Meeting Objectives

• Review inundation maps and selected OCOF scenarios

• Validate ART lower scenario maps (1, 2, 3, ft)

• Validate OCOF maps (3 scenarios)

• Summarize inventory of assets at risk

• Present recommendation for 30 draft assets/ explain rationale for their selection

• Begin soliciting feedback on the draft 30 assets

• Confirm asset manager support

Agenda

© ARCADIS11 December 20151

San Mateo County

Shoreline Risk & Vulnerability Assessment

Inundation Scenarios

December 10, 2015

Three sea level rise scenarios selected

• Based on the guidance in the California Coastal

Commission*

• Consistent with local SLR planning efforts

• Reflect conditions today and realistic future

conditions

• Used guidance from the County and

Conservancy and input from the Technical

Working Group

*August 2015 Sea Level Rise Guidance Document: Interpretive Guidelines for

Addressing Sea Level Rise in Local Coastal Programs and Coastal

Development Permits

Three sea level rise scenarios selected

The three selected scenarios are:

• MHHW with 1% AEP storm* with no SLR

(current conditions)

• MHHW with 1% AEP storm* with 3.3 feet SLR

(medium condition)

• MHHW with 1% AEP storm* with 6.6 feet SLR

(high condition)

In addition:

• Mapped Future Erosion Zones on the coast

*1% AEP storm is a storm event with a 1% annual exceedance probability.

MHHW = Mean high high water

Inundation calculated using Our Coast Our

Future (OCOF) Tool

• Online tool for Bay Area flood scenarios Pacific Coast and San Francisco Bay

• Combination of 40 different sea level rise and

storm scenarios, plus a King Tide scenario,

using the USGS Coastal Storm Modeling

System (CoSMoS)

• Interactive flood map including flood extent,

depth, duration, and minimum and maximum

flood potential, wave heights, and current

velocity

Inundation maps - Overview

Inundation maps - Detail

Inundation maps - Detail

OCOF / ART Maps Summary

• OCOF Inundation Maps

– First broad brush look at areas vulnerable to SLR and coastal flooding

– Identify WHERE sea level rise and storm exposure zone is

• Create detailed inventory of most vulnerable assets

• ART Inundation Maps

– Finer scale assessment

– Identify WHEN assets could be impacted

• (e.g., 24 or 36 inches of SLR?)

– Identify HOW they are at risk• (e.g., what are the pathways of inundation? from local or broad overtopping?)

• Methods and tools for San Mateo developed through previous Alameda County ART project

• Multi-agency effort (BCDC, MTC, Caltrans, BART, Alameda County)

• “One Map = Many Futures Approach” 1 water level can represent many possible futures

• Project includes: Vulnerability and risk assessment

Adaptation strategy development

Conceptual engineering of selected adaptation options

Adapting To Rising Tides (ART)

FEMA San Francisco Bay Area Coastal Study

• Large-scale regional modeling to characterize existing coastal hazards (tides, storm surge, and waves)

• Comprehensive data set that provides water level data along the entire complex shoreline

Water Level Analysis – Key Terms• Mean Higher High Water

(MHHW) Typical daily high tide

Frequent inundation (permanent)

• 100-yr (1% annual chance) Stillwater Elevation (SWEL) Extreme high tide + storm surge

Flooding (temporary) event

Wave effects not included

100-Year SWEL

MHHW

Topographic Data• LiDAR collected by USGS in

2010

• 1-meter grid spacing DEM

• DEM modified with As-Built survey data: SFO

Foster City

Redwood Shores

San Mateo

San Mateo SLR Inundation Maps• County Wide Inundation

Mapping (10 scenarios)– MHHW + 12” SLR

– MHHW + 24” SLR

– MHHW + 36” SLR

– MHHW + 48” SLR

– MHHW + 52” SLR

– MHHW + 66” SLR

– MHHW + 77” SLR

– MHHW + 84” SLR

– MHHW + 96” SLR

– MHHW + 108” SLR

Low-lying

areaLow-lying

area

MHHW

Low-lying

area

Low-lying

area

MHHW

MHHW

Sea Level Rise

Permanent

InundationLow-lying

area

Extreme Tide

Temporary

Flooding

Extreme Tide

Temporary

Flooding

Sea Level Rise

Permanent

Inundation

Extreme Tide (temporary)

