On May 5th, 2012 the Estuarine Field Studies class from the University of Washington Tacoma (UWT) conducted water quality measurements at three locations within the San Juans.These measurements were collected for the purpose of helping students understand the oceanographic processes present within the straits of Juan de Fuca and San Juan Channel, along with practicing different sampling techniques and common lab procedures. Sampling was done aboard the Centennial, which was captained by Dr. David Duggins. The San Juan Channel lies within the San Juan Islands archipelago, separating San Juan, Orcas, Shaw, and Lopez Island. The islands are located in between the Strait of Juan de Fuca and Georgia Strait.

Pacific Ocean water enters at the bottom of the Strait of Juan de Fuca entering Puget Sound. Freshwater exits Puget Sound and into the Pacific Ocean. As freshwater flows through the Haro Strait, the rough bathymetry present at the channel entrance causes mixing of fresh and salt water to occur. During the time this study was conducted, strong tidal forces were observed due to the perigee super moon occuring May 5th-6th (NASA). As a result, the turbidity of the channel was extremely high and strong circulation patterns occurred within the channel and caused it to be well mixed. Therefore, these factors caused our data to be slightly different from classes in the past. Usually the water is stratified throughout the channel when there are not strong tides present, with salty dense water residing at the bottom of the channel and less dense fresh water on the surface.