Sea Level Rise Vulnerability of San Juan County, Washington
Presentation Abstract
The objective of this study was to attain greater understanding of the areas within San Juan County that are vulnerable to implications of sea level rise. The resulting countywide mapping tool highlights areas potentially at risk to both inundation and bluff recession, for which management strategies can be developed to reduce, avert, and mitigate these SLR impacts. Inundation modeling was paired with bluff recession estimates across two SLR scenarios (moderate, high) and planning horizons (2050, 2100). Inundation mapping was conducted by linking local topography data (LIDAR) to tidal datum and elevations for each scenario and planning horizon. Inundation areas were mapped between MHHW, the highest observed water level, and each of the scenarios and planning horizons. Bluff recession estimates were developed based on a stratified sample of background erosion/change rates from different geomorphic shoretypes in the county (stratified by exposure and orientation). Change rates were measured using historic air photo analysis and digital shoreline analysis systems (DSAS). Historic recession rates were used to project future bluff recession (with accelerated recession rates based on rate of sea level rise), across the two scenarios and planning horizons. Projected bluff recession estimates were buffered from the bluff crest to map vulnerability areas. Roads and structures located within vulnerable areas were highlighted to facilitate adaptation planning. Results identified 19 miles of vulnerable roads (11.1 miles of which were county roads) and over 1,300 vulnerable structures. Together these tools can form the foundation for the development of a SLR adaptation strategy for San Juan County and increase the effectiveness of existing management approaches. In addition, these results can be used to identify additional long-term restoration and conservation targets throughout the County.
Session Title
Session S-04H: Technical Tools to Support Sea Level Rise Adaptation in the Salish Sea
Conference Track
Shorelines
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 8:30 AM
End Date
1-5-2014 10:00 AM
Location
Room 607
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Sea levels--Washington (State)--San Juan County--Maps; Climatic changes--Washington (State)--San Juan County--Maps; Climate change mitigation--Washington (State)--San Juan County--Maps; Beach erosion--Washington (State)--San Juan County--Maps
Geographic Coverage
Salish Sea (B.C. and Wash.); San Juan County (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Sea Level Rise Vulnerability of San Juan County, Washington
Room 607
The objective of this study was to attain greater understanding of the areas within San Juan County that are vulnerable to implications of sea level rise. The resulting countywide mapping tool highlights areas potentially at risk to both inundation and bluff recession, for which management strategies can be developed to reduce, avert, and mitigate these SLR impacts. Inundation modeling was paired with bluff recession estimates across two SLR scenarios (moderate, high) and planning horizons (2050, 2100). Inundation mapping was conducted by linking local topography data (LIDAR) to tidal datum and elevations for each scenario and planning horizon. Inundation areas were mapped between MHHW, the highest observed water level, and each of the scenarios and planning horizons. Bluff recession estimates were developed based on a stratified sample of background erosion/change rates from different geomorphic shoretypes in the county (stratified by exposure and orientation). Change rates were measured using historic air photo analysis and digital shoreline analysis systems (DSAS). Historic recession rates were used to project future bluff recession (with accelerated recession rates based on rate of sea level rise), across the two scenarios and planning horizons. Projected bluff recession estimates were buffered from the bluff crest to map vulnerability areas. Roads and structures located within vulnerable areas were highlighted to facilitate adaptation planning. Results identified 19 miles of vulnerable roads (11.1 miles of which were county roads) and over 1,300 vulnerable structures. Together these tools can form the foundation for the development of a SLR adaptation strategy for San Juan County and increase the effectiveness of existing management approaches. In addition, these results can be used to identify additional long-term restoration and conservation targets throughout the County.
