Lake Qarun (Nile River, Egypt)

Lake Qarun is a saline lake about 45m below sea level located in the Faiyum Depression just 80km southwest of Cairo. Of hydrological significance for me is its connectedness to the Nile River. It seems that it is fed in part by the Nile River, although in reality this feeder system most likely never reaches the lake itself and is instead completely withdrawn for the intensive irrigation needed for the agricultural production in the depression. Upstream of Cairo, the Nile River has a much smaller parallel river to the west, one that must have been originally formed during the routine flooding of the Nile, but which is now stabilized in its location since that flooding has stopped (due to the Aswan High Dam). This parallel river, called ???, originates when it splits off via a manmade channel from the mainstem of the Nile much farther upstream (just south of Mallawi). That river can be seen in this map from the website of the Lake Qarum Project of the University College London

(image url: http://ecrc.geog.ucl.ac.uk/qarun/images/faiyum_map.gif):

On the same website, the History of Lake Qarum gives a good overview of the basin itself. As I mentioned, of hydrological significance is the question of Nile connectivity. The following image from Google Maps shows the exact point where that connectivity occurs (the image that follows shows, with the green arrow, where this occurs in relation to the depression). The river comes in from the south and splits here: the north and northwest channels both send the water northwest into the Faiyum, whereas the eastward flowing channel sends the water back along the course of the Nile and into the delta.