Wave Damage and Subsidence Analysis at King Harbor, Redondo Beach, California
Coastal Environments conducted a detailed analysis of wave damage, subsidence, and differential settlement of marine structures at King Harbor, in Redondo Beach, California. Work included bathymetry, sidescan, and subbottom profiling; coring; wave measurements inside and outside the harbor; sea-level measurements to estimate benchmark elevation; and numerical modeling to estimate if a 2-ft subsidence had an effect on damage caused by the January 1988 storm. The subsidence portion of the study included a review of the time dependent performance of the regional benchmark system monitored by Los Angeles County.
Individual benchmarks were also studied to determine if their historic movement was altered by local geologic conditions. A historical review of aerial photographs was conducted in conjunction with this project. Recent and historical coring logs were also reviewed. Bathymetry and sub-bottom geophysical profiles within and around the harbor were analyzed to obtain a detailed map. Cross-sections were created of local geologic conditions, including location of the Redondo Canyon and stability of sediments at the edge of the canyon, the location and activity of the Palos Verdes fault, and thickness and lateral distribution of compressible sediments. The wave analysis included computer modeling of the damaging waves that struck King Harbor during January 1988.
The results of the study demonstrated 1) the effects of the Redondo Canyon on focusing wave energy 2) the importance of local and regional geologic conditions on the performance of marine structures as breakwaters and moles 3) the role of rare events, such as the January 1988 storm waves, on damage to coastal structures.
Photograph at King Harbor during the 17-18 January 1998 wave storm.
Client:
Neal, Haushalter and O’Neill Law Offices
Client Contact:
John M. Haushalter, Neal, Haushalter and O’Neill Law Offices, 18201 Von Karman Avenue Suite 1100 Irvine, CA 92715