A History of the South Jetty at the Mouth of the Columbia River

The Mouth of the Columbia River (MCR) is known for its treacherous conditions. Factors contributing to this deadly reputation are strong winds, erratic weather, 40-ft ocean waves, precarious swells, shifting sand bars and shoals. The MCR is part of the Graveyard of the Pacific. More than 2,000 vessels have been lost within the MCR since 1792.

Traveling through the MCR before the late 1800s required special knowledge and there was no guarantee of safety. In the 1700s and 1800s, European and American sailors initially navigated the MCR with help from local Chinookan guides. Later in the 1800s the Columbia River Bar Pilots helped ships navigate the MCR. Conditions at the MCR often prevented ships from navigating to port cities upriver. Ships routinely remained offshore or in port until high tide. In 1882, Congress tasked the U.S. Army Corps of Engineers (Corps) to come up with a plan to tame the MCR. Congress passed the Rivers and Harbors Appropriation Act of 1884. The act authorized funds to construct a 4.5-mile-long jetty on the Oregon bank of the MCR extending into the Pacific Ocean. Initial construction of the South Jetty was completed in 1895.  

 

Historic Maps of the MCR: 1874-1913

The MCR changed dramatically from the late 1800s to the early 1900s due to the construction of a system of jetties. Flip through the historic map images to see how shoaling at the MCR changed as the South Jetty, and later jetties, were built. 

Columbia River entrance map showing conditions a decade before construction of the South Jetty began.
Columbia River entrance map showing conditions four years before construction of the South Jetty began.
Columbia River entrance map showing conditions as construction of the South Jetty began.
Columbia River entrance map showing conditions as construction of the South Jetty is underway.
Columbia River entrance map showing conditions as South Jetty construction entered its fifth year.
The initial phase of South Jetty construction is nearly complete. The South Jetty was 4.5 miles long, 30 ft high, and made of 9 million tons of boulders. The jetty helped increase the depth of the navigation channel to 30 ft at low tide, fulfilling one of the Corps’ primary engineering goals.
Columbia River entrance map showing conditions when work began to repair and extend the South Jetty. The South Jetty was extended by 2.33-miles.
The South Jetty has been extended to a total length of nearly 7 miles. Around 5.8 million tons of stone were added during repairs in the early 1900s. The North Jetty was next constructed on the Washington side of the MCR between 1913 and 1917. The North and South Jetties stabilized the MCR. The two jetties helped to maintain a 40-ft-deep navigation channel through the MCR. The third jetty in this system, Jetty A, was completed in 1939.

Initial Construction:1885-1895

Trestles supported a railroad system to help with the initial construction of the South Jetty. The trestles extended between nearby Fort Stevens and the site of the future South Jetty. Timbers for the trestles were driven into the ocean floor with a steam piledriver. Massive boulders were mined from local quarries and transported to Fort Stevens on barges. Boulders were loaded onto specially designed dump cars. Steam locomotives hauled the cars along the railroad trestles; and boulders were dumped in place along the South Jetty. Hundreds of workers were employed in this herculean effort. The construction of the South Jetty was considered an engineering marvel when it was first built. It was even featured at the Chicago World’s Fair in 1893.

Early Construction

Construction of the South Jetty was a remarkable feat of engineering.

