HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: THE SOURCE OF THE DARDARA SPRING
First Interim Report
May 20, 2012
By: Issam Bou Jaoude
To: FAO
1 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
List of Abbreviations
BG below ground level
BTD Bureau Technique pour le Developpement
FAO Food and Agriculture Organization
Hr hour km kilometers l/s liters per second m meters m3 meter cubed masl meters above sea level
µS micro siemens mS milli siemens mg/l milligrams per liters ppm parts per million ppt parts per thousand
SBEB South Bekaa Eocene Basin
SLWE South Lebanon Water Establishment
TDS total dissolved solids
UNDP United Nations Development Programme
2 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Table of Contents List of Abbreviations ...... 2 List of Figures ...... 5 List of Table ...... 6 1 INTRODUCTION ...... 7 2 LOCATION ...... 7 2.1 Southern Bekaa Eocene Basin (SBEB) ...... 8 2.2 The el Marj plain zone ...... 9 3 HYDROLOGICAL SETTING ...... 11 3.1 Hydrological setting of the SBEB ...... 11 3.2 Hydrological setting of the el Marj plain ...... 13 4 GEOLOGICAL / HYDROGEOLOGICAL SETTING ...... 14 4.1 The Geological / Hydrogeological Setting of the Southern Bekaa Eocene Basin (SBEB) ...... 14 4.1.1 Hydro‐stratigraphical setting of the SBEB ...... 14 4.1.2 Structural setting of the SBEB ...... 18 4.1.3 Hydrogeological setting of the SBEB ...... 20 4.2 The Geological / Hydrogeological setting of el Marj plain ...... 23 4.2.1 Hydrostratigraphical Setting of el Marj Plain ...... 23 4.2.2 Structural setting of the el Marj Plain ...... 25 4.2.3 Hydrogeological Setting of the el Marj Plain ...... 28 5 PREVIOUS STUDIES ...... 30 5.1 Studies on the Southern Bekaa Eocene Basin (SBEB) ...... 30 5.1.1 Liban Etude Des Eaux Souterraines, United Nations Development Program (UNDP), 1970. 30 5.2 Water Management and Hydro‐Diplomacy in Lebanon, Comair, G. F. 2009...... 32 5.3 Studies on the Dardara Spring / el Marj plain ...... 33 5.3.1 Project d’exploitation de l’aquifere des sources de Dardara et de Hammam caza de Marjayoun, BTD, 1983...... 33 5.4 The Dardara Water System in South Lebanon, Collaborative Planning Situational Analysis. United States Agency for International Development. 2002...... 37 6 WELLS AND SPRINGS SURVEY ...... 37 6.1 Spring Survey ...... 38 6.1.1 Dardara spring ...... 40 6.1.2 Hammam spring ...... 43 6.1.3 Other springs ...... 43 6.2 Well survey ...... 44
3 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
7 PRECIPITATION DATA ...... 51 8 MONITORING PLAN ...... 53 8.1 Basic plan ...... 53 8.2 Advanced plan in case of additional funding ...... 54 9 ONGOING DATA COLLECTION AND ASSESSMENT ...... 56 10 References ...... 57 APPENDICES ...... 58 APPENDIX 1 (Geological map of SBEB)...... 59 APPENDIX 2 (Structural geological map of SBEB) ...... 60 APPENDIX 3 (El Marj plain zone geological and structural geology map) ...... 61 APPENDIX 4 (The cross‐sections of el Marj plain (1:20,000)) ...... 62 APPENDIX 5 (Well survey) ...... 63 APPENDIX 6 (Spring survey) ...... 64 APPENDIX 7 (Data of Monitored wells) ...... 65 APPENDIX 8 (Data of Monitored springs) ...... 66 Appendix 9 (The Well and spring survey sheet) ...... 67
4 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
List of Figures
Figure 1 Map of Lebanon showing the location of the two study zones...... 8 Figure 2 Map of el Marj plain showing the study area with the four cazas located around the plain...... 10 Figure 3 A digital elevation model for the el Marj plain zone showing some elevations in and around the plain...... 11 Figure 4 Map of the main rivers that flow through the SBEB (delineated in white hatch) and their watersheds...... 12 Figure 5 The drainages and river watersheds of the el Marj plain zone...... 13 Figure 6 The west side of the el Marj plain showing the lithological boundary between the Abeih Formation (yellow rocks on the top of the high) and the Mdeirej Formation (center of the photo). . 16 Figure 7 The lithological boundary between the Abeih Formation (yellow rocks on the left) and the Mdeirej Formation (lower right of the photo). East of the monastery of Kseir, on the west border of the el Marj plain showing the steep dips of the eastern limb of the Marjoeun anticline...... 17 Figure 8 The highly fractured Eocene Formation with a flower structure faulting clearly identified in its center (white arrow). This is the excepted location of were the mid Marj fault passes ...... 17 Figure 9 The Chekka Formation near Dibbine and Blat villages...... 18 Figure 10 Structural setting of the SBEB highlighting major structural elements surrounding this basin ...... 19 Figure 11 Hydrogeological setting of the SBEB showing the three sub‐basins subdivided according to the UNDP (1970)...... 21 Figure 12 A schematic model of the groundwater flows in the SBEB ...... 22 Figure 13 Geological map of the el Marj plain ...... 24 Figure 14 The south view of the el Marj plain showing the Metullah high (arrow) in Occupied Palestine...... 25 Figure 15 Small scale folding close to the Marjayoun village on the side of the Yammouneh fault. The white arrows show the dip direction of the bedding planes of the Abeih Formation’s limestone blocks...... 26 Figure 16 A fault between the Chouf Sandstone Formation (left) and Abeih Formation (right). The Marj Quaternary deposits are located in the lower half of the photograph...... 26 Figure 17 The Tel Dibbine high in the northern section of the el Marj Plain probably flattened by early human settles for there is an archeological site on top...... 27 Figure 18 A groundwater flow map of possible water directions in the el Marj plain...... 29 Figure 19 A groundwater flow model of possible water directions to the plain’s main springs...... 30 Figure 20 Tracer tests conducted by the BTD 1983 study ...... 34 Figure 21 Variation in conductivity values between the Dardar and Hammam springs (BTD, 1983) 36 Figure 22: Map showing the location of springs in the el Marj plain zone ...... 39 Figure 23 The Dardara spring basin shown in the photograph and Google Earth ...... 40 Figure 24 Discharge of Dardara and Hammam Springs ...... 41
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Figure 25 pH of Dardara and Hammam Springs...... 41 Figure 26 Temperature of Dardara and Hammam Springs ...... 42 Figure 27 Conductivity for the Dardara and Hammam Springs ...... 42 Figure 28 The Hammam spring basin shown in the photograph and google map ...... 43 Figure 29 The Moqbiye spring near Tel Dibbine ...... 44 Figure 30 The Qseir spring ...... 44 Figure 31 Location of wells in the el Marj plain zone...... 46 Figure 32 Well 5, an artesian, sulfurous water well ...... 47 Figure 33 Example of the water level decrease of Well 2 ...... 47 Figure 34 Example of the decrease of the water level in Well 5 ...... 48 Figure 35 Maps showing the wells, with their water level and their depth to water ...... 49 Figure 36 The location of the weather stations surrounding the el Marj plain ...... 51 Figure 37 Precipitation rates in the el Marj plain over the period of 4 years (assorted sources) ...... 52 Figure 38 Precipitation rates in Marjayoun from the years 1947 to 1974 (reference?) ...... 52
List of Table
Table 1 Hydrostratigraphy of Lebanon (modified from Walley, 1997) ...... 15 Table 2 Condition and properties of the three sub basins of the SBEB ...... 31 Table 3 General Budget of the SBEB ...... 32 Table 4 The three sub basins in Comair, 2009 ...... 32 Table 5 Wells located in the El Marj plain (BTD, 1983) ...... 34 Table 6 Summary of result of pumping tests conducted in the el Marj plain by BTD (1980) ...... 35 Table 7 The recession coefficient and discharge rate of the Dardara and Hammam springs ...... 35 Table 8 The water budget in the el Marj plain ...... 37 Table 9 Pumping test summary (USAID, 2002) ...... 37 Table 10: The pH reading of the sampled wells ...... 50 Table 11: the TDS readings for the sampled wells ...... 50 Table 12 The Conductivity values of the Wells ...... 50 Table 13 Table of the water temperature of the monitored wells ...... 51 Table 14 The weather stations with their characteristics ...... 51 Table 15 A list of the wells and springs that are being monitored in the el Marj plain...... 53 Table 16 Approximate cost of the groundwater probes in wells ...... 54
6 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
1 INTRODUCTION
The aim of this hydrogeological study is to assess the groundwater, in terms of quantity and quality, in and around the el Marj plain, with emphasis on the Dardara spring. This better highlights the maximum and minimum groundwater flow of the Dardara spring. This is undertaken to better define the irrigation potential in the el Marj plain.
In this hydrogeological study two zones of investigation are addressed. The first is the large scope zone which consists of the entirety of the Eocene aquifer in the southern Bekaa. It is a major aquifer that might feed into the el Marj plain and will be identified in this report as the Southern Bekaa Eocene Aquifer Basin (SBEB). The second zone, which is the southernmost extension of the Eocene aquifer which is the el Marj plain and its environs; it will be identified as the el Marj plain zone.
