Best way to increase GPM from existing deep well

I have a 2.5 gpm deep (400’) well that I’d like to draw more from. It’s consistently delivered 2.5 for decades at 104’ (nearby river depth)
The two options I’m considering are some sort of fracing or an additional well. Concerned fracing might compromise existing well since it’s so low flow..

tnx

 

Are you planning to do a lot of irrigation? For house use, a deep well use has significant storage ability. Replenishing at 2 gpm would normally support a big house. Did you run dry at some point? If so, maybe lowering the pump would be worthwhile.

With a 4 inch well and a pump hanging on 1 inch pipe, there is about 58 gallons of storage in 100 ft. With a 5 inch well, about 95 gallons. With a 6 inch well about 140 gallons. These storage numbers do not include new water coming in during the draw.

These gallon numbers are a little lower than you will sometimes see, because it subtracts the space for the 1.315 inch OD drop pipe.

 

Can't empty that out normally, so it doesn't count IMO.

 

Thanks for all the input.
The flow rate is more of a demand and pressure issue (high flow rates can exceed the pumps recovery rate). It's largely irrigation (flower beds mostly) when it does occur. We do use drip irrigation and sequence it throughout the day, which made a huge difference in water usage, but I'd like to be able to provide more flow without drawing the system down too much. I monitor the pressures, flow and well depth in realtime so I probably worry too much , but I don't like it getting below 140+'. The pump is at 350' I believe, so I realize there's more water available, but I like to think of it as a reserve and find more on demand water vs storage (ie cistern).

Am I correct in assuming that fracking can cause as much damage as improvement? Our last earthquake (albeit a small one) caused a lot of extra silt, although no change it flow. I'm pretty sure we're closely linked to the nearby river, as when we have a large rainfall that causes the river to rise several feet, I can see our well level go up as well within a very short period..

If I did install a new well, would I be able to connect it in parallel to the existing system (assuming the pressure switch points were set appropriately)?

Thanks!

 

Seems like zoning that out to reduce the peak demand, and spacing out the irrigation, would be a lot simpler than digging a new well or adding storage.

Cheers, Wayne

 

Good comments..
I already space out the irrigation, it sequences itself automatically depending on the soil moisture and weather reports. I'm sure I'm overly concerned, I just like to have spares of everything

I haven't dropped it that low, but I've accidentally (hose left on before I built a hi flow/low well level alarm) dropped it down to the 250' area several times. When I graph the refill rate, it's almost identical to the normal refill rate (2.5 gpm) which is curious. I think it's partially due to why I have such a slow flow rate, as the ground content at 104' (where the water is sourcing from) must be somewhat restricted. My normal depth sits at 96.5' (except when the river rises significantly), and I attribute that 7.5' rise to the pressure of the inlet water (~3 psi) which isn't all that much push..

Thanks

 

While you said the well is 400' deep, how deep does the casing extend and how deep is the screen located? If the casing extends to 400' and if the screen is located near the bottom of the casing, then water will only enter into the casing through the screen and through the open bottom end of the casing and so will rise within the casing to the static level. If pumping the water level down closer to the screen location, the well may recover faster than when pumping down to only 140 or 250'.

 

It sounds like the 400 foot depth only serves as expensive storage. If the water enters at 104 feet, then pumping lower than that will not increase the recovery rate.

 

This assumes 100% of the water is actually entering the casing at 104'.

With a 400' well with the pump placed at 350', I anticipate water will enter the casing at a greater depth.