# Questions tagged [hydroelectric-dams]

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1answer
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### calculating flow rate in 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 ...
2answers
123 views

### 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 = ...
0answers
36 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 ...
0answers
17 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 ...
1answer
47 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'...
1answer
63 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 ...
0answers
32 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 ...
1answer
95 views

### 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 ...
1answer
37 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.
5answers
105 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 ...
5answers
8k views

### Why don't hydroelectric plants use cascades of turbines instead of single turbines?

In a gas turbine engine there're multiple sets of blades - one set after another and combustion products pass all the sets and each set of blades gets some of the power. This increases utilization of ...
2answers
4k 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 ...
1answer
3k views

### 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 ...
2answers
129 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 ...