To pump 10,000 gph, that is a per minute rate of 167 gal. I recently rigged up a gear pump from an oilfield tanker truck that will pump at that rate or better. I've got it bolted onto an old brushhog and drive it with the PTO on my JD 4020, a 95 hp farm tractor. I haven't tested the flow rate yet, but it seems to pump pretty darn well (about a 6 ft stream out of a 3 inch pipe at idle).
