Establishing sea-cliff erosion rates is a vital component of coastal zone management. Laser scanning technology can provide a fast, reliable, and accurate means to survey sea-cliffs covering large areas of the coastline and to establish local erosion rates. The technology allows for the rapid laterally continuous survey of sea-cliffs with Dynamic Laser Scanning (DLS) and Light Detection and Ranging (LiDAR) surveys. Data collected from DLS and LiDAR surveys for southern Santa Barbara County were compared in a Geographic Information System (GIS). This study establishes regional erosion rates using NOAA LiDAR data along southern Santa Barbara County coastal bluffs from Point Conception to Rincon Point (Carpinteria, California). Regional retreat rates for southern Santa Barbara County calculated in GIS from 1998 and 2010 NOAA LiDAR data range from 4 to 73 cm yr-1. Local erosion rates were also established along Lagoon Road on the University of California, Santa Barbara (UCSB) campus and at Point Conception. The average retreat rate at UCSB calculated from 1997 LiDAR and 2012 DLS data was 24 cm yr-1. Areas along Lagoon Road protected by rip rap have lower average retreat rates of 15 cm yr-1. The Lagoon Road retreat rates are similar to manually surveyed rates along these same cliffs.

Erosion rates along the Lagoon Road sea-cliff with active drain pipes, seepage, and tree falls were expected to experience higher cliff erosion rates than sections of the sea-cliff without these influences, but the results of this study did not confirm my hypothesis. Retreat rates at Lagoon Road were higher than retreat rates at Point Conception. The higher rates are attributed to the presence of excessive surface runoff and the orientation of the dip of the beds. Comparison of 100 m of overlapping DLS data along Lagoon Road from November 2011 and January 2012 suggests that the top of the cliff is retreating at a higher rate than the base, which is a consequence of excess surface runoff. The aspect of the sea-cliff was also found to have an influence on erosion rates, with higher retreat rates correlating to south facing sea-cliffs. Unless measures are taken to impede the current rate of erosion along Lagoon Road, the road will be undercut in 60 years.