Orange, the longest river of South Africa, almost traversing the continent from ocean to ocean. It rises in Basutoland, less than 200 m. from the Indian Ocean, and flows west, with wide sweeps south and north, to the Atlantic. It drains, with its tributaries, an area estimated at over 400,000 sq. m., passing through more than twelve degrees of longitude or 750 m. in a straight line from source to mouth. The valley of the river exceeds l000 m., and the stream has a length of not less than 1300 m. Its headstreams are in the highest part of the Drakensberg range, the principal source, the Senku, rising, at an elevation of more than 10,000 ft., on the south face of the Mont aux. Sources in 28° 48' E., 28° 50' S. The other headstreams are S.E. of the Senku source, in Champagne Castle, Giant's Castle and other heights of the Drakensberg. The Giant's Castle source is not more than 130 m. west of the Indian ocean in a direct line.
Rising on the inner slopes of the hills these rivulets all join the Senku, which receives from the north several streams which rise in the Maluti Mountains. Of these the largest are the Semene and Senkunyane (little Senku) and the best known the Maletsunyane, by reason of its magnificent waterfall - an unbroken leap of 630 ft. Increased by the perennial waters of these numerous torrents the Senku makes its way S.W. across the upland valleys between the Maluti and Drakensberg ranges. After a course of some 200 m., passing the S.W. corner of the Maluti Mountains, the Senku, already known as the Orange, receives the Makhaleng or Kornet Spruit (90 m.), which rises in Machacha Mountain. The Orange here enters the great inner plateau of South Africa, which at Aliwal North, the first town of any size on the banks of the river, 80 m. below the Kornet Spruit confluence, has an elevation of 4300 ft. Forty miles lower down the Orange is joined by the first of its large tributaries, the Caledon (230 m.), which, rising on the western side of the Mont aux Sources, flows, first west and then south, through a broad and fertile valley north of the Maluti Mountains. At the confluence the united stream has a width of 350 yards. Thirty miles lower down the Orange reaches, in 25° 40' E., its southernmost point30° 40' S., approaching within 20 m. of the Zuurberg range. In this part of its course the river receives from the south the streams, often intermittent, which rise on the northern slopes of the Stormberg, Zuurberg and Sneeuwberg ranges - the mountain chain which forms the water-parting between the coast and inland drainage systems of South Africa. Of these southern rivers the chief are the Kraai, which joins the Orange near Aliwal North, the Stormberg and the Zeekoe (Sea Cow), the last named having a length of 120 m. From its most southern point the Orange turns sharply N.W. for 200 m., when having reached 29° 3' S., 23° 36' E. it is joined by its second great affluent, the Vaal. Here it bends south again, and with many a zigzag continues its general westerly direction, crossing the arid plains of Bechuana, Bushman and Namaqualands. Flowing between steep banks, considerably below the general level of the country, here about 3000 ft., it receives, between the Vaal confluence and the Atlantic, a distance of more than 400 m. in a direct line, no perennial tributary but on the contrary loses a great deal of its water by evaporation. In this region,` nevertheless, skeleton river systems cover the country north and south. These usually dry sandy beds, which on many maps appear rivers of imposing length, for a few hours or days following rare but violent thunderstorms, are deep and turbulent streams. The northern system consists of the Nosob and its tributaries, the Molopo and the Kuruman. These unite their waters in about 20° 40' E. and 27° S., whence a channel known as the Molopo or Hygap runs south to the Orange. The southern system, which at one time rendered fertile the great plains of. western Cape Colony, is represented by the Brak and Ongers rivers, and, farther west, by the Zak and Olifants rivers, which, united as the Hartebeest, reach the Orange about 25 m. above the mouth of the Molopo. These rivers, in the wet season and in places, have plenty of water, generally dissipated in vleis, pans and vloers (marshy and lake land).
