Shallow Well for Irrigation HELP !!
#1
06-29-08, 02:23 PM
Shallow Well for Irrigation HELP !!
I live in the SC Lowlands near Hilton Head Island and thought that a shallow well would be very easy thing. HELP ! I started with a SS screened 3' x 1 1/4 pipe well point. Dug down about 4' till I was in water and attached 1 1/4" pipe and then pounded it down another 15' before I tested it with a 3/4 HP shallow well pump w/ check valve. I wish I had tested it at about 7 ' 10 feet ..??? At 19' I got small flow on the 3/4' hose @ 5 psi. At 21' I got some mud and then water, but not much better pressure. At 23' I got cold clear water at only 10 psi. I have no problems picking up the prime, but I'm statring to worry that I may have passed the water layer or may be getting too deep for a shallow well pump. I DO have water 6 - 8 feet below in the pipe, but I NEED about 35-50 psi ....5 to 8 GPM. Grateful for advice...
#2
06-29-08, 03:29 PM
I'm pretty sure that your area is in drought and has been in drought for quite a while. Not as bad as further west, but still pretty bad.
Even now, in the rainy season, there is still drought there:
http://www.drought.unl.edu/dm/DM_southeast.htm
You might want to try another one maybe 10 feet away. This time test as you go by jamming as much water as you can with two faucets and hoses at the same time and see if it backs up. If it backs up, keep pounding.
Let's say your luck is bad and you get another low producer. You could gang the two wells together with a valve on each one to balance the suction so one doesn't get pulled too much. Just make sure that you slope all the suction pipes up towards the pump.
Depth of operation for a shallow well is based on where the "drawdown" level is. That's the level where the water is after the pump is running. That is what has to stay above 25 feet. The well can be 50 feet deep, but the drawdown no more than 25.
Trying to pull water from 20+ feet takes some power, maybe more than you can do with a 3/4 hp pump. I know what the specs say, but without a pump curve, it will be hard to guess what the pump can do at that (drawdown) depth.
Even now, in the rainy season, there is still drought there:
http://www.drought.unl.edu/dm/DM_southeast.htm
You might want to try another one maybe 10 feet away. This time test as you go by jamming as much water as you can with two faucets and hoses at the same time and see if it backs up. If it backs up, keep pounding.
Let's say your luck is bad and you get another low producer. You could gang the two wells together with a valve on each one to balance the suction so one doesn't get pulled too much. Just make sure that you slope all the suction pipes up towards the pump.
Depth of operation for a shallow well is based on where the "drawdown" level is. That's the level where the water is after the pump is running. That is what has to stay above 25 feet. The well can be 50 feet deep, but the drawdown no more than 25.
Trying to pull water from 20+ feet takes some power, maybe more than you can do with a 3/4 hp pump. I know what the specs say, but without a pump curve, it will be hard to guess what the pump can do at that (drawdown) depth.
#3
06-29-08, 07:12 PM
I am wondering how much "standing" water you have?
I think you need to take some depth measurements, and find out where you "are" before you do anything else.
You know, drop a string down pipe for depth reading, then get a float and see where your static or "standing" water is.
Im a little confused, as you say you "hit" water at only 4 feet?
If you got water at only 4 feet down you should have plenty of water for a shallow well.
What kind of soil are you dealing with? Heavy clay? Sand?
Pay attention to what is coming out when you are priming and pumping, the sand is where the water is. When you reach sand/water, you can feel it, as pipe will go down very easily, as opposed to clay which is very hard and difficult.
When you do reach the water bearing sand, just keep pumping till it runs clear, and you have your well.
When I drove my shallow wells, I had to"adjust" them until I found the right depth with the most water, I also went to deep with mine, so I had to come up some to find the best water yield. So everytime you move the pipe up or down you check the water flow to determine best spot that will give you the most water. You may have to adjust it several times to get this right.
I think you need to take some depth measurements, and find out where you "are" before you do anything else.
You know, drop a string down pipe for depth reading, then get a float and see where your static or "standing" water is.
Im a little confused, as you say you "hit" water at only 4 feet?
If you got water at only 4 feet down you should have plenty of water for a shallow well.
What kind of soil are you dealing with? Heavy clay? Sand?
Pay attention to what is coming out when you are priming and pumping, the sand is where the water is. When you reach sand/water, you can feel it, as pipe will go down very easily, as opposed to clay which is very hard and difficult.
When you do reach the water bearing sand, just keep pumping till it runs clear, and you have your well.
When I drove my shallow wells, I had to"adjust" them until I found the right depth with the most water, I also went to deep with mine, so I had to come up some to find the best water yield. So everytime you move the pipe up or down you check the water flow to determine best spot that will give you the most water. You may have to adjust it several times to get this right.
