There is quite an eerie duality between the lakes of the "wild" west-flowing rivers (in general they flow to wards Lake Eyre) and the "tamed" west flowing rivers. A series of lakes in the "wild rivers" (eg Lake Yamma Yamma, Diamantina lakes, Coongie lakes, etc.) Considerably slows the flow to the treeless salty pit in the end point (Lake Eyre). On the way, these storages are the lifeblood of both wilderness in these catchments(waterholes, trees, wildlife), and for human resources in those same catchments (mainly sheep/cattle grazing).
If you compare this with the Murray/Darling basin, all the human endeavour that has toiled to tame it has merely expanded on this natural system of floods being trapped. Both for the environment and human uses, it is an amazing extension, as the facts remain that floods and drought are as damaging to the natural environment's inhabitants as they are to human habitation. The remaining floods and droughts in the system are still primarily in the gaps where there is no suitable "lake" to absorb floods and make the water available through some of the following drought. I am estimating that by the end of this La Nina year, as much as all the water capacity of all of the Murray Darling water storages will have flowed out through the barrages of Lake Alexandrina. It is an open question as to whether the floods have nicely "reversed" the whole of the environmental damage done through the 10 or so years of it being a closed system (in drought, as it were). Although climate scientists have deemed the last 10 or 20 years as the new normal - I would suggest that it is a very brave call to BET that there will be similar droughts within our lifetime, as opposed to the usual contrived predictions.
If we could have harnessed even half of that water flowing away to the sea, the floods would have been even more controlled. At least we should have generated some osmotic energy from it at Lake Alexandrina, instead of just talking desalination. In the next few years of relatively plentiful water (even if we have a drought immediately after this La Nina) It makes no economic sense to buy (at a high price) water allocations from farmers who would use it to make a profit, for the environment which doesn't need it at that moment because of the soil storage from this recent series of flood events. Just feel grateful that we have got so much flexibility due to large natural and artificial storages, and perhaps plan some more future bountiful lakes that can be huge long term environmental assets for a relatively small environmental and human adjustment upfront price in drowned valleys.