That plume you see is sediment, not sewage

Crossposted from Clean Water Stories 

The power of imagery was on full display in a March 12 front page Seattle Times aerial photograph of West Point Treatment Plant and its adjacent waters. The photo purported to show a plume of sewage and stormwater that had discharged from the plant’s emergency outfall before the bypass gate was closed early in the morning of Feb. 16. The accompanying story began:  “A mighty river of brown, raw sewage and stormwater makes a plume offshore at Discovery Park, plainly seen from the air…It’s from the West Point Treatment plant, gushing untreated wastewater into Puget Sound.”

Unfortunately, that was untrue and the power of the photo is in how it was wrongly described. At King County’s request, the Times clarified its reporting on March 20 to reflect that what its readers were actually seeing is sediment. The sediment plume regularly builds up around West Point in the shallow beach area, south of the lighthouse.

“West Point is a pronounced geographic feature that interrupts natural sediment movement along the shoreline,” says Bruce Nairn, King County’s oceanographer. “On an ebb tide, flows move north.”

This particular Feb. 16 sediment plume is corroborated by field scientists, water quality samples, historical photos, wind patterns, currents, and tidal movements.

Read more at Clean Water Stories