I have a large garden and am trying to figure out what pump size I need. I am going to pump from a pond and looking at a semi trash pump 58 GPM, 163 OHV engine, Inlet dia., 2", Outlet dia., 2", Total Head: 98' and 1,700 ft of pipe from my pond to the garden and with Rainbird impact sprinklers that put out 5.60 gpm @ 30 psi.

So my question is if I reduce the pipe size down to 3/4" and each sprinkler head is mounted 4 ft high mounted to a pole how many impact sprinkler heads can I run simultaneously.