Alabama Coastal Mapping Update

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Alabama Coastal Mapping Update
Presented By Bradley Heilwagen, PE, CFM Jason
Wilson, PE, CFM AMEC Earth and Environmental
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FEMA Priorities

• Conclusion of Map Modernization in Fiscal Year
  2008
• Priorities for 2009 and beyond
• Levees
• Unmapped areas
• Under mapped areas
• COASTALgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgtgt

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Alabamas Coastal Mapping Update

• In January 2009, Alabama Office of Water
  Resources and the Northwest Florida Water
  Management District submitted a proposal to FEMA
  titled Coastal Modeling and DFIRM Production
  Proposal for Coastal Northwest Florida and
  Alabama
• Proposal accepted in February at just over 5
  million dollars for the entire project.
• Grants issued in early summer 2009

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Alabamas Coastal Mapping Update

• Two phase approach
• Phase 1 ADCIRC/Wave set up modeling to
  determine 10, 2, 1 and 0.2 annual chance
  stillwater elevations.
• ADCIRC model being developed by NOAA which covers
  Baldwin and Mobile Counties in Alabama plus
  Escambia, Santa Rosa, Okaloosa, Walton, Bay and
  Gulf Counties in Florida. ADCIRC is an Advanced
  3D Circulation Model used to compute storm surge
  heights from either historic or synthetic storm
  events.
• The storm surge study will be performed for the
  coastline of the eight counties with a single
  storm surge model effort (requires hundreds of
  storm runs and thousands of hours of processing
  time).
• Phase 2 Overland wave or transect modeling and
  DFIRM mapping.

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Alabamas Coastal Mapping UpdateProject Team
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Alabamas Coastal Mapping UpdateProject
TeamPhase I team

• Managed by Ron Bartel, Director of Division of
  Resource Management, NWFWMD
• Study Team
• Jeff Gangai, Project ManagerDewberry, Inc.
• Dr. Don Slinn, University of Florida
• Dr. Scott Hagen, University of Central Florida
• Dr. Chris Reed, URS Corporation

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Alabamas Coastal Mapping UpdateProject
TeamPhase II team

• Managed by Leslie Durham, Chief of the
  Floodplain Management Branch, Alabama Office of
  Water Resources
• Study Team
• Jason Wilson, Project ManagerAMEC (Birmingham,
  AL)
• Dr. Scott Douglass, University of South Alabama
  and South Coast Engineers

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Where do we stand right now?

• Contractor Team Kick-off meeting September 1,
  2009 in Fairhope, AL
• Field reconnaissance under way
• All contractors under contract
• Pre-scoping

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FEMA Guidelines

• Standards relevant to coastal mapping can be
  found in the following documents
• Guidelines and Specifications for Flood Hazard
  Mapping Partners, Appendix D Guidance for
  Coastal Flooding Analyses and Mapping, April
  2003.
• Atlantic Ocean and Gulf of Mexico Coastal
  Guidelines Update, February 2007.

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Coastal Hazard Analyses Present in the Effective
Baldwin/Mobile County FIRMs

• BALDWIN--Coastal Hydrologic Analyses for June 17,
  2002 Countywide Study
• Stillwater surface elevations were not revised
  (work completed in 1983). Based on the effective
  stillwater elevations, coastal hazard analyses
  included wave hindcasting, wave setup, beach
  erosion, wave runup, wave height, and flood
  hazard mapping along the Gulf of Mexico and
  interior bay shorelines in Baldwin County.
• Currently 79 transect locations
• No new hydrologic or hydraulic analyses were
  performed for the July 6, 1998 countywide study.
• Effective analyses completed in 1983no updates
  since.
• Currently 27 transect locations

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Questions so far?

