The wadi floor falls from a level of 484 metres near Erf el Fahid to 375 metres at Bir Muelih, the length of the wadi between the two places being about twenty-seven kilometres; this gives an average fall of about four metres per kilometre; the actual gradient varies from about two metres per kilometre in the broader portions to over six metres per kilometre in the more enclosed parts of the wadi.
The upper parts of Wadi Muelih are barren and sandy, but the lower portions contain a fair amount of vegetation. The principal feeders of Wadi Muelih are Wadi Gerf, which enters by several openings on the left above Gebel Muelih, Wadi Samut, entering on the right in long. 33° 54′, and Wadi Sibrit, entering on the left in long. 33° 50′.
Wadi Gerf is the collective name given to a number of rather complicated drainage channels forming tributaries to Wadi Muelih. The principal heads are to the east and west of Gebel Nugrus. The eastern head is called Wadi Hangalia; it commences at about an altitude of 811 metres due east of the highest point of Gebel Nugrus, at a difficult pass leading over the main watershed to Wadi el Nom, and curves round the north spurs of Gebel Nugrus to join the western head. In the Wadi Hangalia are some old ruins of a mining camp, and also some recent prospecting workings and a well giving a poor supply of water. The Western head of Wadi Gerf commences in nearly level ground on the main divide west of Gebel Nugrus, at an altitude of 691 metres. These two main heads unite close to the east of Gebel Ras Shait, whence Wadi Gerf courses about north-west through low hills. A third head is in lat. 24° 52′, at a pass leading into Wadi Um Khariga. A fourth, called Rod el Atut, takes the drainage from all sides of the conspicuous black cone of Gebel Atut. A fifth, called Rod Um el Farag, drains from the mass of moderately high hills further west called Um el Huetat; these hills contain some old mines, chiefly in talc schists. The drainages from these various heads all eventually take a west-south-west course among low hills and over a sandy plain and enter Wadi Muelih by several openings near longitude 34°. Minor tributaries are Wadi Abu Seyal and Wadi Um Seyal, south-east of Gebel Atut, Rod el Ligaia, in longitude 34° 10′; and Rod el Ligah, in latitude 24° 50′.
The principal hills of the plain over which Wadi Gerf and its tributaries run their course are some very remarkable small black peaks collectively called Khusa el Faraon, a light coloured hill called Marwot Rod el Ligah, and a ridge called Erf el Sagur; these two last rise to 514 and 523 metres above sea-level respectively.
Wadi Gerf possesses a fair amount of vegetation, except where it meanders over the sandy plains; in the tributaries Wadi Um Seyal and Wadi Abu Seyal acacia trees are specially numerous.
Wadi Sibrit is a long narrow wadi following a course somewhat south of west, originating to the west of Gebel Mudergeg and joining Wadi Muelih in longitude 33° 50′. It possesses many trees and a good well, Bir Sibrit. This latter is an excavation in the wadi floor, in longitude 33° 58′; it is said to yield a constant supply. In the spring of 1906 I found the water was at a depth of eight metres below the surface, and of good quality.
Wadi Kharit, one of the greatest trunk wadis of Egypt, has its principal head at Gebel Ras el Kharit, on the main watershed in latitude 14° 10′ and longitude 35°. Pursuing a course the prevailing direction of which is a little north of west, and collecting the drainage from numerous great wadis on its way, it debouches on the Kom Ombo plain and reaches the Nile at the same point as another great wadi, Shait, in latitude 24° 35′. The length of the main channel is over 260 kilometres, and of its tributaries probably more than twenty times as great. It drains an area of more than 23,000 square kilometres. Its average fall is about two metres per kilometre, but in its lower reaches its gradient is less than half this amount.
The principal tributaries of Wadi Kharit, which will be separately described, are the Wadis Natash, Antar, Khashab, Abu Hamamid, Elemikan, and Garara (this last with Wadis Timsah and Ghadrib as great feeders). I now propose to trace out the course of the main wadi in some detail, leaving its greater tributaries for separate description, but including its minor feeders.
The main head of Wadi Kharit is on the Nile-Red Sea divide, between Gebel Ras el Kharit and Gebel Mikbi, at an altitude of considerably more than 600 metres above the sea. The wadi at first courses a little south of west, over a gently falling sandy plain with hills of bouldery granite, and curves round the south spurs of Gebel el Anbat.[85] Here it receives two tributaries, one from the north-west called Wadi Hilgit, and one from the south-east called Wadi Egat.[86]
Wadi Hilgit originates on the main watershed in longitude 34° 52′, near Gebel Um Usher. A very steep and difficult pass over the watershed separates its head from that of another Wadi Hilgit draining northward to Wadi Huluz. The two wadis are called Wadi Hilgit lil Kharit and Wadi Hilgit lil Huluz respectively when it is necessary to distinguish them. On its course southward to Kharit, Wadi Hilgit receives as tributaries Wadi Um Hasidok and Wadi Um el Tiur, draining the mountains of the same names.