Concerning the closure of the Nile, I ran across this in the Sibylline Oracles (V ll. 484 ff.):

Isis, wretched goddess, thou shalt be left solitary by the waters of the Nile, a raving maenad by the sandy shore of Acheron, and no memorial shall be left of thee in all the world. And thou, Serapis, dwelling on thy pile of profitless stones, shall lie a vast ruin in the midst of wretched Egypt. And all in Egypt who sought unto three shall bewail thee with sorrow [...].

It was almost true fifteen hundred years ago, and it will surely be true soon enough...