Eric Ferguson is one of three full-time captains with Wahkiakum County who ferry about 80,000 people a year between Puget Island, Washington, and Westport on the Oscar B, the only remaining interstate ferry on the Columbia River.

Running perpendicular to the flow of the Columbia, the 1,900-foot-long channel requires dredging every few years to allow the Oscar B passage. Recently awarded the contract by the Army Corps of Engineers, regional dredger J.E. McAmis is scheduled to start the maintenance anew after Thanksgiving.

At the top of each hour, captains pull out of the landing at the tip of Puget Island, only a few feet separating the bottom of the Oscar B from the northern banks of the Columbia. A side-scan sonar shows the deepening river as the ferry crosses the shipping channel and the shallowing as it approaches the entrance to the Westport Slough.

“This summer, we really noticed it,” Ferguson said. “We got the low tides, and that’s when we noticed we’re getting down to a few feet of water under us.”

Jeffrey Henon, a spokesman for the Army Corps, said the sediment buildup can come from the riverbed upstream and surrounding shorelines. “Higher water flows on the Columbia River, such as those we experienced in spring 2017, cause more sediment to settle in the channel,” he said.

The ferry route, the only Columbia crossing between the Lewis and Clark Bridge 26 miles upstream and the Astoria Bridge 43 miles downstream, has been operating since 1925, when Walter Coates brought the wooden boat Cathlamet to Puget Island. Coates brought a second ferry, the Westport, later in 1925 and started making runs from Puget Island to Westport, with foot passengers shuttled across the island between the two landings.

In 1938, Wahkiakum County voted to build a bridge from Cathlamet to Puget Island. In the 1960s, county residents voted to take over operation of the ferry from Puget Island to Westport when the existing operator decided to cease passage.

By 1969, the state of Washington accepted the ferry as an extension of State Route 409, connecting via the ferry to Westport Ferry Road and eventually Oregon’s U.S. Highway 30.