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Mouth of the Columbia River Jetty System Major Rehabilitation Project

The Mouth of the Columbia River's jetty system was built from 1885 - 1939. The system consists of three rubble-mound jetties with a total length of 9.7 miles, constructed on massive tidal shoals and designed to minimize navigation channel maintenance and provide safe transit between the Pacific Ocean and the Columbia River.


The north and south jetties have been repaired several times since original construction; the latest repairs occurred in 2005 on the North Jetty and 2006-2007 on the South Jetty. Jetty "A" has only been repaired once since initial construction, in 1965. The recent repairs on the jetties were interim repairs, designed to maintain jetty functionality until a longer-term maintenance and repair plan was designed.


Many areas of each structure are severely damaged due to the extreme waves of the Pacific Ocean interacting with the Columbia River. The structures are routinely exposed to ocean waves ranging from 10 to 20 feet high. The increased storm activity and the loss of sand shoal material upon which they are built have taken a toll on the structural integrity of the jetties.


Of primary concern are critical portions of the jetties, which could breach during a large storm event, allowing sand to be transported and deposited directly into the federal navigation channel. Such an event could shut down commercial navigation at the entrance to the river system, requiring expensive emergency repairs to the jetty and dredging to restore channel depth.

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About this project

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In October 2013 the Corps completed efforts to stabilize the foredune adjacent to the South Jetty’s root, preventing further erosion and minimizing the risk of a breach. The next phase of the Mouth of the Columbia River jetty system rehabilitation shifts the Corps’ attention to the North Jetty.

The Corps will mobilize equipment and personnel to replace a culvert under Jetty Road in Cape Disappointment State Park, and place material in the lagoon at the jetty’s root. The project will stop erosion, and stabilize and protect the root of the structure. This is part of the larger major rehabilitation of the MCR jetty system.

Preparations for critical repairs to the jetty structure begin in June 2015 and continue through 2016. Jetty stone will arrive on large, flat bed trucks starting in spring 2016. About 40,000 tons of armor stone is needed for repairs; armor stones used for North Jetty repairs will weigh up to 30 tons each.

Construction timeline (subject to change)

North jetty lagoon fill  October 2014 - June 2015
North jetty critical repairs June 2015 - October 2016
Jetty A rehabilitation 2015 - 2016
North jetty rehabilitiation 2016 - 2019
South jetty rehabilitation 2017 - 2021

 

Cape Disappointment visitors should expect construction-related traffic, road closures and some traffic delays. Jetty Road will be closed during the culvert replacement, and the west side of the east parking will be closed to accommodate construction staging. Access to Benson Beach from Jetty Road may be temporarily restricted during this time. See map showing the construction area and road closures.

After the culvert work is complete, Jetty Road between the east parking lot and the northern gravel parking lot will be closed Monday through Friday with plans to open on weekends and holidays. Some additional closures may be necessary at times as the lagoon fill project continues into spring 2015. Park visitors can access Benson Beach during the road closure on foot from the east parking lot or the northern gravel parking lot. 

Access to the North Jetty will be restricted beginning in the fall 2014. A fence will identify the active construction site on the North Jetty indicating the area is off limits to the general public.