This multi-year infrastructure improvement was designed to significantly improve fish passage efficiency, operational reliability, and long-term biological performance by modernizing the fish passage and handling systems at the operating federal Dexter Dam which began operating in 1954.
Constructed in accordance with National Marine Fisheries Service (NMFS) criteria and the 2008 Biological Opinion for the Willamette Valley Project, the project prioritized fish-safe design and construction practices while maintaining continuous dam and fish passage operations.
Work included the demolition of the existing fish ladder and construction of approximately 375 linear feet of new weir-and-orifice fish ladder, along with new pre-sort and post-sort fish handling facilities equipped with specialized mechanical, pneumatic, and hydraulic systems. Additional work included installation of return-to-river piping, upgrades to water conveyance systems, fabrication of intake structures, and erection of a five-story structural steel crane frame supporting bridge cranes for facility operations.
Execution of the work required complex temporary works and water management, including installation and removal of multiple cofferdams within active river conditions, barge-supported operations, and temporary utilities. Construction activities were carefully sequenced around strict environmental constraints, including in-water work windows and fish facility shutdown periods, to protect sensitive aquatic species.
This project demonstrated Slayden’s ability to deliver complex, multi-disciplinary infrastructure projects within highly regulated and operationally constrained environments.
Slayden earned First Place in the 2025 AGC Construction Safety Excellence Awards (CSEA) in the Utility Infrastructure Category — Under 500,000 Work Hours.
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Slayden Constructors and Jacobs Engineering recently completed a $78 million expansion of the Robert A. Duff Water Treatment Plant for the Medford Water Commission. The project boosts capacity from 45 to 65 million gallons per day and adds advanced filtration, a new reservoir, a modern pump station, and seismic‑resilient redundancies. This upgrade strengthens long‑term water reliability for Medford and the greater Rogue Valley, supporting regional growth and public health.
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Slayden’s Jeff Wall recently achieved a unique milestone. At the Pacific Northwest Clean Water Association (PNCWA) conference in Spokane, Washington, Jeff became the first contractor to be chosen under the PNCWA to join the Select Society of Sanitary Sludge Shovelers, also known as the 5S society. Members are selected based on “outstanding, meritorious service above and beyond the call of duty.” As recognition for this achievement, Jeff received a one-of-a-kind -5S gold shovel award.
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