An Overview of San Juan Island Water Quality Results 2006-2008

*Fecal coliform must meet two separate conditions in order to determine class. **A circle that contains two colors shares standards.

All surface water sites in San Juan County are to meet the Extraordinary or Class AA Washington State water quality standard.

 

 

 

An Overview of San Juan Island Water Quality Results 2004-2006

*Fecal coliform must meet two separate conditions in order to determine class. **A circle that contains two colors shares standards.

All surface water sites in San Juan County are to meet the Extraordinary or Class AA Washington State water quality standard.

 

 

 

An Overview of San Juan Island Water Quality Results 2002-2004

*Fecal coliform must meet two separate conditions in order to determine class. **A circle that contains two colors shares standards.

All surface water sites in San Juan County are to meet the Extraordinary or Class AA Washington State water quality standard.

Graphed Annual Water Quality Results

NOTE: Fecal coliform must meet two separate conditions in order to determine class (See standards above).

 

Percentage of Fecal coliform Sampling Averages per Class Level

 

NOTE: For graphing purposes, all raw data has been adjusted to correspond with different turbidity background levels (BGL) for each site.

NOTE: Due to sampling dates with no flow data taken, a line has been inserted to connect points separated by a missing flow data point. For example, if the water was still, dry or too dangerous to enter.

 

San Juan Island Watershed Sampling Sites

 

San Juan Island Watershed Map

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 .1mg/L                            

Modified from WAC 173-201A-030

 

 

 

 

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