Assessment of Artificial Groundwater Recharge in Some Wadies in UAE

Assessment of Artificial Groundwater Recharge in Some Wadies in UAE by using Isotope Hydrology Techniques Presented by : Ahmed Saif Al Matri Head , Water Resources Section Ministry of Environment & Water U.A.E

Prepared for : The 8th Gulf Water Conference Manama – Bahrain 3 – 6 March 2008 Location map of the United Arab Emirates

52o 53o 54o 55o 56o Iraq N Ras Al Khaimah Iran Kuwait

Diba Qatar Saudi Dubai

Arabia UAE Gulf Gulf Oman of 25o Arabian Gulf Kalba

Arabian Sea AFRICA

Abu Dhabi

Al Ain 24o

OMAN UNITED ARAB EMIRATES

23o

50 km ARABIA

Al Matri A. S. 2008 Climate

The UAE has an arid to semi-arid climate with high temperature and infrequent irregular low rainfall .

.Mean max. temperature reach > 40 o C in summer . .High relative humidity ( reaches > 97 % ) . .Average daily evaporation 8.2 mm . .Average annual mean rainfall is around 115 mm .

Al Matri A. S. 2008 GEOMORPHOLOGY AND GEOLOGY

The geomorphic features have a major role in controlling the movement of both surface and groundwater. Geology, on the other hand, encompasses the distribution of outcrops, stratigraphic sequences, and structural zones. These greatly influence runoff volumes, infiltration rates and surface and groundwater quality. The following discussion outlines the main geomorphic features in UAE, geologic setting, and structural elements.

Al Matri A. S. 2008 The Main Geomorphic Features in the UAE

52o 53o 54o 55o 56o Ras Al Khaimah N

Mountains Diba Gravel Plains Linear Dunes, Star Dunes and Playa Deposits Dubai Ancient and Recent Dunes Gulf Oman of 25o Coastal Sabkhas Kalba Arabian Gulf

Abu Dhabi

Al Ain 24o

OMAN UNITED ARAB EMIRATES

23o

50 km ARABIA

Al Matri A. S. 2008 Geologic Setting

• The northern Oman Mountains in UAE are composed of two major classes of rocks . The first is an authothonous sequence including Proterzoic basement rocks and some early Paleozoic sediments covered transgessively by carbonate platform deposits ranging in age from late Permian to late Cretaceous, and two allochthonous sequences. The lower sequence is composed of sedimentary rocks and is known as the Hawaina Group. This sequence is overlain by the Semail Suite, which consists of a slab of former oceanic crust . The Maastrichtian to Neogene sediments was laid down after the main episode of nappe emplacement. The actual relief of the Oman Mountains is due to tectonic movements that occurred during “post-nappes” times, i.e. during the Cenozoic. These movements resulted in the uplifting of the mountains.

Al Matri A. S. 2008 Geologic Map of the United Arab Emirates

52o 53o 54o 55o 56o QUATERNARY Eolian Sand N Ras Al Khaimah Surfacial Gravels Diba Gypsum Deposits Sabkha Deposits

Marl and Limestone TERTIARY Dubai Arabian Gulf CRETACEOUS Limestone, Marl and Sandstone Gulf Oman of 25o Semail Ophiolite Hawasina Complex Musndam Limestone Kalba JURRASSIC Hith Anhydrite and arab Formatin Abu Dhabi TRIASSIC Triassic and Permian Rocks

Al Ain

24o

OMAN

UNITED ARAB EMIRATES

23o

50 km ARABIA

Al Matri A. S. 2008 Geologic Structure

The UAE can be differentiated into five structural provinces, from north to south, including: Ru’us Al Gibal, Diba zone, ophiolite sequence, wadi Hatta zone, and the western area . Ru’us Al Gibal area is characterized by thrust faults that are inclined in the east and south directions. Sometimes the thrust plain slopes towards east to the zone of overturned and recumbent folds. The Diba zone is a topographically low and extends for 30 km from northeast to southwest, with an average width of 20 km.

