Hdrogeological and Geophysical Studies on Al-Jaww Plain, Al-Ain

WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

ELECTRICAL RESISTIVITY IMAGING FOR QUATERNARY AQUIFER IN WADI MURAYKHAT AND WADI SA’A, AL AIN AREA, UAE. By: Ahmed. El-Mahmoudi KFU University, Water Studies Centre, KSA WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Figure (#) Map of Al Jaww Plain and locations of Wadi Muraykhat and Wadi Sa’a (modified from Warrak, 1986). WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Objectives These wadis originate from the Oman Mountains range and form the catchment and feeding area of the water resources. So, From the hydrogeological point of view, subsurface investigation of these wadies is very important for better understanding of the Quaternary aquifer system. To Map the subsurface conditions of the Quaternary alluvial aquifer system at Wadi Muraykhat & Wadi Sa’a , Al Jaww Plain through (2-D) electrical Resistivity tomography survey. WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

To achieve these Objectives

Reviewing the Geology of study area. A series of data including:

Borehole data Geophysical Investigations (2-D Resistivity, TEM Data WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

GEOLOGICAL ASPECTS Th WSTA 8 Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain 25

320 000 E 340 000 E 360 000 E 380 000 E 2740 000 N 2740 000 N

Northern A-Geomorphology 2720 000 N Dunes 2720 000 N

IV OMAN MOUNTAINS

2700 000 N 2700 000 N

2680 000 N 2680 000 N

III II AL AIN

2660 000 N 2660 000 N Jabal AL JAWW Hafit PLAIN I

2640 000 N 2640 000 N IV

OMAN Southern MOUNTAINS Dunes

2620 000 N I

I. Mountain areas II. Piedmonts and alluvial plains III. Al Ain urban area 2600 000 N IV. Sand dune area Northern sand dune area Southern sand dune area 10 km Roads

300 000 E 000 300 320 000 E 340 000 E 360 000 E 380 000 E 400 000 E 000 400

Fig. (2.2) Physiographic subdivisions of eastern study area. WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

BIDA BINT SAUD

Towayya AL OHA

Wadi

Jabal Jabal Huwayya Qatar 2588 000 N

Jabal B-Geological Map of the Oha

BUREIMI Study Area, showing the Jimi Wadi Al AL AIN

Jabal d Zarub ifferent rock units Wadi Al Ain

Shik Wadi

Wadi Idan 2572 000 N

Jabal Malaqet

Wadi Muthaymimah Jabal Muthaymimah

Sa’a Wadi

Muraykhat Jabal Hafit Wadi

2556 000 N

5 km

Quaternary alluvium Eocene and Paleocene rocks Thrust fault ~~~~~~ Unconformity ~~~~~~ Unconformity Road Upper For a Formation Simsima Formation Wadi

