptible to sporadic, high-energy events, and particles are subjected to collisions with one another. An increase in energy could be capable of transporting larger clasts via saltation, causing impacts among clasts and contributing to increased angularity. We expect that our studies will reveal a clearer answer as to what causes this unexpected increase in angularity.