steep slopes: the Golan Heights to the east and the Upper Galilee's Naftali Mountains to the west rise to 400 to 900 meters above sea level. Basalt hills of about 200 meters above sea level along the southern side of the valley intercept the Jordan River, and are commonly referred to as the basalt "plug", the Korazim block, or Korazim Plateau (actually a temporary geologic base level), as they restrict water drainage downstream into the Sea of Galilee. Climate The Hula Valley has a Mediterranean climate of hot dry summers and cool rainy winters, although its enclosure within two mountain ranges leads to more extreme seasonal and daily temperature fluctuations than in coastal areas. Annual rainfall varies greatly between different parts of the valley and ranges from about 400 millimeters in the south of the valley, to up to 800 millimeters in the north of the valley. More than 1,500 millimeters of precipitation falls on the Hermon mountain range, only a few kilometers north of the valley, mostly in the form of snow, feeding underground springs, including the sources of the Jordan River (Nahr Hasbani, also known as the "Upper Jordan" river, the Banias river, the Dan river and the brook el-Malaha), all eventually flowing through the valley, and which, before its drainage, could not easily be distinguished because of the marsh. Wetland environment G. Schumacher, visiting the region in 1883, described the Hula valley in the following terms: Ard el Huleh. The whole country of the marshes of the Huleh Lake, a swampy territory thickly overgrown with papyrus. It abounds in snipe, wild ducks, francolins and many other kinds of birds, and is consequently much resorted to by the hunter, but as carefully avoided by the inhabitants on account of the noxious fever. Swamp drainage The draining operations, carried out by the Jewish National Fund (JNF), began in 1951 and were completed by 1958. In 1955 the Israeli government invited John Zuckerman to visit Israel as advisor on a project. It was achieved by two main engineering operations: the deepening and widening of the Jordan River downstream; and two newly-dug peripheral canals diverting the Jordan at the north of the valley. The drying out caused the extinction of the unique endemic fauna of the lake, including the cyprinid fish Acanthobrama hulensis, Oxynoemacheilus galilaeus or Galilean Stone Loach and cichlid fish Tristramella intermedia. Though perceived at the time as a