Adapting to Rising Tides

Transcription

1 Adapting to Rising Tides A regional program that uses findings, processes, tools and relationships built by ART and its partners to lead and support efforts that increase the resilience of San Francisco Bay Area communities to sea level rise and storm events San Francisco Bay Conservation and Development Commission

2 What is Adapting to Rising Tides? A Bay Area Program that: o Provides guidance and support for adaptation at all scales - local, regional, state and federal o Develops, leverages and identifies best available data, information and research o Builds and supports partnerships with agencies and organizations o Identifies challenging issues or regional priorities that need further assessment o Continues to refine adaptation practices to ensure outcomes support taking action

3 Completed ART Program Projects Local-scale projects Alameda County Contra Costa County Hayward Shoreline Resilience Study Oakland/Alameda Shoreline Resilience Study Regional-scale projects Stronger Housing, Safer Communities Hazard Mitigation and Adaptation Plans Regional Sea Level Rise and Shoreline Overtopping Maps and Analysis Sector-specific projects EBRPD Shoreline Parks Bay Area Transportation Climate Resilience CCJPA Intercity Rail Hot Spots Assessment Corte Madera Baylands Tidal Creeks and Flood Control Channels

4 ART Flooding Impacts and Scenarios Impacts from coastal and/or riverine flood events including: o More frequent flooding of existing floodprone areas o Flooding in areas that are not currently at risk o Elevated groundwater and increased salinity intrusion o Permanent inundation along the shoreline, in particular tidal wetland systems o Shoreline erosion and overtopping o Tidal creek and channel flooding

5 Regional Sea Level Rise Maps ART and MTC developed maps depicting areas at risk from sea level rise and storm events o o o o o Uniform mapping for all 9 counties including 10 total water level scenarios for inundation, low-lying disconnected areas, and shoreline overtopping Water levels from the FEMA Bay Coastal Study so 100-year extreme tide levels same as new FIRM maps Grounded in high resolution LiDAR topographic data (1 meter DEM) Uses SFEI s shoreline delineation built on ART method from Alameda County Stakeholder reviewed and validated

6 Purpose of ART Regional Maps Allows each map to represent multiple potential future combinations of sea level rise and extreme water levels. Show the inland areas that are at risk of inundation or flooding Identify the pathways of inundation or flooding from the Bay Support robust, local-scale vulnerability assessment Support development of both near-term and longterm adaptation strategies

7 Inputs: Water Level Data MIKE21 Model of San Francisco Bay Tides Ocean-driven swell Wind-wave generation within the Bay Continuous modeling (Central & North Bay) (South Bay) Riverine inflows Delta inflows modeled Minor riverine inflows approximated Calibrated and Validate to 11 large storm events

8 Tidal Datums

9 ART s One Map = Many Futures o Uses an equivalent water level approach to reduce the number of maps needed to understand flooding o Communicates that areas that may be permanently inundated will first be temporarily flooded o Provides information that allows local jurisdictions and agencies to develop thresholds for action Source: AECOM

10 ART s One Map = Many Futures This single map depicts: High tide permanent inundation from 36 SLR or Temporary flooding from: 2-year extreme tide with 18 SLR 5-year extreme tide with 12 SLR Today s 50-year extreme tide SLR Inundation & Overtopping -36

11 ART s One Map = Many Futures Each map represents a number of projected sea level rise and extreme tides (storm surge) combinations

12 Inputs: Terrain 2010/2011 LiDAR collected by the USGS and NOAA 1-meter bare earth digital elevation model (DEM) Captures most features that provide flood protection features Local knowledge from the FEMA Bay Area Coastal Study used to refine DEM to better represent flood protection features Stakeholder review and feedback to further refine DEM If an area is shown as flooded with 24 of SLR, and it has never flooded during a King Tide or storm event, the area is reviewed

13 Stakeholder Input is Key! Will OAK flood with 12 inches of sea level rise? If so, flooding would have been observed during a King Tide

14 Trouble Spots Ground-truthed Locations identified by the shoreline delineation and the overtopping potential analysis as low spots were field verified to make sure they truly were problem areas

15 Stakeholder Review Process using ArcOnline

16 Shoreline Delineation Original Purpose: Identify the pathways of inundation or flooding from the Bay Delineate features that protect inland areas from flooding Engineered flood protection levees Non-engineered berms Shoreline protection structures Transportation (Roadway/Rail) embankments Wetlands Beaches Natural Shorelines

17 ART Shoreline Overtopping Analysis Overtopping: Water level (MHHW or SWEL) exceeds elevation of shoreline; Depth of overtopping Identifies shoreline locations that may be too low, which helps prioritize where further study or immediate actions may be necessary Freeboard: Elevation of shoreline exceeds water level (MHHW or SWEL). Freeboard = the height of the shoreline above the adjacent water surface SF Bay Water Level Freeboard Overtopping

18 ART Maps: Disconnected Areas

19 Focus Shoreline on Study the Bay Bridge Toll Plaza 36 SLR or Today s 50-year extreme tide or El Niño with 10-year extreme tide

20 Shoreline Overtopping Areas

21 Near-term = local shoreline response Immediate: fortify low spots along Radio Road, have portable pumps and back up power available, temporarily protect the toll plaza and the westbound travel lanes if a storm is predicted Soon: design and build shoreline protection system such as a living levee that considers need for radio tower access and operations of existing stormwater drainage system

22 When to use the data? Support robust, local-scale vulnerability assessments in San Francisco Bay Support development of both near-term and longterm adaptation strategies for San Francisco Bay Regional scale vulnerability assessments in San Francisco Bay

23 Where to get the data? Geodatabases Map books Technical documentation Example analysis For more information contact:

24 Story Map and Interactive Viewer Coming April 2018!

25 Story Map and Interactive Viewer Coming April 2018!

26 Adapting to Rising Tides Thank you! Heather Dennis