Coastal Resiliency, Science, and Community Planning for

Sea Level Rise and the Perfect Storm

Peter Slovinsky, Coastal GeologistMaine Geological Survey, Department of Conservation

Funding from:

Outreach, Partnership Development, and Education

How to achieve said goal?

Outreach and Partnership DevelopmentState Agencies – Regional Planning Commissions - Municipalities

Southern Maine Regional Planning Commission

Available Hazard Vulnerability Assessment ToolsEducation – GIS Data and Tools

Erosion Hazard Area Designation: Regulatory GIS coverage.

Coastal Sand Dune Boundaries: Regulatory GIS coverage.

Shoreline Structures: GIS coverage

LIDAR: 2004 NOAA data available. GIS data.

Digitized Flood Insurance Rate Maps: “homemade” DFIRMs. GIS data.

Maine Beach Scoring System: guidance/management/decision-making tool to assess hazard vulnerability and management need. GIS coverage (Historic shorelines, short term erosion, etc.)

Sea Level Rise/Inundation Mapping: GIS coverages simulating the potential impacts of 2 feet of sea level rise.

Portland Sea Level

Portland Tide gauge = global ocean over last century 1.8 mm/yr (IPCC, 2007).In Maine, this is the fastest in past 3000 yearsSatellite altimetry (1993-2003) = global sea level 3.1 + 0.7 mm/yr (IPCC, 2007)

Future Sea Level RiseCoastal Sand Dune Rules (Chapter 355 NRPA)

Maine is planning for 2 feet of sea level rise over the next 100 years, which is generally a “middle-of-the road” prediction for global sea level rise changes.

“Coastal wetlands” means all tidal and subtidal lands; all areas with vegetation present that is tolerant of salt water and occurs primarily in salt water or estuarine habitat; and any swamp, marsh, bog, beach, flat or other contiguous lowland that is subject to tidal action during the highest tide level for each year in which an activity is proposed as identified in tide tables published by the National Ocean Service. Coastal wetlands may include portions of coastal sand dunes.

Coastal wetlands

Sea Level Rise Inundation ToolSteps:

1) Demonstrate accuracy in simulating existing conditions for tidal elevations and defining marsh habitats

2) Simulate impacts of sea level rise on:a) Existing infrastructureb) Marsh habitatc) Flood Insurance Rate Map boundaries

3) Identify at risk areas4) Identify adaptation strategies

Saco Bay

.

Ocean Park

Scarborough

OldOrchardBeach

Marshes

Saco

Biddeford

“Groundtruthing”

Identify marsh boundaries

Overlay LIDAR

Identify using tidal elevations

Examine Potential Impacts on Marshes

Ocean ParkOld Orchard Beach

Coastal InundationExisting Conditions

Old Orchard Beach, ME

OOB_HAT

OOB_MHW

OOB_OW

1

1

Coastal InundationExisting Conditions

2

2

Coastal InundationExisting Conditions

3

3

Coastal InundationExisting Conditions

4

4

ExistingInundationProblems

Allow potential marshtransgression?

Identify potential future floodingStructure renovation, removal,relocation

2007 Patriots’ Day Storm = HAT+2 ftIndicator of Future Conditions!100 year storm = 10 year storm + 1 ft SL rise

Old Orchard Beach, ME

HAT + 2 ft SL

<= 2.46 m NAVD

4/16/2007

<= 2.48 m NAVD

Potential Future Flood Depths

Flood Depth (HAT+2ft)

m, NAVD88

-2 - -1.75

-1.75 - -1.5

-1.5 - -1.25

-1.25 - -1

-1.0 - -0.75

-0.75 - -0.5

-0.5 - -0.25

-0.25 - 0

April 16, 2007, approximately10:00 amImages courtesy of Bill Edmunds, www.mainecoastimages.com and NOAA NWS

1-2+ ft flooding

Potential Future Flood Depths

Flood Depth (HAT+2ft)

m, NAVD88

-2 - -1.75

-1.75 - -1.5

-1.5 - -1.25

-1.25 - -1

-1.0 - -0.75

-0.75 - -0.5

-0.5 - -0.25

-0.25 - 0

April 16, 2007, approximately10:00 amImages courtesy of Bill Edmunds, www.mainecoastimages.com and NOAA NWS

1-2 ft flooding

Potential Future Flood Depths

Flood Depth (HAT+2ft)

m, NAVD88

-2 - -1.75

-1.75 - -1.5

-1.5 - -1.25

-1.25 - -1

-1.0 - -0.75

-0.75 - -0.5

-0.5 - -0.25

-0.25 - 0

April 16, 2007, approximately 10:00 amImages courtesy of Bill Edmunds, www.mainecoastimages.com and NOAA NWS

1-2+ ft flooding

Old Orchard Beach, ME

FIRM

ZONE_LID

AE

AO

VE

DramaticA-zone expansion

Potential Responses

Adaptation Techniques

Wetland RestorationOpen Space Designation/Acquisition“Future” Flood or Wetland Areas

Adaptation Techniques

Tidal Flow ControlManagement

Adaptation Techniques

April 16, 2007, approximately10:00 amImages courtesy of Bill Edwards, www.mainecoastimages.com and NOAA NWS

Emergency Access ReroutingStormwater Improvements

Elevation and siting

Adaptation Techniques

Elevation and sitingFuture requirement?

Adaptation Techniques

Utility Relocation

Adaptation Techniques

State Level:•Regulatory changes (i.e., defining the future coastal wetland or the future floodplain)• State funded land acquisition, marsh conservation, restoration programs

Municipal Level:• Improved coordination amongst communities to address hazards, SL rise and wetlands management• Land use/development planning• Capital improvements planning• Stormwater and road infrastructure management• Habitat restoration• Land acquisition and conservation• Flood proofing, elevating • Emergency access planning• Shoreland Zoning changes, comprehensive plans, etc.

Project Strategies:Sea Level Rise

Introduction of concepts Feedback

Project Process/Outcomes

Strategy adoption into comprehensive plans, ordinances, etc.

Multi-year project

IntercommunityIntercommunitycoordinationplanning

Identificationof Strategies

Tool, data, improvementNeeds identification

Hazards do not followgeopolitical boundaries!