Aiguebrun, so irrational!

The Aiguebrun takes its source of the north side of the Luberon to flow into the Durance on the south side! Three explanations to this illogical route: 1) The weakened zone, faulted and collapsed between Grand and Petit Luberon will collect run-off waters to the south. 2) The Luberon mountain, by rising, caused the depression of the river that was already there (antecedence phenomenon). 3) The drying up of the Mediterranean Sea, about 6 million years ago, will further accentuate this depression.