Wadi Saalek is a short wadi with many feeders, draining the hills round Gebel Saalek; one of its northern feeders leads to a pass into the head of Wadi Muegil, while one of its south branches heads in a pass leading round the west side of Gebel Um Reit to Wadi and Bir Um Reit.
Wadi Um Reit heads in the granite mountain called Gebel Um Reit and flows north-eastward, to the south of the mountain, for about twenty-two kilometres, to its junction with Arned and Saalek to form Wadi Hodein. The head of Wadi Um Reit leads to a pass north-west of the mountain into Wadi Saalek, while the western head of Um Reit, which bears the name Wadi el Dub, leads on to a sandy plain forming the main watershed, whence there are easy tracks to the various feeders of Wadi Timsah. The well called Bir Um Reit is a deep excavation, in the wadi floor at the foot of the mountain, near a large tree. Dr. Hume, who visited it in 1906, found it to yield water of only mediocre character. It is about one hundred kilometres by road from Bir Abu Hashim, the nearest well to the west, but only about thirty kilometres from Abu Saafa Springs, the nearest water eastward; to get to Abu Saafa from Bir Um Reit, one has only to follow down the wadi, and the supply at Abu Saafa can always be relied on for quantity and quality. Near the well, Wadi Um Reit receives feeders draining the high granite hills of Etresia; the principal of these is called Wadi Malhat. The lower part of the course of Um Reit is almost entirely in sandstone hills; it has not been mapped in detail except near its junction with Hodein.
We turn now to the main channel of Wadi Hodein, which originates, as above-mentioned, by the union of the Wadis Um Reit, Saalek, Arned, and other smaller wadis in a small plain, and shall follow its course onwards to the sea. Three small feeders, Talet Um Danaqa and Talet Kurit on the south, and Talet Um Sideri on the north, join the channel a few kilometres below its head, while about nine kilometres from the head there enters a larger wadi coming from the south, called the Wadi el Gihab. The main Wadi Gihab has not been followed, but its eastern branch, called Wadi Gihab Abu Derb, contains a large and very easily accessible galt about four kilometres from Hodein, and leads about ten kilometres further on, to a very steep and difficult pass into Wadi Dif; this pass is practicable only on foot, being risky even for unladen camels.
The Springs of Abu Saafa are situated in the Wadi Hodein, about two kilometres below the point of influx of Wadi Gihab, at an altitude of 310 metres above sea-level. The Wadi Hodein is here narrow, and shut in by very high steep sandstone scarps. There are four springs, all issuing from the northern scarp at intervals of about sixty metres along the wadi, and all about three metres above the wadi floor, trickling into pools about a metre in diameter close by. The most westerly of the four springs is a mere trickle; the next yields a rather greater flow, from a carved niche in the rock, with a Greek cornice; the third is the one most used, having the greatest flow of the four, while the easternmost is almost stagnant and has yellow incrustations near it. The rate of flow, even from the largest spring, is very slow, probably not more than ten litres per minute, and the overflow from the pools is only a tiny stream a few centimetres wide which soon loses itself in the sand of the wadi floor; but the pools are large enough for a dozen or more camels to drink from, and soon fill up again when emptied. The water is of excellent quality, very clear, and the supply never fails. Near the springs there are five or six small date palms, and the wadi hereabouts has many other trees. After rain, this part of Wadi Hodein at times becomes a stream; this was the case in October 1907, for I found numerous pools in the wadi floor, and scum and froth showing that an impetuous stream about half a metre deep had flowed down the wadi only a few days prior to my visit. Just below Abu Saafa Springs, Wadi Hodein receives the short Wadi Maghal from the north-west; this wadi, which is walled in by high sandstone plateaux, contains water holes about three kilometres from Wadi Hodein; but these are less important than the springs of Abu Saafa, and are, moreover, off the main road.