To meet the objectives of this report, several activities will be conducted including review of previous investigation, collection of precipitation data, geological mapping, spring and well surveys in and around el Marj plain, monitoring of water levels in wells, indentifying quality and quantity of relevant water in springs, and finally set up of a plan for a one year monitoring program.
The project time frame is one year, divided mainly into three main milestones; the first is the compilation and analyses of the previous work, the field geological investigation, the spring and well survey and the establishment of a monitoring plan; the second is an interim report on the monitoring data collected 4 months after completion of the first milestone; the final report will compile all that has been undertaken after one year, and focuses on the budget of the plain and recommendations for its exploitation.
This first interim report outlines the field activity and investigation completed for the first milestone.
This project is under the supervision of the FAOR, with the direct supervision of the FAO, and in close collaboration with AVSI. The project is composed of a decentralized cooperation partnership which includes the FAO organization, the Italian Government, the Lebanese Government, the Italian region of Lombardy, the AVSI Foundation, and the local municipalities of the caza of Marjayoun.
The project could not have been achieved without the help of Ms. Rena Karanouh and Ms. Nanor Momjian and under the guidance of the FAO personnel and directors.
2 LOCATION
This section outlines the location of the two zones under investigation the SBEB (Southern Bekaa Eocene aquifer) zone and its subzone the el Marj plain.
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2.1 Southern Bekaa Eocene Basin (SBEB)
The SBEB is located in the southern part of the Bekaa basin. It was chosen because it mainly feeds several springs including the ones in the el Marj plain (Figure 1).
The SBEB covers approximately 250km2 in area and trends in a NNE-SSW direction. It has a length of approximately 60km and a maximum width of approximately 10km. It is part of the Upper Litani Basin and extends between the Barouk-Niha range to the west and Jabal Bir el Dahr to the east. Jabal al Arid runs through the center of the zone trending in a NE-SW direction.
The SBEB lies within coordinates of N33˚43’52.38’’ to N33˚16’56.80’’ and E35˚33’13.75’’ to E35˚56’6.62’’, within the districts of Bekaa and Nabatiye and the cazas of Zahle, Bekaa, Rachaya, Marjayoun, Hasbaya and Jezzine (Figure 2).
Figure 1 Map of Lebanon showing the location of the two study zones. The plain is delineated by the red line. Inset shows the location of the study area in Lebanon.
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2.2 The el Marj plain zone
The el Marj plain zone is the southernmost section of the SBEB zone along with the el Marj plain. The southernmost parts of the SBEB encompass several small ridges including the Blat high stretching in a NE-SW direction and the el Marj low land plain in-between (Figure 2). This zone is situated in the district of Nabatiyeh, in Marjayoun Caza (Figure 2) and stretches between the coordinates N33˚12’58.48’’ to N33˚16’56.80’’ and E35˚33’13.75’’ to E35˚36’27.76’’.
The el Marj plain is approximately 19.5km2 in surface area and is nearly 8km at its longest length and nearly 2.5km at it’s widest. The plain is a basin like low lying feature that stretches in a NE-SW direction and lies between a series of highs. It is bordered from the east by the Jabal Ard el Gharbie and Jabal Ard el Hinta high on which Khiam village is located, from the west by the Marjayoun high and Tel el Nhas highs where the villages of Borj el Mlouk, Qlaiaa and Marjayoun villages are located. To the north the plain is bordered by the Blat high and to the south it is bordered by the Metullah high.
The El Marj plain lies between the villages of Marjayoun to the North West, Ebel el Saqi to the north east, Khiam to the east and Qlaiaa to the west (Figure 3). The highest elevation in the plain is 614m asl (Figure 3) on Tell Dibbine in the northern section of the plain, and the lowest, at about 494m is close the plain’s southern most point. The whole plain is gently inclined at an angle less than 1 degree towards the south. This could indicate the general direction of surface and groundwater flow which runs along this dip direction.
Two major springs are located in the plain’s basin are Nabaa el Dardara and Nabaa el Hammam. Both might be considered as the natural outlets of the southern zone of the SBEB along with small diffused seepages into plain. Other smaller seasonal springs are scattered around the plain. The el Marj plain is mainly used for agriculture where a variety of staples are cultivated with wheat, seasonal vegetables and olive trees.
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Figure 2 Map of el Marj plain showing the study area with the four cazas located around the plain.
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Hamman Spring
Dardara Spring
El Marj Plain
Figure 3 A digital elevation model for the el Marj plain zone showing some elevations in and around the plain.
3 HYDROLOGICAL SETTING
3.1 Hydrological setting of the SBEB
The SBEB lies in the southern Bekaa valley. There are five rivers that flow in the SBEB zone. The one with the highest flow and the longest length is the Litani River. It flows through nearly the entire length of the SBEB, running through its center, at a NNE-SSW trend. Approximately 70km of the Litani River flows through SBEB. The Hasbani River flows through the SBEB from the merging of a number of drainages in the Jabal Bir el Dahr, at a NNE-SSW trend. Approximately 65km of the lower Hasbani River flows through the south-east section of the SBEB.
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About ~80% of the SBEB is located in the Litani River watershed, while the remaining ~20% of it is located in the Hasbani River watershed (Figure 4).
North and west of the SBEB the Damour, Zahrani and Awali Rivers are located. The Awali River flows from a series of drainages that merge together which begin in the Jabal-Niha Barouk range (Figure 4).
Figure 4 Map of the main rivers that flow through the SBEB (delineated in white hatch) and their watersheds.
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3.2 Hydrological setting of the el Marj plain
The el Marj plain is located in the watershed of the Hasbani River (Figure 5). The connection between the main Hasbani River and the tributary draining the el Marj zone sub watershed is further south from the Lebanese border with the occupied territories (Figure 5).
Figure 5 The drainages and river watersheds of the el Marj plain zone.
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The series of drainages that drain into the plain are small tributaries of the Hasbani River. These drainages drain the Marjayoun and Borj el Mlouk highs from west to east, and the Jabal Ard el Gharbie high, near Khiam village, from east to west direction.
Most of the drainages in the plain dry in the summer season while the main drainages flowing in the summer are recharged from the springs. In winter they flow due to high levels of precipitation and snowmelt with some areas in the plain also flooding and forming seasonal swamps.
4 GEOLOGICAL / HYDROGEOLOGICAL SETTING
The geology and hydrogeology of the studied areas, including subsurface hydro-stratigraphy and structure, were developed based on: 1) review of available maps (Dubertret 1956, geological maps of the area 1:50000) and existing literature, 2) analysis of aerial photographs and Google Earth, and 3) geological mapping and site visits.
Two geological maps, one for the SBEB basin at a scale of 1:100,000 and the other for the el Marj plain zone at a scale of 1:20,000 were constructed (Appendix 1). Four cross sections for the el Marj plain geological map were constructed (Appendix 4).
4.1 The Geological / Hydrogeological Setting of the Southern Bekaa Eocene Basin (SBEB)
4.1.1 Hydro-stratigraphical setting of the SBEB
The geology of the area is characterized by the exposure of 14 different formations of various ages, ranging from Jurassic to Quaternary aged rocks (Table 1 and Appendix 3). The Kesrouane Formation (J4), middle Jurassic in age, is the oldest outcropping rocks in the area and is exposed in the western and eastern parts of the study area. It is the main formation of the two major geological structures in the area, the Barouk-Niha range and Jabal el Shiekh mountain range. The Pliocene basalts unconformably overlying most of the geological succession in the southeastern and eastern parts of the area close to the Hasbani river valley. The Quaternary deposits are the youngest in age and cover most of the low lying plain especially the Bekaa plain in the north and the el Marj plain in the southern parts of the area. The thickness of the Quaternary deposits reaches nearly 50m in some places in el Marj plain, while it is more than 100m in the Bekka plain (Appendix 4). The complete lithological succession and hydrogeological nature of each formation is presented in Table 1.
The central SBEB consists of Middle Eocene aged rocks and lies between Jurassic aged rocks of the Jabal el Sheikh to the east, and Jabal Niha-Barouk to the west. It is important to note that these Middle Eocene aged rocks consist of two different lithologies. The lower unit (e2a) consists mainly of marls and marly limestone and is considered to be an aquiclude. It has a thickness ranging between 200 to 400m when in complete succession. The upper unit (e2b) consists of karstified nummulitic limestone and forms a major aquifer and is at its maximum thickness reaching around 900m in its complete
14 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012 succession. Underneath the Hammam spring the thickness of this aquifer is close to approximately 100 to 1500 m (Appendix 4) while underneath the Dardara spring it is around 50 m (Appendix 4).
The exposures of the Eocene rocks forming the SBEB are approximately 250km2 in the central part of the study area. The exposure extend in a NNE-SSW direction and is approximately 10km in width in the northern section, before plunging beneath the Quaternary deposits where it narrows to less than 1km in the south, before also plunging underneath Quaternary deposits in the el Marj plain.
Below the Eocene Formation the Upper Cretaceous succession is present starting with the marl of the Chekka (C6) Formation, which is around 500m thick (Table 1). This formation is considered as an aquiclude.
