Adaptation in a Sea of Uncertainty

Jason M. Evans, Ph.D.Assistant Professor of Environmental Science

Stetson University

November 16, 2016Florida Water and Climate Alliance

Arcadia, FL

Sea-Level Rise Planning at the Local Level

Stormwater outfalls, Satellite Beach, FL

July 19, 2016

Photo by Emily Niederman

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My Past Few Years

Satellite Beach, FL Public Works

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Assertion #1

Climate change adaptation is one of the most complex and daunting challenges ever faced by human civilization.

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Sea Level Rise is a big deal for FL…

5News release on July 28, 2014

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Miami Beach

http://s13.thereal deal.com/trd/m/up/2013/07/Miami-flooding-4-13-13.jpg.jpg

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Tidal flooding on Tybee Island, GA US Highway 80

October 27, 2015

http://sav-cdn.com/sites/default/ files/imagecache/superphoto/14845662.j pg

Third highest tide on record (since 1935) for this gauge

Only exceeded by tropical storm surges

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1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Nuisance Floods Per Year at Key West

*Nuisance flooding threshold for Monroe County,as defined by Sweet et al. (2014)

Sweet, W., J. Park, J. Marra, C. Zervas, and C. Gill. 2014. Sea Level Rise and Nuisance Flood Frequency Changes around the United States. NOAA Technical Report NOS CO-OPS 073.

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1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Nuisance Floods Per Year at Vaca Key (Marathon, FL)

*Nuisance flooding threshold for Monroe County is 1.08 ft above MHHW,as defined by Sweet et al. (2014)

Sweet, W., J. Park, J. Marra, C. Zervas, and C. Gill. 2014. Sea Level Rise and Nuisance Flood Frequency Changes around the United States. NOAA Technical Report NOS CO-OPS 073.

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Nuisance Floods by Year at Tybee Island, GA (Ft. Pulaski Tide Gauge)

Data Source: https://tidesandcurrents.noaa.gov/stationhome.html ?id=8670870

NOAA nuisance flood threshold for Fort Pulaski: 9.2 feet above MLLW

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Assertion #2

Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worst-case scenario at 2100.

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For example…

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Population growth = Underestimation of problem

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1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

Projected Populations

Current Populations

Scenario: ~2 meters of sea level rise at 2100

Pe

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sea

leve

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Credit: M.J. Hauer, J.M. Evans and D. Mishra

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Assertion #2

Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worst-case scenario at 2100.

This is understandable – even appropriate –given uncertainty about the future over such a long time-horizon.

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BIG difference between low and high scenario

~6.1 million people

affectedStatewide in

FL

~1.2 million people affected

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Garden Shed or Nuclear Power Plant?

“Risk-based” scenario planning for sea-level rise…

http://www.homebase.co.uk/cmsresource/i mage/42316/landscape_rati o3x2/440/300/563f6a641d7134842bc93d991c4fa65a/zj/how-to-erect-a-shed---header-image.jpg

https://nuclear.gepower.com/content/dam/gepower-nuclear/global/en_US/images/her o-images/Nine-Mile-Point-Nuclear-Plant-cropped.jpg

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Assertion #3

Almost all coastal communities, even those not yet seeing dramatic direct saltwaterflooding from king tides, are being impacted by various stormwater drainage failures.

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General Timeline of Sea Level Rise Impactson the Built Environment

Stormwaterdrainage

issues

Saltwater flooding of yards and

roads

Potential for saltwater

corrosion and intrusion of

underground pipes

Flooding of ancillary

structures (pavilions, sheds, etc.)

Ground floor flooding of houses and commercial buildings

Flooding of high value

critical infrastructure

such as wastewater

facilities and electrical

substations

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Figure by Emily Niederman

XXX

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SW Tybee Island, GA: November 14, 2012

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SW Tybee Island, GA: Local Government Action

Action: Stormwater backflow preventers and pipe enlargement

~$3 Million Investment

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St. Marys, GA: Mean Higher High Water, Today

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St. Marys, GA: Mean Higher High Water, 1 Foot SLR

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St. Marys, GA: Mean Higher High Water, 2 Foot SLR

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St. Marys, GA: Mean Higher High Water, 2 Foot SLR

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Osborne Waterfront Stormwater Drainage

St. Marys, GA

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Osborne Ave., St. Marys, GA (Facing North)

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Osborne Ave., St. Marys, GA (Facing South)

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What Happens When it Rains????

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Idealized Tidal Scenarios (24-Hour Rainfall Event)

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Cosine Tide

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Osborne Waterfront Stormwater Drainage

St. Marys, GA

25-Year Rainfall withPeak Flow at High Tide

(Cosine Scenario)

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Assertion #4

People start to really take notice when roads start flooding on a sunny day.

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General Timeline of Sea Level Rise Impactson the Built Environment

Stormwaterdrainage

issues

Saltwater flooding of yards and

roads

Potential for saltwater

corrosion and intrusion of

underground pipes

Flooding of ancillary

structures (pavilions, sheds, etc.)

Ground floor flooding of houses and commercial buildings

Flooding of high value

critical infrastructure

such as wastewater

facilities and electrical

substations

37

Tidal flooding on Tybee Island, GA US Highway 80

October 27, 2015

http://sav-cdn.com/sites/default/ files/imagecache/superphoto/14845662.j pg

Third highest tide on record (since 1935) for this gauge

Only exceeded by tropical storm surges

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September 29, 2015

Photo credit: Greg Corning, provided by Monroe County staff

“Nuisance” flooding in Big Pine Key

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http://sls.geoplan.ufl.edu/documents-links/

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*General planning assessment tool requires additional data for use in site-level decisions

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September 29, 2015

Photo credit: Greg Corning, provided by Monroe County staff

“Nuisance” flooding in Big Pine Key

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Modeling: More Accurate by the Day Policy Framing: Much More Difficult

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1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Tides Higher than 1.08 MHHW* at Vaca Key Tide GaugeWhat is an appropriate level of service for maintaining stormwater and roads under sea level rise?

Cost of upgrades and maintenance for elevation of road bed, improved drainage, pumps, etc.?

How much are citizens willing to pay for enhanced stormwater and road service?

What thresholds may make a public road no longer viable from an economic and/or engineering perspective?

When does retreat become the only option?

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Thanks and acknowledgments

Monroe County BOCC and staff

Tybee Island, GA City Council and staffSt. Marys City Council and staff

University of Florida GeoPlan: Crystal Goodison

FL Sea Grant: Thomas Ruppert, J.D.Stetson University undergraduates: Emily Niederman, Justin Baumann, Zella Conyers, Alex Clark, Enric Cordoba, George Winsten