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 VALVE 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