science

Haneji Dam

Haneji Dam is a science 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 Haneji Dam rather than just read about it. In short: The Haneji Dam (羽地ダム) is a rock-fill embankment dam on the Haneji River in Nago, Okinawa Prefecture, Japan. The purpose of the dam is flood control and water supply.

Key takeaways

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

Reference excerpt

The Haneji Dam (羽地ダム) is a rock-fill embankment dam on the Haneji River in Nago, Okinawa Prefecture, Japan. The purpose of the dam is flood control and water supply.

History Planning for the dam was conducted in the late 1960s by the U.S. Army Corps of Engineers and construction on the dam began in 1981. Construction on the river diversion tunnels commenced in 1993 and work on the dam's body began in 1998. The body of the dam was complete in 2000 and the entire project in 2004.

Design The dam is a 67 m (220 ft) tall and 198 m (650 ft) long rock-fill embankment type with a structural volume of 1,050,000 m3 (1,373,348 cu yd) and a crest elevation of 74 m (243 ft). The dam sits at the head of an 11 km2 (4 sq mi) catchment area and its reservoir has a surface area of 1 km2 (247 acres). The reservoir's capacity is 19,800,000 m3 (16,052 acre⋅ft) while 19,200,000 m3 (15,566 acre⋅ft) serves as active (or "useful") capacity. The dam is equipped with an uncontrolled chute spillway.

Innovations The dam and its facilities are equipped with several innovations to improve water quality and the environment. Water in the reservoir is aerated using a dam energy-air system. Water discharged from the dam powers two small turbines which provide electricity for the operation of shallow and deep aerators. Given the height of the dam, a traditional fish ladder was not viable. An airlift system was developed which transfers fish through tubes in and out of the reservoir. The radial gate that controls the intake was split and reversed in design. This design takes advantage of tensile strength instead of compression strength which allows for a more compact and less costly design.

References

Illustrations

Worked examples

Example 1 — a first encounter with Haneji Dam

Start with the simplest possible case. Write down what Haneji Dam claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Haneji 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 Haneji 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 Haneji Dam

In research: Haneji Dam appears in science 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 Haneji 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: Haneji Dam is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dams completed in 2000, Dams in Okinawa Prefecture, Dams with fish ladders, so understanding it makes those chapters shorter.
In everyday life: Look for Haneji 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 Haneji Dam in 20 minutes

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

Frequently asked questions

What is Haneji Dam in simple terms?

The Haneji Dam (羽地ダム) is a rock-fill embankment dam on the Haneji River in Nago, Okinawa Prefecture, Japan. The purpose of the dam is flood control and water supply.

Why does Haneji Dam matter?

Because it connects several science 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 Haneji 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 Haneji Dam.