Coastal Geologic Hazards and Sea-Level Rise: Climate Change in Rhode Island
This presentation was given at the Shoreline Change SAMP Stakeholder Meeting on April 4th, 2013 by Jon C. Boothroyd (Rhode Island Geological Survey and Department of Geosciences, University of Rhode Island) and Bryan A. Oakley (Environmental Earth Science Department, Eastern Connecticut State University).
Coastal Geologic Hazards and Sea-Level Rise: Climate Change in Rhode Island
1. COASTAL GEOLOGIC HAZARDS
AND SEA-LEVEL RISE:
CLIMATE CHANGE IN RHODE ISLAND
Shoreline Change SAMP Stakeholders Meeting
4 April 2013
Jon C. Boothroyd1,2and Bryan A. Oakley3
(1) Rhode Island Geological Survey
(2) Department of Geosciences, University of Rhode Island, Kingston RI 02881
(3) Environmental Earth Science Department, Eastern Connecticut State
University, Willimantic, CT 06226
2. Summary for Rhode Island:
• Glacial Geology, Past and Present,
the Underlying Key to Understanding Processes and
Products
• Storms the Most Important Driver in Coastal Change
Sea-Level Rise a Secondary Effect
• Shoreface Sediment Transport Not Well Understood
at Present
• Future Major Storms Combined With Sea-Level Rise
a Very Large Problem
• Accelerated Sea-Level Rise Resulting in Inundation
also a Very Large Potential Problem
• RICRMC Planning for a 3-5 foot Rise by 2100 and a
1.5 foot Rise by 2050
3. S New England, E New York, Continental Shelf at LGM ~ 26,000 yBP
You are
here RI
Map Generated By:
BA Oakley and JC Boothroyd
4. Eustatic
Sea-Level
Rise
+ Isostatic
Rebound
Isostatic
Rebound
at Laurentide
Block Island Ice Sheet?
Laurentide
2m.100yr-1
Ice Sheet?
RI Relative 2m.100yr-1
Sea Level
Antarctic Ice
Sheet?
Eustatic 2-5m.100yr-1
Sea Level
Explanation
Oakley and Boothroyd,
July 2012
11. Shoreface – Inner Shelf Deposition
Block Island Sound
Offshore Movement of Sand
12. Sandy Geologic Summary:
• Sandy a Tropical – Extratropical Hybrid
• Significant Wave Height 31 feet at Inner Shelf Buoy;
Max Recorded Wave Height 47 feet
• RI Received a Glancing Blow ; But Public
Misconception by Some Believe it a 100 Year Event
• Greatest Geologic Change and Infrastructure
Damage Since Hurricane Carol, 1954
• Washover Fan Deposition an Underestimated
Problem
• Shoreline Change Special Area Management Plan
Needed to Better Prepare for Next Event – Already
Started
13. Superstorm Sandy – Tropical-Extratropical Hybrid
29 October 2012
Newport Tide Gauge
SET UP
PREDICTED
http://tidesandcurrents.noaa.gov/
STORM SURGE data_menu.shtml?stn=8452660%20Newport,%20RI&type=Tide+Data
14. How High Maximum Water Level
was the 9.46 Feet, 2.88 meters
Above MHHW
Water ? Boothroyd and
Carol Water Level Hehre 2008
Why above
MHHW?
Sandy Water Level
Water
4.25 Feet, 1.30 meters
Levels Above MHHW
Newport, RI
MHHW = 3.85 ft, 1.173 m
Adapted from:
www.ngs.noaa.gov/newsy
s-cgi-
MLLW = 0.0 ft, 0.0 m bin/ngs_opsd.prl?PID=LW
0493&EPOCH=1983-2001
15. Frequency?
Next Month or
Next Year
Superstorm Sandy
Oct 2012
Tropical Storm
Irene Aug 2011
Hurricane Bob
Aug 1991
Adapted from
NOAA;
USACE 1988;
Hehre 2007
16. Measuring Shore Transects with:
“2 Sticks and A String” or, the Modified Emery Method
-22cm
Eric Woodward 12 Oct 2012
17. Cha-Ez Profile - Charlestown Barrier - Post Sandy
Washover Fan
Deposition
S McCandless
30 Oct 2012
18. Post
Sandy Pre-Sandy
FEMA Dune
Erosion
Protocol
25. Napatree Barrier – Westerly, RI
Little Narragansett Bay
Watch Hill
Hehre and Boothroyd, 2007
26. Napatree Barrier – Shoreline Change Map
2004 – Sound Side
1939 – Sound Side
-71.6m
1939 – 2004 – Ocean Side
Ocean Side
Hehre and Boothroyd, 2007
27. Washover Fan Deposition
Misquamicut Barrier - Westerly
Atlantic Ave
Washover Fan
RI DOT
30 Oct 2012
28. Charlestown Beach, RI – Hurricane Bob 1991
Washover Fan Deposition
Removal is a Bad Idea …….
Barriers Naturally Retreat Aug 1991
Landward and Upward JC Boothroyd
30. Misquamicut Andrea
Hotel
Shoreline
“Protection”
Structure –
Late 1950s to
Early 1960s
1957
Ford
Providence Journal?
31. Andrea Hotel - Misquamicut Headland - Westerly
The Managed Retreat Begins
Frieda Squires, Providence Journal 10 mar 2013
32. The Fate of Washover Fans –
Misquamicut State Beach
And Hopefully, the Exercise of
Scott Rasmussen
Scientific Rationale for Replenishment 15 Feb 2013
33. A Very Brief Look
at
Climate Change
and the
Future Shore Zone
of
Rhode Island