The depth of the Columbia River ranges from 20 feet to 170 feet at various points along its route, and its total length is 1,243 miles. Locks, dams and reservoirs built on the Columbia River alter its depth.
The navigation channel for the Columbia River is 55 feet deep for 5 miles starting at the Columbia River bar, according to the Port of Portland. It continues at a 43-foot depth for 100 miles to the Portland Harbor. The headwaters of the Columbia River are in British Columbia, then it flows south into Washington State and finally passes through Oregon on its way to the Pacific Ocean.