I am working on making improvements to an existing water system and have a few questions.  Background: 66 homes spread over 6 miles; distribution pipes are 4", 2", and 1.5"; Currently the well's 10 hp submersible pump runs continuously at about 90 gpm, causing the reservoir (located 2 miles away) to continuously overflow.

My preferred pump control option is to use a radio SCADA system to turn the pump on and off based on the reservoir water level.  Since I will be turning the pump on and off, I am concerned about pressure surges, but don't want to make this system more complicated than it needs to be. 
> Is a pump control valve needed?  It seems like they require a lot of additional valves (surge anticipator valve, check valves, and isolation valves) plus a way to discharge water
> Is a check valve sufficient? (there is aleady a check valve installed)
> Would a pressure reducing valve work?
> Would a cycle stop valve work?

I am also not sure about needing to install a soft start for the pump since it would now be turning on and off.  Are there any advantages to intalling a soft start?  Are they just an added expense that isn't really necesary?  Would having a softstart reduce the potential for pressure surges?

Sorry for the long list of questions. I would appreciate any insight you can give.

You definitely should have a pump control valve if you will be starting and stopping the pump. The pump control valve should include a slow closing check valve. Contact Cla-valve for recommended sizing.

The pump control valve will eliminate most of the pressure surges when starting the pump. The slow closing check valve will decrease the back surge should a power failure occur.

If you are discharging into the top of the reservoir, your suggestion of a level control system along with SCADA on the reservoir will work.

Turning the pump on/off is probably the least expensive method to control the system. If you are pumping into the bottom of the reservior, you can also use an inexpensive pressure switch to control the pump operation (instead of level control).

You may want to consider the use of a variable speed drive for the well pump. The benefit of the variable speed drive is that surge pressures from the starting/stopping of the pump will be eliminated.

The pipe network can obviously accommodate the surge pressure because it is existing and it has not blown up yet with switching on and off of the pump!.

You are going to with on and off much more frequently. The problem with uPVC pipe is it suffers fatigue and needs to be down rated for surge pressure. The amount of down rating depends on the frequency of the surge.  Unlike ductile iron pipe surge pressures in PVC pipe have to be accommodated within the pressure rating of the pipe.

A 10hp pump is not a big pump and adding a soft start/stop should not be too costly