Advice on residential well pump system

I am looking for some advice on the best system for my application. My well is 700 feet deep, my static water level is 40 feet, and the delivery from the well is 5 gpm. In the short term I want to fill a large holding tank of about 2500 gallons about once per month to water my animals while running the pump from a 5 kW generator and in the long term supply potable water to my residence, which is 3 1/2 baths, and two outbuildings while running the pump from the grid.

I have now consulted three different suppliers of pumps and also have studied pump curves. One basic problem is that pumps which can deliver 5 gpm from 700 feet exceed their recommended maximum flow rate at 40 feet. From talking with a representative from Gould, my understanding is that upthrust is created when the maximum recommended flow rate is exceeded and that this is damaging to the pump. A couple of people have mentioned adding a Dole valve but this seems to me wasteful of energy because this valve creates a restriction to develop back pressure and because once connected to the residence, the pump will be working mainly near the static level.

A second basic problem is that the start up current required by a hard start is high which the generator can not deliver for a decent sized pump of 1 1/2 to 2 hp.

Conceptually at least, the solution that makes some sense is to have a system which monitors the flow rate and limits this so that the maximum is not exceeded. Such a system would require variable speed with a soft start which would have the added advantage that the generator capacity could deliver enough current to get the pump started.

While I have seen variable speed systems that deliver constant pressure, I have not seen a system that limits maximum flow. Also in reading about variable speed systems on another thread, these are not reliable.

Another solution suggested to me by the Gould rep was to put a small pump in the well to keep the tank full, use a booster pump to the residence, and a UV purifier. My main issue with this is that I would like to distribute potable water to multiple buildings (up to 3) in which case a UV purifier would be needed for each building.

Considering all of these issues, what would you recommend.

On the well log where was the incoming water...Upper

You can use water at a much higher rate than 5 GPM until the water level in the well drops to 700'. With 660' of water in the well, you have about 1,000 gallons stored that you can use as fast as you want. I would use a 7GS20 that can pump 10 GPM from as deep as 500'. Then add a 10 GPM Dole valve to keep it from up-thrusting. A Dole valve does not waste energy. The amps will be less at 10 GPM with a Dole valve, than they are at 14 GPM and up-thrusting.

This will give you up to 10 GPM without needing a storage tank and booster pump. You can even do more GPM if you want.

To protect the pump from Dry Running, you need a Cycle Senor that looks for low amps, knows when the well is dry, and shuts the pump off.

If you use 620' of #8 wire, and finish with 80' of #6, this will give you a reduced voltage soft start. This will give you a 20% reduction in starting current, and a 36% reduction in starting torque. Should make it easier to start with the generator.