engineering

Lake Powell

Lake Powell 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 Lake Powell rather than just read about it. In short: Lake Powell is a reservoir on the Colorado River in Utah and Arizona, United States. It is a major vacation destination visited by approximately two million people every year.

Key takeaways

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

Reference excerpt

Lake Powell is a reservoir on the Colorado River in Utah and Arizona, United States. It is a major vacation destination visited by approximately two million people every year. It holds 24,322,000 acre-feet (3.0001×1010 m3) of water when full, second in the United States to only the downstream reservoir of Lake Mead – though Lake Mead has fallen below Lake Powell in size several times during the 21st century in terms of volume of water, depth and surface area. Lake Powell was created by the flooding of Glen Canyon by the Glen Canyon Dam, which also led to the 1972 creation of Glen Canyon National Recreation Area, a popular summer destination of public land managed by the National Park Service. The reservoir is named for John Wesley Powell, a Civil War veteran who explored the river via three wooden boats in 1869. It lies primarily in southern Utah, with a small portion in northern Arizona. Lake Powell is a water storage facility for the Upper Basin states of the Colorado River Compact (Colorado, Utah, Wyoming and New Mexico). The Compact specifies that the Upper Basin states are to provide a minimum annual flow of 7,500,000 acre-feet (9.3 km3) to the Lower Basin states (Arizona, Nevada, and California). According to US Geological Survey and the Bureau of Reclamation report, in addition to water loss, Lake Powell faced an average annual loss in storage capacity of about 33,270 acre-feet, or 11 billion gallons, per year between 1963 and 2018 because of sediments flowing in from the Colorado and San Juan rivers. Those settle at the bottom of the reservoir and decrease the total amount of water the reservoir can hold. Environmentalists have pushed to drain Lake Powell and restore Glen Canyon to its natural, free-flowing state.

History

Planning In the 1940s and early 1950s, the United States Bureau of Reclamation planned to construct a series of Colorado River dams in the rugged Colorado Plateau province of Colorado, Utah, and Arizona. Glen Canyon Dam was born of a controversial damsite the Bureau selected in Echo Park, in what became Dinosaur National Monument in Colorado. A small but politically effective group of objectors, led by David Brower of the Sierra Club, succeeded in defeating the Bureau's bid, citing Echo Park's natural and scenic qualities as too valuable to submerge. Glen Canyon Dam was built to solve the downstream delivery obligations of the Upper Basin states. Lake Powell is an "aquatic bank" built to fulfill the terms of the "Compact Calls" of Lower Basin.

Construction

Construction on Glen Canyon Dam began with a demolition blast keyed by the push of a button by President Dwight D. Eisenhower at his desk in the Oval Office on October 1, 1956, which started clearing tunnels for water diversion. On February 11, 1959, water flowed through the tunnels so dam construction could begin. Later that year, the bridge was completed, allowing trucks to deliver equipment and materials for the dam and also for the new town of Page, Arizona. Concrete placement started around the clock on June 17, 1960. The last bucket of over 5 million cubic yards (4,000,000 m3) was poured on September 13, 1963. The dam is 710 feet (216 m) high and the surface elevation of the water at full-pool is approximately 3700 feet (1100 m). Construction cost $155 million, and 18 lives were lost. On September 22, 1966, Glen Canyon Dam was dedicated by Lady Bird Johnson. From 1970 to 1980, turbines and generators were installed for hydroelectricity.

Filling and operations Upon completion of Glen Canyon Dam on September 13, 1963, the Colorado River began to back up, no longer being diverted through the tunnels. The newly flooded Glen Canyon formed Lake Powell. Sixteen years elapsed before the lake filled to the 3,700 feet (1,100 m) level on June 22, 1980. The lake level fluctuates considerably depending on the seasonal snow runoff from the Rocky Mountains. The all-time highest water level was reached on July 14, 1983, during one of the heaviest Colorado River floods in recorded history, in part influenced by a strong El Niño event. The lake rose to 3,708.34 feet (1,130.30 m) above sea level, with a water content of 25,757,086 acre-feet (31.770898 km3). It lies primarily in parts of Garfield, Kane, and San Juan counties in southern Utah, with a small portion in Coconino County in northern Arizona. The northern limits of the lake extend at least as far as the Hite Crossing Bridge.

21st century drought and push to drain

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Lake Powell

Start with the simplest possible case. Write down what Lake Powell 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 Lake Powell 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 Lake Powell 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 Lake Powell

In research: Lake Powell 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 Lake Powell 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: Lake Powell is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1963 establishments in Arizona, 1963 establishments in Utah, Buildings and structures in Garfield County, Utah, so understanding it makes those chapters shorter.
In everyday life: Look for Lake Powell 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 Lake Powell in 20 minutes

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

Frequently asked questions

What is Lake Powell in simple terms?

Lake Powell is a reservoir on the Colorado River in Utah and Arizona, United States. It is a major vacation destination visited by approximately two million people every year.

Why does Lake Powell 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 Lake Powell?

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 Lake Powell.