• Coastal Research Reconnaissance

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Coastal Research

• General Geographic Setting
• Extreme Tropical Flooding Events
• Summary of Previous Studies

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General Geographic Setting
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Extreme Tropical Flooding Events

• 1926 Great Miami Hurricane
• 1950 Hurricane Baker
• 1953 Hurricane Florence
• 1969 Hurricane Camille
• 1974 Hurricane Carmen
• 1975 Hurricane Eloise
• 1977 Hurricane Babe
• 1979 Hurricane Frederic
• 1985 Hurricane Danny
• 1985 Hurricane Elena
• 1988 Tropical Storm Beryl
• 1988 Hurricane Florence
• 1994 Tropical Storm Alberto
• 1995 Hurricane Erin

• 1995 Hurricane Opal
• 1997 Hurricane Danny
• 1998 Hurricane Georges
• 2000 Tropical Depression Nine
• 2002 Tropical Storm Hanna
• 2002 Tropical Storm Isidore
• 2003 Tropical Storm Bill
• 2004 Hurricane Ivan
• 2004 Tropical Storm Matthew
• 2005 Tropical Storm Arlene
• 2005 Hurricane Dennis
• 2005 Hurricane Katrina
• 2008 Tropical Storm Fay
• 2008 Hurricane Gustav

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Great Miami Hurricane - 1926

• September 20, 1926
• Brief landfall near Perdido Beach
• Winds up to 116 mph recorded near Pensacola
• 11 foot tidal surge
• Most Costly Hurricane in U.S. History (when
  adjusted for inflation)

Graphic Courtesy of NOAA Coastal Coastal Services
Center
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Hurricane Camille - 1969

• Category 5 - August 18, 1969
• Landfall at Bay St. Louis, MS
• Storm surge of 6 9 feet recorded throughout
  Alabama Coast.

Graphic Courtesy of NOAA Coastal Coastal Services
Center
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Hurricane Frederic - 1979

• Category 3 - September 12, 1979
• Landfall at Dauphin Island, AL
• Storm Surge 14 feet at Dauphin Island
• Storm Surge 10 feet at Fort Morgan
• Calibration Storm for 1983 FIS Work

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Hurricane Ivan - 2004

• Category 5 September 16, 2004
• Landfall at Gulf Shores, AL
• 14 foot storm surge recorded between Gulf Shores
  and Orange Beach.
• 100-yr flood elevations exceeded throughout
  Alabama.

Graphic Courtesy of NOAA Coastal Coastal Services
Center
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Hurricane Ivan vs. Effective FIS
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Hurricane Katrina - 2005

• Category 3 August 29, 2005
• Landfall near New Orleans, LA
• 100-yr flood elevations exceeded throughout
  Alabama.
• Dauphin Island overwashed.

Graphic Courtesy of NOAA Coastal Coastal Services
Center
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Hurricane Katrina vs. Effective FIS
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Previous Studies

• Baldwin County Flood Insurance Study
• Surge Elevations Revised 1983
• Wave Elevations Revised June 2002
• Mobile County Flood Insurance Study
• Surge Wave Elevations Revised 1983
• Jackson County, MS Flood Insurance Study
• Scoping Meeting July 14, 2004 (Hurricane Katrina
  August 29, 2005)
• Effective March 16, 2009
• 4 6 foot difference in Coastal Flood Elevations!

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Coastal Reconnaissance

• Inspect characteristics of beach, dunes and
  Primary Frontal Dune (PDF) location
• Document obstructions
• Vegetation
• Marsh
• Buildings
• Coastal structures
• High Water Marks

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Characteristics of Beach, Dunes, PFD

• Most of Alabamas PFD lost during Hurricane
  Frederic 1979
• USGS Coastal Classification (2006)
• Absent
• Overwash Terrace
• Discontinuous
• Continuous
• Continuous/Discontinuous Dunes
• Kiva Golf Course Beach Club
• Bon Secour NWR
• Orange Beach

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Absent
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Overwash Terrace
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Discontinuous
Photo Courtesy of USFWS (2008)
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Continuous
Photo Courtesy of USGS (2006)
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Vegetation

• Marsh Grasses
• Diameter (lower 1/3, middle 1/3, upper 1/3)
• Density (plants / square foot)
• Rigid Vegetation
• Spacing
• Diameter
• Height
• Aerial vs. Ground

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Aerial vs. Ground
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Aerial vs. Ground
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Aerial vs. Ground
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Aerial vs. Ground
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Buildings

• Density (Ratio of building to open space)
• Number of Rows
• Elevated on slab or grade

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High Density Single Row Not Elevated
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Low Density No Rows - Elevated
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High Water Marks
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Hurricane Ivan Celebrated HWMGulf Shores, AL

• September 16, 2004
• 14 foot storm surge

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Shrimp Basket
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Original Oyster House
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Boudreauxs Seafood Market
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Questions/Comments

• Jason.Wilson_at_amec.com
• Brad.Heilwagen_at_amec.com