Editing Columbia River (section)

=== Opening the passage to Lewiston ===

As early as 1881, industrialists proposed altering the natural channel of the Columbia to improve navigation.<ref name="opbtimeline" /> Changes to the river over the years have included the construction of [[jetty|jetties]] at the river's mouth, [[dredging]], and the construction of [[canal]]s and [[lock (water transport)|navigation locks]]. Today, ocean freighters can travel upriver as far as Portland and Vancouver, and barges can reach as far inland as [[Lewiston, Idaho]].<ref name="ccrh-hist" />

The shifting Columbia Bar makes passage between the river and the Pacific Ocean difficult and dangerous, and numerous rapids along the river hinder navigation. ''Pacific Graveyard,'' a 1964 book by [[James A. Gibbs]], describes the many shipwrecks near the mouth of the Columbia.{{sfn|Gibbs|1964}} Jetties, first constructed in 1886,<ref name="opbtimeline" /> extend the river's channel into the ocean. Strong currents and the shifting sandbar remain a threat to ships entering the river and necessitate continuous maintenance of the jetties.

In 1891, the Columbia was dredged to enhance shipping. The channel between the ocean and Portland and Vancouver was deepened from {{convert|17|to|25|ft|m}}. ''[[The Columbian]]'' called for the channel to be deepened to {{convert|40|ft|m}} as early as 1905, but that depth was not attained until 1976.<ref>{{cite news |title = Rewind—Editorials from Our Archives: 1905: 40-Ft. Depth Wanted |work = The Columbian |date = December 26, 2005 |url = http://nl.newsbank.com/nl-search/we/Archives?p_product=VC&p_theme=vc&p_action=search&p_maxdocs=200&s_dispstring=Rewind--Editorials%20from%20our%20archives:%201905:%2040-ft.%20depth%20wanted&p_field_date-0=YMD_date&p_params_date-0=date:B,E&p_text_date-0=2005&p_field_advanced-0=&p_text_advanced-0=(Rewind--Editorials%20from%20our%20archives:%201905:%2040-ft.%20depth%20wanted)&p_perpage=10&p_sort=_rank_:DÊl_ranksort=4Êl_useweights=yes |access-date = September 11, 2008 |url-access = subscription |archive-url = https://web.archive.org/web/20191228191901/http://nl.newsbank.com/nl-search/we/Archives?p_product=VC&p_theme=vc&p_action=search&p_maxdocs=200&s_dispstring=Rewind--Editorials%20from%20our%20archives:%201905:%2040-ft.%20depth%20wanted&p_field_date-0=YMD_date&p_params_date-0=date:B,E&p_text_date-0=2005&p_field_advanced-0=&p_text_advanced-0=(Rewind--Editorials%20from%20our%20archives:%201905:%2040-ft.%20depth%20wanted)&p_perpage=10&p_sort=_rank_:D%C3%8Al_ranksort=4%C3%8Al_useweights=yes |archive-date = December 28, 2019 |url-status = live }}</ref>

[[Cascade Locks and Canal]] were first constructed in 1896 around the Cascades Rapids,<ref>''The Oregonian'', January 1, 1895, p. 8</ref> enabling boats to travel safely through the Columbia River Gorge.{{sfn|Scott|Scott|1924|p=190}} The [[Celilo Canal]], bypassing Celilo Falls, opened to river traffic in 1915.<ref>{{cite web |title = The Dalles-Celilo Canal on Columbia River opens to traffic on May 5, 1915 |url = http://www.historylink.org/essays/output.cfm?file_id=5195 |publisher = HistoryLink.org |access-date = November 26, 2007 |archive-url = https://web.archive.org/web/20071116003845/http://www.historylink.org/essays/output.cfm?file_id=5195 |archive-date = November 16, 2007 |url-status = dead }}</ref> In the mid-20th&nbsp;century, the construction of dams along the length of the river submerged the rapids beneath a series of reservoirs. An extensive system of locks allowed ships and barges to pass easily between reservoirs. A [[Snake River#Dams|navigation channel reaching Lewiston, Idaho]], along the Columbia and Snake rivers, was completed in 1975.<ref name="opbtimeline" /> Among the main commodities are wheat and other grains, mainly for export. As of 2016, the Columbia ranked third, behind the [[Mississippi River|Mississippi]] and [[Paraná River|Paraná]] rivers, among the world's largest export corridors for grain.<ref>{{cite web |author = U.S. Wheat Associates |title = Overview of Wheat Movement on the Columbia River |url = http://www.pnwa.net/wp-content/uploads/PNWA_Handout.pdf |publisher = Pacific Northwest Waterways Association |year = 2016 |access-date = August 30, 2017 |archive-url = https://web.archive.org/web/20170831045923/http://www.pnwa.net/wp-content/uploads/PNWA_Handout.pdf |archive-date = August 31, 2017 |url-status = live }}</ref>

The 1980 eruption of Mount St. Helens caused mudslides in the area, which reduced the Columbia's depth by {{convert|25|ft|m}} for a {{convert|4|mi|km|adj=on}} stretch, disrupting Portland's economy.{{sfn|Harris|1988|p=209}}