Al Matri A. S. 2008 Geologic Structure

Al Matri A. S. 2008 Major Drainage Basins Main Geologic Structures

56o 55o 56o N N 26o Shaam OMAN

26o Arabian Shaam Gulf Arabian 1 OMAN Ras Al Khaimah Gulf 2 Gulf Diba Gulf Umm Al Quwain 18 of of Oman Oman Ras Al Khaimah Ajman 3 Sharjah Dubai Umm Al Quwain Diba 4 Fujairah 19 13 Kalba 25o Ajman 6 5 14 24 Sharjah Khor Fakkan Water 7 Dubai Divide 27 9 17 10 UNITED 22 Fujairah ARAB 16 OMAN EMIRATES UNITED 15 Kalba 25o 8 ARAB Fold 12 Fault EMIRATES Thrust Fault 23 Fracture 24o OMAN

Al Matri A. S. 2008 Water Resources > Conventional Surface runoff : 25 main wadies with average runoff 185 MCM Groundwater : The groundwater is main resource for agriculture. Renewable : shallow alluvial aquifers ( gravel plains ) . Non-renewable (fossil ) : deep aquifers ( sedimentary rocks ). Falajes & Springs : Annual discharge 20 MCM . > Non - conventional

Desalinated Water : Total capacity 1370 MCM / y Sewage Recycled Water : Total capacity 309 MCM / y

Al Matri A. S. 2008 The main aquifers in the UAE include :

•Limestone aquifer in the North and East. •Fractured ophiolite group in the East . •Gravel aquifers flaking the Eastern Mountain ranges on the East and West. •Sand dunes aquifers in the South and West.

Al Matri A. S. 2008 The Main Aquifers in the United Arab Emirates

52o 53o 54o 55o 56o Ras Al Khaimah N Northern limestone aquifer Ophiolite aquifer Eastern gravel aquifer Diba Western gravel aquifer Dubai

Sand dune aquifer Gulf Oman of 25o Coastal sabkhas Kalba

Arabian Gulf

Abu Dhabi

Al Ain 24o

OMAN UNITED ARAB EMIRATES

23o

50 km ARABIA

Al Matri A. S. 2008 The main objective of Dams construction project is to retain surface runoff in the wadies which is going losses to the sea , and achieve : Recharge the g. w . aquifers . Improve water quality and level. Reduce seawater intrusion at the coastal areas. Water harvesting . Flood protection and control . Enhance soil characteristics in the farms by adding silt removed from dams’ reservoirs.

Al Matri A. S. 2008 Groundwater Flow Systems in UAE

Regional groundwater flow system W Intermediate groundwater flow system E

Local groundwater flow system

Mountains

NorthernOman Springs

Sabkha Western Desert Gulf of Jabal Hafit Jabal

Arabian Al Jaww andSiji Khatt Deposits Area Oman Gulf Spring Sakhnah Bu Plain Sea Level

Al Matri A. S. 2008 Wurrayah Dam

Al Matri A. S. 2008 Dam Location Wadi Wurrayah – Fuj.

Completion Date December 1997 Dam Purpose Groundwater Recharge and Flood Protection

Reservoir Capacity 5.2 million cubic meters

Dam Type Earth – Rock Fill Dam Height 33 meter Dam Length 150 meter Benefited Area Khor fakkan , Bedyah

Al Matri A. S. 2008 Water storage in Wur Dam during the period 2001 - 2006

3.50 3.00 2.50 2.00 1.50 1.00 Storage ( MCM ) 0.50 0.00 Year 2001 2002 2003 2004 2005 2006

Al Matri A. S. 2008 Mean annual variation in groundwater level for some observation wells in Wurrayah

180 160 140 Wur - 1 Wur - 3 120 Wur - 4 100 Wur - 5 80 60 40

20 Water level from msl ( meter ) meter ( msl from level Water 0 Year 2001 2002 2003 2004 2005 2006

Al Matri a. S. 2008 Ground water level variation during rain season ( 2007 ) for some observation wells in Wurrayah

180 160

140 Wur - 1 120 Wur - 3 100 Wur - 4 80 Wur - 5 60 40

Water level from msl (meter ) (meter msl from level Water 20 0 Month AUG SEPT OCT NOV DEC