Table 1 Hydrostratigraphy of Lebanon (modified from Walley, 1997) HYDRO- FORMATION SYMB THICKNESS PERIOD LITHOLOGY GEOLOGICAL REMARKS (AGE) OL (m) CLASSIFICATION Water percolates through QUATERNARY Alluvial deposits (gravel, Q 20-30m Semi-aquifer these deposits and feed DEPOSITS sand, silt and clay) the underlying aquifer. Thick conglomerates, marls and lignites Some PLEIOCENE Pl basalts deposits in the 0-100m Semi-aquifer - DEPOSITS
southwest area of the el Marj plain.
Marls, calcarious MIOCENE breccias, detrital clays, m 150m Aquifer -
TERTIARY DEPOSITS conglomerates, sandy silty marls, and lignites Nummulitic limestone, Important aquifer due to e2b marly limestone, reefal 900m Aquifer developed karstification EOCENE limestone and efficient recharge DEPOSITS Chalky marl, limestone 200-400m Aquiclude - e2a with cherts
CHEKKA White chalks, and marly C6 100 – 500m Aquiclude - FORMATION chalks, with cherts
MAAMELTEIN White grey marls, marly Important aquifer due to C5 200 - 300m Aquifer FORMATION limestone developed karstification and efficient recharge. Massive to thin bedded SANNINE Both formations act as C4 limestone and marly 500 - 700m Aquifer FORMATION one aquifer limestone – karstic Variable sequence of thin bedded limestone, soft marls, and terrigenous sands. Creamish to Aquiclude HAMMANA greenish marly C3 170 – 200m (aquiferous in top - CRETACEOUS FORMATION limestone. Highly sequences) fossiliferous with molded gastropods and fossilized oysters. Quartz geodes common. Grayish oolitic micro- MDAIREJ C2b crystalline and massive 45 - 50m Aquifer - FORMATION micritic karstic limestone
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Upper sections yellowish and brownish fossiliferous limestone, Marl and clay horizons ABEIH C2a while lower sections 90 - 125m Aquiclude acts as impermeable FORMATION intercalations of blue and horizons green marls, and yellowish limestone Often ferruginous brown to white sandstones interbedded with clays, shales, lignites, and tuffs, CHOUF and locally basalts at the SANDSTONE C1 200 - 230m Semi-aquifer - bottom. Cross bedded, FORMATION hematitic sandstone and sands with impermeable lenses of bluish gray clay and marl with peat Brown yellow ferruginous SALIMA oolitic limestone J7 0 - 45 m Aquiclude - FORMATION alternating with brown marl. Water is lost to adjacent Blue gray massive oolitic and underlying formations BIKFAYA hard and massive micritic by leaking through J6 70 - 90m Minor Aquifer FORMATION limestone with chert fractures due to bands and nodules widespread structural disturbances Alternating ochre yellow JURASSIC BHANNES oolitic limestone, friable J5 70m Aquiclude - FORMATION brown shale and yellowish marl Blue gray massive hard KESEROUANE J4 and massive micritic 1000m Aquifer Intensely karstified FORMATION limestone
Figure 6 The west side of the el Marj plain showing the lithological boundary between the Abeih Formation (yellow rocks on the top of the high) and the Mdeirej Formation (center of the photo).
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Figure 7 The lithological boundary between the Abeih Formation (yellow rocks on the left) and the Mdeirej Formation (lower right of the photo). East of the monastery of Kseir, on the west border of the el Marj plain showing the steep dips of the eastern limb of the Marjayoun anticline.
Figure 8 The highly fractured Eocene Formation with a flower structure faulting clearly identified in its center (white arrow). This is the excepted location of where the mid Marj fault passes
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Figure 9 The Chekka Formation near Dibbine and Blat villages.
4.1.2 Structural setting of the SBEB
The SBEB area encompasses three major faults trending NNE-SSW, three major anticlines trending also NNE-SSW, several minor anticlines trending NNE-SSW and minor faults trending NW-SE and N-S (Figure 10).
The major faults in the SBEB are the Yammouneh fault, Hasbaya fault and Rashaya fault. The three extend in a NNE-SSW direction and cross the area from the south to the north. The Yammouneh fault passes along the western edge of the el Marj plain, near the villages of Marjayoun, Blat, Ain el Tine to the south and Machgara, Aitanit and Kefraya to the north. The Yammouneh fault is a dextral strike slip fault consisting of a series of branches, uplifts and extensional basins. The el Marj plain is one of these extensional basins that can be located along this fault. The Yammouneh fault has a horizontal displacement that varies in each location and it is in total around 80 km and vertical component that also varies but it is in the order of 100’s of meters (Walley, 1998). The Hasbaya and Rashaya faults have smaller throws.
The mid-Marj fault is suspected to trend below the Quaternary deposits of the el Marj plain, through its center (Figure 10). From the cross-sections it can be indicated that this fault has a dip-slip component. It displaces the Cretaceous succession, effectively folding the strata to the west of the fault. Its displacement is approximately 200m.
Three major folds are present in the study area, the Barouk-Niha anticline, the Jabal el Shiekh anticline and the SBEB syncline. The Barouk-Niha anticline is an overturned anticline extending parallel to the Yammouneh fault and consists of the Kesrouane Formation at its core. The Jabal el Shiek anticline is similar in nature.
While the SBEB, which is part of the focus of this study, forms a NNE-SSW trending syncline extending from Majdal Anjar village in the north to Borj el Mlouk village in the south. It is an open syncline in its
18 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012 northern parts with beds dipping 40 degrees on each limb. In its southern parts, it is tight syncline with beds also dipping in the order of 30 degrees on each limb. In its northern part the syncline plunges underneath the Quaternary deposits of the Bekaa valley and it also plunges underneath the Quaternary deposits underneath the el Marj plain in the south.
The northern part the syncline is bounded by the Barouk-Niha range anticline and the Yammouneh fault from west and by the Jabal el Shiek high and Hasbaya fault from the eastern side. While in the southern parts the western limb of the SBEB syncline is cut by the Yammouneh fault while at the east the syncline is bounded by the Khiam anticline (Figure 10).
Figure 10 Structural setting of the SBEB highlighting major structural elements surrounding this basin
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4.1.3 Hydrogeological setting of the SBEB
The study areas consists of a five different major aquifers including the Eocene aquifer, the Sannine- Maameltein aquifer, the Keserouane aquifer and minor aquifers consist of the Bikfaya and Mdeirej Formations and the Chouf Sandstone (Figure 11). With the exception of the Chouf sandstone aquifer all of these aquifers are karstic in nature. The extent and depth of karstification varies between those aquifers. Unconformably overlying the aquifers, the semi aquifers and the aquicludes is the Qauternary semi- aquifer. This semi-aquifer is mainly present in good exposures in the northern parts in the Bekaa plain and in the south in the el Marj plain.
The Eocene aquifer forming the SBEB will be addressed in detail because part of this major aquifer might possibly feed the el Marj plain aquifers and springs.
This karstified limestone of the Eocene forming the SBEB forms a major syncline that is crossed by the Litani valley. The lower boundary of this aquifer is the lower Eocene Formation (e2a) and Chekka Formation (C6) consisting of marls and limiting the groundwater flow in the vertical direction. From the eastern and upper western sections the aquifer is bounded by the lower Eocene Formation (e2a) and Chekka Formation (C6) both of which are marls. From the northeast and southwest the boundaries of this basin are the Bekaa plain and the el Marj plain respectively. From the lower western section were the aquifer is in direct contact with the Kesrouane Formation through the displacement of the Yammouneh fault the boundary is not clear whether it is a no flow boundary or not.
According to the UNDP (1970) the SBEB can be divided into three sub-basins which act hydrogeologically independent of each other; the Northern Basin; the Central Basin; the Southern Basin (Figure 11 and Figure 12).
In the Northern Basin, near the villages of Bire and Lala, groundwater flows towards Soultan Yaakoub village meeting the groundwater flowing from Majdal Anjar. The Eocene aquifer in this sub-basin is thick and plunges under the Quaternary deposits of the Bekaa valley in this area. No barrier is present to prevent the continued flow of groundwater in the subsurface so the water continues to flow underground through the aquifer. For this no major springs are present at the boundary between the Eocene aquifer and the Quaternary deposits. A series of wells have tapped this water supply since the 1960’s (UNDP, 1970).
In the Central Basin, near the Jabal el Aarbi and Bir ed Dahr villages, the waters flow towards Litani valley and exists at the low points at Ain el Zarka and Ain Borghos. The lower Eocene marls are in close proximity to the low points allowing restriction of vertical flow of groundwater.
In the Southern Basin, between Hasbaya and Blat villages, groundwater flows toward the south and emerges at the springs of the eI Marj plain. The lower marl formations restrict the flow of groundwater in this area in the vertical and southern direction and causing the groundwater to bank and overflow (Figure 12). The banked waters reach Daradara spring as overflow first,
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since it is at a lower elevation than Hammam spring. It takes a higher level of overflow to reach the Hammam spring and in consequence this spring’s discharge is less than that of Dardara spring.
Figure 11 Hydrogeological setting of the SBEB showing the three sub-basins subdivided according to the UNDP (1970).
