Title
Briefing on Long-term Sea Level Rise Monitoring and Metrics for Adaptive Management
Recommended Action
Briefing only. No action requested.
Report
Issue:
Briefing on long-term sea level rise monitoring and metrics for adaptive management.
Staff Contact:
Natalie Weiss, Climate Resilience Coordinator, 360.570.5828
Presenter(s):
Natalie Weiss, Climate Resilience Coordinator
Justin Vandever, AECOM
Julia-Grace Sanders, AECOM
Background and Analysis:
In July 2025, the Collaborative Partners contracted with AECOM to develop a long-term sea level rise monitoring plan to track changing environmental conditions and support adaptive management. The key outcomes of the contract are a local evaluation of vertical land motion, updated sea level rise projections, and a long-term monitoring and metrics plan.
Assessed vertical land motion:
AECOM conducted an analysis of vertical land motion (VLM) in the Sea Level Rise Response Plan project area. Vertical land motion is the slow, long-term uplifting or sinking of land. In Olympia, we primarily experience sinking (or subsidence), which can influence flood risk as enhanced rates of subsidence can accelerate observed and future rates of relative sea level rise. AECOM assessed localized VLM and used those estimates to adjust regional sea level rise projections to local conditions. AECOM estimated a subsidence rate of -2 to -4 mm/yr.
Updated sea level rise projections:
Using the outputs of the VLM evaluation, AECOM developed projections for future sea level rise and maps showing the extent and frequency of sea level rise flood exposure. AECOM conducted a literature review of projections that have been published since the development of the Sea Level Rise Response Plan in 2019, and recommended using the NOAA (2022) regional sea level rise estimates. The updated projections, including VLM, show 12-18 inches of sea level rise by 2050, and 41-66 inches of sea level rise by 2100.
A long-term monitoring and metr...
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