Al Matri A. S. 2008 Schoeller – Berkaloff Diagram (Wur Basin)

140 Mean Wur 3 120 Mean Wur 5 Mean Wur 6 100 Mean Wur Dam 80

60 Content(mg/l)

SO4 HCO3+CO3

Al Matri A. S. 2008 Variation of 3H content in the Dam water and observation wells in Wurryah Basin

3 2,5 2 1,5 1 WUR3 WUR5

0,5 WUR6 Dam Tritium content (TU) content Tritium 0

2002.12.01 2002.12.09 2002.12.14 2002.12.18 2002.12.22 2002.12.28 2003.01.04 2003.01.15 2003.01.22 2003.01.28 2003.02.05 2003.02.16 2003.03.16 2003.03.23

Date of sampling

Al Matri A. S. 2008 Tawyeen Dam

Al Matri A. S. 2008 Schoeller-Berkaloff Diagram (Tw Basin )

600 Mean TW 2 Mean TW 6 500 Mean TW 8 Mean TW 9 400 Mean TW 10 Mean TW Dam 300

200 Content (mg/l) Content

100

Na Ca

SO4 HCO3+CO3

Al Matri A. S. 2008 Characteristic stable isotope concentrations of some major aquifer in the Gulf region and Middle East

20 Sea water 10 Quaternary Wadi Al Bih Aquifer UAE 0 Aquifer UAE Yarmok Basin Liwa Middle Aquifer Jabal Hafit Aquifer Jordan UAE -10 aquifer UAE Yarmok Basin Shallow Basalt Aquifer Aquifer -20 Syria Qatar

Dammam -30 Aquifer Kuwait

Neogene -40 Saudi Arabia Umm er Raduma Saudi Arabia Deuterium (o/oo SMOW) (o/oo Deuterium -50 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 Oxygen-18 (o/oo SMOW) Al Matri A.S. 2008 Variation of 3H content in the Dam water and observation wells in Tawyeen basin

8 TW2 TW6 TW8 7 6 Dam TW9 TW10 5 4 3 2

Tritium content (TU) content Tritium 1 0

2002.11.20 2002.07.11 2002.11.20 2002.12.06 2002.12.06 2003.10.14 2002.11.04 2003.07.28 2002.11.04

Date of sampling

Al Matri A. S. 2008 18O / 2H Diagram of Wurrayah , Tawyeen Dams and Observation Wells

Wur wells 60 Suposed position TW wells of the EMWL Wur dam confirmed by the non TW dam evaporated rain water 40 North UAE MWL GMAL OMWL EMWL 20 Rain Avarage in UAE Evaporation line of the two Rain avarage in North UAE dams water, the Wur wells water and the evaporated Non evaporated rain rain in north UAE

0 waters

( SMOW ‰ vs )

H H Evaporation line of the 2  TW wells -20 Isotopic composition of the two dams waters before its evaporation

-40 Isotopic composition of the rain water recharching the TW wells before its evaporation

-60 -10 -8 -6 -4 -2 0 2 4 6 8 10

18O (‰ vs SMOW)

Al Matri A. S. 2008 Wur. Dam reservoir contribution estimated by the isotopic balance

Average 18 O Dam reservoir contribution ( % ) Wur - 2 - 2.71 43.2

Wur -5 - 2.53 34.1

Wur - 6 - 2.32 22.9

Al Matri A. S. 2008 Discussion :

Drawdown range between 4 – 10 m due to extensive use . Groundwater level increase due to the storage in the Dam reservoir 2 – 11 m . Isotope analysis show the a relatively similar variation in the concentration of major elements in both Dam and Observation wells. There is meaningful contribution to the recharge through the Wur. Dam in the wadi .

Al Matri A. S. 2008 Recommendations Considering the significant results obtained from Wurrayah Basin , it is highly recommended :

.Promote the isotopic methods in water management . .Continue investigations for other Basins in the UAE with contribution and support of IAEA . .Encourage the use of isotopic tracers for various investigations .

Al Matri A. S. 2008