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Figure 12 A schematic model of the groundwater flows in the SBEB
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4.2 The Geological / Hydrogeological setting of el Marj plain
4.2.1 Hydrostratigraphical Setting of el Marj Plain
The sequence of lithologies present in and around the el Marj plain range from Jurassic, Cretaceous and to the youngest aged rocks, the Quaternary deposits. They have different hydrological properties and are presented in Table 1.
The el Marj lowland plain is covered by Quaternary deposits. Those relatively recent deposits have a thickness of up to 50 m in the central part of the plain. These deposits cover Eocene and Cretaceous aged rocks. The characteristics of each formation is summarized in Table 1 Hydrostratigraphy of Lebanon (modified from Walley, 1997)
The el Marj plain is surrounded by elongate exposures of Cretaceous and Tertiary deposits. From the eastern side in Khiam village, elongate exposure of Sannine-Maameltein karstic aquifers are present (Figure 13). On the northern side, the Eocene rocks are exposed and emerge from beneath the Quaternary deposits close to the Hammam spring and widen to reach approximately 10km in the extreme northern part of the study area.
The thickness of this Eocene karstic aquifer (e2b) reaches more than 100m, and thins to approximately 50m close to the Dardara spring.
On the western side elongate exposures of middle Cretaceous aged rocks are present forming the Marjayoun Anticline. This area has been heavily faulted and has undergone tectonic activities that have caused the formation of anticlines. Further erosion and tectonic activities has eroded parts of the succession allowing patches of the underlying formation to be exposed. From the southern side the Metullah high consists of the Sannine-Maamletein Formation. East of the el Marj plain Pliocene basalts unconformably cover the Sannine-Maameltein Formation.
23 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Syncline
Marjayoyn Anticline
Jabal el Hinta Anticline
Mid Marj Fault
Hasbaya Fault Bourj el Mlouk Anticline Yammouneh Fault
Figure 13 Geological map of the el Marj plain
24 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
4.2.2 Structural setting of the el Marj Plain
The el Marj plain is most likely a pull-apart structure that has developed along the Yammouneh fault. The plain is surrounded by highs, forming geological structures surrounding the plain. They consist of a series of anticlines and synclines. The eastern flank of the plain is dominated by the Khiam anticline at Jabal Aarid el Hinta near the village of Khiam. The western flank of the plain consists of the anticlines of Borj el Mlouk and Marjayoun anticlines. The northern section of the plain consists of the Blat anticline while the southern boundary of the plain is defined by the Metullah anticline (Figure 13 & Figure 14).
Figure 14 The south view of the el Marj plain showing the Metullah high (arrow) in Occupied Palestine.
The area is heavily faulted because the Yammouneh fault, a major fault in Lebanon, passes in the area, trending in a NNE-SSW direction along the western limit of the el Marj plain. The fault zone is around 50m with a vertical throw expected to be in the order of hundreds of meters while the horizontal displacement is not clearly defined but expected to be much bigger than the vertical one. The Yammouneh fault has caused major displacements and deformation in the area observed in great variation of bedding dip and small scale folding (Figure 15).
The bedding dip in the area ranges from sub-horizontal to approximately 20˚ dipping to the east on the western edge and to the west on the eastern edge.
The mid Marj Fault is suspected to trend from NNE-SSW, below the Quaternary deposits of the plain. This fault has displaced the strata by about 200m causing different lithologies to lie below the Quaternary deposits. East of the fault the e2b lies just below the Quaternary deposits while to the west the e2a marl formations lies below the Quaternary deposits. This displacement of the subsurface strata is of importance to groundwater flow since it can affect the placement of aquifers and aquicludes.
25 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Fold
Figure 15 Small scale folding close to the Marjayoun village on the side of the Yammouneh fault. The white arrows show the dip direction of the bedding planes of the Abeih Formation’s limestone blocks.
The Hasbaya fault is one of the subsidiary splays of the Yammouneh fault. This faults trends in NE-SW direction and eventually exits Lebanon near Aita al Foukhar mainly through the Cretaceous aged rocks.
Smaller scale faults trending NNE-SSW and NW-SE are also present in the el Marj plain area (Figure 16). These tend to be dip-slip faults that have deformed the area at a much smaller scale than the major faults. These secondary faults tend to be the reasons along which erosion has taken place and underlying formations have been exposed to the surface. They are also some of the reasons why some formations lie unconformably next to each other.
Figure 16 A fault between the Chouf Sandstone Formation (left) and Abeih Formation (right). The Marj Quaternary deposits are located in the lower half of the photograph.
Marjayoun village extends along nearly the entire axis of the Marjayoun anticline, which trends in a NNE- SSW direction. Its bedding dips on the eastern limb are about 20˚ dipping to the east, while the western limb’s bedding dip are also approximately 20˚, dipping to the west. The anticline consists of Abeih and
26 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Mdeirej formations forming the western flank, while the eastern flank consists mainly of the Abeih Formation. These formations have been divided and exposed by the secondary faults (Figure 13).
The Borj el Mlouk anticline encompasses both Borj el Mlouk and Qlaiaa villages and is formed of Abeih, Hammana, Mdeirej and Sannine-Maameltein Formations. It trends in a NNE-SSW direction. It consists of a flower structure that has displaced the formations along secondary faults allowing the different formations to be exposed. The bedding dips of both flanks of the anticline are approximately 20˚ (Figure 13).
The Blat anticline is composed of the Upper Eocene Formation with its Chekka core exposed at the top due to erosion. The bedding dip is approximately 20˚. The Yammouneh fault trends along the lower western edge of the anticline.
Khiam village lies at the top of this anticline with Jabal el Gharbi and Jabal el Hinta making up the Jabal el Hinta anticline. It consists mainly of the Sannine-Maameltein Formation trending in a NNE-SSW direction (Figure 13).
Tell Dibbine high is located on the Dibbine anticline shown in Figure 17. This high is due to an anticline in the subsurface and can be seen in the A-A’ and B-B’ cross-sections (Appendix 4). It consists of lower Eocene marls (e2a) deposits that have been exposed to the surface due to folding. Erosion and human intervention has also played a part in forming the geomorphology of this high which is the only high area in the flat low-lying el Marj plain.
Figure 17 The Tel Dibbine high in the northern section of the el Marj Plain probably flattened by early human settles for there is an archeological site on top.
27 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
4.2.3 Hydrogeological Setting of the el Marj Plain
The Marj acts as a basin to all the surrounding highs so water flows into it from all directions. But the major karstic aquifer that feeds into the plain is the Eocene aquifer, more precisely the south section of the SBEB (Figure 18).
From the west the el Marj plain is bounded by the two anticlines of Borj ele Mlouk and Marjayoun and the Yammouneh Fault (Figure 18). This resulted in a limited groundwater contribution from this side to the plain. To the west groundwater is fed mainly by the Mdeirej and Sannine-Maameltein Formations. These two formations do not have the extent that the Eocene deposits have and so most springs that issue in this section are small. Groundwater flow tends to be along bedding dips so the east directional dips of these formations allow the groundwater to flow towards the el Marj plain.
From the east the el Marj plain is bounded by the Jabal el Hinta anticline and a branch of the Yammouneh fault, the Hasbaya fault. Similar to the western side eastern side has limited groundwater contribution to the plain.
From the north the groundwater flows from the Eocene aquifer towards the south mainly along the axis of the syncline forming the southern sub basin of the SBEB. The groundwater then issues from the Dardara and Hammam springs. The lower limits of this aquifer as observed on the north eastern side are the marls of the lower Eocene and the marls of the Chekka Formations (Figure 18).
Hydrogeologically the el Marj plain can be split into two separate sections. The divide between them is the Mid-Marj fault. The Mid-Marj fault has displaced formations and the Upper Eocene deposits (e2b) are now in contact with the lower Eocene marl deposits (e2a) which is an aquiclude, and so restricts the flow of the groundwater (Appendix 4). This barrier causes the groundwater to bank behind it. The banking level rises with added precipitation and snowmelt, until the water discharges to the surface from the Dardara spring as overflow of the groundwater. This rise reaches Dardara spring first as it is at a lower elevation of 528m asl. El Hamman spring is at a 580m asl elevation. This 52m difference means that banking groundwater needs more time and thus more quantity to rise enough to issue from the Hammam spring which is a possible reason why the discharge of Hammam spring is less than that of Dardara spring (Figure 19).
Any groundwater that passes the mid Marj Fault system and seeps into the Quaternary and other formation further south will bank against the Metullah high.
The Quaternary deposits in the plain also act as a semi-aquifer. The extent of this shallow aquifer is limited and the series of small discharge springs scattered around the plain are many and will probably dry up in the summer months and will be replenished with winter rains and snow.
28 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Figure 18 A groundwater flow map of possible water directions in the el Marj plain.
29 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Figure 19 A groundwater flow model of possible water directions to the plain’s main springs.
It must be noted that locals have postulated that after the South Lebanon Water Authority (now the South Lebanon Water Establishment) decided to drill domestic water wells north of the Dardara and Hammam spring in the early 1990’s the discharge of Hammam spring decreased and began to dry. The locals stated that before these wells were drilled and pumped the Hammam spring discharged enough water for the land north of Dardara spring and south of Hammam and now the spring dries up at the beginning of the summer season.
