The Friday Harbor Marina Water Quality Sampling project is a long running study conducted primarily by the Friday Harbor Elementary 5th grade. Six times a year, students take measurements at six sites to test for water quality. During each sampling period, students measure water temperature, salinity, and direction of water movement in the field, then collect water samples from each testing site. These samples are then tested for Fecal coliform, a harmful pathogen usually found in sewage. Fecal coliform counts are the primary method of establishing water quality in the marina, using a pre-existing criteria for water quality established by the Washington Department of Ecology (shown below). This classification system provides water quality ratings based on colony counts found per 100mL of sampled water. Each student will process their water sample to isolate and identify fecal coliform bacteria. The resulting data is recorded, graphed and shared with the Port of Friday Harbor. Water sampled from the marina is compared to the the marine water surrounding the San Juan Islands, which is designated as Class AA (or Extraordinary Quality) and meets the criteria outlined in WAC-173-201A-030 (2002) see below.
Friday Harbor Marina Monitoring Sites
An Overview of Friday Harbor Marina Water Quality 2002-2023
Washington State Recreation Use Classes For Marine Waters
established by the Dept. of Ecology
Class AA (extraordinary) & Class A (excellent):
Primary contact: (swimming), sport fishing, boating and aesthetic enjoyment.
A Criteria: Fecal coliform bacteria levels shall both not exceed a geometric mean value of 14 colonies/100ml and not have more than 10 percent of all samples obtained for calculating the geometric mean value exceeding 43 colonies/100ml.
Class B (good) & Class C (fair):
Secondary contact: recreation, sport fishing, boating and aesthetic enjoyment.
B Criteria: Fecal coliform colonies shall not exceed a geometric mean of 100 colonies/100ml and 10% of all samples shall not exceed 200 colonies/100ml.
C Criteria: Fecal coliform colonies shall not exceed a geometric mean of 200 colonies/100ml and 10% of all samples shall not exceed 400 colonies/100ml.
Graphed Water Quality Results
F. coliform results (Most Recent Year)
F. coliform results (three year blocks)
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