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Modeling Isla Vista Sea Cliff Retreat Stephen Alexander Gee Seth Gorelik Bryan Karaffa Mark O'Connor. Geog 176C June 7th, 2011. Introduction. Cliff retreat in Isla Vista is occurring Why is understanding it important? Property loss Property damage Environmental risks
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Modeling Isla Vista Sea Cliff RetreatStephen Alexander Gee Seth GorelikBryan KaraffaMark O'Connor Geog 176C June 7th, 2011
Introduction • Cliff retreat in Isla Vista is occurring • Why is understanding it important? • Property loss • Property damage • Environmental risks • Safety risks • Who does it affect? • Isla Vista residents • Property owners • The County of Santa Barbara Image A Image B
Objective • To quantify and design GIS models of past, present, and future sea cliff retreat in Isla Vista. • Three main research questions: • How can sea cliff retreat be modeled using GIS? • How do the rates of local sea cliff retreat vary spatially? • To what degree will ocean front properties in Isla Vista be affected?
Data Sources • Historical Aerial Imagery • 1200 DPI resolution from UCSB Map and Imagery Laboratory • LIDAR DEM Dataset • 1 meter spatial resolution • Provided by BodoBookhagen / Keith Clarke • Land Parcel Dataset • Paul Bartsch, GIS/CAD Specialist, UCSB Design & Construction Services • Software Used: • ArcGIS Suite (ArcMap, ArcCatalog, ArcScene) • ENVI • Google Earth • Excel
Determining Cliff Edge & Retreat Rates Historical imagery Digitize cliff edges Sample rates of retreat Subset of 1967 Image Subset of 2010 Image Subset of 1983 Image The process of digitizing cliff edges utilizing historical imagery, and sampling rates of retreat. Utilizing Remote Sensing to Determining Cliff Edge and Retreat Rates
Results Percent of Land Loss Per Parcel 15 Year Projection: 2010 - 2025 • Percent loss calculated by dividing the measured area of the projected retreat by the area of the 2010 properties Projection: Datum: Data Source: Basemap: UTM, Zone 18N WGS-1984 Paul Bartsch (parcels) Open Street Map
Results • TIN time series of projected cliff retreat TINs generated from a one meter spatial resolution LIDAR DEM
Results • Interactive view of past, present, and future property extents • Users have the ability to: • Select which periods of time they wish to view • Access individual parcel information • View beach level image of corresponding cliff face • Activate one of the two automated tours Check it out! http://bryankaraffa.com/IVSCR.kml
Frequency Distribution of Property Retreat Rates Analysis • In temporal range of data: • Max rate = 1.54 feet per year • Min rate = 0.18 feet per year • Average rate = 0.62 feet per year • The majority of parcels have a retreat rate between 0.30 and 0.60 feet per year • 6700 block of Del Playa Drive is most affected • Of all the properties with the highest erosion rates, 85% of them are located on this block • 52% of the 6700 block are within the two highest categories of erosion rates • With the exclusion of the properties on the 6700 block, the average erosion rate decreases from 0.62 to 0.35 feet per year
Discussion • Varied retreat rates along Del Playa Drive • Retreat rates similar to rates published in previous research Comparison retreat rates source: County of SB
To Improve Research • Orthorectified images • Increase resolution of dataset • temporally • spatially • Incorporate in-situ measurements to increase accuracy • Analyze effects of preventative measures that have been put in place to minimize cliff retreat Image C
References County of SB. "Geologic Hazards." Isla Vista Master Plan Draft EIR. Web. 11 May 2011. <http://www.countyofsb.org/ceo/RDA/docs/masterplan/FEIR/FEIR_3.7.pdf>. Fucci, Tim. "Del Playa Drive Threatened By Erosion | The Bottom Line." The Bottom Line UCSB. Feb. 2011. Web. 28 May 2011. <http://thebottomline.as.ucsb.edu/2011/02/del-playa-drive-threatened-by-erosion>. Jude, Simon. "Exploring Future Coastlines." MasterLA. Web. 14 May 2011. <http://www.masterla.de/conf/pdf/conf2005/22jude_c.pdf>. Morris, Robert M. "Coast & Ocean Vol. 21, Nos. 1&2: Cliff Erosion." California Coast & Ocean. Web. 28 May 2011. <http://www.coastandocean.org/spring_summer2005/pages/five.html>. "Santa Barbara-Ventura Coastal Processes Study - USGS PCMSC." Home Page - USGS Pacific Coastal and Marine Science Center. Web. 28 May 2011. <http://walrus.wr.usgs.gov/coastal_processes/sbventura>. Sylvester, Gibbs. "Isla Vista Cliff Erosion." UCSB Earth Science : Home. Web. 28 May 2011. <http://www.geol.ucsb.edu/faculty/sylvester/UCSB_Beaches/IVCLIFFS/IVclifferosion1.html>. Trimble. "Modeling Sea Cliff Erosion in California." Crisel. Web. 14 May 2011. <http://www.crisel.it/Download/SeaCliffs_Erosion.pdf>. Images: [A] http://www.dailynexus.com/assets/493/7769_5a4bc9ea3cc10724f33ed52ffb5f64fc.jpg [B] http://farm3.static.flickr.com/2748/4388598949_6d2624a645.jpg [C] http://cdn.coastalcare.org/wp-content/uploads/2011/01/isla-vista-erosion.jpg
Acknowledgements • Dr. Keith Clarke • Yihong Yuan • Grant McKenzie • BodoBookhagen • UCSB Map & Imagery Laboratory • Paul Bartsch • A.G Sylvester Thank you!