5 PREVIOUS STUDIES
Since the 1960’s several hydrogeological studies has been conducted on the Dardara spring and its surroundings. The UNDP studied the hydrogeology of Lebanon including the SBEB and the Dardara spring between 1960 and 1970 for better understanding of the hydrogeology of Lebanon; in 1983, the BTD studied the Dardara spring and the el Marj plain for further exploitation and finally in 2002 USAID studied the Dardara spring and its surrounding wells for the agricultural development of the el Marj plain.
5.1 Studies on the Southern Bekaa Eocene Basin (SBEB)
5.1.1 Liban Etude Des Eaux Souterraines, United Nations Development Program (UNDP), 1970.
The UNDP 1970 divided Lebanon into two main provinces, the Mediterranean province and the Interior province. The interior province has several aquifers of which one is the Eocene aquifer. This aquifer is exposed in three main basins in the Interior province in the Bekaa Valley called the Northern, Central and Southern basins. The largest exposure of these Eocene rocks is in the southern Bekaa Eocene Basin (SBEB).
According to the UNDP 1970 the SBEB is actually a karstic aquifer that occupies a syncline that extends from Majdal Aanjar in the north to Marjayoun in the south. The report also splits the SBEB into three sub-
30 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
basins based on three different directions of groundwater flow (Figure 11). These 3 sub-basins can de delineated as follows:
The Northern section: close to Bire and Lela villages the groundwater flows underneath the Quaternary deposits of the bekaa towards Soultan Yaakoub and Majdal Aanjar villages. It is pumped by a series of wells located in the area. The Central section: close to Jabal el Aarbi and Jabal Bir ed Dahr, the water flows towards the two main springs in the Litani valley called Ain Zarka at 578m asl and Ain Borghos at 450masl. The Southern section: the division lies between Hasbaya and Blat villages. The underground water flows south towards the El Marj plain and issues from Dardara at 584masl and Hammam springs at 552masl.
The UNDP, 1970 report discusses the characteristics of the Eocene aquifer, which feeds the Dardara and Hammam springs, through pumping and recession graphs. The report also discusses the physical and chemical characteristics of the plain’s underground water.
Vertical groundwater flow does not exist in the el Marj plain, the piezometric level of the southern part of the SBEB is shown from the levels of the springs issued Ain el Zarka at 578m, and that of Ain Borghos is 450m in the central part and at the extremity of the aquifer. In the south, the Hammam spring is at 584m asl and Dardara at 552m asl. The fluctuation of groundwater in the el Marj plain is in the order of 10m between dry and wet season.
The porosity of the Eocene karstic limestone according to the UNDP 1970 was in the order of 1. However, according to them, the storage coefficient is in the order of 10-2 to 10-3. The coefficient of transmissivity calculated is 0.00122 for Ain el Zarka spring, 0.00318 for Dardara spring and 0.013 for Hammam spring. The small values of transmissivity for the Ain el Zarka spring indicate important dynamic reserves. Table 2 summarizes the sub-basin in the SBEB according to UNDP, 1970.
Table 2 Condition and properties of the three sub basins of the SBEB Nature Yearly Year of Discharge Discharge in Sub Coefficient of of exit Source Discharge investigati in winter summer Porosity Basin transmissivity points (106*m3) on (106*m3) (106*m3) No major 8*10-3 and 2*10- Northern Wells 5 and 13 - - - 2.9 source 2 m/s
Ain el 57 1961-1967 41 16 - 0.00122 Zarka Central Spring Ain 9 1966 6 3 - 0.013 Borghos
Southern Spring Hammam 4 1962-1966 3 1 1 0.00318
31 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Dardara
In the southern section of the SBEB the reserves, based on the storativity coefficient, are in the order of 10 million m3 in a 50m thickness. The budget is summarized in Table 3.
Table 3 General Budget of the SBEB ELEMENTS OF THE BUDGET mm (106 m3) m3/s Precipitation 790 195 6.2 Infiltration 355 North 18 2.8 Center 66 South 4 Runoff 16 4 0.1 Deficient -Evapotranspiration 419 103 3.3
In the southern part the surface of the aquifer plunges below the Quaternary deposits, making exploitation possible. According to the UNDP 1970 reserves allow theoretically 190l/s which correspond to lateral flow of groundwater in the aquifer. But also according to them it is certain that this will cause dewatering of the sources of Hammam and Dardara in the order of around 120l/s. For the Marjayoun region the exploitation is already on its way in the form of wells, both public and private.
5.2 Water Management and Hydro-Diplomacy in Lebanon, Comair, G. F. 2009.
Comair, 2009, based on the UNDP 1973 studies, divided the SBEB into three sub basins with each its own different budget presented in Table 4. Comair, 2009 set the boundaries of the southern part of the SBEB as follows: from the north it is the limit of the anticline of Blat, from the South by the Eocene and Chekka marls under the Quaternary of el Marj plain at the closing of the syncline, from the west by the Yammouneh Fault and from the east by the Eocene and Chekka marls (Table 4).
Table 4 The three sub basins in Comair, 2009 Amount of Area Precipitation Infiltration Sub Basin Extent Infiltration Remarks (km2) (mm/year) (%) (m m3/year) Region of Joub- Jannine from Quantity is almost entirely Northern north of Lala 55 550 40 12 pumped from wells village to Majdal Anjar The springs and the wells Sector Borghos - Central 200 875 50 87 are draining this karstic Zarqa aquifer El Khouk - This sector is drained by Southern Marjayoun – el 16 900 50 7.2 the Dardara and Hammam Marj plain. springs and several wells.
32 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Volume of 1 million m3 diffuses into the superficial Quaternary aquifer
5.3 Studies on the Dardara Spring / el Marj plain
5.3.1 Project d’exploitation de l’aquifere des sources de Dardara et de Hammam caza de Marjayoun, BTD, 1983.
The Bureau Technique pour le Developpement, BTD, studied the el Marj area focusing on the Dardara and Hamman springs and possibility of exploiting the Southern sub-basin of the SBEB. The report was for the Ministry of Electricity and Water Resources.
Five wells were used to conduct tracer tests, pumping tests and well log data measurements. Three wells are located in the el Marj plain, drilled in the Eocene aquifer, one in Ibl el Saki, also in the Eocene aquifer, and one in Blat, in the lower Eocene aquiclude (Figure 20).
33 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Figure 20 Tracer tests conducted by the BTD 1983 study
Geophysical logging of the well indicated that the aquifer is highly fractured and karstified and that there are two zones of karstification one at depth of 17m BG and one at 35m BG. Well 23/50 showed a notable increase in groundwater temperature from 16.8 to 17.3°C at a depth of 100m BG which indicates a deep groundwater flow in the Eocene aquifer. Table 5 shows the characteristics of the BTD wells. Table 5 Wells located in the El Marj plain (BTD, 1983) TEMPERATURE/ DEPTH AV. GW DISTANCE TO TRACER TEST WELL NO CONDUCTIVITY WELL NO (m) DEPTH BG SPRING RESULTS LOG Tracer detected in 1500 m to 10-26m Heterothemic zone Hammam spring after 4hr Hammam (10.4cm/s) 23/50 23/50 123 9.5m 29-98m Low permeability zone El Marj plain El Marj plain Dardarra spring tracer 3500m to After 98m Impermeable zone detected after 32hr Dardara (3cm/s)
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1550 m to No tracer detection at Hammam 0-36m Impermeable zone Hammam spring 23/51 23/51 107 10.77 El Marj plain El Marj plain 36-89m Low permeability zone Dardarra spring tracer 3550m to detected after 20 hours Dardara 1500 m to No tracer detection at Hammam Hammam spring 23/52 19-36m Heterothermic zone 23/52 El Marj 104 16.62 Dardarra spring tracer El Marj plain 36-89m Low permeability zone plain 3500m to detected after 22hr Dardara (4.6cm/s) 23/53 41-80m Permeable zone 23/53 107 - - - Ibl el Saki After 80m Low permeability Ibl el Saki 23/54 23/54 125 9.85 Low permeability zone - - Blat Blat
The results of pumping tests conducted by the BTD are summarized in Table 6. The pumping tests showed the pumping rate that was used for the exploitation of these wells which is around 68.6 l/s had no major influence on the spring and the radius of influence was in the order of 50 m with a maximum drawdown of 10 m. The three transmissivity coefficients reveal the karstic nature of this aquifer.
Table 6 Summary of result of pumping tests conducted in the el Marj plain by BTD (1980) Pumping Max. Observation Duration of Pumping rate Transmissivity well drawdown Remarks well (OW) pumping (hr) (l/s) coefficient (m2/s) (PW) in PW (m) 8.7*10-3 Did not reach stabilization. 23/50 23/51 8.5 68.6 7 4.25*10-3 Fault encountered at 17m and 1.7*10-2 35m form pumping wells 1.5*10-2 Did not reach stabilization. 23/50 23/54 119 68.6 10 3*10-2 Fault encountered at 25m and 4.06*10-3 48m form pumping wells
Quality and quantity of the Dardara and Hammam springs were analyzed. The discharge and recession coefficient of the two springs are summarized in Table 7 showing the changes of discharge of the springs in the years ranging from 1962 to 1980. It can also be noted that Hammam spring has a no discharge data in the years of 1969, 1971, and 1972. The average conductivity of the Dardara spring water is around 353µs/cm while that of the Hammam spring water is lower at around 303µs/cm. The recession coefficient of the Dardara spring and Hammam springs is around 6.95*10-3 and 1.44*10-3 respectively (Table 7).
