Overnight drilling starts late August on Ketchikan's 1950s viaducts, whose replacement is unfunded

Drilling crews will work overnight in late August on Tongass Avenue and Water Street, gathering ground data for two viaducts that carry more than 14,000 vehicles a day. Most of the drilling supports repairs the state has already funded. Replacing the viaducts themselves still has no money behind it.

The Alaska Department of Transportation and Public Facilities published notice of the geotechnical investigation on Aug. 17. It says the department proposes to rehabilitate the Water Street and Tongass Avenue viaducts and the South Tongass Highway Tunnel, though no drilling is described for the tunnel. The department issued a similar notice for the two viaducts in October 2024.

Landslide Technology will drill 13 holes over an estimated four to five days: two borings at an abandoned bridge near the Jim Creek culvert, to be replaced with dirt fill, three cores "to investigate the presence and extent of voids along with asphalt thickness," and eight more on Tongass Avenue to support pavement renovation designs. The abandoned bridge is not part of either viaduct, and its removal is one of the funded projects.

"Due to the busy corridor of Tongass Avenue and Water Street, night work is anticipated for this investigation effort with tentative work hours of 10:00 PM to 6:00 AM," the department said in the notice. The project team obtained a noise ordinance permit from the City of Ketchikan. All lanes and sidewalks stay open during the day.

The two viaducts date to 1955 (Water Street) and 1956 (Tongass Avenue). The 2025 National Bridge Inventory rates the Water Street viaduct in poor condition, with a substructure score of 4 out of 9 and a structural evaluation of 4. Tongass Avenue is rated fair, substructure 5. The inventory records 14,046 vehicles a day on Water Street and 14,564 on Tongass Avenue, counted in 2018 and unchanged in the record since. Both ratings trace to a June 2023 inspection, before the emergency repair the viaduct received around 2024.

The corridor plan runs 15 years and five projects. Three are funded and could begin as early as 2027: spot pavement repairs, spot repairs to the bridges, and the Jim Creek culvert replacement north of Schoenbar Road. The department calls the bridge work repairs "to prevent unexpected closures and other safety measures from impacting the traveling public until the bridges can be replaced." The two replacements themselves are unfunded, with new construction placed at 2030 onward.

A borough manager's report from December 2025 relayed the department's view that the replacements are the region's top priority for incoming funding. By that report's account, a 10-year timeline applies only if load restrictions or closures hit the bridges first.

The department says the right-of-way is very narrow and its team may need to buy temporary or permanent property rights along the corridor, purchases governed by the federal Uniform Act. Property owners can reach Kaden Phillips at the Southcoast right-of-way office at 907-465-4428, and questions about the drilling go to the project team at [email protected]. This account comes from state documents and the federal bridge inventory. Nobody was asked.