Every year, the Columbia and Snake Rivers carry 17 million tons of cargo to and from the Pacific Ocean along a 465-mile waterway. This is another example of technology and coordinated planning leading to the Columbia Basin being put to multiple use. Specifically, a series of eight locks facilitates the passage of ships from the ocean to as far inland as Lewiston, Idaho. These locks are part of the same projects and reservoirs that produce hydropower and help control flooding.

From the ocean to Portland, Oregon and Vancouver, Washington dredging assures that a 40-foot-deep open river channel remains open year-long for ocean-going vessels. This 106-mile segment then connects with a 359-mile segment that extends to Lewiston, Idaho. Within this second segment, a 14-foot-deep channel for barges and other craft is kept open. To maintain this channel depth, maximum and minimum reservoir elevations are set. These elevations are determined within the context of meeting needs for electrical generation, flood control, and the release of water to help fish passage.