Sea Level Rise(permanent)

Sea Level Rise + Extreme Tide

MHHW + 12 Inches SLR (King Tide)MHHW + 12 Inches SLR (King Tide)

MHHW + 24 Inches SLR

MHHW + 36 Inches SLR

Shoreline Delineation• Leverage SFEI shoreline

• Delineate structures that currently prevent floodwater conveyance Levees Engineered structures High ground Roadways Etc.

• Delineate natural shorelines and wetlands

Overtopping Potential

• Overtopping: Water level (MHHW or SWEL) exceeds elevation of asset: “Depth of overtopping”.

• Freeboard: Elevation of asset exceeds water level (MHHW or SWEL). Freeboard = the height of the asset above the adjacent water surface.

Overtopping Example

SF Bay

Shoreline Delineation

Identify Critical Pathways

Identify Critical Pathways

© ARCADIS11 December 20151

San Mateo County Sea Level Rise

Vulnerability Assessment

December 10, 2015

Technical Working Group meeting #2

San Mateo County

© ARCADIS11 December 20152

We are here

Asset organization, mapping, and

inventories

Categorize and classify assets

Collect data and information on assets

Create asset exposure maps

Develop asset exposure inventory

Examples of asset types

Police Stations Caltrain Recreational Facilities

Airports Bart Parks

Highways 101, I-380 Businesses Public Health Facilities

Evacuation Routes Cultural Resources Housing

Hazardous Facilities Community Centers State Beaches

Critical Energy

FacilitiesCritical habitat

Schools

Telecom Wetlands Ports

What types of assets are we considering?

Over 120 asset types and this approach

enables consideration of all assets

Framework, which vulnerabilities to address first

Why categorize and classify assets?

Credit: Dave YuhasCredit: Anita Hart

Given the large number of assets in SMC

• Helps us think about things differently

• What does it mean to have a flooded asset?

Source: US Climate Resilience Toolkit

Reedsburg, WI

June, 2008

Part I-Asset Categories

• Airport

• Community land use, services,

facilities

• Contaminated lands

• Energy infrastructure and pipelines

• Ground transportation

• Hazardous materials

• Natural areas

• Parks and recreation areas

• Seaport

• Structural Shorelines

• Storm water

• Wastewater

Assets are organized into the categories identified

in Adapting to Rising Tides approach

Part II-Asset Classes

Assets are organized into classes based on:

Public health, safety, welfare (built assets)

Ecosystem and habitat (natural assets)

Built Assets (ASCE 24-14)

Class Description: Buildings or other assets

I • That represent a low risk to human health in the event of failure (flood)

II • All except those listed in categories I, III, IV

III The failure of which could pose a substantial risk to human health

With the potential to cause a substantial economic impact and/or mass

disruption of day to day civilian life in the event of a flood

IV Essential facilities

The failure of which could pose substantial hazard to the community

Containing highly toxic substances, dangerous to the public

Required to maintain function of other category IV structures

Natural Assets

Class Description

N-W Natural Assets- Wetlands/ Marsh/Estuaries

N-B Natural Assets- Beaches/ Dunes

N- R Natural Assets-Rocky intertidal

N-S Natural Assets-Species of concern

N-O Natural Assets-Other

What types of information did we collect?

• GIS Data from local, state, national datasets

Some more complete than others

County GIS portal has many of the layers

With supplementary information

• Kickoff Meeting

• TWG, PAC

• Stakeholder

discussions

• Draft maps &

inventories reflect data

collected thru

10/21/2015

Do you have additional data?

