El Estado frente a los pasivos ambientales

Groundwater resources in the West Bank are derived from three aquifer basins through wells and natural springs. The total water use from the West Bank aquifers is about 134.3 MCM/Y of which 89 MCM/Y was extracted from wells and 45.3 MCM/Y was used from the major springs. Another 36 MCM/Y of water is usually purchased from external sources (such as Mekorot) or from public springs or from private irrigation wells (PWA, 2003).

3.4.1 Groundwater Wells

Currently there are about 550 groundwater wells in the West Bank, the current number of working wells is about 370, of which 53 wells are being used for drinking purposes and 323 wells are being used for irrigation (PWA, 2003). In addition to the Palestinian wells, there are 36 wells owned by the Israeli settlements established in the West Bank after 1967 which produce about 50 MCM/Y (PWA, 2003).

Tens of wells (observation, production and a few oil wells) have been drilled in the Jerusalem Desert (eastern slopes), 16 in the Upper Cenomanian and 22 in the Lower Cenomanian. Most of the production wells are located in three pumping fields: Herodion, Jerusalem and Mizpe Jericho. Figure 3.5 show the springs and wells location which has been sampled and investigated through out this study. Most of the water is extracted from

the lower aquifer of the Ajlun Group (Judea Group). The depths of the wells range from 350 to 900m, depending on their geological location and the depth of the lower aquifer.

Pumping has begun in the early 1970s. Since then, it has been steadily increasing, owing to the addition of new wells. A few new Palestinian production wells have been added in recent years, mostly in the Herodion area.

Figure 3.5: A geological map showing the wells and springs location in the study area.

3.4.2 Springs

Springs are the second important source for groundwater exploitation throughout the West Bank and the study area. It is used for drinking and irrigation use such as in Auja area and Jericho which depend on spring water to a much greater extent. There are more than 500 springs and seeps in the West Bank. The number of springs which are subjected

to flow measurements on a regular basis by the Palestinian Water Authority is 114. These springs have a minimum flow discharge of 0.1l/s. These springs discharge flow in two general directions, East and West. These 114 springs are distributed through 10 spring systems based on their watersheds; each system is subdivided into several groups. Six spring systems with 79 springs discharge their flow to the East towards the Jordan Valley and the Dead Sea and to the Northeast towards Bet Sha`n area in Israel, while another 4 spring systems with 35 springs discharge their flow to the West (Isaac & Sabbah, 1998).

The fluctuations in the springs discharge pattern depend on the precipitation rate in the recharge zone (Wolfer, 1998).

According to the geographical distribution and discharge behavior, the springs in the study area can be divided into three groups:

a) Wadi Qilt Spring Group: this group of springs (Ein Qilt, Ein Fawwar and Ein Fara springs) is located in wadi Qilt and its tributaries. These wadis are deeply incised canyons and only here the Turonian aquifer is exposed were the spring outflow occurs. The springs discharging in this area are characterized by an immediate response to precipitation and a highly fluctuating discharge pattern.

b) Jericho-Auja Sprig Group: this group of springs is located in the Lower Jordan Valley to the North of the study area and is related to the Samia fault (Ein Sultan, Ein Duyuk and Nuwe’meh springs). Due to various step faults close to the Jordan Valley the base of the uppermost aquifer is exposed. These springs discharge at a constant rate. The main springs of this group are described as follow:

Ein Sultan: Sultan is located 2km NW of Jericho and discharges at an elevation of 215 m.b.s.l. The outflow of the spring is structurally controlled by a large SW-NE trending normal fault and the spring can be classified as a fault spring (Wolfer, 1998).

Ein Duyuk and Nuwe’meh Spring: these springs discharges at the margin of the Eastern slopes 3.7km NW of Ein Sultan. The system consists of three springs emerging at 110 m.b.s.l.

Auja-Fazael Springs: They are the outlet of the upper sub-aquifer. The springs are characterized by a quick response to climate changes. Guttman (2004) investigated the behavior of the Auja spring as an example of a typical karstic spring in the study area. The maximum discharge appears a little after the rainiest month. It can be seen that the discharge dies out towards the end of the winter season.

The Jericho springs discharges are more stable and constant and do not show high response to climate change like in Auja spring. The reason is that the recharge area of the spring is

far from the spring outlet and the storage is much greater than the storage of the other springs like in Auja and in Ein Samiya.

c) Feshcha Spring Group (the regional spring group): this group of springs which is located along the Western shore of the Dead Sea. These springs are the outlet of the regional aquifer. The average annual discharge is about 50-80 MCM/Y (Guttman &

Simon, 1984). The recharge area is far from the springs outlets. The springs have large storage and are characterized by stable discharge with only small annual fluctuations. The main springs of this group are described as follow:

Ein Feshcha: The Feshcha springs are located along the Dead Sea shore, looking toward the Dead Sea to the East, a large area with vegetation can be seen. Ein Feshcha springs spread over a relatively large area of 3-4km along the Dead Sea shore. This is the discharge zone for large amounts of groundwater from alluvial aquifer to the Dead Sea.

They represent the outlet of the Judea Group aquifer (Upper and Lower aquifers). There are large variation in salinities and chemical composition among the numerous springs of this area.

Kane-Samar: The Kane-Samar springs are located few hundred meters to the South of Ein Feshcha. This is the discharge zone of groundwater from alluvial aquifer to the Dead Sea.

To the West of Kane-Samar springs were large discharge of groundwater occurs, several wells were drilled in the area. In this area there is evidence for at lest two distinct sub-aquifer in the alluvial sub-aquifer. This is best demonstrated in Turieb-4 well where higher salinity, higher temperature and higher water level is found in the lower sub-aquifer.