Lower For a Formation ~~~~~~ Unconformity Geologic contact ~~~~~~ Unconformity Semail Nappe Formation Asmari Formation Thrust fault

~~~~~~ Unconformity Haybi Complex and Hawasina Series

Fig. (2.4) Geology of Al Ain area (modified from Hunting Geology and Geophysics, Ltd., 1979; Warrak, 1987). WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

C-Surface Lithologic units at Al Jaww Plain

OMAN

F Al Jaww Plain

D F

WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Structure Setting Structure

- D

Bouguer anomaly map of Al Jaww Plain showing gravity anomaly lows in the centre and gradual increase to the east of the survey area (After Ali et. al 2008). WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

340 000 E 360 000 E 380 000 E 340 000 E 360 000 E 380 000 E -28 2740 000 N 2740 000 N IQS 2740 000 N 2740 000 N -28 IQS N OMAN N OMAN MOUNTAINS MOUNTAINS

2720 000 N 2720 000 N 2720 000 N 2720 000 N

10 km 10 km

18 -18 - 25 IQS IQS

2700 000 N 2700 000 N 2700 000 N 2700 000 N ) -8 -8

IQS IQS aaproximate

2680 000 N 2680 000 N 2680 000 N

-11 IQS AL AIN AL AIN

-11

Boundary of concession area concession of ( Boundary IQS 7 2660 000 N 2660 000 N 2660 000 N 2660 000 N Jabal Hafit

Jabal Mountains Mountains Hafit Thrust Fault AL JAWW AL JAWW IQS-8 PLAIN Reprocessed Seismic Line PLAIN Reprocessed Seismic Line Primary Roads Primary Roads 2640 000 N 25 Ground water research project well 2640 000 N 340 000 E 360 000 E 380 000 E 340 000 E 360 000 E 380 000 E Amoco seismic lines and uphole-survey Generalized subsurface structural features locations (after Woodward, 1994). in Al Ain area (after Woodward, 1994). WEST EAST IQS-8 Anticline Syncline F2c 320 DISTAL 320 ANTICLINE F5b ALTITUDE IN 280 280 METERS ABOVE SEA LEVEL 240 0 0 LAND SURFACE 240

200 200

DEPTH BELOW DATUM OF 91.5 METERS ABOVE 1 1 SEA LEVEL, IN SECONDS OF 2-WAY SEISMIC TRAVEL-TIME SEISMIC REFLECTOR 2 2

0 4 8 12 16 20 24 28 32 36 IQS-11 420 420 F7 ALTITUDE IN 380 Syncline Anticline 380380 METERS ABOVE F5b SEA LEVEL 340 340 0 0 300 300 Interpreted seismic lines at Al Jaww Plain DEPTH BELOW DATUM and north of Al Jaww OF 91.5 METERS ABOVE 1 1 SEA LEVEL, IN SECONDS Plain, (modified after OF 2-WAY SEISMIC TRAVEL-TIME Woodward, 1994).

2 2

0 4 8 12 16 20 IQS-18 320 F1 320 F2a ALTITUDE IN 280 280 METERS ABOVE DISTAL ANTICLINE ? SEA LEVEL 240 ? 240 0 200 0 200

DEPTH BELOW DATUM OF 91.5 METERS ABOVE 1 1 SEA LEVEL, IN SECONDS OF 2-WAY SEISMIC TRAVEL-TIME SEISMIC REFLECTOR 2 2

0 4 8 12 16 20 24 28 32 36 IQS-28 320 F2b F4a F3b F3a 320 DISTAL ALTITUDE IN 280 ANTICLINE 280 F5a F4b METERS ABOVE F6 SEA LEVEL 240 0 0 240 LAND SURFACE 200 200

DEPTH BELOW DATUM OF 91.5 METERS ABOVE 1 1 SEA LEVEL, IN SECONDS OF 2-WAY SEISMIC TRAVEL-TIME

2 2

0 4 8 12 16 20 24 28 32 36 DISTANCE, IN KILOMETERS WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Combined interpretation of the data, which is consistent with all available geological and geophysical data. The position of folds and reverse faults are shown. Also shown are the approximate positions of the Hawasina and Semail Ophiolite thrust fronts, (After Ali et. al 2008). WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

HYDROGEOLOGICAL ASPECTS 52o Th 53o 54o 55o 56o WSTA 8 Gulf Water Conference, 3-6 March 2008 , Manama,ShaBahrain’am

OMAN LEGEND A-Different Aquifers in Ras Al Khaimah Northern limestone aquifer Dibba N UAE. Al Khatt Ophiolite aquifer Umm Al Qaiwin Eastern gravel aquifer Khor Ajman Fakkan Western gravel aquifer Masafi Sharjah Gulf of Oman Al Dhaid Sand dune aquifer Dubai Fujairah

o Coastal sabkha o 25 A r a b i a n G u l f Al Faiyah 25 Cultivated areas Kalba Al Madam Main Cities

Al Shiuab Hatta

Dalma Al Hayer Abu Dhabi Bani Yas

Al Ain Jabal Dhanna Al Jaww Jabal 24o Hafit Plain 24o

Al Sih

O M A N

Madinat Al Wagan Zayed

U N I T E D A R A B E M I R A T E S

S A U D I 23o 23o Liwa

A R A B I A 50 km

52o 53o 54o 55o 56o WSTA 8 Th Gulf Water Conference,B- 3-6 March 2008 , Manama, Bahrain Geologic Framework of the Eastern Region of Abu Dhabi Emirate (after Bright, 1998)

Geologic Age Approximate Hydrologic Unit Sequence Thickness (m) Unsaturated Eolian Sand Eolian 25 overburden Sand Quaternary Surficial Quaternary Clastic Alluvium 30 Alluvium Limestone Aquifer

system Altered Tertiary Pliocene- Post-Fars Deposits Miocene 200 Unaltered Upper Fars Tertiary Deposits Deep Limestone

