HR: 1340h
AN: ED43A-0264    [Abstracts]
TI: The Different Faces of San Francisco's Ocean Beach: Analyzing Sand Size and Beach Shape
AU: Grove, K
EM: kgrove@sfsu.edu
AF: San Francisco State University, Dept. of Geosciences, San Francisco, CA 94132 United States
AU: Labit, R
EM: ryda1216@yahoo.com
AF: Philip and Sala Burton High School, 400 Mansell St., San Francisco, CA 94134 United States
AU: * Lui, S
EM: samudaenen@aol.com
AF: Balboa High School, 1000 Cayuga Ave., San Francisco, CA 94112 United States
AU: Rodriquez, I
EM: lzrdrgz@aol.com
AF: Philip and Sala Burton High School, 400 Mansell St., San Francisco, CA 94134 United States
AU: Yi, C
EM: cyi@lmi.net
AF: San Francisco State University, Dept. of Geosciences, San Francisco, CA 94132 United States
AU: Yu, M
EM: legolas8788@hotmail.com
AF: Philip and Sala Burton High School, 400 Mansell St., San Francisco, CA 94134 United States
AB: Ocean Beach is located along the western edge of San Francisco adjacent to the Pacific Ocean. Erosion along the southern part of the beach is threatening a nearby highway and water treatment plant. To better understand this beach and the processes that form it, our SF-ROCKS research group collected data from seven locations along its length. We used an auto-level surveying instrument to measure beach profiles and we collected sand samples that were measured using sieves and a sieve shaker. We plotted profiles and grain-size data using Excel and Surfer software. The sediment is mostly fine sand, and the means of all samples range between 0.19-0.26 mm. There may be little variation along the beach because only small sand grains have survived the long journey from their Sierra Nevada source. Profile shape does vary along the beach. The profile at the northern end is about three times wider than the profile at the southern end. The northern profile is flatter overall, but all profiles had a steep beach face in August, when the data were collected. The differences in beach profiles may be related to position relative to the offshore bar, which appears to provide sand to the northern part of the beach. Our group will collect more data in November to see what changes have occurred after the large-wave season has begun. We will use Surfer software to compare summer and fall profiles, to see where sediment has been added and where sediment has been removed. We will also compare our results to the data collected by Dr. Patrick Barnard and his research group at the U.S. Geological Survey, who are using an All-Terrain Vehicle to measure beach profiles and a camera to measure sediment size. We will use our analysis of beach variations to make recommendations for reducing beach erosion.
UR: http://sf-rocks.sfsu.edu/
DE: 4546 Nearshore processes
DE: 3022 Marine sediments--processes and transport
DE: 1815 Erosion and sedimentation
DE: 0805 Elementary and secondary education
SC: Education and Human Resourcese [ED]
MN: 2004 AGU Fall Meeting