1 - 10 of 10 Posts

#### warrington

·
##### Registered
Joined
·
3 Posts
Discussion Starter · ·
I need to pump water from one pond to fill up another pond. I was thinking about starting with a 3" trash pump to draw the water out up hill 25 feet, and then pumping it 1000 yards on a slight incline. To keep back pressure I was thinking about running 3" hose for 100Feet then coneing it down to 2" the rest of the way. A couple of questions, 1) will this even work 2) by coneing it down would that put too much back pressure 3) is there any way to increase the size of teh fuel tank so I dont have to refil it every 2 hours 4)any other ideas that might help. Thanks for your help

#### Daniel Holzman

·
##### Civil Engineer
Joined
·
5,832 Posts
You need to determine the elevation difference between the two ponds. The total head required of the pump consists of the static elevation difference between the ponds, plus the dynamic losses in the hose. The larger the hose diameter, the lower the friction losses. For example, if the difference in elevation of the ponds is 15 feet, and your pump can put out 25 feet of dynamic head, the total operational head on the pump is approximately 40 feet. This is somewhat simplified, but you need to check if your pump can handle the head difference.

Different pumps have very different characteristic curves, for example some pumps pump at a high flow rate but at low head (most trash pumps are like this), while other pumps put out a small amount of flow at high head (a submersible well pump is like that). Every pump manufacturer publishes the curve that shows how much water can be pumped at a given head, so you start by getting this curve from the pump manufacturer. Then you can compute the amount of flow you will get, and you can decide if the pump is large enough for your needs.

#### Ron6519

·
##### Registered
Joined
·
11,194 Posts
If the head height cuts down on water movement, you can pump it in stages. Put a tank at some point between the ponds. Have a set of pumps deliver it to the tank and another set to move it forward.
Maybe you'll need more then one tank, depending on the height difference.
You might use 2 different pump catagories to move the water.

#### warrington

·
##### Registered
Joined
·
3 Posts
Discussion Starter · ·
pump

when using a 3" trash pump, can you cone that down to 2" 100' down the discharge line or will that cause you problems

#### Maintenance 6

·
##### Mold!! Let's kill it!
Joined
·
2,849 Posts
You would need several trash pumps in series to move water 1000 yards through 2" line. Even at only 100 GPM, the friction loss in 2" hose over 3000 feet is 240 psi. That means that if you introduced the water into the hose at 240psi it would exit the line at zero pressure. Trash pumps won't build that kind of pressure. Pumping into 100 feet of 3" and then reducing to 2900 feet of 2" will still take 232 psi to move 100 GPM. Even at 50 GPM you'll need 60psi to overcome the friction loss. And you'll need to add roughly .5 psi for every foot of elevation from the water surface level of pond 1 to the highest point in your hose lay. That means you'll need 12.5 psi to overcome the first 25 feet and then add whatever the incline is. Even a good fire pump would run full tilt to deliver 100 GPM. Forget the tank. Flow from the discharge of one pump into the intake of the next pump in series. Pumping the entire run through 3" hose may be do-able depending on the discharge pressure of your pump, since the friction loss at 100GPM would drop to 21 psi.

#### joed

·
##### Super Moderator
Joined
·
23,505 Posts
I don't understand why you want to reduce the size the output hose. Leave it the full 3" all the way.

#### warrington

·
##### Registered
Joined
·
3 Posts
Discussion Starter · ·
reducing the size

reducing the size is due to th expense of 3" vs 2" pipe. Another idea of mine is to pump 600 feet up hill 30 feet, put a holding tank there, place a second pump there which is above the end point, and pump it with a 2" pump. dropping 30 feet from there.

#### Ron6519

·
##### Registered
Joined
·
11,194 Posts
reducing the size is due to th expense of 3" vs 2" pipe. Another idea of mine is to pump 600 feet up hill 30 feet, put a holding tank there, place a second pump there which is above the end point, and pump it with a 2" pump. dropping 30 feet from there.
Great idea.

#### joed

·
##### Super Moderator
Joined
·
23,505 Posts
reducing the size is due to th expense of 3" vs 2" pipe. Another idea of mine is to pump 600 feet up hill 30 feet, put a holding tank there, place a second pump there which is above the end point, and pump it with a 2" pump. dropping 30 feet from there.
Dropping 30' you won't even need to pump it. It should flow on its own.

#### Maintenance 6

·
##### Mold!! Let's kill it!
Joined
·
2,849 Posts
reducing the size is due to th expense of 3" vs 2" pipe. Another idea of mine is to pump 600 feet up hill 30 feet, put a holding tank there, place a second pump there which is above the end point, and pump it with a 2" pump. dropping 30 feet from there.
After you're reached the high point anything below that is a pressure increase. The same .5 psi per foot applies going down as it did going up. Only on the way down it is an increase. You shouldn't need to pump it down hill. Are you doing this in hose or hard pipe? Hard pipe will have a lower co-efficient of friction than rubber lined hose.

1 - 10 of 10 Posts