NASA MODIS Image of the Day: May 8, 2011 – Sediment off the coast of Washington
On April 22, 2011 the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite passed over the Pacific Northwest of the United States and captured this true-color image of sediment off the coast of Washington.
At the boundary line of Washington (north) and Oregon (south) a large dark plume of sediment extends from the Columbia River far into the Pacific Ocean, where it spreads into an expanding cloud of dark tan, which drifts south off the coast of Oregon then curls northward further out to sea.
Two smaller sediment plumes can also be seen along the Washington coast, one from Grays Harbor (northernmost plume) and Willapia Bay (south of Grays Harbor). The Columbia River is the largest river by volume flowing into the Pacific Ocean from North America, with an average flow at the mouth of about 265,000 cubic feet per second. The watershed covers 260,000 square miles, with a population of 8 million people living within the watershed. The Columbia is about 1,200 miles long, beginning at the headwaters in the Rocky Mountains of British Columbia, Canada and ending in the Pacific Ocean. The Columbia supports a large population of wild steelhead and salmon which migrate in the late summer through fall from the Pacific Ocean upriver to spawn in fresh inland waters. In the spring, the fish migrate outwards to the ocean waters. The many dams on the Columbia can impede migration, but efforts are made to allow passage of the fish, despite the dams. In spring, water is spilled to allow the fish to return to the sea. Spring spill starts at the Columbia River projects on April 10 and continues 24 hours a day at all eight dams in the project until out-migration is complete.
