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Columbia River

The Columbia is one of Oregon's most polluted rivers, second only to the Willamette. Stretches of the Columbia are contaminated with toxics such as dioxin and PCBs, and the river has problems with high temperatures and numerous other pollutants.

Length: 306 miles long
Basin area: approximately 50,000 square miles

The Columbia is one of Oregon's most polluted rivers, second only to the Willamette. Stretches of the Columbia are contaminated with toxics such as dioxin and PCBs, and the river has problems with high temperatures and numerous other pollutants.

Columbia River

The mighty Columbia is one of the largest rivers in North America. It drains a 259,000 square-mile basin that encompasses parts of seven states (Oregon, Washington, Idaho, Montana, Nevada, Wyoming, and Utah) and British Columbia. The Columbia begins in Canada and flows through eastern Washington before forming the border between Oregon and Washington, and eventually reaching the Pacific Ocean. It cuts through the Cascade Mountains, creating the 100-mile-long and 3,000-foot-deep Columbia River Gorge. Many of Oregon's other major rivers flow into the Columbia, including the Deschutes, John Day, Snake, Umatilla and Willamette. There are eleven major dams on the mainstem of the Columbia, four of which are on the section bordering Oregon. The hydroelectric dams are the foundation of the Northwest's power supply, but they harm endangered salmon and significantly impact water quality. The lower 146 miles of the river, up to Bonneville dam, are influenced by ocean tides, and this entire area is considered to be an estuary.

A Closer Look

The federal Environmental Protection Agency (EPA) has identified the Columbia as one of its top water priorities and has named it one of the Nation's Great Water Bodies. Because the Columbia and its tributaries drain an area about the size of France, "legacy pollutants" - chemicals banned in the 1970s such as PCBs, DDT and its derivative DDE - still flush into the river from farms, roads,

construction sites and stormwater systems. These toxins are primarily found in sediment and fish tissues, and they accumulate in fish at some of the highest levels in the Northwest. The EPA has suggested that for some Native Americans, who eat up to eleven times more fish than other Americans, the risk of cancer from toxins in Columbia River fish may be as high as 1 in 50 for sturgeon and 7 in 10,000 for salmon. According to the EPA, pollutants are generally of concern if they exceed a "one in a million" risk of cancer. Newer chemicals for which water quality standards have not yet been established are found at increasing levels in the Columbia, such as certain pesticides and flame retardants. Dioxins, some of the most carcinogenic substances in the world, are also present in the Columbia River. They come from the chlorine bleaching of paper at pulp and paper mills along the river's shores. A plan has been developed for reducing Columbia River dioxins, but no testing has been done yet to see if it is working. Water temperatures in the Columbia have been slowly climbing over the last 65 years, and temperatures are highest in August and September.

Large reservoirs behind the Columbia's dams absorb the sun's heat and make temperatures warmer than the natural snowmelt waters fish are adapted to. The Columbia's dams also contribute to the river's high dissolved gas levels due to the turbulence caused by their spillways. The loss of streamside vegetation on tributary streams and the impacts of stormwater runoff from developed areas also harm the river. Clean Water Plans, known as Total Maximum Daily Loads, have been completed by the Oregon Department of Environmental Quality for dioxin and total dissolved gas in the Columbia River. Efforts are underway to develop clean water plans for temperature and toxics.

Filling in the Data Gaps

In 2001, there were only five ongoing water quality monitoring sites on the mainstem of the lower Columbia River between Bonneville Dam and the river's mouth. Four were monitored by DEQ and one by the U.S. Geological Survey (USGS). Although these sites provided a great deal of water quality data, the condition of this 146 mile stretch of river could not be adequately characterized and there was not enough data to identify localized problems. To help fill some of the gaps and educate and involve students and the public in water quality issues and monitoring, the Lower Columbia River Estuary Partnership began organizing an annual Water Quality Monitoring Event. Each September the event engages hundreds of students and volunteers in monitoring water quality on the lower Columbia River and its tributaries.

In 2003, the Estuary Partnership was awarded funding through Bonneville Power Administration's Fish and Wildlife Program to expand monitoring on the lower river. They worked with USGS to collect and analyze water quality samples that will provide detailed data on over 130 emerging contaminants such as pharmaceuticals, estrogen compounds, and personal care products; over 180 pesticides; nearly 20 trace elements including chromium, copper, and lead; and more than 25 suspended organic contaminants. These important monitoring efforts will help all organizations working in the lower Columbia Basin focus their restoration and pollution prevention efforts where they are most needed to protect the environment and human health.

Browse by status river:

  1. Deschutes
  2. Grande Ronde
  3. John Day
  4. Malheur
  5. Owyhee
  6. Rogue
  7. Snake
  8. Umpqua
  9. Willamette

Pollutants in the Columbia

Columbia River Data

Local Resources - Columbia River

Columbia Riverkeeper (Hood River) | (541) 387-3030 |

Columbia River Inter-Tribal Fish Commission (Portland) | (503) 238-0667 |

Lower Columbia River Estuary Partnership (Portland) | (503) 226-1565 |

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