Lowell Creek Diversion Tunnel, Tunnel in the United States

The Lowell Creek Diversion Tunnel is a flood control system completed in 1940 in Seward, Alaska. It consists of a dam about 400 feet long and 25 feet high, a tunnel over 2,000 feet long running through Bear Mountain, and a concrete flume that directs water into Resurrection Bay.

The tunnel was built by the U.S. Army Corps of Engineers in 1939-1940 and was Alaska's first major flood control project. It followed earlier attempts by the Alaska Railroad in the late 1920s that had failed and deteriorated over time.

The tunnel is located near Lowell Canyon Road and Lowell Point Road in Seward and is accessible for visitors to view the entrance and engineering system. Be prepared for mountain terrain and variable weather conditions in the area.

The 2,068-foot tunnel through Bear Mountain was completed in 1940 and withstood the 1964 Alaska earthquake; floods in 1966, 1986 and 1995 pushed water within inches of the dam crest. Debris still collects at the flume outlet, and a wider replacement tunnel through Bear Mountain, estimated at $30 million, has been considered.