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where the river meets the sea

Estuaries are among the most productive ecosystems in the world as the water filtering through them brings in important nutrients collected on its journey through the mountains, land, and to the sea.


Unfortunately, this water also picks up harmful pollutants on this voyage, depositing it directly into estuaries. 


For these reasons, estuaries are some of the most fertile ecosystems on Earth, yet they may also be some of the most polluted.

This is especially seen in the Puget Sound basin and overall Salish Sea.

salish sea map2.png

A fresh and salty BASIN

The foundation of this estuarine ecosystem is the interaction between these fresh water discharges from rivers flowing into the inland sea and the salt water from the Pacific Ocean.

Rivers flow into salt marshes, wetlands, and bays providing important nutrients from the fertile valleys they flow through on their way down.  Unfortunately, a lot of the summer freshwater flows are decreasing in the Salish Sea due to less rain, depleted snow back, and warmer temperatures. This low summer flow can affect wildlife including important salmon runs and residential, agruicultural, and industrial water supplies. Read more here


Text adapted from the man who named the Salish Sea, Bert Webber

estuarine ecosystem

at work

The animation from PNNL shows this interaction as the fresh water from the rivers (blue) and the salt water from the ocean (red) mix, creating a circulation of water in the inland sea that is the imperative for the estuarine ecosystem. 


The biggest freshwater discharge in the Salish Sea is from the Fraser River in Canada (top blue). The Fraser River's annual fresh water discharge at its mouth is 125,000 cu ft/s while also discharging 20 million tons of sediment into the ocean.


Map courtesy of Cascadia Institute, © 2010, used with permission




"We live here in a great bowl of green waters. From the crestlines of mountain ranges on either side, “many rivers flow down to an inland sea.” These waters are shaped like a giant waterbird arcing in flight to the northwest. Its body is Puget Sound, its wings the Strait of Juan de Fuca and the great Fraser River, and its long curving neck is the Strait of Georgia, heading north to Alaska."

-David McCloskey, The Ish River Map Story

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