Table 7 The recession coefficient and discharge rate of the Dardara and Hammam springs Dardara spring Hamman spring Discharge rate at Discharge rate Year Recession Recession end of September at end of coefficient (α) coefficient (α) (l/s) September (l/s) 1962 0.0482 40.85 0.013 6.38 1965 0.0482 47.79 0.014 7.2 1966 0.00956 29.9 0.00976 11.56 1967 0.00361 59.6 0.0143 16.86 1968 0.00589 40.39 0.021 3.37 1969 0.01 36.58 - -
35 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
1970 0.005 51.91 0.0144 4.03 1971 0.0099 60.13 - - 1972 0.003 63.06 - - 1980 0.00695 47.8 - 8.23
Tracer tests showed the existence of two permeabilities in the aquifer since there were two speeds of flow. This could be attributed to two different water flows in the aquifer. Another indication of two subsurface flows is seen in the temperature log of well 23/50 where, at around 100m, there is a shift in the water temperature, indicating that a second groundwater flow has been tapped which has a different temperature and hence a different origin.
Tracers injected in well 23/50 emerged in both Dardara and Hammam spring after 4 and 32 hours respectively; while tracer test injected in 23/51 and 23/52 did not show in Hammam but did show in Dardara spring after 20 and 22 hours respectively (Table 5 and Figure 19 A groundwater flow model of possible water directions to the plain’s main springs.
410 Dardara 390 Hammam 370
s/cm) 350 (
330
310
Conductivity 290
270
250 14 16 18 20 22 24 26 28 30 32 34
Time (days) Figure 21 Variation in conductivity values between the Dardara and Hammam springs (BTD, 1983)
According to the tests conducted the study by BTD did not see any observable influence from the pumping test on the springs.
The safe exploitation potential of the Eocene aquifer, especially in the dry periods, according to BTD (1983), is 7 million m3 which is equivalent to 250l/s. This is already being exploited by many wells in the area. The Quaternary cover’s surface extent on top of the Eocene aquifer is 20km2 in area, with a thickness of saturation at 50m, and rock porosity of around 2%. Groundwater volume is estimated at 10.32x106m3 and the volume of water entering the aquifer from precipitation is around 7.136x106m3. Wells in the area are pumping at a rate of approximately 7x106m3 however the natural overflow of the springs in the area is
36 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
around 5.7 x 106m3. The dynamic reserves were estimated at 0.71x106m3 and the static reserves at 9.61x106m3 (Table 8).
Table 8 The water budget in the el Marj plain Volume of Natural Artificial water Area of Area of Volume of Preci- Evapo- discharge discharg Dynamic Static Infiltration entering aquifer aquifer Storage water in pitation transpiration from springs e from reserves reserves (mm) the aquifer with Q without Q (%) aquifer P(mm) (mm) and in Q springs (*106m3) (*106m3) form P (km2) (km2) (*106m3) (*106m3) (*106m3) (*106m3) 900 404 496 7.136 20 16 2 10.32 5.7 1.3 0.71 9.61
5.4 The Dardara Water System in South Lebanon, Collaborative Planning Situational Analysis. United States Agency for International Development. 2002.
The USAID 2002 report cited four wells in the Marj plain, of unknown location, where pumping tests were undertaken. It is believed that one of the pumping wells was in the USAID farm.
The tests revealed that the pumping at that rate is not affecting the level of the water in the aquifer. However, it should be noted that these pumping tests were carried out in September at a time where no or little irrigation was taking place (Table 9).
It is also indicated that the pumping tests was conducted at a much lower rate than necessary and the only data that can be utilized is that at these low pumping rates there is no affect on the spring discharges of the Dardara and the Hammam springs.
Table 9 Pumping test summary (USAID, 2002) Observation Flowrate Time of Drawdown Well well (m3/hr) test (hr) (cm) W1 - 25.2 5.5 78 W3 - 19 1 13 W5 W10 6.1 3 3 W9 - 15 1 0
6 WELLS AND SPRINGS SURVEY
A comprehensive well and spring survey was conducted to assess the groundwater condition in the study area and to estimate the natural water outflow of the aquifer and the artificial extraction. Appendix 5 and 6 outlines the wells and springs identified and surveyed in the area until now.
The discharge measurement was conducted for this study using a handheld flow meter, the Global Water FP111-FP211 flow prop. The bucket method was also used to measure the low discharge rates of some springs. The pH, Conductivity, Temperature, and TDS of the water in the springs is tested on site using an OAKTON Handheld Water Meter, Eutec Instruments (Appendix 6 & 7). While the water level in the wells was measured using an Insitu level tape 100 meter.
37 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Water samples from wells was not possible to attain for chemical testing several times for either the owner was not operating the well or there was no electrical power during the site visits.
6.1 Spring Survey
Seven springs were identified in the el Marj area (Figure 22 & Appendix 6). The two major springs in the el Marj plain are the Dardara and the Hammam springs. Smaller scale springs are present but are considered not to be of any great significance since they issue from semi-aquifers and the shallow Quaternary aquifer. They probably dry up in the summer months.
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Figure 22: Map showing the location of springs in the el Marj plain zone
39 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
6.1.1 Dardara spring
Figure 23 The Dardara spring basin shown in the photograph and Google Earth
The Dardara spring is located at an elevation of 528masl in the east-central part of the plain. The area of the pool around the spring is around 0.084km2 (Figure 23).
A water network had been developed/constructed from the spring to the surrounding villages. The western canal of the water network, supplies water to Al Qlaiaa region while the southern canal supplies water to Khiam, Al Qlaia and Borj el Mlouk villages.
The spring issues from Quaternary deposits, however, as it will be shown in the hydrogeology section, the groundwater flows from the karstic Eocene aquifer which has banked on the displaced lower Eocene Formation, that was in turn displaced by the mid-Marj fault.
The discharge measurements of the Dardara spring ranged between 125 l/s measured on the 5th of April 2012, and the lowest measured was 65 l/s on the 4th of May 2012 (Figure 25).
The flow decreases in both Dardara and Hammam Springs, with Dardara springs’ discharge higher than that of the Hammam spring. The first measurement of Hammam spring was taken on the 22nd of March, whereas the first measurement of Dardara Spring was taken on the 29th of March. There are high measurements on the 5th of April, due to high precipitation rates proceeding the day of the measurement (Figure 25).
40 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
140
Dardara Hammam 120
100
(l/s) 80
60 Discharge
40
20
0 16/Mar/12 24/Mar/12 01/Apr/12 09/Apr/12 17/Apr/12 25/Apr/12 03/May/12 11/May/12
Figure 24 Discharge of Dardara and Hammam Springs
The pH values for the Dardara spring water ranged between 6.9 minimum, on the 29th of March, and 7.38 as maximum on the 4th of May (Figure 25). On the 5th of April the temperature measured was the highest at around 18°C (Figure 26).The conductivity values for the Dardara spring was around 460µS/cm and the lowest on 22nd March at 454µS (Figure 27).
7.4 Dardara pH Hammam pH 7.2
7 pH
6.8
6.6
6.4 22/Mar/12 29/Mar/12 05/Apr/12 12/Apr/12 04/May/12
Figure 25 pH of Dardara and Hammam Springs
41 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
20 19.5 Dardara spring Hammam spring 19 18.5 C) ˚ ( 18 17.5 17
Temperature 16.5 16 15.5 15 12‐Mar‐12 22‐Mar‐12 1‐Apr‐12 11‐Apr‐12 21‐Apr‐12 1‐May‐12 11‐May‐12
Figure 26 Temperature of Dardara and Hammam Springs
480
460
440 Dardara Conductivity Hammam Conductivity 420 (µS/cm)
400
380
360 Conductivity
340
320
300 22/Mar/12 01/Apr/12 11/Apr/12 21/Apr/12 01/May/12
Figure 27 Conductivity for the Dardara and Hammam Springs
42 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
6.1.2 Hammam spring
Figure 28 The Hammam spring basin shown in the photograph and google map
The Hammam spring discharges at lower rate than the Dardara Spring (Figure 25). According to the locals, this spring dries immediately after the rainy season and they also stated that the last time that there was a flow similar to the flow of this year (2012), was in the year 2001. The Hammam spring is still flowing in April of this year 2012, due to the long and intense winter season (Figure 30).
The Hammam spring is at an elevation of 581m asl. There is a circular pond beside the spring measuring 314.16m2 in area. The overflow of the pond runs into a channel that irrigates the surrounding area.
The minimum flow measurement was at with 4.05l/s however, there was discharge values of up to 126.8l/s on the 5th of April, which was measured directly after high precipitation rates. A decreasing discharge trend then dominates the consecutive measurements.