Miocene- Lower Fars Fm. 500 Asmari Fm. Basal Oligocene Pre-Tertiary Confining Deposits Dammam Fm. system Paleocene- Rus Fm. 1,200 Eocene Umm er-Radhuma Fm. Simsima Fm. Cretaceous Qahlah Fm. 3,000 Juweiza Fm. WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

C-Quaternary Aquifer Geometry WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

D-Flow System and water level assessment (After Al Nuaimi, 2003)

2685000 2685000 1995 1996

2680000 2680000

2675000 2675000

2670000 2670000

2665000 2665000

2660000 2660000

360000 365000 370000 375000 380000 385000 390000 395000 400000 360000 365000 370000 375000 380000 385000 390000 395000 400000 WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Geophysical Investigations WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

A-2-D Resistivity Data Acquisition Base Map of 2-D Resistivity Profiles

Well No.GWP-18

2676000

2672000

2668000

5 13` 13 6 12` 5` 12 11` 2664000 4` 6` 7 10` 11 J a 4 3` b 2` 8 7` 10 9` a l 1` 2 3 H 8` 9 a 1 f it

2660000 Legend Wells provided by WED Main Road

3 3` 2-D Resistivity Profile 2656000 376000 380000 384000 388000 392000 396000 400000 Typical TEM data from sounding Zarub-2-2 and Zarub-2-11.

Zarub-2-2

Zarub-2-11

The observed data and the model response Interpreted layer resistivity. WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Base map showing the Electromagnetic survey at Al Qura'a area north of Al Ain (after US Geological Survey, 1993) WSTA 8 Th Gulf Water Conference, 3-6 March 2008 136, Manama, Bahrain

Resistivity model of typical resistivities for interdune soundings at Al Qura’a, north of Al Ain (after US Geological survey, 1993).

DESCRIPTION

RESISTIVITY (Ohm.meters)

DEPTH (m) DEPTH Below land surfaceland Below LITHOLOGY 0 3,000 R1: Surface resistive layer (aeolian sand and alluvium, dry) 10 2.6 C1: Upper conductive layer (mostly clay and silt) 75.3 R2: Upper resistive layer (alluvial sand and gravel; possible calcareous cement) 20

30 R3: Primary resistive layer (alluvial sand and gravel; good permeability; fresh water 587 where saturated)

50 8.4 C2: Conductive layer (mostly clay and silt)

100 2.7 C3: Conductive layer (mostly clay and mudstone; poor water quality) 110

120

130

140

150 WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain GWP-18

1 10 100 1000

sand & gravel

calcareously 40 cemented sand

gravelly Depth (meters) Depth Depth (meters) Depth 50 clay

60 clay

1 10 100 1000 Resistivity (ohm-m) Well GWP-18 log information. The solid and dashed lines) green &red) are the deep and medium induction logs. The heavy line (Blue) is the blocked resistivity model based upon the induction logs. Layer lithology is shown (After Fitterman , et al.1991). 2 2`

6 6`

12 12` Surface resistive layer (Dry alluvium) 1 Gravel and sand zone of moderate resistivity Paleo channel 1`

Conductive Layer Conductive Layer (Clay & Mudstone (Clay & Mudstone

Figure (#) 2-D Resistivity profile along line 1-1`

Gravel and sand zone Of moderate resistivity Paleo channel Surface resistive layer (Dry alluvium) 11 11`

Conductive Layer Conductive Layer (Clay & Mudstone (Clay & Mudstone

Figure (#) 2-D Resistivity profile along line 11-11` WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Conclusions  2-D resistivity tomograms of the Thirteen profiles indicate clearly the different hydrostratigraphic units of Quaternary aquifer along the eastern margin of Al Jaww plain  Erosional unconformities at the base of the Quaternary alluvium are traced along some of the (2-D) profiles. These unconformities represent the paleochannels in the bed rock that were formed in the geological past by the ancient wadies.  These paleochannels are promising targets for fresh groundwater, as they contain appreciable thickness of water-bearing formations that are recharged from the surrounding mountain region. ( Channel Deposits serve as both storage reservoirs and recharge zones for the shallow aquifer system in Al Jaww Plain.

 This contribution will provide the technical support for planners, decision makers, and researchers in the field of groundwater development and management. Especially, Now days Aquifer Storage and Recovery system (ASR) Projects are implemented in Al Ain area and elsewhere at UAE. WSTA 8 Th Gulf Water Conference, 3-6 March 2008 , Manama, Bahrain

Thank You For your attention