1 / 25

Historical Changes of Goulds Inlet, Georgia From Geospatial Analysis of Aerial Photography

Historical Changes of Goulds Inlet, Georgia From Geospatial Analysis of Aerial Photography. Rochelle Petruccelli-UWG Chester W. Jackson, Jr.-UGA David M. Bush-UWG Clark Alexander-Skidaway. Savannah. Goulds Inlet. Sea Island. Goulds Inlet Between St. Simons and Sea Islands, Georgia

media
Download Presentation

Historical Changes of Goulds Inlet, Georgia From Geospatial Analysis of Aerial Photography

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Historical Changes of Goulds Inlet, Georgia From Geospatial Analysis of Aerial Photography Rochelle Petruccelli-UWG Chester W. Jackson, Jr.-UGA David M. Bush-UWG Clark Alexander-Skidaway

  2. Savannah Goulds Inlet

  3. Sea Island • Goulds Inlet • Between St. Simons and Sea Islands, Georgia • Mesotidal, spring tide range • is 3.1 meters • Small, stable inlet

  4. Sea Island spit seawall Johnson rocks

  5. A B C D

  6. Previous Work • Griffin, Martha M., and Henry, Vernon J. 1984, Historical Changes in the Mean High Water Shoreline of Georgia, 1857-1982.

  7. Griffin and Henry: Shoreline changes between 1857/60 - 1980

  8. 1924-1974 1857/60 - 1974 Griffin and Henry: Changes to St. Simons and Sea Island

  9. Griffin and Henry: Goulds Inlet system changes 1860 - 1974

  10. Goals • Assess the coastal hazards vulnerability of homes along East Beach, St. Simons Island, GA • GIS evaluation of historical behavior of Goulds Inlet • Shoreline positions • Inlet channel positions • Inlet-associated shoals • Predict future behavior of inlet system • Recommend management options

  11. Methods • Acquire historical information • Air photos • T-sheets • DOQQs • Digitize • Inlet channel • Historical shorelines • Inlet shoals • Analyze position data • Shorelines • Inlet 1963

  12. Goulds Inlet, Georgia 1942 1964 1979 1984 1993

  13. Inlet channel has migrated over time Current tidal channel location Sea Island spit seawall Previous tidal channel location(~late1800s)

  14. 76 transects, 50-meter spacing

  15. Shoreline Change Statistics • EPR = End Point Rate—Distance between oldest and youngest shorelines divided by total time elapsed (m/yr)  • AOR = Average of Rates—average of separate EPRs for all combinations of shorelines when more than two are available • LRR = Linear Regression Rate—slope of the best-fit line using all data points • JKR = Jackknife Rate—average of slopes of all points, leaving out one point each iteration • AOE = Average of Eras—change rates are calculated between each set of air photos, then averaged

  16. 1869-1933 Era 1933-1957 Era East Beach, St. Simons Island 1957-1979 Era 1979-1993 Era End Point Rates for selected eras 1993-1999 Era Accretion Erosion

  17. Shoreline Change Summary 76 transects 22 show erosion 54 show accretion 1869-2003 Era accretion erosion

  18. Inlet Shoals 1963

  19. Persistence of Inlet Shoals Green and yellow = frequent shoaling Blue = infrequent shoaling

  20. St. Simons Island Sea Island St. Simons Island Sea Island St. Simons Island Sea Island

  21. Results • Sea Island spit has steadily accreted • Northern tip of St. Simon’s has experienced long-term erosion • St. Simons East Beach has experienced net long-term accretion • Goulds Inlet appears relatively stable, though it does exhibit slow southerly migration

  22. Recommendations for homes along East Beach, St. Simons Island, GA • Major Engineering • Remove seawall, relocate inlet channel • Reorient inlet channel by dredging • Augment existing rocks, add sand, vegetate • Minor Engineering • Retreat /relocation • Retrofit buildings • Do nothing (preferred alternative)

  23. Acknowledgements • Mike Robinson, Skidaway Institute of Oceanography • Clark Alexander, Skidaway Institute of Oceanography • John Gay, St. Simons Island • John Congleton, UWG Geosciences • Jeong Seong, UWG Geosciences • Georgia Department of Transportation • University of West Georgia • Georgia Sea Grant College Program

More Related