The South Jetty trestles supported a railroad system that carried boulders, equipment, and workers from Fort Stevens along the top of the jetty. Photo courtesy of the Clatsop County Historical Society, ca. 1907-1913.
The railroad trestles of the South Jetty, viewed from beneath. Photo courtesy of the Clatsop County Historical Society, ca. late 1880s.
A steam powered pile driver used to build the South Jetty trestle system. Photo courtesy of the Oregon Historical Society, ca. 1905-1913.
Boulders were brought to Fort Stevens on barges and loaded onto trains with cranes before being transported to the South Jetty. Photo courtesy of the Columbia River Maritime Museum, ca. 1905 to 1913.
One of the giant boulders used to build the South Jetty. Photo ca. 1905-1913. Boulders weighed between 6 and 28 tons. Photo courtesy of the Clatsop County Historical Society.
Self-righting geared dump cars were engineered for the early phases of the South Jetty construction.
One of the locomotives that carried boulders to be placed along the South Jetty. Photo courtesy of the Clatsop County Historical Society, ca. 1905-1913.
A full dump car off loading boulders along the South Jetty. Photo courtesy of the Clatsop County Historical Society, ca. 1905-1913.
Some of the workers who built the South Jetty enjoying a well-deserved rest and a game of baseball at the Fort Stevens barracks during the late 1880s. Photo courtesy of Columbia River Maritime Museum.
Inside the South Jetty workers’ barracks at Fort Stevens during the late 1880s. Photo courtesy of Columbia River Maritime Museum.
The Corps presented a miniature scale model representing several of the infrastructural innovations used to construct the South Jetty at the 1893 “World’s Columbian Exposition” (a.k.a. the Chicago World’s Fair) in Chicago. The South Jetty construction model was exhibited in the U.S. Government Building with other examples of river and harbor improvements. The model depicted the trestle system, a steam operated pile driver, and a model train with dump cars unloading miniature boulders. Photo published in The Book of the Fair, 1893.

Reconstruction: 1930s-1940s

Storms raging across the Pacific Ocean wreaked havoc on the MCR jetties. Repairs to the South Jetty started in 1931 with the construction of a new railroad trestle. The new trestle system replaced the original one which that had fallen into disrepair. Asphalt and beach sand were added to the jetty in 1936 in an effort to strengthen the structure. Unfortunately, the added materials failed to stop the continual breakdown of the jetty. A concrete terminus was added to the South Jetty’s ocean end in 1941. This period of repairs was the last time trestles were used on the South Jetty. By 1946, the MCR jetty system (South Jetty, North Jetty, and Jetty A) contained about 13 million tons of stone and 16,000 cubic yards of concrete. 

 

Storm Damage and Repairs

The rough waters of the Pacific Ocean have pummeled the MCR jetties for decades causing damage.

Giant waves and frequent storms made working conditions at the South Jetty extremely dangerous. Photo early 1900s. Photo courtesy of Columbia River Maritime Museum.
Storm damage to the South Jetty railroad trestles on January 24, 1939.
A locomotive and dump cars derailed by a storm. Photo courtesy of the Clatsop County Historical Society, ca. 1905-1913.
An asphalt and sand mixture was infused between the boulders of the South Jetty in 1936 in an unsuccessful effort to strengthen the structure.
A concrete terminus was installed on the west end of the South Jetty in 1941.

Interim Repairs and Rehabilitation: 1960s to Present

Repairs of storm damage continued on the South Jetty (and other jetties in the MCR jetty system) since the 1960s. The Corps began a major rehabilitation project on the MCR jetty system in the early 2000s. The goal of the rehabilitation was to ensure continued safe function of the navigation channel. The navigation channel is vital to the Pacific Northwest and supports $24 billion in shipping, commerce, and recreation annually. Interim repairs of the South Jetty placed 168,000 tons of new boulders in 2007. Rehabilitation of Jetty A and North Jetty were completed in 2017 and 2019, respectively. Rehabilitation of the South Jetty is the Corps’ most ambitious MCR jetty repair project to date. The project began in 2019 and is scheduled to be completed in 2025. Even with modern machinery, placing an additional 425,000 tons of boulders along the 7-mile-long South Jetty remains a daunting task. Thanks to advances in engineering, the new boulders are now carefully interlocked rather than simply dumped into place. The major rehabilitation of the South Jetty and other jetties is designed to extend the life of these structures for at least another 50 years. With these efforts, the South Jetty and the MCR jetty system continue to support a reliable and safe navigation system from the MCR up the Columbia-Snake Rivers for future generations.