engineering

Holtwood Dam

Holtwood 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 Holtwood Dam rather than just read about it. In short: Holtwood Dam (also Holtwood Hydroelectric Dam, Holtwood Hydroelectric Plant, McCalls Ferry Dam) is the oldest of three major dams built across the lower Susquehanna River, and the middle location of the three. It was constructed as the McCalls Ferry Dam between 1905 and 1910 by the Pennsylvania Water & Power (PW&P) Company.

Key takeaways

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

Reference excerpt

Holtwood Dam (also Holtwood Hydroelectric Dam, Holtwood Hydroelectric Plant, McCalls Ferry Dam) is the oldest of three major dams built across the lower Susquehanna River, and the middle location of the three. It was constructed as the McCalls Ferry Dam between 1905 and 1910 by the Pennsylvania Water & Power (PW&P) Company. The dam was renamed Holtwood in honor of two company executives. PW&P merged with Pennsylvania Power & Light (PPL) in 1955. In 2015 Talen Energy took over PPL's generation and immediately sold the Holtwood plant to Brookfield Renewable Energy Partners to comply with federal antitrust requirements.

Holtwood hydroelectric plant The Holtwood Hydroelectric Plant produces 252 Megawatts of power, using 14 turbine driven generators. The dam consists of a main concrete dam, which is mostly one continuous spillway, with a power house at the eastern end. The water level is raised by wooden flash boards and inflatable dam sections. The western end of the dam has the original, and ineffective, fish ladder. In the mid 1990s, construction started on a fish lift. The fish lift and dam were damaged by heavy rain and rapid snowmelt from the severe 1996 flood in January of that year. The new fish lift was completed in time for the 1997 season and began lifting american shad and other migratory fish species. The Kingsbury thrust bearing of Holtwood's Generator No. 5 is designated an International Historic Mechanical Engineering Landmark. Previously used roller bearings would last about 2 months under the generator's 220 ton load, but the Kingsbury bearing has been in use since 1912. The impounded water, Lake Aldred, was originally dredged for anthracite coal silt, or fines, washed downstream from the Coal Region of Pennsylvania. This coal was used in the adjacent Holtwood Steam Generator station. When Safe Harbor Dam was built upstream, its impoundment was then "mined" for coal as well. More efficient primary mining upstream reduced the availability of fines, and 1972 environmental laws made the dredging impractical, so coal was brought in by train.

Expansion project In 2008, PPL announced plans to expand the plant with a second powerhouse. PPL received the approval to add the second powerhouse in November 2009 from the Federal Energy Regulatory Commission. Expansion of the plant started in 2010. Preliminary construction began in January 2010, with full construction beginning in April 2010. The project was completed in December 2013. The second powerhouse added 125 MW of additional capacity, increasing total generating capacity to more than 230 megawatts. One worker was killed during construction of the second powerhouse. Bruce Hardy, 59, of Bainbridge, Lancaster County, died after being crushed between a wall and an excavator bucket. The area below the dam is popular with whitewater kayakers, with eleven named hydraulic features. Scheduled whitewater releases from the dam are made, when conditions permit.

Illustrations

Worked examples

Example 1 — a first encounter with Holtwood Dam

Start with the simplest possible case. Write down what Holtwood 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 Holtwood 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 Holtwood 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 Holtwood Dam

In research: Holtwood 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 Holtwood 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: Holtwood Dam is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures in Lancaster County, Pennsylvania, Buildings and structures in York County, Pennsylvania, Dams completed in 1910, so understanding it makes those chapters shorter.
In everyday life: Look for Holtwood 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 Holtwood Dam in 20 minutes

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

Frequently asked questions

What is Holtwood Dam in simple terms?

Why does Holtwood 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 Holtwood 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 Holtwood Dam.