Based on the field measurement, the water’s pH values ranged between 6.57 minimum on the 29th of March, and maximum at 7.27 measured on 4th of May.
The conductivity levels ranging between 356-366µS. The conductivity is lower for Hammam spring than the Dardara Spring (Figure 27)
6.1.3 Other springs
There have been other springs surveyed in the el Marj plain zone. They are Qseir spring (Figure 30), adjacent to Qseir Monastery and Haouche spring, adjacent to its restaurant. There are also some minor, seasonal springs such as the Bou Daher and Mouqbiye springs located in the plain. The monitoring plan
43 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
will include the Qseir and Haouche springs as long as they have enough flow to be measured. Bou Daher and the Mouqbiye springs (Figure 29) are fed by shallow aquifers, so they could dry in the summer season (Appendix 6).
Figure 29 The Moqbiye spring near Tel Dibbine
Figure 30 The Qseir spring
6.2 Well survey Overall, forty wells were identified in and around the el Marj plain. Their locations are shown in Figure 31. These wells have been identified from previous studies and site visits. Out of these forty wells, 25 wells were identified in the field survey, 8 wells from the BTD study, and 7 wells were located as public wells in the caza of Marjayoun.
Out of these surveyed wells 14 have been monitored regularly, additional wells could be considered depending on the development of the monitoring process and the water levels in the wells. The depths of
44 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
wells range from 35m (Well 6) up to 220m (Well 23). Not all the wells have known depths and hence the clear definition of their tapping formation. Accordingly, for each well, the parameters to choose the well for monitoring is based on its location, in relation to geological and structural consideration, depth, and aquifer tapped in the plain area and its importance for the hydrogeological assessment.
The basic use of the wells is mainly for irrigation purposes, especially the ones that are in/or around the plain. The estimate of the water abstracted is based on the season, type of crops, quantity of water needed, and the availability of electricity. Further investigation will be carried out to make an inventory of the approximate amount of abstracted water from the wells during following field visits.
Well 2 whose depth is less than 70m, and drilled in an area with an outcrop of Eocene deposits, is assumed to tap the Eocene aquifer, since it is far from the mid-Marj fault, where the Eocene deposits decreases in thickness (Figure 33).
Well 3, although drilled in Quaternary deposits, is drilled up to 70m, so it is approximated that the well is tapping the Eocene aquifer, however, well 4, which is also drilled in the Quaternary deposits, is drilled deeper (110m), and in the last water level measurement it appeared to be dry. It is assumed that this well is drilled in the Eocene Marl Formation beneath the Eocene Aquifer.
45 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Figure 31 Location of wells in the el Marj plain zone.
Well 5 is an artesian well, and it overflows in the high rainfall season. It is 50m deep, with the outcropping formation Quaternary in age, therefore, the tapped aquifer is assumed to be the Chekka Formation, and verified by the odor of sulfur in the water, in the well and white deposits on the vent of the well as seen in Figure 32.
46 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Although well 6 is very close to Well 5, it is shallower, with less yield, and is therefore assumed to tap the Quaternary aquifer.
Figure 32 Well 5, an artesian, sulfurous water well
Well 7 is 90m deep and the outcropping formation is Mdeirej. Knowing the thickness of the Mdeirej Formation underlying Abeih Formation, it also overflows. It becames a low yield well in the summer and can be assumed to tap the Abeih Formation.
Well 12, is 150m deep, and is drilled in an area with outcrops of the Chekka Formation, perhaps it taps the Sannine-Maameltein aquifer.
Well 19 and 21 are drilled in the Quaternary deposits. The former is 300m deep and the latter is 117m deep. The water level in Well 19 is around 65m and is around 25m in Well 21.
Well 23 is drilled through Quaternary deposits and is around 220m deep. It is located on the western side of the el Marj plain, where the Quaternary rocks overlie the Sannine/Maameltein aquifer.
542
asl) 541.5
(m 541
540.5 Level
540 539.5
Water 12/Mar/12 27/Mar/12 11/Apr/12 26/Apr/12 11/May/12
Figure 33 Example of the water level decrease of Well 2
47 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
559.8 as)
559.6
(m 559.4
559.2
Level 559
558.8 558.6 Water 12/Mar/12 27/Mar/12 11/Apr/12 26/Apr/12 11/May/12
Figure 34 Example of the decrease of the water level in Well 5
Water Levels were measured five times, and on five separate maps, the depth to water, the water level above sea level, and the name of the well can be seen for the five different days in Figure 35).
48 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
Figure 35 Maps showing the wells, with their water level and their depth to water
49 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
For the first round of the monitoring process water samples were taken from some of the monitoring wells, depending on whether the pump was on, or whether the well enabled lowering a sampling bottle. Well 2 was measured once while pumping of the well was being undertaken. More than two hours elapsed before the water sample was taken. Well 5 was sampled twice, once when there was an overflow of its water. Well 7 was measured once, when there was an overflow of water. Well 12 was measured when the pump was still on and had been pumping for 30 minutes. Well 2, Well 5, Well 7, and Well 12, are monitored for their water quality.
The well samples were tested for the pH, Conductivity, TDS and temperature. The highest pH reading among the tested wells was Well 2, with 6.91, and the lowest pH was measured in Well 7 with 6.52 (Table 10).
Table 10: The pH reading of the sampled wells Well 2 Well 5 Well 7 Well 12 22 March 2012 - - - - 29 March 2012 - 6.63 6.52 - 5 April 2012 - 6.47 - - 12 April 2012 - - - - 4 May 2012 6.91 - - 6.77
The highest TDS level was measured in Well 12 at 505ppm, and the lowest value measured was in Well 2 at 333ppm. The other wells’ values measured are shown in Table 11.
Table 11: the TDS readings for the sampled wells Well 2 Well 5 Well 7 Well 12 22 March 2012 - - - - 29 March 2012 - 480 429 - 5 April 2012 - 482 - - 12 April 2012 - - - - 4 May 2012 333 - - 505
Conductivity values were also measured from these four wells, and they show that Well 12 has the highest values at 722µS, and the lowest values is Well 2, with 477µS, The other wells’ values are shown in Table 12 The Conductivity values of the WellsTable 12.
Table 12 The Conductivity values of the Wells Well 2 Well 5 Well 7 Well 12 22 March 2012 - - - - 29 March 2012 - 688 612 - 5 April 2012 - 688 - - 12 April 2012 - - - - 4 May 2012 477 - - 722
50 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
For the water temperature measurements, Well 2 and Well 12 have similar ranges of temperature values at around 19°C. Well 5 has a higher temperature at around 21°C (Table 13). For detailed data about the wells refer to Appendix 7.
Table 13 Table of the water temperature of the monitored wells Well 2 Well 5 Well 7 Well 12 22 March 2012 - - - - 29 March 2012 - 19.3 23.8 - 5 April 2012 - 21.1 - - 12 April 2012 - - - - 4 May 2012 19.5 - - 19.2
This data will be updated in the upcoming phases and the next period of the monitoring plan.
7 PRECIPITATION DATA
The precipitation data was been assembled from a number of sources chiefly the Airport weather station, LARI, AVSI, and METOS. The five weather stations that are the closest to the el Marj plain are Rachaya, Marjayoun, AVSI Marjayoun, Mimes and Khiam (Table 14 and Figure 36). Table 14 The weather stations with their characteristics OPERATOR STATIONS X- Y- ELEVATION CLASS START DATE S coordinate coordinate (asl) TYPE LARI-20 EL KHIAM 35.614166 33.331111 714m B8 LARI-39 MIMES 35.70035 33.440183 820m C11 LARI-41 RACHAYA 35.662581 33.358739 797m C13 01 April 2003 DGAC-35 MARJEYOUN 35.582333 33.355317 827m AVSI AVSI MARJAYOUN 35.58300 33.33200 520m 8 March 2009
Figure 36 The location of the weather stations surrounding the el Marj plain
51 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
1000 900 800 700 Mimes (mm) 600 Rachaya 500 Khiam Marjayoun 400
Precipitation 300 200 100 0 November November April April November November April November April August September October December January February July August September October December January February March May March May July August September October December January February July August September October December March May July August September October December January February March May June June June June ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 11 09 12 10 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 11 09 12 10 11 09 12 10 09 12 10 11 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 09 12 10 11 08 ‐ 11 ‐ 09 ‐ 12 10 ‐ ‐ ‐ ‐ ‐ ‐ 09 12 10 11 08 11 09 12 10 ‐ ‐ ‐ ‐ 09 12 10 11 ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 08 11 09 12 10 08 11 09 12 10 08 11 09 12 10
Month‐Year
Figure 37 Precipitation rates in the el Marj plain over the period of 4 years (assorted sources)
The average rainfall (taken from the five weather stations) in the area in the year 2009 is 707mm/year, in 2010 is 494mm/year, 2011 is 570mm/year (Figure 37). The average rainfall taken from the Marjayoun weather station as shown in Figure 38 shows the rainfall per year and its trend over a period of 27 years. The rainfall varies between the lowest values in 1947 at nearly 450mm/year and the highest in 1969 at 1150mm/year. The red trend line in Figure 38 shows the average rainfall in Marjayoun village as about 850mm/year.
