DAYTON, Wash.– A fish separator system at the Little Goose Lock and Dam Juvenile Fish Facility became plugged and overflowed because of abnormally high seasonal debris from the lower Snake River on Tuesday, April 11, according to U.S. Army Corps of Engineers officials. The plugging and overflowing caused the death of 94 juvenile salmon and steelhead.
The juvenile collection system and separator routes juvenile fish for sampling, barging or release back into the river. The inadvertent plugging and overflow occurred at about 1:30 p.m. on Tuesday, The Corps had been periodically checking the juvenile bypass system for operational compliance when the plugging and overflow occurred.
Once the problem was discovered, and to prevent further overflow and fish mortality, a “switch gate” in the separator system was moved to a bypass position until debris could be removed, routing fish around the blockage. Juvenile fish separation and sampling resumed at about 2:30 p.m.
To help prevent future incidents, the Corps will maintain increased monitoring of the system. Also, on April 12, the separator was disassembled to remove additional debris.
Snake River flows have been very high this year due to precipitation and runoff. Little Goose has seen higher-than-normal debris come through the area.
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Release no. 17-049