| lake borullus of the nile delta: a short history and an uncertain future. | borullus, the most centrally situated of the nile delta lakes, probably evolved around the eighth century ad from a preexisting salt marsh by fluviatile deposition of sand dunes north of the lake and subsidence of the preexisting tidal swamp behind this barrier. it was flooded yearly (september-december) by the sebennytic branch of the nile, and evacuated water through an exit, bughaz. at low river levels, this process reversed and bughaz functioned as a marine inlet. because of this switch, its ... | 2007 | 18240684 |