The Arch Cape Tunnel: Gateway to Oswald West State Park
“The longest highway tunnel built on the Oregon highway system up to this time is being completed on the Coast highway in Clatsop County, approximately 32 miles south of Astoria. This bore, which was started in February, 1936, is being driven through Arch Cape, a basaltic promontory which rises several hundred feet almost vertically above the Pacific Ocean at its base.” — Western Construction News, July 1937, p. 253.
Among the incredible natural beauty of Arch Cape is a man-made wonder that serves as the northern entrance to Oswald West State Park: The Arch Cape Tunnel.
As detailed by authors David and Alma English in their remarkable book Arch Cape Chronicles, a piece of 1919 legislation approved the construction of a 345-mile coastal highway running from Astoria at the northern tip of Oregon south to the California border. Originally part of the Roosevelt Coast Military Highway, the name was later changed to the Oregon Coast Highway.
In February 1936, the Oregon Highway Department approved a plan to build a 1230-foot long, 36-foot wide, 23-foot high tunnel through the Arch Cape headland at the far south end of Arch Cape. The original timetable called for the tunnel to be completed by the end of 1936, but multiple problems and delays pushed back the completion date to March 1940.
According to authors David and Alma English:
“The tunnel was an extremely difficult project. Some of the tunnel material was sandstone and some was a much harder basalt rock. Sandstone is less stable than basalt and when exposed to air, sandstone immediately becomes soft and crumbles like dirt. Therefore, sandstone was more difficult to drill and blast than ordinary rock as it necessitated the building of a timber lining to prevent a cave-in.” (p. 26)
Charles Haddix, who worked on the project in 1936, described the work in Arch Cape Chronicles:
“The crews worked around the clock. The blasting crew left shortly before we came to work and left a huge pile of rubble inside the tunnel for us to haul away. A gasoline-powered shovel was used to load the trucks. A large pipe on the west side of the tunnel drew out some of the fumes from the blasting operation and from the gas-powered shovel and trucks. Before our shift began, we gathered a 50-gallon drum filled with oil, which provided heat and some light. As soon as the tunnel was clear enough for work, the shovel and trucks began removing the broken rubble to the bridge approaches on both sides of Arch Cape Creek, which had to be crossed before driving up a steep, winding road to the dump site. Severe headaches from carbon monoxide gasses inside the tunnel caused some men to quit. I managed to last three months.”
Intense rain, muddy conditions, unsuitable equipment and poor project management were among the causes for the delays, according to reports by E.H. Clymer of the Oregon State Highway Department.
During the project, tunnel workers bunked at the Arch Cape Hotel next to Arch Cape Creek or in primitive cabins off Leech Lane.
According to F.D. Eason, a division engineer from the Oregon State Highway Department, in the July 1937 issue of Western Construction News, the cost of the project topped $200,000.