Let us know!

Maps and inventories tell us what is at risk

And where it is located

DRAFT Asset Exposure Maps- built assets

DRAFT Asset Exposure Maps

Maps intended to tell a story

about where risks are.

DRAFT Asset Exposure Maps

Each map has a

corresponding inventory

Disadvantaged

community

DRAFT Asset Exposure Maps- natural

assets

DRAFT Asset Exposure Inventory

• Developed for each city/region

Identifies population and assets exposed to flood and SLR

Asset Exposure Inventories

San Mateo County at a Glance

Population: 131,722

(42,991 vuln. community)

Fire:11

Police: 3

Schools: 45

Power plants: 4

Beaches: 1,024 acres

Wetlands: 9,000 acres

Emergency room: 1

Credit: Roy Latham

Fitzgerald Marine Reserve

Assets at risk

Questions?

Asset Vulnerability Profiles (AVPs)

What is an AVP?

Purpose

Selection process

Next steps

Source: Mydoctor.kaiserpermanente.orgSource: Baytrail.org

AVP is a more detailed look into an asset

• Current vulnerability

Exposure

Sensitivity

Adaptive Capacity

Consequences

• Future vulnerabilities

Flooding and erosion

• Regulatory oversight

• Adaptation options

AVPs provide insight into

Vulnerabilities

Consequences

Stakeholders

On the ground

Types of vulnerabilities facing county assets.

Range and magnitude of potential impacts.

Cross section of individuals, agencies affected by

loss of an asset or service; challenges.

Better understanding of what could be

inundated and what that means.

Analysis AVP selection does not represent priorities.

AVP Process is interactive

Asset maps and inventories

Select 30 assets using criteria

Gather input on draft asset selection

Develop asset vulnerability profiles

AVP Selection Criteria

• Geographic coverage

• Representative across:

Asset types and categories

Agencies and jurisdictions

Sectors – private & public

• Service area

• Availability of data

• Asset owner support

• *see handout for how preliminary

selection meets criteria South San Francisco Water Quality Control Plant.

Photo by ssf.net

Ravenswood Salt Pond, Photo by baytrail.org

Preliminary AVP Selection

Preliminary AVP Selection

Name1 Mirada West-Coastal Trail

2 Mid Coastside Sewer Authority

WWTP

3 State Route 1 (segment)

4 Fitzgerald Marine Reserve

5 State Route 1 (segment)

6 Linda Mar/Pacifica State Beach

7 Mussel Rock Disposal Site/Dolger

8 Oyster Point Marina

9 Sanitary Pump Station no. 8

10 South San Francisco Water Quality

Control Plant

11 SamTrans Island (Depot)

12 Highline Canal Tide Gate

13 Caltrain/BART near SFO

Name14 Burlingame Fire Station no. 36

15 US Highway 101/92

16 San Mateo Police Department

17 Silicon Valley Clean Water WWTP

18 South Bay Salt Ponds/Bair Island

Area Wetlands

19 Shoreway Environmental

Center/Recology

20 San Carlos Airport

21 Port of Redwood City

22 InnVision Homeless Shelter

23 Kaiser Permanente Medical Center

24 Ravenswood Substation

25 State Route 84/101

26 East Palo Alto

What’s next? (This is where you all come in)

• Feedback and input on the assets (survey)

• Gather existing information on the assets

• Questionnaire

• Asset manager interviews

• Site visits

We need your help to make this a success

Pacifica during King Tides Photo by Jack Sutton, all rights reserved

Information we’ll need from you

• Exposure, sensitivity

and adaptive capacity

of the asset

Physical

Characteristics

Construction and site

drawings, elevation

Foundation materials

Known vulnerabilities

• Consequences

Historical flooding

documentation and

photos

Past damages

experienced

Impacts from loss of

service

Replacement or repair

costs

Questions?