Circulation

One of the first working models of Puget Sound was a scaled-down concrete reproduction, with actual water running through channels, around islands and into bays, inlets, and harbors. Motors, pumps and timing gears are part of an elaborate mechanism that replicates tides and river flows in the still-functioning model.

Estuaries around the world including Puget Sound perform an amazing feat of continuous water mixing called estuarine exchange flow. 

In a new series we are calling Ask a Scientist we interview local researchers to get their thoughts on some of the important but lesser-known scientific facts about the Puget Sound ecosystem. Today, we speak with University of Washington oceanographer Parker MacCready about Puget Sound’s “underwater Amazon” and why it has profound implications for Puget Sound science and policy. It all begins, he says, with the mixing of fresh and salt water and something called the estuarine exchange flow.

The year 2021 was generally drier and warmer including a heat wave in June. Higher river flows followed a rainy and cloudy fall. In 2021, EOPS aerial images continued to capture the diversity of phenomena on the water, with support from its wonderful contributors who documented visible water quality issues across the larger Puget Sound region. With our Artists Corner and story maps on critters in the mud, we hope to continue to inspire, educate, and motivate our community to keep curious and watchful eyes over the environment.

Despite a La Niña, precipitation and rain have been lower since March, leaving only snow-fed rivers running high. Due to lower rainfall and warm summer temperatures the salinity of Puget Sound is now generally higher. Strong blooms and large patches of organic material and macro-algae are building up in many places and wash onto beaches. During very hot summer days, tidal mudflats and beaches can get really warm. Beach wrack can harbor increased bacteria numbers now. See SCUBA cleaning up at Redondo beach.

After a wet winter/spring transition it has been noticeably drier, warmer and sunnier. River flows are near normal levels and in Puget Sound and coastal bays salinity is increasing above normal. The spring bloom is developing but not very pronounced, yet, Noctiluca is already visible in southern Hood Canal. Suspended sediment near rivers and creeks, failing bluffs, and shellfish activities are frequent. Capturing herring spawning from the plane is informative; pilots share their observations.