Urban water bodies face increasing pressures from climate change and human activity, threatening cold-water habitat for fish species such as salmon. This study presents a hydrodynamic modeling framework to evaluate temperature management strategies in the Lake Washington and Lake Washington Ship Canal (LWSC) system in Seattle, Washington. A three-dimensional model was calibrated and validated over three years, accurately reproducing water surface elevations, temperature profiles, and salinity patterns, confirming its reliability for water resources decision-making.
Scenario analyses tested cold-water supplementation using diffusers placed in the Montlake and Fremont Cuts. Results show that targeted cold-water introduction reduces temperatures during critical salmon migration periods, lowering the frequency of thermally stressful conditions relative to WRIA 8 thresholds. Higher supplementation volumes also suppressed salt wedge intrusion and improved circulation in deeper waters.
These findings support cold-water supplementation as a practical, scalable strategy for reducing thermal stress in urban salmon migration corridors. The study also demonstrates the value of detailed lock simulation for evaluating structural and operational management options, offering actionable guidance for water resource managers addressing climate-driven temperature challenges.
Presenter:
Paul M. Craig, P.E. Principal ConsultantDSI, LLC
Participation Details:
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