The U.S. Army Corps of Engineers is set to start seismic and survey work in Seward next week, which is part of the preparatory effort for a new diversion tunnel in Lowell Creek.

The water system produces between one and three severe floods per year, according to Alaska.org, and until the original diversion tunnel was built in 1939, debris would flow down to Jefferson Street and into the delta. The current diversion tunnel that runs through Bear Mountain is 10 feet in diameter and more than 2,000 feet long.

Contractors with the Corps will work in Lowell Canyon, west of the current tunnel and diversion dam, July 12 through July 15, the City of Seward said in a press release.

Starting next Saturday, the Corps will work in the outflow area by the bridge and waterfall around four hours prior to low tide to up to four hours after low tide. The work will impose lower speed limits and up to 15-minute traffic delays, and the sides of road and beach area around the bridge will be closed during work times for vehicles, pedestrians and bikes.

The seismic work will also include underground blasting in the outflow area. The blasting will be “mostly inaudible” and shouldn’t be felt more than 10 feet away, the release said.

The seismic and survey work is set to last through July 20.

Reach reporter Camille Botello at camille.botello@peninsulaclarion.com.