Scenario Planning Workshop

Tillamook County Coastal Futures Project

Scenario Planning Process

Tillamook County Coastal Futures Project Identify System, Develop

Initial Datasets

Develop System Models

Create Scenarios

Evaluate Scenarios

Develop Preferred Scenario

Implement Plan

• Engage you in a discussion with coastal planning/policy experts on current issues, management and policy approaches for coastal planning in Oregon

• Update you on the status of the models used in this project

• Update you on the current understanding of climate impacts on coastal communities in Oregon

• Engage you in a hands-on exercise to begin to define project “scenarios” of future change – focus on “policy options”

Goals for the Workshop…

Tillamook County Coastal Futures Project

Tillamook County Coastal Futures Project

ENV

ISIO

N

Flooding Structures, Infrastructure

Impacted, Economic Value of Structures

Impacted

Economic Costs/Returns Economic Development

Evaluative Models/Metrics Data Sources

Landscape Change Models

Landscape Data •Land Use/Land Cover •Zoning, Population, Structures •Topography, Climate •Many more…

Total Water Level

Policy Sets Stakeholder Engagement

Population Growth Residential Land Supply

Envision Tillamook 2050

Development

Erosion Structures, Infrastructure

Impacted, Economic Value of Structures

Impacted

Tillamook County Coastal Futures Project

What is a total water level?

𝑇𝑊𝐿 = 𝑀𝑆𝐿 + 𝜂𝐴 + 𝜂𝑁𝑇𝑅 + 𝑅

𝑀𝑆𝐿 = mean sea

level 𝜂𝐴 = astronomical

tide 𝜂𝑁𝑇𝑅 = non-tidal

residual 𝑅 = runup, (a function of beach slope, wave height, and wave length)

𝜂𝑁𝑇𝑅

NAVD88 𝑀𝑆𝐿

𝜂𝐴

𝑅 𝑇𝑊𝐿

Tillamook County Coastal Futures Project

Van

Vu

ren

et

al.,

20

11

Climate Change Scenarios

Mid-Century Projection (2010-2045) - Waves

- Dynamically downscaled from Global Climate Models (GCMs) using a mid-level emissions scenario (RCP 4.5)

- Sea Level - High sea level rise scenario,

45 cm increase from 2000-2050 N

RC

, 20

12

Tillamook County Coastal Futures Project

Baseline (Plan Trend) – current plans are captured as closely as possible and played forward

Retreat – emphasizes policies/strategies that move new development away from coastal hazard areas

Defend – emphasizes policies/strategies that supports, “hardens” new and existing development

in hazard areas

Preferred – a composite of the “best” of each of the above scenarios, determined after stakeholder

review

Draft Scenarios

For all scenarios, we will examine at least two climate scenarios representing high and low climate impacts

Tillamook County Coastal Futures Project

Mean Total Water Level

3.9

3.95

4

4.05

4.1

4.15

4.2

4.25

4.3

4.35

4.4

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

TWL.Mean TWL (m)

Tillamook County Coastal Futures Project

Average Dune Toe Impact Days/Year

0

10

20

30

40

50

60

70

80

90

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Tillamook County Coastal Futures Project

Number of Flooded Structures

0

50

100

150

200

250

300

350

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Baseline

Defend

Retreat

Tillamook County Coastal Futures Project

Number of Structures Exposed to Beach Erosion

0

20

40

60

80

100

120

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Baseline

Defend

Retreat

Tillamook County Coastal Futures Project

Economic Value of Eroded Property ($)

0

5000000

10000000

15000000

20000000

25000000

30000000

35000000

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Baseline

Defend

Retreat

Tillamook County Coastal Futures Project

0

10

20

30

40

50

60

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Baseline

Defend

Retreat

Rockaway – Number of Flooded Structures

Tillamook County Coastal Futures Project

Rockaway – Number of Structures Exposed to Beach Erosion

0

5

10

15

20

25

30

35

40

45

50

2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Baseline

Defend

Retreat

Tillamook County Coastal Futures Project

Group Exercise

(e.g. sea level change, population growth)

(e.g. value of flooded structures )

– Identifying “endpoints” that can be used to identify and measure preferable outcomes

• Take a somewhat deeper dive into:

– Drivers of change related to coastal community hazards

– Identifying policies/strategies/actions that should be considered for achieving those outcomes

(e.g. restrict additional development in flood-prone areas)

Tillamook County Coastal Futures Project

Scenario

Retreat Defend

Land Use

Infrastructure

Economic Development