engineering

Lower Granite Dam

Lower Granite Dam is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lower Granite Dam rather than just read about it. In short: Lower Granite Lock and Dam is a concrete gravity run-of-the-river dam in southeastern Washington in the United States. On the lower Snake River, it bridges Whitman and Garfield counties.

Key takeaways

Lower Granite Dam belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lower Granite Dam to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lower Granite Dam from memory before moving on to harder problems.

Reference excerpt

Lower Granite Lock and Dam is a concrete gravity run-of-the-river dam in southeastern Washington in the United States. On the lower Snake River, it bridges Whitman and Garfield counties. Opened 51 years ago in 1975, the dam is located 22 miles (35 km) south of Colfax and 35 miles (56 km) north of Pomeroy. Lower Granite Dam is part of the Columbia River Basin system of dams, built and operated by the U.S. Army Corps of Engineers; power generated is distributed by the Bonneville Power Administration (BPA). Behind the dam, Lower Granite Lake extends 39 miles (63 km) east to the confluence with the Clearwater River at Lewiston, Idaho, and allowed the city to become a port. The first barge to Portland on the 374-mile (602 km) navigation route was loaded with wheat and departed Lewiston on August 9, 1975. Lake Bryan, formed from Little Goose Dam, runs 37 miles (60 km) downstream from the base of the dam.

Construction Construction began in July 1965, but was halted less than two years later due to lack of funding. Work restarted in 1970, concrete was first poured in 1971, and the main structure and three generators were completed in 1975, with dedication ceremonies on June 19. An additional three generators were finished in May 1978, bringing the generating capacity to 810 megawatts, with an overload capacity of 932 MW. The spillway has eight gates and is 512 feet (156 m) in length. An 86-by-674-foot (26 by 205 m) navigation lock was also included in construction. Just downstream (northwest) of the dam on the east bank, Boyer Park was constructed by the Corps of Engineers and opened in April 1973.

Fishery

Lower Granite Dam is the most upstream dam in the Snake River system that has a fish ladder to allow adult salmon and steelhead to migrate upstream. The Columbia River treaty tribes, along with some environmental groups, have recommended that this dam along with the other three lower Snake River dams be decommissioned and/or removed because of their impact on threatened and endangered chinook (threatened) and sockeye salmon (endangered) and steelhead (threatened) populations., The Corps of Engineers recognized in 1971 that the dam would have a detrimental impact on wildlife. A significant increase in the sockeye salmon return to the Columbia River in 2008 proved a pleasant surprise and raised hopes for increased salmon runs across the Lower Granite. Wildlife officials were not certain of the reason for the increased salmon return (Idaho Statesman, June 28, 2008). The Corps of Engineers has installed new devices, such as removable spillway weirs, in an attempt to make the dam less harmful to juvenile salmon. There is also a juvenile bypass/collection facility that collects juvenile migrating salmon and steelhead so they can be transported downstream by barge.

Navigation lock Single-lift Width: 86 feet (26 m) Length: 674 feet (205 m)

Asotin Dam Authorized by Congress in 1962, a fifth dam on the lower Snake River was proposed several miles upstream (south) of Lewiston. Concerns over its environmental and recreational impact stalled the Asotin Dam project, and it was ultimately canceled in 1980. The Asotin County public utilities district attempted to revive the project in 1988, but it was quickly blocked by Congress, and a law banning future dams was signed into law by President Reagan on November 17. Other proposed dams further upstream were not built either: the High Mountain Sheep Dam above the confluence with the Salmon River, and the Nez Perce Dam, just below it.

Road closed Following the September 11 attacks in 2001, the road across the Lower Granite Dam was closed for over six years; it reopened for weekend traffic in May 2008. The sand dune area downstream on the south shore (46.696°N 117.48°W / 46.696; -117.48), accessed over the dam, was popular with local college students from Washington State University and the University of Idaho.

Illustrations

Worked examples

Example 1 — a first encounter with Lower Granite Dam

Start with the simplest possible case. Write down what Lower Granite Dam claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lower Granite Dam before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lower Granite Dam ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lower Granite Dam

In research: Lower Granite Dam appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lower Granite Dam in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lower Granite Dam is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1975 establishments in Washington (state), Buildings and structures in Garfield County, Washington, Buildings and structures in Whitman County, Washington, so understanding it makes those chapters shorter.
In everyday life: Look for Lower Granite Dam outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lower Granite Dam in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lower Granite Dam means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lower Granite Dam out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lower Granite Dam in simple terms?

Lower Granite Lock and Dam is a concrete gravity run-of-the-river dam in southeastern Washington in the United States. On the lower Snake River, it bridges Whitman and Garfield counties.

Why does Lower Granite Dam matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lower Granite Dam?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lower Granite Dam.