In respect to Sydney dam, the Shoal Haven river is a good examole of how a water system is puctured by mining and the flow diverts into the aquifer, In 2002 something very strange happened to Warragamba Dam, the water mafia have been very quiet about this and have not offered any explanation as to why the levels refuse to rise above 60%, some clues may be found in the re-opening of the aquifer pumps under the Warragamba dam structure, Sydney is actually sitting on more than 50 gl's of water distributed in 3 aquifers, the largest being in the west, 30 gl to the north, in the sandstone country around Hornsby almost 20 gl, and the smallest between Centenial park and Botany bay 5-10 gls, with the potential of being much greater if the Botany swamps were restored. If our drainage system was change so it did not discharge into the sea, but recharged the aquifers we would have more water in Sydney than the population could use in a life time. A little off topic now, but another interesting feature of the Botany swamp, or where it once was, is that it carries an electrical charge, aprox. 2 to 4v and it appears that this is with unlimited amps. It is theorised by some that the swamp acts as a giant battery and by others that a mineral strata possibly quartz acts like a giant capacitor.. I have personally measured this phenomena and can confirm it does exist, I dont subscribe to either of these theories and offer no explanation