The Governorate‘s renewable groundwater stems from relatively high annual winter rainfall, especially in the western part. However, towards the east, the yearly precipitation diminishes rapidly and reaches arid conditions towards Jericho Governorate.
JWU service area is covered by Cretaceous mainly, carbonate rocks. Limy and dolomitic formations, such as Jerusalem, partly Bethlehem, Hebron and the Beit Kahil formations form aquifers in the area. These aquifers are separated by more marly formations such as Yatta, Bethlehem and lower upper Beit Kahil.
These aquifers are divided regionally into a western mountain basin with predominantly western groundwater flow and an eastern mountain basin with eastern and southeastern groundwater flow directions. Both aquifer systems are subdivided into upper and lower aquifers. The upper, mostly phreatic aquifer extends from Jerusalem formation down to Hebron formation. The lower aquifer has outcrops at the axis of the West Bank anticline and undergoes change to confined conditions towards the east and the west, where it is tapped by wells.
There are no precise estimations on the safe yield of the aquifers in the Governorate. However, estimations on the overall recharge of the West Bank basin are given by various sources. According to these sources, the so-called Western basin that stretches from the anticline axis towards the 1949 Armistice line in the West has the highest recharge with a total estimated annual recharge of 360 MCM. With only 172 MCM annual recharge, the Eastern basin is by far not productive as the Western basin. According to Oslo - II interim agreement, Palestinians are only allowed to exploit 70-80 MCM per annum for future development.
JWU Well fields
Due to the status quo regarding the utilization of basin and to some hydrogeological factors, Ein Samia well field (Eastern Sub basin) is JWU only own source of water. Ein Samia well field is located about 20 km NE of Ramallah. It lies 500 m lower than the city at an altitude of 400 m above sea level, halfway down towards the Jordan valley. The history and use of Ein Samia well field, the spring of Princess Samia, dates back to the Roman time and even before. Ruins of a mill, an aqueduct and mosaics of Roman to Ottoman age are found there. Its modern history as a well field started after 1948 during the Jordanian rule. The following Map shows the assumed boundaries, recharge and distribution estimates of the West Bank basins, and the location of Ein Samia well field thereof.
Assumed boundaries of West Bank Aquifers (modified after ARIJ,1998) and Detailed Sketch Map of Ein Samia Well Field (MESSERSCHMID, 1999)
In the years 1996 and 1998, JWU carried out two drilling attempts at selected sites to the North of Ramallah in Ein Senia area. With no feasible success for both sites, drilling reached the low formation equivalent to the Kurnub aquifer in Jordan. The boreholes were capped and considered as non-productive wells but would be used as monitoring ones.
Another potential groundwater source for JWU is in the Western part of its service area, which lies on the Western watershed. However and despite the desperate need, the Israeli government did not allow JWU to develop any water resources in this part of the watershed.
Based on the a.m., Ein Samia well field currently comprises the only own source of water for JWU.
In the years 1996 and 1998, JWU carried out two drilling attempts at selected sites to the North of Ramallah in Ein Senia area. With no feasible success for both sites, drilling reached the low formation equivalent to the Kurnub aquifer in Jordan. The boreholes were capped and considered as non-productive wells but would be used as monitoring ones. Another potential groundwater source for JWU is in the Western part of its service area, which lies on the Western watershed. However and despite the desperate need, the Israeli government did not allow JWU to develop any water resources in this part of the watershed. Based on the a.m., Ein Samia well field currently comprises the only own source of water for JWU Ein
Samia Well Field: Facts and Figures
The average total production of the well field ranges from 550-600 m3/h, equivalent to around 5.70 MCM/annum. In years of dry winters such as 1998, 1999 and 2000, the total production capacity was negatively affected. Currently, 5 wells operate in Ein Samia. The wells are distributed over a small area and tap different aquifers at different depths. A brief description for each existing well is detailed hereafter.
