The Columbia Slough is a narrow waterway, about 19 miles long, in the floodplain of the Columbia River in the U.S. state of Oregon. It is a remnant of the historic wetlands between the mouths of the Sandy River and the Willamette River. Levees surround much of the main slough as well as many side sloughs, detached slougs, and nearby lakes.
About Columbia Slough in brief
The Columbia Slough is a narrow waterway, about 19 miles long, in the floodplain of the Columbia River in the U.S. state of Oregon. It is a remnant of the historic wetlands between the mouths of the Sandy River and the Willamette River. Levees surround much of the main slough as well as many side sloughs, detached slougs, and nearby lakes. Five percent of Oregon’s population, about 158,000 people, live in the slough watershed of about 51 square miles. Tidal fluctuations cause reverse flow on the lower slough. The slough is classified as a \”stream\” in the Geographic Names Information System of the United States Geological Survey. The 40-Mile Loop and other hiking and biking trails follow the waterways and connect the parks. The businesses and industries in the watershed employ about 57,000 people, which is also frequented by more than 150 bird species and 26 fish species and animals including otters, beaver, and coyotes. The Columbia’s name belonged to the tradition of naming things after explorer Christopher Columbus, who sailed part of the Redway in 1792, and named the river after his ship, Columbiaiviva. The city of Vanport was never rebuilt after a flood pouring through a levee break in 1948 destroyed the city of vanport, which was never rebuilding. In 1952, Portland began sewage treatment, and over the next six decades the federal Clean Water Act and similar legislation mandated further cleanup. The name Columbia usually rhymes with shoe in the US, except in New England, where it usuallyrhymes with now, the preferred British pronunciation.
Slough may mean a place of deep mud or mire, a swamp, a river inlet or backwater, or a creek in a marsh or tide flat. It was historically a channel or an inlet, and was named after Robert Gray, a Boston fur trader and whaler who sailed parts of the river up the Columbia in the 1792-1793 period. In the early 19th-century fur trappers and explorers including Lewis and Clark visited the area before large migrations of settlers began arriving from the east. Increased investment in the Floodplain led to larger losses during floods, and these losses prompted levee building that greatly altered the area. A regional agency operates Portland International Airport along the middle slough and marine terminals near theLower Slough. One of the nation’s largest freshwater urban wetlands, Smith and Bybee Wetlands Natural Area, shares the lowerslough watershed with a sewage treatment plant, marine terminals, a golf course, and a car racetrack. The lower sloug flows roughly 0.4 to 1 miles parallel to the Columbia and about 7 miles to its confluence with the WillAmette River in Multnomah County. It begins at Fairview in the lake city of Fairview and immediately enters theCity of Gresham. Less than 1 mile later, it enters the town of Portland and continues generally westward for about another 18 miles. Throughout its course, it is nearly 10 feet above sea level.