Despite having purely utilitarian reasons for existence, Bonneville Dam and Bonneville Dam Historic District have been a National Historic Landmark since 1987.
Named after Army Captain Benjamin Bonneville, Bonneville Dam is one of the oldest on the Columbia River. It has quite an unusual construction consisting of several dams on separate river channels divided by three islands. Out of the three, only Bradford Island, once an Indian burial site, is natural. Robins and Cascades Islands are man-made.
Bonneville Dam and Lock
Bonneville Dam and Lock are located near Cascade Locks, Oregon, and North Bonneville, Washington, 40 miles (64 km) east of Portland, Oregon.
Built and managed by the US Army Corps of Engineers, the primary functions of Bonneville Lock and Dam are electrical power generation and river navigation.
Bonneville Dam is a concrete gravity (i.e. the Earth’s gravity is the force that holds it in place) and run-of-the-river (i.e. the dam has little to no water storage) dam with two powerhouses and a combined electrical output of over 1,000 megawatts. It is 197 feet (60 m) high and 2,690 feet (820 m) long.
The 48 mile (77 km) reservoir created by the dam is called Lake Bonneville. It stretches between the Bonneville and The Dalles Dams and lies in the three Oregon counties (Multnomah, Hood River, Wasco) and two Washington counties (Skamania, Klickitat).
The level of water upstream is usually around 60 feet (18 m) higher than that of downstream, and it takes approximately 30 minutes for a vessel to transition through Bonneville Lock.
In the 1929 report, US Army Corps of Engineers recommended construction of ten dams along the Columbia River for the purposes of flood control, hydroelectricity generation, navigation, and irrigation. No action had been taken, however, until President Roosevelt implemented the New Deal, a series of programs aimed at countering the consequences of the Great Depression.
Bonneville project presented quite a few engineering challenges, including water depth, unstable bottom, current velocity, weather conditions, and annual summer floods. The construction of the first powerhouse began in 1934 on the Oregon side and was finished in 1937. Growing energy needs of the Northwest resulted in the decision to build a second powerhouse. The construction started in 1974 on the Washington side and was finished in 1981.
The first lock was built at Bonneville in 1938 and could hold two barges and a tugboat. It was regarded as the world’s largest single-lift lock at that time. Later, however, the construction of new locks upriver capable of holding up to five barges, made Bonneville a Columbia River bottleneck.
In 1993, a new lock was opened to facilitate the traffic. It can now hold five barges, like all the seven locks upstream. The lockage time has been reduced from several hours to less than 30 minutes. The old lock is still there, but no longer in use.
Power production remains the primary purpose of Bonneville Dam. It is part of the series of dams that produce almost 60% of power for the Pacific Northwest and part of California.
The dam is essential for the commercial sector allowing goods to travel 465 miles inland as far as Lewiston, Idaho. Additionally, Bonneville Dam is a popular recreation site. It has three recreation areas, the oldest fish hatchery in Oregon, and trails. Lake Bonneville offers fishing, boating, swimming, and windsurfing opportunities. The powerhouse was previously open to the public, but after the events of 9/11, the access was limited to several guided tours per day.
Construction of Bonneville Dam created a number of environmental issues, including blocked fish migration routes. To address this, the Corps’ engineers and environmental scientists designed fish ladders simulating waterfalls and pools of natural streams. That helps shad, salmon, and steelhead get past the dam on their journey upstream to spawn.
Things to Do & See
Besides hydroelectric power productions, flood control, navigation, the Bonneville Dam area and reservoir offers a variety of recreational opportunities including wildlife watching, fishing, boating, picnicking, and hiking.
The largest Oregon hatchery, Bonneville Dam Fish Hatchery is a favorite stop for visitors. Surrounded by flower garden, fish tanks contain salmon and rainbow trout. If you have quarters, buy food for the fish in machines. Also, there is a Sturgeon Pond, where you can see big sturgeon through the underwater viewing window. Spawning season from May through September is the best time to visit the hatchery.
There are three visitor centers. One of them on Bradford Island is open daily from 9 am to 5 pm. Bradford Island Recreation Area itself open from 7 am to 5 pm. On the way to the visitor center, you will cross a retractable bridge above the shipping locks, pass the fish-diversion canal, powerhouse and turbine room. The Bradford Island Visitor Center exhibits give you a glimpse into the region history, development navigation along the Columbia River, and provide information about life-cycles of salmon and other species.
Navigation Lock Visitor Area is open seasonally from Memorial Day through Labor Day, 1 pm to 4 pm. Visitors can see the navigation lock in action.
A large picnic shelter, Robins Island Recreation Area can accommodate 100 guests ans has playground, open daily from 7 am to 5 pm.
Washington Shore Visitor Complex is open daily 9 am to 5 pm, powerhouse tours are available.
American Shad Fishing
American shad was introduced to the West Coast from the Atlantic Coast by Seth Green in 1871. Affectionately nicknamed the poor man’s salmon, the fish are known for having exquisite meat with a delicious taste.
- Head east on I-84 and travel about 36 miles to exit 40
- Take exit 40 and head under the interstate through a tunnel towards the dam.
(541) 374-8820 (Oregon)
(509) 427-4281 (Washington)
Address: Bonneville Lock and Dam, Cascade Locks, Oregon