Note dated April 1957 on the Borehole records that states that letter dated 14 Nov 1956 says Submersible Pump installed instead of an Air Lift water pump. An air lift works by using compressed air bubbled into the water. This makes the water less dense than water in the well and causes an upward movement. Articles suggest that air has to be bubbled into the water at least as deep below water level as the hight of lift required. Accurate metering would require the entrained air bubbles removed.