Between the mouths of the Hartebeest and Molopo, in 28° 35' S., 20° 20' E., are the great waterfalls of the Orange, where in a series of cataracts and cascades the river drops 400 ft. in 16 m. The Aughrabies or Hundred Falls, as they are called, are divided by ledges, reefs and islets, the last named often assuming fantastic shapes. Below the falls the river rushes through a rocky gorge, and openings in the cliffs to the water are rare. These openings are usually the sandy beds of dried-up or intermittent affluents, such as the Bak, Ham, Houm, Aub (or Great Fish) rivers of Great Namaqualand. As it approaches the Atlantic, the Orange, in its efforts to pierce the mountain barrier which guards the coast, is deflected north and then south, making a loop of fully 90 m., of which the two ends are but 38 m. apart. Crossing the narrow coast plain the river, with a south-westerly sweep, enters the ocean by a single mouth, studded with small islands, in 28° 37' S., 16° 30' E. A large sand bar obstructs the entrance to the river, which is not quite 1 m. wide. The river when in flood, at which time it has a depth, of 40 ft., scours a channel through the bar, but the Orange is at all times inaccessible to sea-going vessels. Above the bar it is navigable by small vessels for 30 or 40 m. In the neighbourhood of the Vaal, confluence, where the river passes through alluvial land, and at some other places, the waters of the Orange are used, and are capable of being much more largely used, for irrigation purposes.
The Hottentots call the Orange the Garib (great water), corrupted by the Dutch into Gariep. The early Dutch settlers -called it simply Groote-Rivier. It was first visited by Europeans about the beginning of the 18th century. In 1685 Simon van, der Stell, then governor of the Cape, led an expedition into Little Namaqualand and discovered the Koper Berg. In 1704 and 1705 other expeditions to Namaqualand were made. Attempts to mine the copper followed, and the prospectors and hunters who penetrated northward sent to the Cape reports of the existence of a great river whose waters always flowed. The first scientific expedition to reach the Orange was that under Captain Henry Hop sent by Governor Tulbagh in 1761, partly to investigate the reports concerning a semi-civilized yellow race living north of the great river. Hop crossed the Orange in September 1761, but shortly afterwards returned. Andrew Sparrman, the Swedish naturalist, when exploring in the Sneeuwberg in 1776, learned from the Hottentots that eight or ten days' journey north there was a large perennial stream, which he rightly concluded was the groote-rivier of Hop. The next year Captain (afterwards Colonel) R. J. Gordon, a Dutch officer -of Scottish extraction, who commanded the garrison at Cape Town, reached the river in its middle course at the spot indicated by Sparrman and named it the Orange in honour of the prince of Orange. In 1778 Lieut. W. Paterson, an English traveller, reached the river in its lower course, and in 1779 Paterson and Gordon journeyed along the west coast of the colony and explored the mouth of the river. F. Le Vaillant also visited the 'Orange near its mouth in 1784. Mission stations north of the 'Orange were established a few years later, and in 1813 the Rev. John Campbell, after visiting Griqualand West for the London Missionary Society, traced the Harts river, and from its junction with the Vaal followed the latter stream to its confluence with the Orange, journeying thence by the banks of the Orange as far as Pella, in Little Namaqualand, discovering the great falls. These falls were in 1885 visited and described by G. A. Farini, from whom they received the name of the Hundred Falls. The source of the Orange was first reached by the French Protestant missionaries T. Arbousset and F. Daumas in 1836.
The story of Hop's expedition is told in the Nouvelle description .du Cap de Bonne Esperance (Amsterdam, 1778). Lieut. Paterson;gave his experiences in A Narrative of Four Journeys into the (Country of the Hottentots and Caffraria in the Years 1777-1778-1779 o(London, 1789). See also Campbell's Travels in South Africa (London, 1815), Arbousset and Daumas ' Relation d'un voyage d'exploration au nord-est de la colonie du Cap de Bonne Esperance en 1836 (Paris, 1842), and Farini's Through the Kalahari Desert (London, 1886).
