engineering

John Day Dam

John Day 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 John Day Dam rather than just read about it. In short: The John Day Dam is a concrete gravity dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides.

Key takeaways

John Day 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 John Day Dam to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of John Day Dam from memory before moving on to harder problems.

Reference excerpt

The John Day Dam is a concrete gravity dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift (at 110 feet or 34 meters) of any U.S. lock. The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4 miles (123.0 km) up the river channel to the foot of the McNary Dam. The John Day Dam is part of the Columbia River Basin system of dams and was established for the purpose of generating hydroelectricity via the run-of-the-river power station.

Location The John Day Dam is located 28 miles (45 km) east of the city of The Dalles, Oregon, and just below the mouth of the John Day River. The closest town on the Washington side is Goldendale, 20 miles (32 km) north. The closest town on the Oregon side is Rufus. The dam's crest elevation is approximately 570 feet (170 m) above sea level. It joins Sherman County, Oregon with Klickitat County, Washington, 216 miles (348 km) upriver from the mouth of the Columbia near Astoria, Oregon.

History Construction of the dam began in 1958 and was completed in 1971, making it the newest dam on the lower Columbia, at a total cost of US$511 million. The pool was filled in 1968 and a dedication ceremony was held on September 28, 1968. The first vessel through the new lock was the Coast Guard buoy tender USCGC Blueberry. The John Day Dam was built by and is operated by the U.S. Army Corps of Engineers. The condemnation of land upstream of the dam led to the Supreme Court case United States v. Rands, a well-known case regarding the constitutional doctrine of navigable servitude. The dam's power generation overload capacity is 2,485 megawatts (3,332,000 hp). Skeleton units for eventual installation of four additional generators were fitted to the powerhouse during construction, allowing for a 20% increase in output should the decision be taken to complete them. The dam underwent a major repair to the upper lock gate in 2010, as documented in an episode of the National Geographic Channel program World's Toughest Fixes. As of 2007, the 76-mile-long (122 km) reservoir formed the deadliest stretch of the Columbia River for migrating young salmon. The reservoir is the longest lake on the Columbia that young salmon must swim on their way to the ocean. The single-lift navigation lock is 86 feet (26 m) wide and 675 feet (206 m) long.

Gallery

Illustrations

Worked examples

Example 1 — a first encounter with John Day Dam

Start with the simplest possible case. Write down what John Day 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 John Day 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 John Day 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 John Day Dam

In research: John Day 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 John Day 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: John Day Dam is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1971 establishments in Oregon, 1971 establishments in Washington (state), Buildings and structures in Klickitat County, Washington, so understanding it makes those chapters shorter.
In everyday life: Look for John Day 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 John Day Dam in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what John Day 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 John Day Dam out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is John Day Dam in simple terms?

The John Day Dam is a concrete gravity dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides.

Why does John Day 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 John Day 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 John Day Dam.