Wadi Hodein now opens out, the high sandstone scarps of Gebels Abraq and Hodein running north and south-east, and enters a sandy plain with very low hills, from among which some small feeders join the main wadi. About fifteen kilometres below the opening of scarps, Wadi Hodein receives, from the north-west, the Wadi Naam,[96] a great tributary draining the mountains of Zergat Naam, Um Bisilla, and Abu Dahr. The next influx is from Wadi Dif, which enters Wadi Hodein from the south-west about six kilometres further on; Wadi Dif itself is only a short wadi, but it collects the drainage of an immense area to the south by long feeders, and contains a good well. Nearly opposite to Wadi Dif, the Wadi Orga el Atshani joins Wadi Hodein from the north-west; the Wadi Hodein has here two large island-like masses of low hills in it, between which the main drainage line passes. Lower down, Wadi Orga el Rayani enters by two mouths from the north. Both the Wadis Orga are said to originate near Gebel Orga, some thirty kilometres to the north, but their courses have not been mapped; the one called El Rayani is said to lead to a good well, Bir Orga, about twelve or fourteen kilometres above its junction with Hodein. On the opposite (south) side, Wadi Hodein receives the Wadi Anfeib, draining the high sandstone plateau of Gebel Anfeib. A little further on the small Wadi el Khasiya comes in from the north, by two channels, one on either side of a small group of isolated hills; and nearly opposite is the mouth of Wadi Madi, which drains the west side of the great mountain mass of Gerf, some sixty kilometres to the south, and possesses a good well about fifty kilometres up its course from Wadi Hodein. Several feeders come in from the north a little further down the wadi, of which the chief is the Wadi Um Tenedba, draining the mountain of the same name, while others drain the hill country round Gebel Harhagit. On the other (south) side is the mouth of Wadi Khashab, draining the west side of Gebel Khashab and the hills west of it. A few kilometres further on, Wadi Hodein widens considerably, and from here onward it is very sandy and arid. A long spur running north-west from Gebel el Anbat nearly cuts across the wadi, the main channel of which passes north and east of the spur, while to the west of it is a rather broad sandy plain with ill-marked drainage lines from the hills, of which the chief bears the name of Wadi Um Seleim. Near Gebel el Anbat are numerous small feeders of Wadi Hodein from that hill and the other hills to the north-east. About eight kilometres below Gebel el Anbat, Wadi Hodein quits the hills and, turning a little north of east, merges into the coast-plain, over which its remaining course of about twenty-seven kilometres is very ill-defined. Just where it leaves the hills, Wadi Hodein is joined from the south-west by Wadi Beida, draining the mountain of the same name and containing two wells; and a little further on it receives Wadi el Kreiga, which drains the hill country round Bir Meneiga. The junctions of Wadi Beida and Wadi Kreiga with Wadi Hodein are very difficult to trace on the ground, being almost lost in the general sandy plain.
Bir Shalatein, a very salt well in the Wadi Hodein, about two kilometres from its mouth and only about seven metres above the sea, is chiefly of importance by reason of its marking the administrative limit of the Egyptian and Sudan spheres of government. It is merely a few shallow pits sunk in the wadi bed, yielding water drinkable only by camels. An iron beacon two metres high has been erected on a low bank close to the well, and will enable the well, which is itself inconspicuous, to be easily found.
Wadi Naam, a great tributary of Wadi Hodein coming from the north-north-west, originates about ten kilometres south-east of Gebel Zergat Naam by the union of the Wadis Abu Seyal, El Fil, and Um Bisilla, and courses south-south-east for about forty-nine kilometres to its junction with Wadi Hodein. It is a very barren wadi, being for most of its length a broad, shallow, and very sandy drainage line among low hills, and in its lower parts, where it crosses the plain of Abraq, its course is very ill-marked. Its slope decreases from five metres per kilometre near its head to about three metres per kilometre in its lower reaches. Besides the three wadis which, as above-mentioned, unite to form its head, Wadi Naam has several large tributaries, of which the chief are the Wadis Silsila and Abraq on the west, and Wadis Erf Um Araka, Arais, and Betan on the east.
The Wadi el Fil, which may be regarded as the main head of Wadi Naam, though it is not the longest, drains the north-east portion of Gebel Zergat Naam (sometimes called Hagar el Fil). The rocky gullies forming its heads contain rock basins which yield water for a short time after rain.
Wadi Abu Seyal drains the south part of the same range; its head is very steep, and is said to contain a very large galt, which holds supplies of water for five months after rain.
Wadi Um Bisilla drains Gebel Um Bisilla, which it half encircles, its main head being north-east of the mountain, where there is an easy pass into Wadi Abu Nilih, and thence an easy road to the head of Wadi Lahami. About eleven kilometres west of the mountain, Wadi Um Bisilla receives, from the north-east, the Wadi el Khiua, which, with its tributaries, Wadis Abu Fagir and Abu Nilih, drains the low hill country north of Gebel Um Bisilla. The lower parts of Wadis Um Bisilla and Khiua have not been surveyed in detail; their courses as shown on the map are only approximate, but being based on guides’ statements near the spot they are probably substantially correct.