Please critique my pump/pipe plans

[Valveman]

If while pumping 10+ GPM the water level only pulled down to 72', then you have more than 10 GPM recovery from 72'. It doesn't matter the recovery rate to get water back to full static level. What matters is how much water you can pump without drawing the well down and running the pump dry. If the water level did not get any deeper than 72' while pumping 10+ GPM, then your pumping level is 72' and the well can produce 10+ GPM.

 

[DStyduhar]

Sorry, should have been clearer. They didn't pump down until the level stopped changing....only for 20min or so. Should I have asked them to keep going until the level stabilized?

If it was pumping 10GPM, wouldn't the level stabilize only when the recovery is the same amount?

 

[Sponsor]

 

[Valveman]

So now you really don't know how much the well will produce. All you know is how long it takes to recover to the static level. I would have run the pump until the water level was 10' above the pump, or stopped dropping, regulated the flow with a ball valve to make the level stay 10' above the pump, then I would know how much and from what depth the well will produce.

 

[DStyduhar]

The original driller said the well will produce 25 GPM and the pumping level was 125'. I guess I assumed this means the level stabilizes @ 125' but that doesn't make sense now that I think about it......... as wouldn't that mean the recovery would be 25GPM at that depth??? So likely, the original pumping level test was run over time. When I called to ask him, he didn't have any info on pumping level tests and standard times during the mid 80's.

How does recovery change over depth? If I'm seeing 2GPM @ 50-70 feet, would it be significantly different at 150ft? Don't need numbers, just
an idea. Similar? Could it be multiple times different?

Is it possible I would be running that pump wide open all damn day to get it down to where I "think" the pump is hanging?

thanks,

Drew

 

[Reach4]

Is your interest mainly academic? Are you wondering if you should install a monitor to shut down the pump for a while if you run short of water? Are you thinking of adding higher water use activities if you can?

 

[Valveman]

That means your well will produce 25 GPM from 125'. That is really all you need to know. The lower you pull the water level in the well, the lower the down hole pressure, and the more water will come into the well. Your well will only make 2 GPM from 75', but it makes 25 GPM from 125'. The real production of the well is how much you can pump 24/7/365. If your well has a 25 GPM production rate, the recovery rate to the static level doesn't really mean anything. Recovery rate is important with low producing wells, as you have to wait for it to recover.

 

[Boycedrilling]

We can usually reduce a flow test to gpm per foot of drawdown. If a well produces 2 gpm per foot of drawdown, we can make projections. At 10 gpm it would drawdown 5 feet. At 20 gpm it would draw down 10 feet. This is only valid if we know what the flow rate is at a non-fluctuating pumping level.

 

[Boycedrilling]

So far you only know what the pump will produce. Not what the well will produce.

 

[DStyduhar]

Is your interest mainly academic? Are you wondering if you should install a monitor to shut down the pump for a while if you run short of water? Are you thinking of adding higher water use activities if you can?

Yes to all three. I plan to do some small scale irrigation, nothing crazy. Likely have two impact sprinklers and run an hr on/ hr off during the night. Just trying to get a better feel for my well before I start dumping money into it.

 

[DStyduhar]

That means your well will produce 25 GPM from 125'. That is really all you need to know. The lower you pull the water level in the well, the lower the down hole pressure, and the more water will come into the well. Your well will only make 2 GPM from 75', but it makes 25 GPM from 125'. The real production of the well is how much you can pump 24/7/365. If your well has a 25 GPM production rate, the recovery rate to the static level doesn't really mean anything. Recovery rate is important with low producing wells, as you have to wait for it to recover.

Ok. when I talked to the original well driller, he quoted 125' as the "pumping level" so wouldn't that imply that is where the water level stabilized when pumping 25GPM? Let's say he pumped the well @ 25GPM over 2 hours and it was @ 125' and still dropping. He couldn't call that the pumping level since it never stabilized, no? Again, not sure how long he pumped it for but once it stabilizes over a certain amount of time, don't folks assume that is the 24/7/365? Maybe I'm not understanding what you said...

thanks,

Drew

 

[Reach4]

Ok. when I talked to the original well driller, he quoted 125' as the "pumping level" so wouldn't that imply that is where the water level stabilized when pumping 25GPM?

That is where he mounted the pump.

 

[DStyduhar]

Ok, please help a dummy understand this.

The driller put a pump @ 125' deep...I assume a 25GPM or??? He let it pump and then how did he determine the well is capable of 25GPM? Because it never drew the well down to the pump?

Why wouldn't the driller have done the same thing but 20-25 off the bottom to better determine a real position of the pump?

thanks for the help guys.

Drew

 

[Valveman]

If while pumping 25 GPM the level stabilized at 125', then 125' is your pumping level and 25 GPM is your well yield. But if the water level was still dropping and he just quit because the pump was at 125', then you still don't know how much the well will make and from what depth. Yes I would have put a pump closer to the bottom and throttled it with a valve until I figure the yield and pumping level. But if the level stabilized at 125', you could set the pump just lower than that.