Speaker: David L. Revell

THE BREN SCHOOL OF Environmental Science & Management
at the University of California, Santa Barbara

Presents

David L. Revell
Consultant
Philip Williams and Associates


Tuesday, April 28, 2009
12:30 - 1:30 p.m.
Bren Hall 1414

"Regional Shoreline and Beach Changes in the Santa Barbara Sandshed"

Hosted by Acting Dean John Melack and Milena Viljoen

 

Abstract

With regional sand management of the Santa Barbara Littoral Cell as a background focus, we focus on some of the results of a historic change analysis of the beaches in Santa Barbara and Ventura counties over the past 125 years. This regional approach along a 70-kilometer stretch of coastline enables changes and alterations across a variety of time and space scales to be examined. The methodology applies a variety of air photo and Lidar analyses to examine both shoreline and beach width changes.

The effects of dam impoundment and shore protection structures on sand delivery have been studied in Santa Barbara and show an approximate 40-percent reduction in sand supplied by the sandshed to the littoral cell. Yet, harbor dredging records have remained essentially constant for the past 40-plus years, indicating a steady supply of sediment. What effect has this reduction in supply had on the health of the beaches? Can the impacts of these human alterations be separated from climate variability?

Historic map and aerial photography results hint at an interdecadal climate response that is mostly out of phase with precipitation and sediment discharge records. The long- term beach width analyses highlight human impacts of shoreline armoring caused by passive erosion and placement lost in which  more than 59 percent of the beaches in front of structures show significant changes. Large El Niño storm events from 1982-83 and 1997-98 show similar impacts by reducing beach widths by more than 50 percent. The 1997-98 El Nino analyses used high-resolution topographic LIDAR data flown in October 1997 and April 1998 to quantify erosion hotspots, beach widths, slopes, volume changes, and the spatial response of the shoreline. El Niño results also indicate that beaches rotate in response to the direction of dominant wave energy.

This research investigates large-scale coastal behavior, shoreline rotation, storm responses, sand pulses, and the effects of shoreline armoring and other human alterations through a combination of remote sensing, GIS, fieldwork, and sediment budget analyses. These results have significant implications for managing the Santa Barbara and Ventura County coastlines but also provide a template for how to analyze a variety of regional data sets to inform decision-making along other coastlines around the world.

Biography

David L. Revell is a coastal geomorphologist with more than ten years of experience working on coastal and marine management issues along the West Coast of North America. He received his PhD in Earth Sciences from UC Santa Cruz in 2007, following doctoral research that focused on the shoreline evolution of the beaches of Santa Barbara and Ventura counties. He received his master's in Marine Resource Management from Oregon State University for studies in assessing regional coastal hazards. He has worked as a technical advisor on GIS and coastal hazards for the Oregon Coastal Management Program, and he promoted beach access, ocean water-quality testing, and marine protected areas for the Surfrider Foundation. During that time, he served on steering committees for the Baja to Bering Marine Conservation Initiative and the Oregon State Beach Access and Snowy Plover Recovery programs. Dr. Revell graduated with honors from UCSB in 1996, having pursued Environmental Studies and Geography. During his college years he founded the Isla Vista Surfrider Chapter and worked on the Gaviota Coast National Seashore Effort. Currently, he works as a consultant for Philip Williams and Associates where he manages projects on sea-level rise, Goleta Beach, Surfer’s Point, and Coastal Lagoon Restoration. He also works for CoastalWatch, USA, a camera company that extracts coastal process and management data from video imagery. He currently serves on the Board of Directors for the American Shore and Beach Preservation Association and is an avid surfer and a new father.

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