This report summarizes an investigation conducted from 1998-2002 on the effects of the two primary anthropogen stressors, sediment and temperature, on salmonids in the Navarro River watershed in California. The study addresses the following primary objectives: 1) determine the absolute and relative contribution of the California Department of Transportation (Caltrans) to the stressor loads within the watershed, and 2) determine if the timing, magnitude, and duration of Caltrans inputs were proportionately or disproportionately responsible for the decline of salmonids and the continuing degradation of salmonid habitat within the watershed. The research focused on understanding the background levels of stressors, how those stressors have changed during the period in which salmonid declines have been observed, the mechanism by which those stressors impact salmonids, and finally, the origin of the stressors. Results of the study suggest that the volume of sediment produced by erosional sources along the four mile length of Highway 128 within the North Fork basin account for a small fraction (0.3 %) of the total volume of sediment produced by erosional sources related to other land uses or natural causes in the remainder of the North Fork basin, one of the five watersheds draining into the Navarro River. The report is presented in three volumes: Vol. 1) Status of the salmonids; Vol. 2 ) Stressors on salmonids; and, Vol. 3) Impact of stressors on salmonids.

  • Record URL:
  • Supplemental Notes:
    • Publication Date: October 2002. California Dept. of Transportation, Sacramento CA. Remarks: Also available online via the Caltrans Division of Environmental Analysis Storm Water Management Program website (
  • Corporate Authors:

    Univeristy of California, Davis. John Muir Institute of the Environment

    ,   United States 

    California. Dept. of Transportation Division of Environmental Analysis

  • Authors:
    • Johnson, Michael L
  • Publication Date: 2002


  • English

Media Info

  • Pagination: 3 v.

Subject/Index Terms

Filing Info

  • Accession Number: 00989463
  • Record Type: Publication
  • Source Agency: UC Berkeley Transportation Library
  • Report/Paper Numbers: CTSW-RT-02-040
  • Files: CALTRANS
  • Created Date: May 3 2005 12:00AM