• Juvenile salmon survival increases five-fold after Little Springs Creek reconnected to Lemhi River



    Until a few years ago, most of the major tributaries of Idaho’s Lemhi River were cut off from the mainstem for part or all of the year, greatly reducing available steelhead and chinook spawning and rearing habitat. Since 2009, through the active collaboration of farmers and ranchers, state and federal biologists, habitat restoration has added year- round access to 180 kilometers of tributary habitat and seasonal access to an additional 103 km of tributary habitat – a total increase of 99 percent.  


      Little Springs Creek is one of the most recent successes in the Lemhi. Prior to fall 2011, Little Springs Creek was fully appropriated for irrigation. In 2011, the irrigation diversions on Little Springs Creek were aggregated and replaced by a withdrawal from the mainstem, and the Creek was re-connected to the Lemhi. Juvenile Chinook salmon and steelhead were immediately attracted to the Creek, likely seeking refuge in the cooler spring water available. In 2012, the irrigation diversions in Little Springs Creek were decommissioned and culverts removed or replaced. Channels were reconstructed and riparian plantings added.  
    Little Springs Creek, before restoration

    That year (2012), 29 percent of the juvenile Chinook salmon reared in Little Springs Creek survived to emigrate from the Lemhi River. The year following the restoration, in 2013, that percentage increased to 80 percent. The abundance of juvenile Chinook salmon increased five-fold. The abundance of juvenile steelhead increased from 436 in 2012 to 1,297.










    The Lemhi is one of several intensively-monitored watersheds in the Columbia River Basin, allowing scientists to compare the status of fish in one tributary with the population in the watershed at large. In 2013, for instance, while the abundance of juvenile Chinook salmon in Little Springs Creek increased 500 percent, abundance in the Lemhi River overall was 62 percent lower than in 2012. The comparison adds to the certainty that the habitat restoration actions in Little Springs Creek resulted in a dramatic increase in juvenile survival.



    Little Springs Creek, 2013, after restoration

    Flows increased, plantings have restored the area to natural state. Juvenile salmon and steelhead abundance and survival improved dramatically after restoration.


  • Project at a glance

    Location: Little Springs Creek, Lemhi Valley, Idaho   


    Biological objectives: Recover aquatic and riparian habitats and reduce water temperatures in order to maximize productivity of listed and non-listed fish. 


    Species: ESA-listed Snake River steelhead and spring/summer chinook salmon


    Partners:  Bureau of Reclamation, State of Idaho, BPA 


    References: NOAA Fisheries 2010/2014 FCRPS Biological Opinion for ESA-listed salmon and steelhead