#4
06-30-08, 08:14 AM
Originally Posted by Vey
I'm pretty sure that your area is in drought and has been in drought for quite a while. Not as bad as further west, but still pretty bad.
Even now, in the rainy season, there is still drought there:
http://www.drought.unl.edu/dm/DM_southeast.htm
You might want to try another one maybe 10 feet away. This time test as you go by jamming as much water as you can with two faucets and hoses at the same time and see if it backs up. If it backs up, keep pounding.
Let's say your luck is bad and you get another low producer. You could gang the two wells together with a valve on each one to balance the suction so one doesn't get pulled too much. Just make sure that you slope all the suction pipes up towards the pump.
Depth of operation for a shallow well is based on where the "drawdown" level is. That's the level where the water is after the pump is running. That is what has to stay above 25 feet. The well can be 50 feet deep, but the drawdown no more than 25.
Trying to pull water from 20+ feet takes some power, maybe more than you can do with a 3/4 hp pump. I know what the specs say, but without a pump curve, it will be hard to guess what the pump can do at that (drawdown) depth.
Even now, in the rainy season, there is still drought there:
http://www.drought.unl.edu/dm/DM_southeast.htm
You might want to try another one maybe 10 feet away. This time test as you go by jamming as much water as you can with two faucets and hoses at the same time and see if it backs up. If it backs up, keep pounding.
Let's say your luck is bad and you get another low producer. You could gang the two wells together with a valve on each one to balance the suction so one doesn't get pulled too much. Just make sure that you slope all the suction pipes up towards the pump.
Depth of operation for a shallow well is based on where the "drawdown" level is. That's the level where the water is after the pump is running. That is what has to stay above 25 feet. The well can be 50 feet deep, but the drawdown no more than 25.
Trying to pull water from 20+ feet takes some power, maybe more than you can do with a 3/4 hp pump. I know what the specs say, but without a pump curve, it will be hard to guess what the pump can do at that (drawdown) depth.
#5
06-30-08, 12:04 PM
Please try to describe what you are doing.
You say you "dug" down? What did you dig with?
Are you using 1 1/4 galvanized pipe?
Are you driving pipe down with post driver?
How much force does it take to drive pipe?
Do you know if you are in clay? Sand?
You can pull pipe up by bolting a muffer clamp to pipe, and then using a hydraulic jack or maybe a bumper type jack to lift it up.
If you have standing water at only 6-8 feet down, you dont need to go down, but maybe 15-20 feet.
The more info you can give us, the better we can try to help you. My experience comes from my own 3 shallow wells, that I drove in with a post driver. if thats what you are doing, then I can help you.
You say you "dug" down? What did you dig with?
Are you using 1 1/4 galvanized pipe?
Are you driving pipe down with post driver?
How much force does it take to drive pipe?
Do you know if you are in clay? Sand?
You can pull pipe up by bolting a muffer clamp to pipe, and then using a hydraulic jack or maybe a bumper type jack to lift it up.
If you have standing water at only 6-8 feet down, you dont need to go down, but maybe 15-20 feet.
The more info you can give us, the better we can try to help you. My experience comes from my own 3 shallow wells, that I drove in with a post driver. if thats what you are doing, then I can help you.
#6
06-30-08, 12:13 PM
Also, if your goal is to get at least 5 gpm, then you will need about 10 feet of standing water. but this does depend on how much water you have coming into well.
#7
07-02-08, 06:01 AM
this morning I am going to use 1/2 PVC to reach the bottom of my well, which I think is 25' deep and it has standing water in the pipe at around 6' below the ground. I intend to try to flush with 2 hoses and after it flushes out any mud that I suspect is sitting in the bottom, I will test it again. Then I'm going to try to jack the pipe up a few feet to where I remembering having a better flow ( 10 psi on a 3/4 garden hose with 1 sprinkler on it) and see if I didn't pass by some more promising levels as we sledged our way down. I'll keep ya'll posted. thanks BobHed 
#8
07-02-08, 08:00 AM
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At 19' I got small flow on the 3/4' hose @ 5 psi. At 21' I got some mud and then water, but not much better pressure. At 23' I got cold clear water at only 10 psi. I have no problems picking up the prime, but I'm statring to worry that I may have passed the water layer or may be getting too deep for a shallow well pump. I DO have water 6 - 8 feet below in the pipe, but I NEED about 35-50 psi ....5 to 8 GPM. Grateful for advice...
You have said a lot but not answered any questions that have been asked of you. Without answers, they can't help you. So how are you driving this Well? What size is it? What kind of SS Screen is it (this is very important)?
Another thing. A garden hose is not a good way to measure flow. What comes directly out of the pump in gallons per minute at "0" pressure is what we are looking for.
bob...
