Sea Level Rise Planning at the Local Level

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Owen Owens
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1 Sea Level Rise Planning at the Local Level Jason M. Evans, Ph.D. Assistant Professor of Environmental Science Stetson University Stormwater outfalls, Satellite Beach, FL July 19, 2016 May 11, 2017 Sea-Level Rise: Assessing and Addressing Flooding and Liability for Local Governments Largo, FL Photo by Emily Niederman

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

3 News release on July 28, 2014

5 Third highest tide on record (since 1935) for this gauge Only exceeded by tropical storm surges

6 Nuisance Floods by Year at Tybee Island, GA (Ft. Pulaski Tide Gauge) 20 NOAA nuisance flood threshold for Fort Pulaski: 9.2 feet above MLLW Data Source:

Nuisance Floods Per Year at Key West 35 30 25 *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.

7 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 Sea Level Rise and Nuisance Flood Frequency Changes around the United States. NOAA Technical Report NOS CO-OPS

8 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 Sea Level Rise and Nuisance Flood Frequency Changes around the United States. NOAA Technical Report NOS CO-OPS

9 Assertion #2 Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worst-case scenario at 2100.

11 People displaced by sea level rise 7,000,000 Scenario: ~2 meters of sea level rise at ,000,000 5,000,000 4,000,000 3,000,000 Hernando County: 11,661 Hillsborough County: 137,749 Manatee County: Projected Populations88,880 Pasco County: 67,056 Pinellas County: Current Populations391,872 Sarasota County: 80,660 2,000,000 1,000,000 0

12 Assertion #2 Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worst-case scenario at This is understandable even appropriate given uncertainty about the future over such a long time-horizon.

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14 Garden Shed or Nuclear Power Plant? Risk-based scenario planning for sea-level rise 316/landscape_ratio3x2/440/300/563f6a641d bc93d991c4fa65a/zj/how-to-erect-a-shed--- header-image.jpg nuclear/global/en_us/images/hero-images/nine-mile- Point-Nuclear-Plant-cropped.jpg 14

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

16 Stormwater drainage issues Potential for saltwater corrosion and intrusion of underground pipes Ground floor flooding of houses and commercial buildings Saltwater flooding of yards and roads Flooding of ancillary structures (pavilions, sheds, etc.) Flooding of high value critical infrastructure such as wastewater facilities and electrical substations

17 Third highest tide on record (since 1935) for this gauge Only exceeded by tropical storm surges

18 Nuisance flooding in Big Pine Key September 29, 2015 Photo credit: Greg Corning, provided by Monroe County staff

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

21 Nuisance flooding in Big Pine Key September 29, 2015 Photo credit: Greg Corning, provided by Monroe County staff

22 Road flooding, 3 inches of sea level rise (2030 Low)

23 Road flooding, 7 inches of sea level rise (2030 High)

24 Almost all coastal communities in the coastal southeast, even those not yet seeing dramatic direct saltwater flooding from king tides, are already being impacted by various stormwater drainage issues and failures.

Stormwater drainage issues Potential for saltwater corrosion and intrusion of underground pipes Ground floor flooding of houses and commercial buildings Saltwater flooding of

25 Stormwater drainage issues Potential for saltwater corrosion and intrusion of underground pipes Ground floor flooding of houses and commercial buildings Saltwater flooding of yards and roads Flooding of ancillary structures (pavilions, sheds, etc.) Flooding of high value critical infrastructure such as wastewater facilities and electrical substations

26 Graphic by Emily Niederman, Stetson University

28 Action: Stormwater backflow preventers and pipe enlargement ~$3 Million Investment

29 Graphic by Emily Niederman, Stetson University

30 1) Systematically documenting stormwater drainage failures, such as street flooding 2) Digital mapping of stormwater infrastructure a) Outfall and infall points b) Pipe extents c) Invert elevations 3) Near-term retrofits duct tape adaptation a) Backflow preventers b) Decrease run-off coefficients, reduce impervious connectivity 4) Long-term retrofits a) Increase pipe sizes b) Green infrastructure c) Pumps More expensive further down the list! Long-term and dedicated funding mechanisms very much implied

31 What is an appropriate level of service for maintaining Tides stormwater Higher and than roads 1.08 under MHHW* sea at level Vacarise? Key Tide Gauge 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?

32 Monroe County, FL BOCC and staff Tybee Island, GA City Council and staff Satellite Beach, FL City Council and staff University of Florida GeoPlan: Crystal Goodison University of Georgia: Mathew Hauer, Jill Gambill, Dr. Mark Risse,, Dr. Charles Hopkinson, Maddie Russell Stetson University undergraduates: Emily Niederman, Justin Baumann, Zella Conyers, Alex Clark, Enric Cordoba, George Winsten

Adaptation in a Sea of Uncertainty

Adaptation in a Sea of Uncertainty Sea-Level Rise Planning at the Local Level Jason M. Evans, Ph.D. Assistant Professor of Environmental Science Stetson University Stormwater outfalls, Satellite Beach,