EE WAS REMOVING A 4"" INTAKE HOSE FROM OUR WATER TRUCK AFTER IT HAD REACHED FULL CAPACITY. AS HE WAS REMOVING THIS HOSE, HE STEPPED ON A 2"" WATER HOSE THAT WAS RUNNING. THIS CAUSED WATER FROM THE 2"" HOSE TO SPRAY HIM. HE WAS JUMPING OUT OF THE WAY WHEN HE HIT THE LEFT SIDE OF HIS RIGHT KNEE ON A 1 1/2"" SQUARE METAL DRAIN PLUG WHICH PROTRUDED FROM THE REAR SIDE OF THE WATER TRUCK.