> >
>

# Pump Calculation

#1
11-06-09, 10:53 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Pump Calculation

I have a water garden that 4 waterfalls made of 1/2" PVC. The pond is 100" X 39"X26". I have 4 waterfalls made of the same 1/2" Pvc. I have 4 waterfall pushing water through 1/2" PVC that are 28" from lead 1/2 Pvc T. We are using a shower head for a fountain (which I would like it to go up in the air 5"). And statuette of a frog spitting water. How much gph would be suffiecent for this feature? Please show how you came up with it! JohnBeer 4U2

#2
11-10-09, 07:23 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
I do not understand what you mean by four waterfalls and then you mention using a showerhead as a fountain.

If you are creating waterfalls are you running a separate 1/2" pipe to each? Or, are you running your 1/2" pipe to only the top one and then the water falls through the other waterfalls? It is important to know how high the upper waterfall is above your pond level and also how many 90 & 45 degree bends you have in the plumbing since they add to the resistance in the plumbing.

#3
01-31-10, 03:20 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Four waterfalls into 2 and 1 1/4" PVC

I am actually building 2 waterfalls through the PVC onto rocks. How do I calculate this so I get the right GPH pump to carry the water so I have at least 3/4" of water coming out? Where should the pump(s) be ? I have a 750 GPH pump! Beer 4U2. I going to a 3' depth! John

#4
01-31-10, 03:28 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts

There is one 'T' joint to seperate 2 90 degree elbows. What size of pump do I need to supplant the other pump to achieve this? I would like to drill a 11/2" hole trough flaggstone to a height of 3' how is this done what kind of drill bit do you recommend without it breaking? John

#5
01-31-10, 06:05 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
What is the height you are raising the water? The distance from the top of the water in the pool at the bottom to the waterfall at the top?

You can use a diamond or carbide abrasive drill bit to dril through stone.

#6
01-31-10, 09:24 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Measurement

The Measurement + 3' depth = 61" Beer 4U2

#7
02-01-10, 08:43 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
The depth of the water in the bottom pool does not matter. You just need to know how much you will be raising the water (from the surface of your bottom pool to the water level where the water will exit the hose up on your waterfall).

#8
02-01-10, 01:31 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
25"

that measurement is 25" ! John

#9
02-02-10, 07:21 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
Earlier you mentioned four waterfalls and then two. How many will you have and are they all the same 25" above the top of your lower pool?

You mentioned that you want the water 3/4" deep coming out of your waterfall. How wide are the waterfalls since wider will need more water?

You will be greatly restricting the output of your 750gmp pump by using 1/2" piping. There is really no way to get 3/4" deep water going over your waterfalls by feeding them with only 1/2" pipe. You will have to run crazy pressure (which your pump will not do) to get any decent flow through plumbing that small.

#10
02-07-10, 08:22 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
4 waterfalls

You mentioned that you want the water 3/4" deep coming out of your waterfall?
I would like to have that much water flowing through the falls, which there will be four waterfalls. What would recommend for piping AND pump GPH? John

Last edited by RBCC; 02-07-10 at 08:44 PM. Reason: adding more answers to questions
#11
02-08-10, 05:33 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Waterfalls

How are the waterfalls arranged in relation to each other?

Are they side by side or are they one above the other in stair step fashion?

#12
02-08-10, 12:05 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Stair Step fashion

They are in a stair step fashion! John

#13
02-08-10, 01:22 PM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Pump

Then your pump needs to fill the top waterfall. That waterfall will then feed the one immediately below it and on down the line to the bottom.

#14
02-09-10, 10:58 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts

Side by Side, I made a mistake! JohnBeer 4U2

#15
02-09-10, 11:06 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
There is 3' between the pump and the waterfalls! John

#16
02-13-10, 06:06 AM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Distance between pump and waterfall

where should the pump be? There is 56" between the pump and the falls! John

#17
02-13-10, 07:22 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Vertical Distance

There is 3' between the pump and the waterfalls!
There is 56" between the pump and the falls!
The measurements keep changing!

The pump goes at the low point so it pushes the water to the top.

#18
03-12-10, 10:58 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Changing measurements

The measurement should read 3'. Also the pump is 3' away from the falls, should it be moved up? JohnBeer 4U2

#19
03-13-10, 06:22 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Pump

The lift is the vertical distance from the surface of the pond to the water outlet pipe at the top of the falls. Horizontal distance only means more pipe, not more lift. Is this in operation yet? How is it working?

#20
03-13-10, 06:30 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts

The height you must lift the water is the most important detail. Extra pluming length will cut the flow slightly because of the friction against the extra pipe but it has much less effect than the height to which you are pushing the water. I would locate the pump in the lowest part of the pond to help conceal it as much as possible even if it mean a couple extra feet of tubing.

#21
03-16-10, 10:35 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
No it is not in operation

This is in the planning stages, will be operational as soon I get the proper GPH, it will have a 3' lift of water and be 3' deep of water.

The question I do have, is that does it matter if the pump is 3' from the falls? or should they be right underneath the falls. Either way it could be in the deepest part!

Also I am going up to 1 1/4" PVC pipe. Will this make a difference if I want 1" waterfalls?

JohnBeer 4U2

#22
03-17-10, 07:10 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
The pump location in the lower pond is not critical. The extra 3ft of pipe will not add much resistance so it is better to place it where it is convenient for you go get at and where it looks best.

The pipe/tubing size needs to be determined by the size pump and gallons per hour. By choosing a pipe size before knowing how much flow you need you are boxing yourself in. You will end up choosing a pump to fit the plumbing regardless of how much water you want over the falls.

What do you mean by 1" waterfalls?

