# Water dam calculation

1. Oct 21, 2011

### pheonixchin

Hi

I have questions about building a dam. (a simple dam)

Part1

1. Will the force (red arrow) that water exert on the dam equal from the surface till the bottom? If yes then how can I calculate the force exert on the dam?
If not then how can I calculate the force exert on the dam at a specific point?

2. What variables will I need to know in order to calculate? water height? , volume of water?
3. Which part of the dam is subjected to most stress
4. Which part of the dam is subjected to least stress
5. What calculation and information do I need in order to build a dam that can withstand the water (roughly)? e.g. dam thickness, dam height?

http://img64.imageshack.us/img64/7277/dam1.png [Broken]

Part2

1. Will the knowledge from part 1 sufficient to let me calculate how high and wide of water I need in the second dam(smaller dam) in order to prevent the first dam from failing?
2. What is the optimum high of water I need in second dam and the optimum distance I need in the second dam in order to prevent the first dam from failing?
3. Is it better to have more distance between the two dam and less water height or more water height and less distance between the dam?

http://img43.imageshack.us/img43/8016/dam2x.png [Broken]

Thank you very much

Last edited by a moderator: May 5, 2017
2. Oct 21, 2011

### Staff: Mentor

All you need for pressure is p=mgh

To actually design a dam? That can't be explained in an internet forum thread.

3. Oct 22, 2011

### pheonixchin

p=mgh?

m=mass?

mass of water?

or you mean P=ρgh?

4. Oct 22, 2011

### Staff: Mentor

Dang, sorry - that should be p=ρgh.... that's rho. Density.