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Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest. Today, we’re discussing the Lower Granite Lock and Dam at Snake River mile 107.5. The project was enabled by the River and Harbor Act of 1945. Construction began in 1965 and was completed in 1984. 

The reservoir lake “created by the dam extends upstream on the Snake River about 40 miles to Lewiston, Idaho, more than 460 river miles from the Pacific Ocean.”[1]

“In 2015, traffic through the navigation lock consisted of grains, petroleum products, fertilizer, wood products, and miscellaneous cargo that amounted to more than 1.1 trillion tons.”[2]

[1-2] https://www.nww.usace.army.mil/Locations/District-Locks-and-Dams/Lower-Granite-Lock-and-Dam/

Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest.

Ever wonder where dam construction workers live while these dams are being built? These photos show employee housing around the Grand Coulee Dam. The majority of homes were 2-bedroom and 3-bedroom permanent type residences.

Welcome to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest.

Today, we’re discussing the installation of turbines and generators. Water turbines are a type of rotary machine that converts water’s kinetic energy into electric power.

The U.S. Army Corps of Engineers explains how turbines and generators work: “A hydraulic turbine converts the energy of flowing water into mechanical energy. A hydroelectric generator converts this mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday. He found that when a magnet is moved past a conductor, it causes electricity to flow. In a large generator, electromagnets are made by circulating direct current through loops of wire wound around stacks of magnetic steel laminations. These are called field poles, and are mounted on the perimeter of the rotor. The rotor is attached to the turbine shaft, and rotates at a fixed speed. When the rotor turns, it causes the field poles (the electromagnets) to move past the conductors mounted in the stator. This, in turn, causes electricity to flow and a voltage to develop at the generator output terminals.”[1]

[1] https://www.usgs.gov/special-topic/water-science-school/science/hydroelectric-power-how-it-works?qt-science_center_objects=0#qt-science_center_objects

Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest. Today, we’re discussing the Grand Coulee Dam and irrigation pumping plants and discharge pipes.

The Grand Coulee Dam is part of the larger Columbia Basin Irrigation Project which was commissioned by Congress in 1943 (although “construction of the irrigation system did not start until after World War II”).[1] The Project “is an immense irrigation development in central Washington state that provides water from the Columbia River to about 671,000 acres on the Columbia Plateau.”[2]

Here’s how the system works: “water from Lake Roosevelt behind Grand Coulee Dam is pumped uphill to a 27-mile-long reservoir, Banks Lake, from which it flows by gravity into a series of canals. Outlets for unused water empty into the Columbia above Richland and Pasco more than 125 miles to the south. The project includes more than 300 miles of main canals, 2,000 miles of laterals and 3,500 miles of drains and wasteways. The project provides irrigation water to 2,050 farms. Apples, wheat and corn are the largest-volume crops. There also are large herds of dairy cows and beef cattle. Annually, the cash value of farm production in the Columbia Basin Project is about $630 million.”[3]

Additionally, “O’Sullivan Dam on Crab Creek about 15 miles south of Moses Lake creates Potholes Reservoir, which captures return flows from the northern half of the project. The Potholes Canal flows out of the lake and serves the southern part of the project.”[4] Said in another way, “Potholes Reservoir collects runoff from the north for farms in the south. Water from drains and waste ways returns to the canal system to be reused,” as “irrigation water from the Columbia Basin Project is often used more than once before it returns to the Columbia River near Pasco [Washington].”[5]

“In addition to supplying water for irrigation, producing electricity, controlling floods, providing recreation, and regulating streamflow, the Columbia Basin Project also provides water for cities, industries, navigation, and endangered species.”[6]

[1] https://www.usbr.gov/pn/grandcoulee/cbp/index.html

[2-4] https://www.nwcouncil.org/reports/columbia-river-history/columbiabasinproject

[5-6] https://www.usbr.gov/pn/grandcoulee/cbp/index.html

Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest.

Today, we’re discussing Little Goose Lock and Dam on the Snake River. The project was enabled by the River and Harbor Act of 1945. Construction began in 1963 and operation began in 1970. It creates the reservoir Lake Bray, which “extends upstream about 37.2 miles and provides navigation to Lower Granite Lock and Dam.”[1]

The lock is a “single-lift lock, 86 feet wide by 668 feet long, with a 100-foot vertical lift. More than 1.9 million tons of commodities passed through the Little Goose navigation lock during 2015.”[2]

[1-2] https://www.nww.usace.army.mil/Locations/District-Locks-and-Dams/Little-Goose-Lock-and-Dam/

That’s a wrap on our series, Oh Dam! We hope you learned something about dams in the Pacific Northwest!

Stay tuned for our next series, Women’s Recreation Wednesday, beginning on Wednesday!

Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest.

Today we’re discussing Dworshak Dam, the third tallest dam in the United States and “the highest straight-axis concrete dam in the Western Hemisphere.”[1] It is located two miles upstream on the North Fork of the Clearwater River from the town of Ahsahka, Idaho.

The project was instigated by the Flood Control Act of 1962. Construction began in 1966 and the dam “became operational for flood damage reduction in June 1972. Power came online in March 1973.”[2]

According to the U.S. Army Corps of Engineers, Walla Walla District website, the Dworshak Dam has “prevented more than $2.8 million in local potential flood damages” since 1972. In 2015, the dam “prevented about $18 million in potential flood damages on the Columbia River.”[3]

However, there are also drawbacks to the dam. “The filling of the reservoir resulted in the loss of about 15,000 acres of terrestrial habitat. The greatest loss of wildlife habitat was the winter range for Rocky Mountain elk and white-tailed deer.”[4] Construction of the dam also resulted in large losses of anadromous steelhead trout.

To address the loss of wildlife habitat, “mitigation lands have been developed and are managed for winter range. About 7,000 acres were purchased are managed specifically for elk mitigation.”[5] To address the loss of fish populations, the U.S. Army Corps of Engineers constructed the Dworshak National Fish Hatchery, which is operated by the U.S. Fish and Wildlife Service. “The Dworshak hatchery is the largest steelhead hatchery in the world. After Dworshak Reservoir was filled, kokanee salmon and small mouth bass were stocked and became self-sustaining in the reservoir. The abundance of kokanee salmon in the reservoir has made it a favored sport species in the reservoir.”[6]

Clearly, there are pros and cons to large hydraulic dams like Dworshak Dam in Idaho. Stay tuned for next week’s edition of Oh Dam! where we’ll discuss preparing a site for dam construction!

[1-6] https://www.nww.usace.army.mil/Locations/District-Locks-and-Dams/Dworshak-Dam-and-Reservoir/

Welcome back to another week of Oh Dam!, our mini-series on dams in the Pacific Northwest.

Last week, we talked about turbines and generators. Today, we have photos of the power house – “the structure that houses generators and turbines.”[1]

[1] https://www.energy.gov/eere/water/glossary-hydropower-terms