The San Juan Islands Watershed Project was initiated in 2002 in partnership with the San Juan Islands Conservation District, with the purpose of collecting baseline watershed water quality data and educating local students about watershed health. Students from Friday Harbor High School, Spring Street International School, Lopez School, and Griffin Bay High School have been involved in the study. The water quality of 12 major watersheds was monitored on San Juan, Lopez and Orcas Islands every 6-8 weeks. Seven parameters were assessed at most sites: dissolved oxygen, fecal coliform, turbidity, pH and temperature, nutrients (nitrates, orthophosphates), and flow. Classroom sessions, field trips and activities introducing the importance of watersheds and water quality monitoring still occur to enhance present high school science curriculum.
Sampling and lab protocols were developed to meet the Washington State Department of Ecology’s (WSDOE) quality assurance standards. All of the sampling equipment (DO/pH/temperature probes, incubators, fecal coliform filter dishes) meet EPA standards to ensure reliable, accurate data. The surface waters of the San Juan Islands are designated as Class AA or Extraordinary Primary Contact waters and are to meet the criteria outlined in WAC 173-201A-030 (2002). To learn more about present watershed water quality standards in Washington visit WSDOE.
County Watersheds
Water Quality Results
The data we collected were shared with the San Juan Islands Conservation District (SJICD), the San Juan County Health Department, and WSDOE. These data served as an early warning system alerting resource managers that water quality impairment may be developing. SJICD also used the data to assess potential non-point source pollution problems within a watershed as a means of identifying appropriate ‘Best Management Practices’ for landowners.
To review water quality results by island, click below:
CLICK below for access to the full set of watershed data (PDFs).
Fresh Water Classes and Standards for Surface Waters in Washington (2002)
Class AA (Extraordinary)
- pH – 6.5-8.5
- Turbidity– shall not exceed 5 NTU (over background level)
- Temperature– shall not exceed 16°C
- Dissolved Oxygen– shall exceed 9.5 mg/L
- Fecal coliform – shall not exceed a geometric mean of 50 colonies/ 100mL and not have more than 10 percent of all samples collected exceed 100 col./100mL
Class A (Excellent)
- pH – 6.5-8.5
- Turbidity– shall not exceed 5 NTU (over background level)
- Temperature– shall not exceed 18°C
- Dissolved Oxygen– shall exceed8.0 mg/L
- Fecal coliform – shall not exceed a geometric mean of 100 colonies/ 100mL and not have more than 10 percent of all samples collected exceed 200 col./100mL
Class B (Good)
- pH – 6.5-8.5
- Turbidity– shall not exceed 10 NTU (over background level)
- Temperature– shall not exceed 21°C
- Dissolved Oxygen– shall exceed 6.5mg/L
- Fecal coliform – shall not exceed a geometric mean of 200 colonies/ 100mL and not have more than10 percent of all samples collected exceed 400 col./100mL
Class C (fair)
- pH – 6.5-9.0
- Turbidity– shall not exceed 10 NTU (over background level)
- Temperature– shall not exceed 22°C
- Dissolved Oxygen– shall exceed4.0mg/L
- Fecal coliform – shall not exceed a geometric mean of 200 colonies/ 100mL and not have more than 10 percent of all samples collected exceed 400 col./100mL
Below Standards
- pH – > 9.0
- Turbidity– exceeding 10 NTU (over background level)
- Temperature– exceeding 22°C
- Dissolved Oxygen– 4.0mg/Lor less
- Fecal coliform – exceeding a geometric mean of 200 colonies/ 100mL and more than 10 percent of all samples collected exceed 400 col./100mL
Nutrients – Are not very clear-cut it depends on the background levels for the particular area. So the following numbers are
Guidelines:
Nitrates should not exceed 1mg/L
Phosphates should not exceed 0.1mg/L
Modified from WAC 173-201A-030
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