MCR jetties: supporting safe passage for more than 100 years

By Michelle Helms, Public Affairs Office; Rod Moritz, Coastal Engineer; Heidi Moritz, Coastal Engineer

Flatbed rail cars hauled huge stones along a tramway that extended from the beach to the end of the jetty. Reports made during construction of the south jetty say that at times the power of the ocean would cause portions of the tramway to sway so violently that trains could not run on it. (Corps of Engineers photo)

Flatbed rail cars hauled huge stones along a tramway that extended from the beach to the end of the jetty. Reports made during construction of the south jetty say that at times the power of the ocean would cause portions of the tramway to sway so violently that trains could not run on it. (Corps of Engineers photo)

 

It is one of the most treacherous bar crossings in the world. Since 1792 more than 2,000 ships have sunk in and around the Mouth of the Columbia River, also known as the Graveyard of the Pacific. For the past 130 years, mariners seeking to safely transit the Columbia bar have relied on three simple-looking structures, fingers of rock reaching out from the Oregon and Washington shores into the Pacific Ocean. The U.S. Army Corps of Engineers’ MCR jetty system is that vital link between the mighty Columbia River and the Pacific Ocean, supporting commerce, recreation and homeland security.

“Mere description can give but little idea of the terrors of the bar of the Columbia; those who have seen it have spoken of the wilderness of the ocean, and the incessant roar of the waters, representing it as one of the most fearful sights that can possibly meet the eye of the sailor” -- Commander Charles Wilkes, U.S. Navy ~1860 (Corps of Engineers photo)

“Mere description can give but little idea of the terrors of the bar of the Columbia; those who have seen it have spoken of the wilderness of the ocean, and the incessant roar of the waters, representing it as one of the most fearful sights that can possibly meet the eye of the sailor” — Commander Charles Wilkes, U.S. Navy ~1860 (Corps of Engineers photo)

Prior to 1885, the tidal channels through the MCR shifted between to Cape Disappointment, Washington, to the north and Fort Stevens, Oregon, to the south, a distance of about 5.5 miles. Ships often had trouble crossing the Columbia River bar, the area in which the flow of the estuary rushes headlong into towering ocean waves. Outbound ships often had to wait a several weeks until bar conditions were favorable for crossing. To make navigating through the MCR even worse, sailing ships had to approach either of the two natural channels at a right angles to the wind and waves. The natural channels often shifted widely over several tidal cycles. At best, crossing the bar was dangerous. At worst, it was impossible.

With the opening of the American West during the latter half of the 19th century, a consistent and reliable link from inland areas of the Pacific Northwest to other parts of the country and world was needed – meaning a consistent and reliable navigation channel through the MCR.

Enter the Corps of Engineers and the River and Harbor Act of Aug. 2, 1882, which authorized a study of the MCR and a plan for stabilizing the navigation channel.

Taming the channel began by constructing the south jetty on the Oregon side of the river. It took a decade, from 1885 to 1895, to complete the 6.6-mile long structure. On the Washington side of the Columbia, the 2.5-mile long north jetty was built from 1913 to 1917, while jetty A, measuring just 0.3 mile long, was completed in 1939.

Flatbed rail cars hauled huge stones along a tramway that extended from the beach to the end of the jetty. Reports made during construction of the south jetty say that at times the power of the ocean would cause portions of the tramway to sway so violently that trains could not run on it. (Corps of Engineers photo)It took 12.9 million tons of stone and a current value $1.7 billion investment to build the three rubble mound structures that reformed a broad and treacherous 5.5-mile wide system of variable sand bars into a stable two mile-wide inlet with a reliable navigation channel.

Fast forward 130 years …. The jetties still reach into the Pacific Ocean, redirecting currents through the entrance of the MCR and calming the water for ships, fishing boats and other vessels as they transit the Columbia bar.  It can still be dangerous, especially during the winter months when the rugged northern Pacific coast environment exposes jetties to intense weather systems that buffet the MCR and the coast. It’s not unusual during winter storms to see waves 30 feet high attacking the seaward end of the jetties.  In spite of the brutal beatings they take during storms, the MCR jetties have stood the test of time. The Corps undertook interim repairs to the north and south jetties between 2004 to 2007, and in 2013 the Corps began the first of several construction phases to rehabilitate the entire system by 2021.

More than 100 years ago, the United States government recognized the critical role the Columbia River played to the country’s economic success. Today the river remains critical to the nation’s economy and security. Authorizing the Corps to study, plan and build a system to stabilize the river’s entrance in 1885 was an investment in the country’s future; rehabilitating these structures today, protects that initial investment as the nation continues to move forward.

The Graveyard of the Pacific is still a dangerous place, the MCR jetties mean $20 billion a year in cargo passes through in relative safety. The 6-mile long, deep-draft navigation channel at the MCR is the ocean gateway for access to and from the 500-mile long Columbia/Snake River inland navigation system. Thanks to the jetties, it remains a critical gateway linking the Northwest, Mountain, Midwest, and East Coast states to growing markets in the Asia and the Pacific Rim. If the Corps of Engineers has any say in the matter, the jetties will remain on the job for another 130 years.

121024-A-KK463-048-webUnderstanding coast jetties

The Portland District maintains 11 jetty systems on the Oregon coast, from the mouth of the Columbia River near Astoria to the Chetco River at Brookings, Oregon.

Jetties ensure a consistent and safe navigation channel from ocean to inland waters.  The structures’ design hasn’t changed in the 130 years since the Corps began building jetties on the Oregon coast. Their foundations consist of rocks placed on the ocean floor, topped with larger boulders that form the main body of the jetty. Layers of boulders form the outer “armor” of the structure, with larger boulders used toward the end of the jetty to “cap” the structure, where it is most vulnerable to powerful waves. Although the boulders weigh anywhere from 30 to 50 tons, the powerful Pacific Ocean currents cause the stones to shift, allowing smaller rocks and sand to be washed away, leaving caverns beneath the surface of the structure.

Links:

Understanding coastal jetties – http://www.nwp.usace.army.mil/Portals/24/docs/pubs/coastal_jetties.pdf

Columbia Snake River System facts – http://www.pnwa.net/new/Articles/CSRSFactSheet.pdf