Parts of the Syrian plateaus and most of the Jordanian highlands have an arid climate.’ Rainfall declines from north to south and from west to east, which explains why the limited surplus water is confined to the northern and coastal uplands in Israel. The Yarmouk River originates from sources in Jordan and in the eastern Golan in Syria. It forms the Jordanian-Syrian border for about 49 km and then flows through the Addasiya Triangle where it runs along the Israeli-Jordanian border for a few kilometres before joining the Lower Jordan River.