THE PILOT REPORTED THAT JUST AFTER LIFTOFF FROM THE WATER, HE ENCOUNTERED A CHANGING WIND CONDITION THAT CAUSED THE AIRPLANE TO SETTLE BACK ONTO THE WATER. WITH INSUFFICIENT STOPPING ROOM ON THE LAKE, HE JERKED THE AIRPLANE BACK INTO THE AIR IN ORDER TO CLEAR THE 4 TO 6 FOOT HIGH SHORELINE. THE AIRPLANE THEN SETTLED TO THE GROUND AND NOSED OVER ABOUT 40 YARDS FROM THE LAKE.