Adaptation in a Sea of Uncertainty

Transcription

1 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, FL July 19, 2016 Photo by Emily Niederman November 16, 2016 Florida Water and Climate Alliance Arcadia, FL

2 My Past Few Years Satellite Beach, FL Public Works 2

3 Assertion #1 Climate change adaptation is one of the most complex and daunting challenges ever faced by human civilization. 3

4 Sea Level Rise is a big deal for FL 4

5 News release on July 28,

6 Miami Beach deal.com/trd/m/up/2013/07/miami-flooding jpg.jpg 6

7 Tidal flooding on Tybee Island, GA US Highway 80 October 27, pg Third highest tide on record (since 1935) for this gauge Only exceeded by tropical storm surges 7

8 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

9 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

10 25 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: 10

11 Assertion #2 Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worstcase scenario at

12 For example 12

13 Population growth = Underestimation of problem People displaced by sea level rise 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 Scenario: ~2 meters of sea level rise at 2100 Projected Populations Current Populations 1,000,

14 Credit: M.J. Hauer, J.M. Evans and D. Mishra 14

15 Assertion #2 Very few development decisions being made today in vulnerable coastal communities are considering the consequences in a worstcase scenario at This is understandable even appropriate given uncertainty about the future over such a long time-horizon. 15

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17 BIG difference between low and high scenario ~6.1 million people affected Statewide in FL ~1.2 million people affected 17

18 Garden Shed or Nuclear Power Plant? Risk-based scenario planning for sea-level rise uk/cmsresource/i mage/ /landscape_rati o3x2/440/300/563f6a641d bc93d991c4fa65a/zj/how-to-erect-a-shed--- header-image.jpg om/c ontent/ dam/gepowernuclear/global/en_us/images/ her o-images/nine-mile- Point-Nuclear-Plant-cropped.jpg 18

19 Assertion #3 Almost all coastal communities, even those not yet seeing dramatic direct saltwater flooding from king tides, are being impacted by various stormwater drainage failures. 19

20 General Timeline of Sea Level Rise Impacts on the Built Environment 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 20

21 XXX Figure by Emily Niederman 21

22 SW Tybee Island, GA: November 14,

23 SW Tybee Island, GA: Local Government Action Action: Stormwater backflow preventers and pipe enlargement ~$3 Million Investment 23

24 St. Marys, GA: Mean Higher High Water, Today 24

25 St. Marys, GA: Mean Higher High Water, 1 Foot SLR 25

26 St. Marys, GA: Mean Higher High Water, 2 Foot SLR 26

27 St. Marys, GA: Mean Higher High Water, 2 Foot SLR 27

28 Osborne Waterfront Stormwater Drainage St. Marys, GA 28

29 Osborne Ave., St. Marys, GA (Facing North) 29

30 Osborne Ave., St. Marys, GA (Facing South) 30

31 What Happens When it Rains???? 31

32 Idealized Tidal Scenarios (24-Hour Rainfall Event) Elevation (Feet Above NAVD88) Elevation (Feet Above NAVD88) Sine Tide Time (Hours) Negative Sine Tide Time (Hours) Elevation (Feet Above NAVD88) Cosine Tide Time (Hours) Elevation (Feet Above NAVD88) Negative Cosine Tide Time (Hours) 32

33 Osborne Waterfront Stormwater Drainage St. Marys, GA 25-Year Rainfall with Peak Flow at High Tide (Cosine Scenario) 33

34 *9.05" in 24-Hours 34

35 Assertion #4 People start to really take notice when roads start flooding on a sunny day. 35

36 General Timeline of Sea Level Rise Impacts on the Built Environment 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 36

37 Tidal flooding on Tybee Island, GA US Highway 80 October 27, pg Third highest tide on record (since 1935) for this gauge Only exceeded by tropical storm surges 37

38 Nuisance flooding in Big Pine Key September 29, 2015 Photo credit: Greg Corning, provided by Monroe County staff 38

39 * *General planning assessment tool requires additional data for use in site-level decisions 39

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42 Nuisance flooding in Big Pine Key September 29, 2015 Photo credit: Greg Corning, provided by Monroe County staff 42

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44 Modeling: More Accurate by the Day Policy Framing: Much More Difficult What is an appropriate level of service for maintaining Tides stormwater Higher and than roads 1.08 under MHHW* sea at level Vaca rise? Key Tide Gauge Cost of upgrades and maintenance for elevation of road bed, improved drainage, pumps, etc.? 25 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?

45 Thanks and acknowledgments Monroe County BOCC and staff Tybee Island, GA City Council and staff St. 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 45