The private pilot positioned the landing gear handle to the "gear down" position in preparation for landing. The gear did not extend and the circuit breaker popped. The attempt to reset the circuit, but was unsuccessful. The pilot then turned toward an unpopulated, desert area and attempted to lower the landing gear through the hand pump. There was no pressure on the pump handle and it was determined that the hydraulic reservoir was low. The pilot, with the assistance of his passenger, opened the reservoir and added water to regain pressure and extend the landing gear. The gear appeared to be down with a visual check but there was no "down and locked" indication on the instrument panel. The pilot diverted his attention inside the cockpit in an attempt to troubleshoot the system. During this time, the airplane impacted the ground in a near level attitude. The nose gear was torn off, the propeller was damaged, and the left wing was substantially damaged. The airplane came to rest in the upright position. The pilot and his passenger were not injured and were able to egress unassisted. The pilot stated in the Pilot/Operator Report that the accident could have been prevented if he had remembered to keep flying the airplane.