In 1944 the flow was less than 1,000 megalitres ( 810 acre-feet ) . Six years later ( 1950 ) there was a flow of 10,900,000 megalitres ( 8.8 million acre feet ) . Annual flows have ranged from less than 1,000 megalitres ( 810 acre-feet ) in 1944 to as much as 10,900,000 megalitres ( 8.8 million acre feet ) in 1950 .