This audio file is a tour of a Seattle Lock Chamber: The U.S. Army Corps of Engineers manages and operates 192 navigational lock sites home to 237 lock chambers across the nation. The Northwestern Division has 10 of those lock chambers. Each year more than 40,000 vessels pass through the Hiram M. Chittenden Locks in the Seattle District. Come and experience a tour with our audio podcast. U.S. Army Corps of Engineers. This is an audio-only file.