YARMUK RIVER

Hebrew Nahar Ha-Yarmuk, Arabic Nahr Al-Yarmuk, river, a tributary of the Jordan River, in southwest Asia. For most of its course, the Yarmuk forms the boundary between Syria to the north and Jordan to the south. Since the Six-Day War of June 1967, the lower 14 miles (23 km) of the river have been under Israeli control. The Yarmuk rises on a lava plain in southwest Syria, near the Jordan frontier, and flows roughly southwestward until its confluence with the Jordan River. The Yarmuk is only 20 miles (32 km) long in a straight line, but because of the many convolutions in its course, the total length of the stream is about 50 miles (80 km). The river has cut through the resistant lava of the plateau to soft, chalky limestone beneath, creating a steep-walled gorge. The Yarmuk was the site of the Battle of the Yarmk River, one of the decisive battles in the history of Palestine. The Arabs, who under Khalid ibn al-Walid had conquered Damascus in 635, were forced to leave the city when they were threatened by a large Byzantine army under Theodorus Trithurius. Khalid concentrated his forces south of the Yarmuk River, and on Aug. 20, 636, he took advantage of the desertion of the Byzantines' Armenian and Christian Arab auxiliaries and attacked the Byzantines' remaining forces, who were almost completely destroyed. This victory marked the beginning of Muslim suzerainty in Palestine, which was broken only by the period of the Crusades (10991291) and lasted until World War I. The Yarmuk River formerly provided hydroelectric power for Jordan, and its valley was the site of a branch railway, but successive Arab-Israeli wars and the accompanying territorial disputes in the area have largely erased these economic developments. After the Six-Day War of 1967, the government of Israel opened the lower Yarmuk river valley, with its fine scenery, hot springs, and interesting ruins of Roman times, to tourist traffic. The Gawr irrigation canal, begun in 1958 and completed in 1966, diverts water from the Yarmuk to irrigate land in the northern Ghar region in Jordan.