#23
03-18-10, 08:22 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
1" Waterfalls

Amount of water that comes out of the pipe and onto the rocks beheath them. There are 2 rows of waterfalls in a this formation: One at each corner, at a 6" height, and the others at a height of 1'6". The pipe will have 1 1/4" of water flow through them into a pool of water no more than 2' below.

I have a 750 GPH Pump, how much more GPH do I need to push the water through the pipe out on the rock with a rate of 1 1/4" per second?

Does this help?

John

#24
03-19-10, 06:19 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
Let's try this a different way. I'm building a pond and I want a waterfall 12" wide with water 1/2" deep as it goes over the falls. I calculate that this requires 1'200 gph flow.

I now need to figure out what pump I need to get 1'200gph flow. I need to know how high I must raise the water and the plumbing details. My top pool is 3ft above the bottom pool and I have 8ft of 1 1/4" pipe with one 90 degree fitting and one straight fitting. This gives me a total head pressure of about 6.8 feet. Now I look at the charts for pond pumps and find one that will pump 1'200gpm at 6.8ft. head.

----
Now, wherever you see a number (how wide you want the waterfall, height of the upper pool above the bottom pool, length of pipe...) substitute your numbers and post it back here.

#25
03-20-10, 11:06 AM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
How?

I want 4 waterfalls 1 1/4" wide with water 1 1/4" deep as it goes over the falls.

I only have (1) pool 3' deep pool and I have (4) 2ft of 1 1/4" pipe with one 90 degree fitting and one straight fitting. This gives me a total head pressure of about 6.8 feet. Now I look at the charts for pond pumps and find one that will pump 1'200gpm at 6.8ft. head. Don't I have to calculate the head pressure?
John

#26
03-21-10, 11:26 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Pump size

Let's try this a different way. I'm building a pond and I want a waterfall 12" wide with water 1/2" deep as it goes over the falls. I calculate that this requires 1'200 gph flow.

I now need to figure out what pump I need to get 1'200gph flow. I need to know how high I must raise the water and the plumbing details. My top pool is 3ft above the bottom pool and I have 8ft of 1 1/4" pipe with one 90 degree fitting and one straight fitting. This gives me a total head pressure of about 6.8 feet. Now I look at the charts for pond pumps and find one that will pump 1'200gpm at 6.8ft. head.
Dane, you seem to be using gph and gpm interchangeably. Which unit of capacity is correct?

#27
03-22-10, 06:23 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
You caught my typo. My reply should have all been in GPH. A 1'200 GPM pump would make a very impressive waterfall though.

#28
03-23-10, 10:41 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Here it is

Beer 4U2Let's try this a different way. I'm building a pond and I want 4 waterfall 1-1/4" wide with water 1 1/4" deep as it goes over the falls. I calculate that this requires 1'200 gph flow.

I now need to figure out what pump I need to get 1'200gph flow. I need to know how high I must raise the water and the plumbing details. My top pool is 21/2ft above the bottom pool and I have 5-1/2ft of 1 1/4" pipe with 4 90 degree fitting and 4 straight fittings. This gives me a total head pressure of about 6.8 feet. Now I look at the charts for pond pumps and find one that will pump 1'200gpm at 6.8ft. head.

How do I calculate the head pressure? and the gph? John

#29
03-24-10, 05:52 AM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,918
Received 55 Likes on 48 Posts
Pump

1,200 gph equals 20 gpm.......................

#30
03-24-10, 11:22 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
1 1/4" high by 1 1/4" wide is a rather odd dimension for the water going over a waterfall. It can be done but it will look & sound a bit more like a hose and less like a waterfall. Generally for the best effect the fall is much wider than the water depth like 6" wide with 1/2" deep water.

Next. You said you want four waterfalls, each with water going over the fall to be 1 1/4" wide x 1 1/4" deep. Area all four falls on the same level pouring out of the same pool (parallel) or are all four falls in a line with one leading to the other (serial)?

#31
03-26-10, 12:48 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts

The Pvc are 1 1/4" and the waterfalls will be 6" high and 12". They will all go into the same pool. Which is only 3' deep but that doesn't matter. The pool measures 25"X33".

The water will be 3/4" X 3/4" coming over the waterfall fed through a 1 1/4" pipe, in a staggered formation, like the diagram.

O O
O O

_____________
| |
| |
------------------

John

#32
03-27-10, 08:42 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
My Pond

http://img46.imageshack.us/img46/2029/poto0022.jpg

Here is a picture of my pond, as of right now i am using 1/2" pipe. But I will be using 1'1/4", with 3/4' flowing out of the waterfalls.

JohnBeer 4U2

#33
03-28-10, 06:53 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
A picture is worth a thousand words. It looks like you have the water squirting directly out from the tubing. I would get a pump to provide about 200 gallon per hour for each fountain/waterfall for a total of about 800 gpm. I would put a ball valve on the output of your pump or one ball valve in the tubing running to each outlet so you can control the flow. Close the valve a bit and you can have the water gently trickle out or open it up and have the water squirting out like a fountain.

#34
04-06-10, 11:51 AM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
How would I get 1" of water out of each tube

How would I get 1" of out of each tube consistently, all the time?
JohnBeer 4U2:

#35
04-06-10, 12:16 PM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 28,323
Received 1,624 Likes on 1,458 Posts
A valve for each fountain jet (waterfall) would allow you to adjust the flow to each one individually so you could get them just the way you want.

#36
05-01-10, 05:44 PM
Member
Join Date: Jul 2005
Location: USA
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
I have a 750 GPH Pump

You said I needed (4) 200 GPH pumps to drive the fountains, I already have a 750GPH pump how can I use this pump to create a 1" water out of a 11/4" PVC Pipe? JohnBeer 4U2