# Questions tagged [hydroelectric-dams]

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### How can a masonry dam not require mortar?

A Masonry Dam is build out of individual stones or bricks. The Wikipedia link says that it is "sometimes" joined with mortar, and has a cite for it but the link is 404 dead. Is that really ...
• 507
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### Where are the energy losses here?

This hydroelectric system, described in The Study of Syphon and Applied in Hydroelectricity Power Production, is said to be continuous once it has been set up. Once set up it is claimed that it will ...
1 vote
90 views

### Pumped storage hydropower, how to power the pumps?

Regarding pumped storage hydropower, In the case of some high altitude upper reservoir that feeds several turbines located at the bottom of a valley, where there's a lower reservoir too. Assuming in ...
106 views

### Does the volume of water going through a hydroelectric dam matter?

How does the volume of water going through a hydroelectric dam affect electricity production? Could the flux of the generators not be modulated to different amounts of electricity with the same flow ...
106 views

### Instead of dams to tap hydroelectric power, why not just pipe the river from further upstream, and then let the water fall down a great height?

Using a canal/aqueduct system for hydroelectric power rather than a dam The hydroelectric power extracted by a river dam is related to the height of the water at the dam (with greater heights ...
119 views

### Different equations for Hydropower

I was doing some reading in hydropower and I came across these two power equations: $$P = ρghQ$$ and $$P = QHg$$ Q is flow rate, ρ is water density, g is gravity, h is height, and H is head. I do ...
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### Can the kinetic energy formula (1/2 m v²) be used in finding amount of energy a hydro electric station can produce?

Say you have 20 kg of water moving at a speed of 10m/s, if the KE formula is used, it would have 1000 joules of energy per second. Is this accurate or is there another way of calculating it?
38 views

### How to move water to a new dam?

There are many videos on Youtube about opening of new dams, where the water is already ready to go though the dam. What I wonder is how engineers moves water to a new dam. To me it seams as a chicken ...
27 views

### calculation for hydropower project

I'm studying a hydro-power project in high rise building. given a 100 story building(3 meter per floor) with 2.5 cubic meter of water per floor DAILY with 1 or more tanks within the floors and turbine ...
162 views

### Calculating Flow rate and Water Velocity of a pipeline

Background I am trying to assess the Power output of a Pumped Hydro project based on this website. I have all the required inputs except the flow rate (m3/s). Problem However, this is where I think I'...
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### Assessing flow rate from open sea into a container

I'm currently assessing sub sea pumped hydro capabilities, and need to use the flow rate in order to calculate power output. I can calculate the energy storage capacity using E = mgh: \$E=mgh = ...
111 views

### I want to determine the flow rate and required turbine size for an offshore hydroelectric scheme and need help

I'm creating a report on the possible implementation of a sub hydro system and need some help. I've attached the image of what I'm proposing, where I've essentially created a head via a riser B with a ...
94 views

### Calculating flow rate from a given water tank and water head in hydropower

I'm calculating feasibility of using grey water in high rise buildings to generate hydroelectricity. Let's assume a given water volume of 100 cubic meters a day and a water head of 100 meter. What ...
1 vote
55 views

### What's the smallest hydropower plant that can blackstart a grid?

One of the most underrated capabilites of classical, large-scale hydropower plants is their ability to "black start" a dead electric grid. I'm not going to go into details on the blackstart ...
47 views

### Why did they move ancient Egyptian temples to prevent them from water damage instead of encircling them with a dam?

Specifically I'm talking about Abu Simbel temple and Philae temple. Which are close to a reservoir created by Aswan dam. It seems to me easier to build a dam than to move a temple.
122 views

### Why do dams deplete rivers?

I have often heard of cases where dams reduce the flow rate of rivers downstream. This makes sense in cases where some of the water that is captured by the dam is used for irrigation and such, but in ...
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### What specific technical concerns exist for China's Three Gorges damn on the Yangtze river?

Recently, many people (specifically geopolitical and financial analysts) have pointed out that there is a serious concern about China's Three Gorges Dam breaking and causing catastrophic flooding that ...
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### How and WHY does the tension in an arch dam or bridge change as the degree of curvature and radius of curvature change?

Arch bridges operate according to the following (I am assuming arch dams are the same): Tensional force in arch bridges are virtually negligible. The natural curve of the arch and its ability to ...
• 133
134 views

### Does a spillway failure have different consequences versus dam failure?

I noticed this Tweet about the Oroville Dam concerns this week: Seems most media is not emphasizing/noting the distinction. Is there a difference in the consequences of a spillway failure? Seems ...
5k views

### Why do hydroelectric plants use turbines instead of an efficient 'water wheel' configuration?

I have been thinking about hydroelectric plants and I have been wondering why they are built the way they are. As in understand it, a stream of water is sprayed at a turbine, located at the bottom of ...
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