The Nimbus Basin on the lower American River will permanently close to all fishing as of March 1, 2018, as per fishing regulations amended by the Fish and Game Commission in December 2017.
The closure will take effect from Nimbus Dam on the lower American River to the U.S. Geological Survey (USGS) gauging station cable crossing approximately one-half mile downriver (California Code of Regulations Title 14, sections 7.50(b)(5)(A) and (B).
Under current regulations, the American River from Nimbus Dam to the Hazel Avenue bridge piers is open to fishing all year (CCR Title 14, section 7.50 (b)(5)(A)), and from the Hazel Avenue bridge piers to the USGS gauging station cable crossing about 300 yards downstream from the Nimbus Hatchery fish weir from Jan. 1 through Aug. 15 (section 7.50(b)(5)(B)).
Closure of the Nimbus Basin to fishing is part of the Nimbus Hatchery Fish Passage Project, which involves reorienting the hatchery’s fish ladder into the Nimbus Basin and removing the existing fish weir. This project will create and maintain a reliable system of collecting adult salmon and steelhead broodstock for the hatchery and increase the amount of natural spawning and rearing habitat available in the lower American River.
The changes will also minimize American River flow fluctuations associated with installation and removal of the hatchery’s weir and eliminate health and safety concerns relative to the deterioration of the existing weir structure. The new spawning habitat opened up by the permanent removal of the weir will improve juvenile salmon production and increase harvest opportunities downstream.
The U.S. Bureau of Reclamation and the California Department of Fish and Wildlife completed a joint Environmental Impact Statement/Environmental Impact Report (EIR/EIS) for the Nimbus Hatchery Fish Passage Project in 2011. Planning is currently underway and construction is scheduled to begin in federal fiscal year 2019. The EIR/EIS is available for download from www.usbr.gov/mp/ccao/hatchery.