1400.00
1200.00 (mm)
1000.00
rate 800.00
600.00
400.00
200.00 Precipitation
0.00 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
Year
Figure 38 Precipitation rates in Marjayoun from the years 1947 to 1974 (reference?)
52 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
8 MONITORING PLAN
8.1 Basic plan
Knowing the limited resources and available budget, a monitoring plan is put forward in the following section. The purpose of the monitoring plan is to evaluate the water resources that could impact the Dardara spring and evaluate the spring itself. For better evaluation of the water resources in the plain and the Dardara spring system the amount of water in the system needs to be considered. One way to measure the amount of water coming in and out of the water system is to monitor the water discharged by the springs as well as measuring water level changes in wells which is an indication of the watertable in the plain. Precipitation and infiltration are also considered so the amount of water entering, leaving and stored in the system can be approximated up to a certain level.
The monitoring will be undertaken for a one year period, taking measurements once per month from various wells. The precipitation and weather conditions that can impact the water level in the monitored wells and springs will also be monitored through local weather stations.
The monitoring points will be the wells and springs that are distributed along the sides of the plain. To date the wells and springs have been monitored five times. The monitored wells where primarily chosen due to their location and the aquifer they tap. The ease of access was also a consideration because some wells are locked or on private land.
A data sheet for each well will be filled with the wells’ characteristics (Appendix 8). The values measured during monitoring are as follows; the water level from ground level; the water characteristics for pumped wells whenever possible, depending on pumping times; the water’s physical and chemical characteristics; the spring discharge rate;
Fifteen wells and four springs (Table 15) will be monitored (Appendix 5, 6, 7). These wells are dispersed around the environs of the plain. Wells 2, 3 and 4 are in the northern section of the plain. Wells 7, 9, 19, 20, 21, 23, and 25 are in the western section of the plain. Wells 5, 16, and 22 lie in the eastern side of the plain. Additional wells and springs might be added to the survey list if deemed necessary.
The ability to test the chemical and physical characteristics of the well water depends on whether the well is being pumped at the time of the visit. Since there is no set time for the well operation it is not always possible to obtain water from the deep wells. Water can be extracted from shallow wells because the water level is close to the surface. A bottle can be lowered to collect this well water.
Table 15 A list of the wells and springs that are being monitored in the el Marj plain. Name (Well / X (Geographic co Y (Geographic Z Well depth # Spring) ordinates) co ordinates) (m asl) (m) 1 Well 1 33º20’11.0 035º35’49.3 564 N/A
53 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
2 Well 2 33º20’23.1 035º35’45.4 562 >70 3 Well 3 33º20’48.1 035º35’52.9 586 ~70 4 Well 4 33º20’50.5 035º35’36.0 593 110 5 Well 5 33º18’48.7 035º35’38.7 518 50 6 Well 6B 33º18’50.5 035º35’36.3 521 35 7 Well 7 33º19’56.3 035º34’34.6 560 90 8 Well 9 33º18’58.1 035º33’53.3 576 N/A 9 Well 12 33º19'12.6 035º35'54.1 552 150 10 well 19 33º18’20.0 035º34’10.3 513 300 11 well 20 33º20’07.9 035º34’21.1 649 N/A 12 Well 21 33º18'28.8 035º34'26.40 500 117 13 well 23 33º20’19.6 035º35’03.8 543 220 14 well 24 33º20’19.6 035º34’52.2 563 120 15 Well 25 33º20'19.6 035º34'52.2 591 115 1 Haouche 33º19’09.8 035º34’24.1 523 2 Hammam 33º20’54.3 035º35’55.6 584 3 Dardara 33º19’54.37 035º35’27.05 552 4 Al Qseir Monastery 33º20’9.60 035º34’51.60 566
8.2 Advanced plan in case of additional funding
The resources available provide one field measurement per month, however an increase in the number of data collected per month will allow better assessment of the resources. Three approaches are considered below that could better assess the groundwater resources.
The first approach is to increase the number of data collected manually per month from 1 measurement to 2 measurements during the allocated time of the project. This will require additional 4,000$.
The second approach is the installation of dedicated probes in wells in the el Marj plain after agreement with the owners. The proposed number required is 6 probes spread in the plain to provide the best results. Two will be located close to Dardara spring, two in the upper part of el Marj plain and two in the lower part. This approach will attain more accurate, detailed and continuous data. The approximate estimated cost of the above listed equipment is provided in (Table 16). Please note that those prices do not include customs and VAT, as these would be subject for exemption for government institutions and international funds. This does not include the overhead and expenses of the consultant. This will help in acquiring more accurate detailed data.
Table 16 Approximate cost of the groundwater probes in wells Approximate Cost Approximate Cost of cable Equipment Comments of probe (USD) per meter (USD) Ground water Monitoring Probe (Pressure & Vented cable but no 3000 USD 12 USD / m Temperature) conductivity Ground water Monitoring Probe (Pressure, Vented cable with 7000 USD 12 USD / m Temperature and Conductivity) conductivity
The third approach, which is the best one, requires the drilling and installation of dedicated monitoring wells at depths ranging between 20m and 75m. This might require the highest budget, but if this approach is considered the detailed price and well design will be established separately because an
54 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012 assessment will be required (Table 17). This approach will acquire more accurate detailed data from specifically chosen locations. There will also be a better understanding of the interaction between the Quaternary and Eocene aquifers.
The need to collect two rounds of water samples (one during the spring and one at the end of the dry season) mainly from springs and some monitored wells (to assess the quality) is important to better determine the nature of the resources.
The laboratory tests include the basic physico-chemical analyses. However, the need to assess the contamination from agricultural practices might be an option in this case too. The cost for each sample is in the order of 500$ without the overhead and expenses of the consultant.
As water flows through an aquifer it assumes a diagnostic chemical composition as a result of interaction with the lithological framework. The chemical analysis of water can show the percentage compositions of ions which in turn can be used to evaluate and assess the origins of the groundwater sampled. A piper diagram can then be used to classify waters as well as identify the mixing of waters. It can show, graphically, the nature of a given groundwater sample, and indicates its relationship to other samples. By classifying samples on the Piper diagram geologic units can be identified, thus defining the evolution in groundwater’s chemistry along the flow path.
Table 17 Summary table of approaches TASK REASON
APPROACH Increase in monitoring measurements Will allow better assessment of the resources. 1 from once to twice a month. APPROACH Acquire more accurate detailed continuous data. Installation of dedicated probes in wells. 2 Acquire more accurate detailed data from specifically chosen APPROACH The drilling and installation of dedicated locations. Better understanding of the interaction between the 3 monitoring wells. Quaternary and Eocene aquifers. Laboratory Construction of a piper diagram and better understanding of Full water sampling analysis tests the chemistry of the groundwater.
55 HYDROGEOLOGICAL STUDY OF THE UNDERGROUND WATER SYSTEM IN THE EL MARJ PLAIN: The Source of Dardara April, 2012
9 ONGOING DATA COLLECTION AND ASSESSMENT
Refinement of the data collected on wells to better judge the discharge rate. Collect this year’s precipitation data. Better judge the extraction rate from the Dardara spring. Assess the natural drainages in the el Marj to determine if they dry during the summer. Implement the basic monitoring plan until further notice. Assess the condition of the flowmeter in the Dardara spring. Assess the leakages from the Dardara pool. Better assess the pumping rate of the SLWE public wells in the area.
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10 References
Abbud, M. and Aker, N. 1986. The study of the aquiferous formations of Lebanon through the chemistry of their typical springs. Lebanese Science Bulletin. Vol 2 number 2.
BTD, 1983. Project d’exploitation de l’aquifere des sources de Dardara et de Hammam caza de Marjayoun. Final Report.
Dubertret L., (1945-1960); Geological map 1:50.000, Hermon Sheet (Rachaya S), Beirut 1960.
Dubertret L., (1952); Geological map 1:50.000, Sheet Merdjayoun, Beirut, 1952.
Dubertret L., (1945-1960); Geological map 1:50.000, Sheet Rachaya N, Beirut 1960.
United States Agency for International Development. The Dardara Water System in South Lebanon, Collaborative Planning Situational Analysis. 2002.
United Nations Development Program (UNDP). 1970. Liban Etude Des Eaux Souterraines. Government of Lebanon, Beirut, Lebanon.
Walley C., 1998. Some outstanding issues in the geology of Lebanon and their importance in the tectonic evolution of the Levantine region. Tectonophysics, Volume 298, Issues 1–3, 30 November 1998, Pages 37–62.
Zeitoun, M, K. Eid-Sabbagh, M. Dajani and M. Talhami, 2012. Hydro--political Baseline of the Upper Jordan River. Beirut, Association of the Friends of Ibrahim Abdel Al.
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APPENDICES
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APPENDIX 1 (Geological map of SBEB)
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APPENDIX 2 (Structural geological map of SBEB)
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APPENDIX 3 (El Marj plain zone geological and structural geology map)
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APPENDIX 4 (The cross-sections of el Marj plain (1:20,000))
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APPENDIX 5 (Well survey)
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APPENDIX 6 (Spring survey)
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APPENDIX 7 (Data of Monitored wells)
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APPENDIX 8 (Data of Monitored springs)
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APPENDIX 9 (The Well and spring survey sheet)
67