Columbia commerce protected by weakened wall

It's a mild October morning on the Oregon Coast.

Yet, even on a windless day with the ocean glassy smooth, it's a rough ride at the point where the Columbia River smashes into the Pacific Ocean. A 60-ton boat, designed to ferry elite pilots to ships waiting offshore, heaves atop 6-foot swells like a rubber duck in a bathtub.

Capt. John Torjusen doesn't flinch at the stomach-gurgling ride.

Torjusen, a Vancouver resident in his eighth year of piloting ships across one of the roughest harbor entries on the planet, has seen much worse. Imagine driving a ship the length of two football fields through a channel less than half a mile wide in a howling gale, with swells the size of three-story buildings. Sliding on the down side of a wave, a ship's rudder and propeller can come out of the water.

"It's like putting your car on ice," he said.

A pair of jetties, jutting into the boiling Pacific from the north and south edges of the river's 2-mile-wide mouth, stand as thin lines of defense against the bar's worst instincts. The jetties tamp down waves from the ocean. They also serve as a barricade against beach sand that would otherwise quickly clog the relatively narrow shipping channel and close the gateway to ports more than 100 miles upriver in Vancouver and Portland.

Battered by storms, the jetties originally constructed from huge boulders mined in Camas are now eroding away.

The government bought some time with a series of repairs beginning four years ago, but that was only temporary. "It's already deteriorating pretty badly," Torjusen said. Meanwhile, the risk of a jetty breach increases with each winter storm.

Maintaining the jetties is imperative.

Together, they serve as the Columbia's front gate, welcoming 2,000 ships per year - nearly 500 bound for Vancouver - and billions of dollars worth of trade. When the bar shuts down, it freezes a conveyer belt of commerce from the ships that enter the river to barges and trains carrying grain from as far as Kansas.

"It's a little frightening to know that if one of those jetties failed, it would all stop very quickly," said Larry Paulson, the Port of Vancouver's executive director.

Next month, the Army Corps of Engineers will unveil a rehabilitation plan involving the placement of a million tons of Volkswagen-sized rocks, as well as several perpendicular rock "groins" designed to shore up the jetties' sand foundations. Repairs will cost hundreds of millions of dollars.

Yet, even after these repairs, a potent combination of natural and man-made factors will pose long-term threats.

The river's peculiarities have vexed ship captains ever since American Capt. Robert Gray found the rumored Great River of the West in May 1792. Over the next century, some 2,000 ships would run aground, costing more than 1,000 lives. With ever-shifting sandbars and violent storms, the treacherous Columbia entrance became known as the Graveyard of the Pacific.

In 1885, upriver business interests convinced Congress to pay for a jetty on the south side of the harbor entrance - opposite the rocky headland of Cape Disappointment.

By 1917, the Army Corps of Engineers had delivered two jetties: one 6 1/2 miles long on the south side of the river's mouth and the other extending 2 1/2 miles out from the Cape Disappointment on the north side.

These jetties eased the passage for ships, but they also changed the river's geometry.

Squeezing the Columbia's current, the jetties created a firehose. The river blasted 500 million to 800 million cubic yards of sand from the estuary into the ocean, where waves piled it along the jetties' back edges. The sediment discharge was at least 10 times faster than "natural" deposition, according to the Corps of Engineers.

Over the short term, this was a positive thing. The firehose effect shored up each jetty's foundation, cleared dangerous sandbars from the shipping channel, and created popular public beaches.

This situation wouldn't last.

The ocean is taking back its sand, redistributing it to beaches and inlets many miles north and south. At the same time, the estuary is no longer being replenished with upriver silt.

The firehose effect continues, but the water has much less sand. By corralling the Columbia's annual springtime torrent, a series of dams capture two-thirds of the sediment that would have flowed to the estuary, according to a new study of coastal erosion co-authored by George Kaminsky, Washington Department of Ecology coastal engineer.

This creates a new and long-term challenge to maintaining the jetties.

"There is insufficient supply from the river/estuary to maintain those shoals and adjacent beaches," Kaminsky said. "The beaches have eroded so much that the jetties are exposed to increasingly energetic wave conditions."

In addition, scientists suggest a warming globe translates to increased frequency and severity of winter storms.

The corps, which builds its projects with an expectation that they'll endure for 50 years, insists that its engineers have taken all this into account. For one thing, project manager Laura Hicks said, some of the new stones will be twice as large as the original jetty stones. "These designs are robust," added Hans Moritz, a hydraulic engineer for the corps.

Compared with other coasts, the North Pacific delivers a wallop.

Scientists say our steep continental shelf doesn't dissipate energy as waves approach our coastline. Where most of the Atlantic seaboard sees a difference of roughly 4 feet between high and low tides, the tidal variation is twice as much in the Pacific Northwest.

Meanwhile, the Columbia can discharge as much as a million cubic feet of water per second.

"There's a collision of titans," Moritz said. "Twice a day, at the mouth of the Columbia River, the ocean tide is trying to come in and the Columbia River is trying to get out."

Over time, the constant battering widens and deepens the rocky foundations of the jetties. The last mile of the south jetty, for instance, has already sunk far below the ocean surface.

Even so, corps officials say they are confident the jetties can be repaired.

"As long as navigation is an important aspect of our nation's economy," Moritz said, "the jetties will still be there."

Bar pilots - and Northwest commerce - are counting on it.

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Information from: The Columbian, http://www.columbian.com