Posted on June 19, 2024
With the official start of summer Thursday, anglers, kayakers, boaters and other water enthusiasts will soon flock to the Columbia River for a little recreation and relaxation. But navigating the busy waterway, with its shifting sandbars, hidden obstacles and commercial shipping traffic can be tricky.
Take for example the Wind River confluence with the Columbia in Skamania County. Boater David Eids said it’s difficult — if not impossible — to use the launch near the mouth of the Wind River because of silt and sand buildup. When water levels drop, he said boaters have a difficult time launching or coming ashore, and many choose to go elsewhere to fish.
“It also poses a problem delaying salmon passage to the upriver Carson National fish hatchery,” Eids said.
While the U.S. Army Corps of Engineers maintains the Columbia River’s main channel, responsibility for smaller tributaries falls to the state, tribes, counties, cities or port districts. They don’t always have the necessary resources, whether it’s due to a lack of funds or equipment.
Skamania County Public Works Director David Waymire said the county wanted to clean out the mouth of Wind River when it was replacing the boat dock, but it couldn’t get the necessary permits in time for the limited window when endangered fish are less likely to be present and in-water work is allowed.
Waymire said tribal authorities are also looking into dredging the area in order to maintain access to tribal fishing areas upstream.
Corps responsibility
Keeping the Columbia’ shipping lane open primarily falls to the U.S. Army Corps of Engineers, which dredges between 6 million and 8 million cubic yards of sand from the 600-foot-wide shipping channel each year. One of the largest rivers, by volume, in North America, an estimated $15 billion in goods travel down the Columbia River to the ports of Longview, Kalama, Woodland, Vancouver and Portland each year. A collaborative project among the Corps and the ports completed a deepening of the channel to 43 feet in 2010.
Karla Ellis, the Portland district’s chief of waterways maintenance, said the Corps is responsible for dredging federally authorized channels only. In the lower Columbia, that means the Columbia and parts of the Willamette and Cowlitz rivers.
“Funding, dredging need and environmental compliance determine where and how often we dredge,” Ellis said. “Typically speaking, there are about four dredges used to accomplish Corps dredging in the Columbia River each year: the Essayons, the Yaquina, a contracted hopper dredge and the pipeline Dredge Oregon.”
The Corps has an additional clamshell contractor working in the river each year, as well. Clamshell dredging extracts sand and gravel from below the water level.
All that dredged sand and silt has to go somewhere. For a long time, dredged materials were dumped at places like Rice Island, East Sand Island and others. Less than a decade ago, there were concerns the federal agency would run out of disposal sites.
Now, the materials are being put to good use to fight erosion and restore critical wildlife habitat. A study conducted by the Corps that was published in 2023 looked at where dredged sand goes after it’s placed, how quickly it disperses and how much moves to the coast. Results of that study are now being used to develop disposal management plans and strategies.
Beneficial use
The Corps puts the dredged materials in a variety of spots — in the water, on shorelines and upland.
“The material is a valuable resource in terms of habitat and the larger river system,” Ellis said. “We are currently in the process of developing a 20-year maintenance plan for the Lower Columbia River to help us manage that material as efficiently as possible into the future.”
As concerns about climate change have moved to the forefront in recent years, Ellis said the Corps is working closely with other agencies to adapt and respond to environmental requirements.
“Our focus is to utilize material in the best possible way,” Ellis said.
The Corps has an acronym for that: BUDM, or Beneficial Use of Dredged Material.
According to the Corps, more than 200 million cubic yards of material is dredged annually from the bottom of federal navigation channels. Approximately 85 percent of that material is available for beneficial use, although currently only 30-35 percent is used for environmental, economic or social benefits.
