Just had a look at the last OB and there DC states that the Namoi is 1/6 the thickness of the Bohena and less areally extensive .. so reduce my guesstimate from 1,600 PJ to say 1,000 - 1,200 ish. But the numbers could be greater due to the high flow rate and of course as the Bohena flow rates and numbers grow the estimate goes up as well.
H