It was fascinating to learn the Willamette River actually experiences Pacific Ocean tidal effects below Willamette Falls. The tides are monitored from the Columbia River all the way to the falls in Oregon City.
The river upstream of Oregon City is blocked from tides by the 40’ waterfall so Willamette Tides river float in Corvallis does not actually experience these effects.
It’s interesting, however, rivers can have tides. 15 percent of the Columbia River’s volume is attributed to the Willamette river tributary which has such a low gradient tide levels can change more than 10 feet beneath the falls.
River tides have a large impact on wildlife and river sizes as well. Many animals, such as salmon, rely on tides. During high tide salmon ride the current upstream and during low tide will ride it back out. If you have your salmon tag and want to cast your line in the Willamette down river of the falls check out tide-forecast.com for tides the salmon are biting.
The salinity of water also plays an impact on freshwater wildlife. As people dredge more river bottom and ocean levels rise the river tides increase allowing more ocean water upstream during high tide. This increase of ocean water in the river reduces habitat for freshwater wildlife.
In order to protect the Willamette River and its natural habitat many organizations are now planning to restore several riparian and wetland sites on the lower Willamette River. Check out Projects for a Healthy Willamette River for more details on these projects.
Willamette Tides is working towards learning more about the positive influence we can contribute to the river. Knowing the impact we have on our river can help us make the decisions that matter for the outdoors, so we may continue to seek adventure.
“Portland Willamette River Oregon Water... - Tideschart.com.” Tideschart, Tideschart, https://www.tideschart.com/United-States/Oregon/Multnomah-County/Portland-Willamette-River-Oreg/Water-Temperature/.
“Proposed work builds on past success - Portland, Oregon.” (2019, January). Retrieved December 9, 2021, from https://www.portlandoregon.gov/bes/article/539517.
Robbins, William. “Willamette River.” The Oregon Encyclopedia, 20 Jan. 2021, https://www.oregonencyclopedia.org/articles/willamette_river/#.YaZaJ9DMKUk.
“Tide Times for Saint Johns, Willamette River.” Tide Times and Tide Charts, https://www.tide-forecast.com/locations/Saint-Johns-Willamette-River-Oregon/tides/latest.
Van Maren, D.S., et al. “The Impact of Channel Deepening and Dredging on Estuarine Sediment Concentration.” Continental Shelf Research, vol. 95, Mar. 2015, pp. 1–14., https://doi.org/10.1016/j.csr.2014.12.010.