|Panoramic View of Ein Samia Well Field |
|Well No. 1, hand shafted in 1964, replaced the former spring Ein Samia. With an average production capacity of 100 m3/h in normal winters, this well consumes water from the most shallow, probably perched, aquifer. Its water table fluctuates between wet and dry seasons, thus the discharge usually drops to half in summer seasons.|
|Well No. 2 was first drilled in 1965/66 with a production capacity of 45 m3/h. By the year 1991, the discharge of the well fell to about 34 m3/h. Deviation in the vertical alignment of the borehole and its small diameter were amongst the technical problems that prevented its possible rehabilitation. Therefore, JWU approached the German Government to finance the drilling of a new substitute well. In the context of the German funded project: Water Supply Development Project of GTZ, the drilling of the substitute well No. 2a began in 1996 at an adjacent location. The completed new well No.2a is 250 m deep and produces 165 m3/h from the Upper Aquifer of Cenomanian age. Its water table lies at 170 m below ground level. |
|Well No. 3 was drilled in 1980 and taps the Lower Aquifer down to a depth of 526 m. The well was rehabilitated in 1996 through the a.m. GTZ project. Since its rehabilitation, it has the second largest yield amongst all JWU wells at 180 m3/h. |
|Well No. 4 was drilled in 1990. Although, it is the deepest well (616m deep), its production capacity does not exceed an average quantity of 1000 m3/d from the lower aquifer (62 m3/h during 16 hours daily). The reason for this low productivity seems to be due to a complicated hydro-geological situation. A deep throwing fault system lies between well No. 4 and the other wells. Most probably, this fault acts as a semi-barrier indicated by a small drop of > 100 m. It decreases the wells recharge considerably. Israeli wells in the area are also affected by this phenomenon. |
|Well No.6: with German funding through GTZ, drilling of Well No.6 commenced in March 1999, completed in July of the same year, the borehole was drilled to 640 m, refilled to 590 m and 26 inch casing was installed to 411 m below ground level. A pump test was conducted at 330 m3/h discharge rate. The draw down of water table amounted to 80 m and almost there was no measurable impact on the other existing wells. |
The Well had been equipped and put into operation since August 2000 with an average production capacity of 200 m3/h and is significantly contributing to alleviate the suffering from the shortage of water in JWU service area.
Well No. 6:Final Test at 330msub3/h Disharge Rate (19-21 July,1999)
||Elev. (m asl)
||Well Depth (m bgl)
||SWL (m bgl)
||Dynamic Water L. (m bgl)
||Pump Setting (m bgl)
||Pumping Rate (m3/h)|
||Upper Aquifer (mainly)
||Upper and Lower Aquifer
|Well No.4 operates only 16h daily.
||Source: JWU-files and own measurements|
Selected Technical Data for Existing Ein Samia Wells
Protection of Water Resources
As aforementioned, Ein Samia well field is the only own water source of JWU. Increased pollution threats to this vital well field arising from agricultural and animal farming, quarrying and the inadequate disposal of solid and liquid wastes, had been realized by JWU and led the Undertaking to initiate immediate actions commensurate with such challenge.
In the course of JWU organization development process, JWU Board of Directors defined the strategies and the corresponding tactics relevant to the preservation of JWU groundwater well fields, as well as to the protection of JWU supply system, as follows:
Strategy Prepare a suitable protection plan to minimize the risk of pollution in the catchments areas Efficient and Effective Protection and Detection Measures for the Supply System Tactic Prepare a suitable protection plan to minimize the risk of pollution in the catchments areas Develop effective monitoring and detection measures that are able to monitor, detect and possibly treat any chemical and/or biological pollution
|Prepare a suitable protection plan to minimize the risk of pollution in the catchments areas
||Prepare a suitable protection plan to minimize the risk of pollution in the catchments areas |
|Efficient and Effective Protection and Detection Measures for the Supply System
||Develop effective monitoring and detection measures that are able to monitor, detect and possibly treat any chemical and/or biological pollution |
According to the latest figures, JWU has to purchase about 83% of its current drinking water supplies from the Israeli Authorities. Therefore, any restrictions on water purchases would have a serious impact on the supplied quantities to JWU customers. Unfortunately, this was the case during the summer season of the year 2000 which caused JWU to ration water supplies to all served areas. JWU Board of Directors and its top management have realized such situation and more than in any other time, are striving towards increasing water supplies from JWU own water sources, including those in the Western Aquifer, in order to minimize dependency on the external ones and decrease the expected water shortages in the coming years. .