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Bonneville Dam

From Portland Hikers Field Guide

Bonneville Dam from Wauna Viewpoint (Jim Sifferle)
Fish ladders at the Bonneville Dam. There is an underwater viewing area (Jeff Statt)
Spring chinook holding tank at the Bonneville Fish Hatchery (Jeff Statt)
The sturgeon tank is a popular spot (Jeff Statt)
The 1937 powerhouse from the Eagle's Nest on the Tooth Rock Loop Hike (Steve Hart)

Contents

Description

Bonneville Dam is one of the oldest dams on the Columbia, constructed between 1933 and 1937. The second powerhouse was added in 1982. The dam is somewhat unusual because it is made up of several dams on separate river channels with islands in between. From the north, the first channel is blocked by the new 1982 powerhouse. Next comes Cascades Island, then the second channel, dammed by the spillway, which regulates the water level in the reservoir. Bradford Island comes next, followed by the south channel, dammed by the original 1937 powerhouse and Robins Island. The final channel is the new lock, built in 1993. Only Bradford Island is natural; the others were created when new river channels were created.

Bonneville Dam is in the middle of a very historic area. There's a rich history here of natural landslides, Indian villages, river rapids, portage railroads and abandoned highways. Some historic sites remain accessible below the dam, others are underwater above the Dam.

From USGS (link below): Bradford Island was once an old Indian burial ground in the middle of the Columbia River. The island now is part of the Bonneville Dam structure. Lewis and Clark called the island "Brant Island", and was so named because of the large flocks of Lesser Canadian Geese observed in the vicinity... (See a 1928 aerial photo of the pre-dam Branford Island)

Bonneville Dam can be viewed from many area hikes including the Buck Point Hike, the Wauna Viewpoint Hike, the Tooth Rock Loop Hike and the Aldrich Butte Hike.

There is a visitor's center which makes a great location for families and school field trips. Here you can view the fish ladders that allow salmon and other species to return upstream to spawn. There is an underground viewing area with windows to give you a better view of the fish passing by (photo). Volunteers here are charged with counting every fish that passes by the window, by species!

There are plenty of interpretive dioramas, maps, and a movie to interest children of all ages (photo).

Since 9-11, the powerhouse is closed to the public except for a few guided tours a day. Call ahead for times and availability.

Any trip to the dam should include the nearby Fish Hatchery. There are dozens of holding tanks spanning across beautifully manicured lawns and landscaping. It's a pretty spot for a picnic. Children will love the tank holding two (very large!) sturgeon.

If you come in early fall, you can see salmon returning up nearby Tanner Creek into the the holding bins.

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Portland Hikers Field Guide is built as a collaborative effort by its user community. While we make every effort to fact-check, information found here should be considered anecdotal. You should cross-check against other references before planning a hike. Trail routing and conditions are subject to change. Please contact us if you notice errors on this page.