|Central Eurasian Water Crisis: Caspian, Aral, and Dead Seas (UNU, 1998, 203 pages)|
|Part IV: The Dead Sea|
|10. Principles for confidence-building measures in the Jordan River watershed|
The Jordan River watershed drains an area of 18,300 km2 in four countries: Lebanon, Syria, Israel, and Jordan (Naff and Matson, 1984, p. 21).
Three springs make up the northern headwaters of the Jordan River: the Hasbani, rising in Lebanon with an average annual flow of 125 MCM/yr, the Banias in Syria, averaging 125 MCM/yr, and the Dan, the largest spring at 250 MCM/yr and originating in Israel. The streams from these springs converge 6 km into Israel and flow south to the Sea of Galilee at 210 m below sea level.2
The Yarmuk River has sources in both Syria and Jordan and forms the border between those countries before it adds about 500 MCM/yr to the Jordan 10 km south of the Sea of Galilee. Beyond this confluence, the Jordan picks up volume from springflow and intermittent tributaries along its 320 km meander southward along the valley floor of the Syrio-African Rift. At its terminus at the Dead Sea (400 m below sea level), the Jordan River has a natural annual flow of 1,400 MCM/yr.
Because much of the Jordan's flow is below sealevel and the small springs that contribute to its flow pass first through the salty remains of ancient seas, the salinity of the water rises greatly, even as its flow increases. Although the headwaters at the Hasbani, Banias, and Dan have a salinity of 15-20 ppm, the level at the south end of the Sea of Galilee is 340 ppm. This is diluted somewhat by the Yarmuk, which has a salinity of 100 ppm, but increases significantly downstream, reaching several thousand parts per million by the Allenby Bridge near Jericho. The Dead Sea, a terminal lake, has a salinity of 250,000 ppm, seven times that of the open ocean.
The Jordan River flows through the transition zone from the Mediterranean subtropical climate of Lebanon and the Galilee region in the north to the arid conditions of the Negev Desert and the Rift Valley to the south. Rainfall patterns likewise vary spatially, with rainfall decreasing generally from north to south and from west to east.
These streamflow values are for average flows of the natural system. The actual amounts are highly variable and dependent on both seasonal fluctuations (75 per cent of precipitation falls during the four winter months) as well as inter-annual variations in rainfall (as high as 25-40 per cent) (Environmental Protection Service, 1988, p. 125). Also, the natural system has been dramatically altered by large-scale diversion projects, discussed later.
The hills along both banks of the Jordan serve as recharge areas for extensive aquifer systems in the West Bank, Israel, and Jordan. Rain that falls on these mountain ridges and that does not run off as surface water percolates down to the water table, contributing to these underground bodies of water. One measure of an aquifer's utility is its safe yield, or the amount of water that can be pumped without adverse effects on the water left in storage. This is usually considered to be equal to the annual recharge rate for the aquifer.
There are three principal aquifer systems west of the Jordan (Kahan, 1987, p. 21); see figure 10.2. The north-east basin recharges in the northern West Bank and discharges in Israel's Bet Shean and Jezreel Valleys; it has a safe yield of 140 MCM/yr. The western (Yarkon-Tanninim) basin also recharges in the hills of the West Bank but discharges westward, toward the Mediterranean coast in Israel; it has a safe yield of 320 MCM/yr. The eastern basin is made up of five separate catchment areas in the West Bank, all of which flow east toward the Jordan Valley; their combined safe yield is 225 MCM/yr.3
Groundwater replenishment within Jordan totals about 270 MCM/yr, in 12 different aquifers, mostly in the Zarqa, Yarmak, and Jordan catchments (Bilbeisi, 1992).
Current water use
Israel has a renewable annual water supply of approximately 1,800 MCM/yr (Environmental Protection Service, 1988, p. 125), of which 60 per cent is groundwater and 40 per cent is surface water - almost entirely from the Jordan River system. Its annual water budget is allocated 73 per cent to agriculture, 22 per cent to domestic consumption, and 5 per cent to industrial use. Israel irrigates 66 per cent of its cropland. It has a population of 4.2 million and an annual population growth rate of 1.6 per cent (excluding immigration) (Poster, 1989a, p. 12).
The 800,000 Palestinians on the West Bank consume about 110 MCM/yr, 90 per cent of which is groundwater. Of this, about 90 MCM is for irrigation and the rest is for domestic use. The 70,000 Israeli settlers use an additional 36 MCM, 95 per cent of which is for agriculture (Kahan, 1987, p. 113). The Arab and Jewish residents of the West Bank irrigate 6 per cent of the cultivable land and have a population growth rate of approximately 3 per cent (Poster, 1989a, p. 14).
Gaza, with a population of about 600,000 and a growth rate of 3.4 per cent, is probably the entity that is most desperate hydrographically speaking. Completely dependent on the 60 MCM/yr of annual groundwater recharge, Gazans currently use approximately 95 MCM/yr. The difference between annual supply and use is made up by overpumping in the shallow coastal aquifer, resulting in dangerous salt-water intrusion of existing wells and ever-decreasing per capita water availability, already the lowest in the region.
Jordan has a total annual water budget of 870 MCM, of which 75 per cent is surface water, mostly from the Yarmuk River (Taubenblatt, 1988, p. 49). Of the total, 85 per cent is allocated for agriculture, 10 per cent for human consumption, and 5 per cent for industrial use. Jordan irrigates 10 per cent of its cropland and has a population of 3.3 million and a growth rate of 3.5 per cent per year (Poster, 1989a, p. 14).
Both Lebanon and Syria are relatively minor consumers of Jordan River water. Their major sources are the Litani and Euphrates rivers, respectively. The Litani, with an average flow of 700 MCM/yr, lies wholly within Lebanon but, because it flows to within 7 km of the Hasbani, it has been included in several diversion schemes in conjunction with the Jordan system. Lebanon irrigates 29 per cent of its cropland and has a population of 2.6 million and an annual population growth rate of 2.1 per cent. Syria irrigates 11 per cent of its cropland and has a population of 10 million growing at a rate of 3.8 per cent per year (Poster, 1989a, p. 14).