Title
Groundwater Study Update
Recommended Action
Information only. No action requested.
Report
Issue:
Update and discussion on the groundwater study conducted to evaluate the potential impact of sea level rise on groundwater levels in downtown Olympia.
Staff Contact:
Pamela Braff, PhD, Director of Climate Programs, 360.753.8249
Presenter(s):
Wendy Steffensen, LOTT Clean Water Alliance
Nathan Starr, Pioneer Technologies Corporation
Background and Analysis:
In March 2019, the City of Olympia, LOTT Clean Water Alliance, and the Port of Olympia completed the Olympia Sea Level Rise (SLR) Response Plan. The Plan outlines strategies to protect key areas-including downtown Olympia, the Port Peninsula, and the LOTT Budd Inlet Treatment Plant-from flooding caused by projected sea level rise. It provides a comprehensive framework for adapting to rising sea levels in both the short and long term.
In addition to physical and operational strategies to address flood risks, the Plan also identifies a range of informational strategies to address data and knowledge gaps in our understanding of local flood risks and vulnerabilities. Improving our understanding of local conditions will help the Collaborative better plan for and respond to sea level rise.
One key knowledge gap identified in the Plan is the potential impact of sea level rise on future groundwater levels. As tide elevations rise above the land, hydraulic pressure could cause groundwater levels to exceed the land surface, potentially undermining the effectiveness of flood barriers.
To address this knowledge gap, in 2023-2024, the Collaborative initiated a groundwater study. The study aimed to assess the potential impact of projected sea level rise on:
* Groundwater elevations in downtown Olympia
* Proposed adaptation measures
* Buried storm and sewer lines
* Surface water ponding due to daylighting groundwater
In 2023, LOTT Clean Water Alliance contracted with PIONEER Technologies Corporation (Pione...
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