Program

• Home
• About Us
  • About Napa RCD
  • About NRCS
  • Board & Staff
• Calendar
  • Board Meetings
  • NSWG Meetings
  • Events
• Programs
  • Education
  • Monitoring
  • Planning
  • Restoration
  • Tech Assistance
  • NSWG
• Library
• Opportunities
• Contact Us

 

Biological Monitoring

What we do

Water temperature monitoring

The RCD collects continuous temperature data throughout the Napa River watershed using submersible data loggers to determine habitat suitability for cold-water fishes.  Salmonids are especially sensitive to water temperatures above about 20° C (68° F).  Exposure to elevated water temperatures may lead to reduced health and fitness, reduced growth rates, increased susceptibility to predation and disease, and depending on life-stage and duration of the exposure, may cause direct mortality. Seasonal fluctuations in water temperatures are caused by several factors including ambient air temperature, instream flow, groundwater influence, and riparian shading.

 

 

Methods

• Sites are selected in potential salmonid rearing pools. 
• The data logger is housed inside a short length of ABS plastic pipe to protect it from damage and direct sunlight. 
• The assembly is anchored to the streambed using a combination of cable and rebar. 
• The data logger is set to record water temperature at 15- or 30-minute intervals depending on site conditions and the duration of the study.
• Physical characteristics of each site are documented at the time of installation including water depth, canopy, substrate, estimated flow, and vegetation. 
• Data are downloaded regularly and put into a database.
• The maximum weekly average temperature (MWAT) and other statistics are calculated for each site.

 

Water Temperature Monitoring Studies

• Southern Napa River Watershed Plan – 2009 (Streams: Browns Valley, Huichica, Milliken, Murphy, Pickle, Redwood, Salvador, Sarco, Spencer, Suscol, Tulucay)
• Central Napa River Watershed Project - 2005 (Streams: Bale, Bell, Canon, Conn, Montgomery, Napa River, Rector, Soda, Wing Canyon, York)
• Napa Creek Salmon Monitoring Project Year 2 report – 2007
• Sulphur Creek Habitat Assessment – 2002
• Carneros Creek Habitat Assessment – 2002