Pacific Netting Products (PNP) designed and built a dual-pontoon floating HDPE fish guidance and debris boom for the Sunnyside Dam irrigation system. This boom helps salmon and steelhead smolts bypass a head gate that diverts water from the Yakima River into an irrigation canal. By guiding fish away from the intake, the system improves survival rates and reduces the number of fish entering the canal. This prevents unnecessary losses and limits their reliance on the canal’s fish bypass system.
The importance of the Sunnyside Valley Dam
The Sunnyside Valley Irrigation District (SVID) supplies irrigation water to 94,000 acres of row crops, hops, grapes, and tree fruit in central Washington. Like many dams in the region, SVID’s Sunnyside Dam creates obstacles for juvenile fish survival. To improve fish passage, SVID chose to hire PNP to implement a new boom fish guidance system. In this interview, SVID General Manager Lori Brady gives Hydro Leader the details.
Two young Chinook salmon. The top fish has the color of an ocean-going smolt while the bottom is colored to blend into a stream bottom.
Smolt, not smelt
The word ‘smolt’ comes from Old English (smeolt). It had several meanings like calm, gentle, smooth but also bright or shining. ”Bright or shiny” definitely describes a young migrating salmon and steelhead. The word ‘smolt’ is similar to the word ‘smelt’, meaning extracting metal from rock by heating and melting or meaning species of small silvery fish that live in both ocean and freshwater. By chance, the fish species called smelts are often distantly related to salmon. — Source: Upper Columbia River Salmon Recovery Board webiste article “Fish Factors Mini-Series | Salmon Smolt Outmigration”
How the MultiFunction Boom™ Sections Were Structured
The structure consists of three single MultiFunction Boom™ sections and six dual PNP MultiFunction Boom sections. A concrete shore anchor and a dam-mounted beam slider assembly keep the boom in place while allowing it to adjust to changing river levels. The upstream single-boom sections feature a reinforced rubber skirt contoured to fit the riverbed. The dual-pontoon sections contain five removable wedge wire fish guidance screens, each four feet deep. Steel structural cross members connect these parallel booms for added stability.
A concrete shore anchor and a dam-mounted beam slider assembly keep the boom in place while allowing it to adjust to changing river levels.
Sunnyside Dam Fish Guidance System Details
The dual-pontoon design prevents excessive rotation in strong currents and keeps the fish guidance screens vertical. The rear pontoon can be ballasted for fine-tuning and alignment, while the front pontoon is foam-filled for added safety. The system is durable, adaptable, and can be modified or reconfigured as needed.
Sunnyside-Valley-Dam showing booms that hold the fish guidance system in place.
Installation Features
- Dual HDPE floating MultiFunction Boom
- Wedge wire screens for design flows up to 4 cfs
- Improves salmonid smolt survival rates
- Reduces irrigation-related fish impacts
- Adjusts to changes in water elevation
- Strong enough to divert large woody debris downstream
