Irrigation in Jordan

Abstract

N x O visitor arriving in Jordan in August would be surprised to learn that shortage of water is one of the country's chief problems. Bare, brown hillsides and dried up watercourses he will find all around him. Some 88 per cent of the country receives less than 200 mms. annual rainfall, and 95 per cent less than 400 mms. Rainfall tends to decrease both from north to south and from west to east, unless influenced by altitude. The hills east and west of the Jordan River have a higher rainfall. The Jordan Rift Valley is in a deep rain shadow between them. Rainfall is everywhere confined to the winter half year. Most of the irrigation schemes (Fig. 1) are to be found in the Rift Valley which south of Jordan's northern frontier falls into Koppen's BS climate, and south of Jisr Damiya into his BW climate. Herein are to be found nearly all the perennial rivers of the country. The most southerly is the Wadi Feifa, a short distance south of the Dead Sea. Here also are level lands which can be easily irrigated. Beyond the hills east of the Jordan lie the level lands of the Sirhan Depression, stretching southeastwards from Azraq. Here there are no perennial streams and the underground water supply is almost unexplored. Some parts may become important irrigation areas in the future, but at present it is a barren waste. In the hill regions shortage of level land restricts irrigation to tiny patches in the valley bottoms (Fig. 2). Well irrigation is important, however, in the Hebron district and some other places. The relatively higher rainfall of the hills makes irrigation less essential in the northern half of the country. The Jordan Rift Valley is not wholly flat although it contains areas of irrigable land. Between the Sea of Tiberias and the Dead Sea the valley bottom falls from -212 meters to -392 meters. South of the Dead Sea it rises gradually to a height of 200 meters and then drops again to sea level at Aqaba. Between the Sea of Tiberias and the Dead Sea, the valley falls into three distinct regions (Fig. 3). Along the River Jordan lies a narrow flood plain (the Zor). Above this on both sides is a bench (the Ghor). Between the two lies a narrow dissected zone (the Qattar). To the east and west of the Ghor rise the hills forming the edge of the Rift. The Ghor itself is dissected by the tributaries of the Jordan, which are more numerous on the east bank than on the west. Generally, an alluvial fan is built up at the point of debouchement from the hills. These features are repeated in some areas to the south of the Dead Sea.