Assessment of Artificial Groundwater Recharge in Some

Wadies in UAE by using Isotope Hydrology

Techniques

Presented by :Ahmed Saif Al Matri

Head , Water Resources SectionMinistry 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

25o

24o

23o

50 km

OMAN

ARABIA

Arabian Gulf

Abu Dhabi

Dubai

Ras Al Khaimah

Gulf

of

Om

anN

Diba

Kalba

Al Ain

UNITED ARAB

EMIRATES

Iran

SaudiArabia

Iraq

Kuwait

Qatar

UAE

ArabianSea

AFRICA

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 incontrolling the movement of both surface andgroundwater. Geology, on the other hand,encompasses the distribution of outcrops,stratigraphic sequences, and structural zones.These greatly influence runoff volumes, infiltrationrates and surface and groundwater quality. Thefollowing discussion outlines the main geomorphicfeatures in UAE, geologic setting, and structuralelements.

Al Matri A. S. 2008

The Main Geomorphic Features in the UAE

52o 53o 54o 55o 56o

25o

24o

23o

50 km

OMAN

ARABIA

UNITED ARAB

EMIRATES

Arabian Gulf

Abu Dhabi

Dubai

Ras Al Khaimah

Gulf

of

Om

an

N

Diba

Kalba

Al Ain

MountainsGravel PlainsLinear Dunes, Star Dunes and Playa DepositsAncient and Recent DunesCoastal Sabkhas

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

25o

24o

23o

50 km

OMAN

ARABIA

Arabian Gulf

Abu Dhabi

Dubai

Ras Al Khaimah

Gulf

of

Om

an

N

Diba

Kalba

Al Ain

UNITED ARAB

EMIRATES

Eolian SandSurfacial GravelsGypsum DepositsSabkha Deposits

Marl and Limestone

Limestone, Marl and SandstoneSemail OphioliteHawasina ComplexMusndam Limestone

Hith Anhydrite and arab Formatin

Triassic and Permian Rocks

QUATERNARY

TERTIARY

CRETACEOUS

JURRASSIC

TRIASSIC

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

The UAE can be differentiated into five structuralprovinces, from north to south, including: Ru’us AlGibal, Diba zone, ophiolite sequence, wadi Hattazone, and the western area .

Ru’us Al Gibal area is characterized by thrust faultsthat are inclined in the east and south directions.Sometimes the thrust plain slopes towards east tothe zone of overturned and recumbent folds.

The Diba zone is a topographically low and extendsfor 30 km from northeast to southwest, with anaverage width of 20 km.

Al Matri A. S. 2008

Major Drainage Basins

56o

26o

OMAN

Shaam

N

UNITED

ARAB

EMIRATES

Ras Al Khaimah

Ajman

Dubai

Diba

Gulf

of

Oman

Arabian

Gulf

25o

Sharjah

Fujairah

Kalba

Khor Fakkan

OMAN

Umm Al Quwain

1

2

18

3

419

13

1424

27

17

22

8

12

23

15

16

10

9

7

6 5

WaterDivide

55o 56o

26o

25o

24o

OMAN

ShaamN

UNITED

ARAB

EMIRATES

Ras Al Khaimah

Umm Al Quwain

Ajman

Sharjah

Dubai

Diba

Fujairah

Kalba

Gulf

of

Oman

Arabian

Gulf

OMAN

FoldFaultThrust FaultFracture

Main Geologic Structures

Al Matri A. S. 2008

Water Resources

> ConventionalSurface 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

25o

24o

23o

50 kmARABIA

Arabian Gulf

Abu Dhabi

Dubai

Ras Al KhaimahN

Al Ain

Gulf

of

Om

an

56o

Kalba

Diba

OMAN

UNITED ARAB

EMIRATES

Northern limestone aquiferOphiolite aquiferEastern gravel aquiferWestern gravel aquiferSand dune aquiferCoastal sabkhas

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

Gulf ofOmanArabian

Gulf

SabkhaDeposits

Western DesertArea B

u S

akh

nah

Sp

rin

g

Jab

al H

afi

t

Kh

att

an

d S

iji

Sp

rin

gs

Al JawwPlain

No

rth

ern

Om

an

M

ou

nta

ins

Sea Level

W ERegional groundwater flow system

Intermediate groundwater flow system

Local groundwater flow system

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

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

Sto

rag

e (

MC

M )

2001 2002 2003 2004 2005 2006Year

Al Matri A. S. 2008

Mean annual variation in groundwater level

for some observation wells in Wurrayah

0

20

40

60

80

100

120

140

160

180

2001 2002 2003 2004 2005 2006Year

Wat

er l

evel

fro

m m

sl (

met

er )

Wur - 1

Wur - 3

Wur - 4

Wur - 5

Al Matri a. S. 2008

Ground water level variation during rain season ( 2007 )

for some observation wells in Wurrayah

0

20

40

60

80

100

120

140

160

180

AUG SEPT OCT NOV DECMonth

Wat

er l

evel

fro

m m

sl (

met

er )

Wur - 1

Wur - 3

Wur - 4

Wur - 5

Al Matri A. S. 2008

Schoeller – Berkaloff Diagram (Wur Basin)

0

20

40

60

80

100

120

140

Na K

Mg

Ca Cl

SO

4

HC

O3+C

O3

Co

nte

nt

(mg

/l)

Mean Wur 3

Mean Wur 5

Mean Wur 6

Mean Wur Dam

Al Matri A. S. 2008

Variation of 3H content in the Dam water and

observation wells in Wurryah Basin

0

0,5

1

1,5

2

2,5

3

2002.1

2.0

1

2002.1

2.0

9

2002.1

2.1

4

2002.1

2.1

8

2002.1

2.2

2

2002.1

2.2

8

2003.0

1.0

4

2003.0

1.1

5

2003.0

1.2

2

2003.0

1.2

8

2003.0

2.0

5

2003.0

2.1

6

2003.0

3.1

6

2003.0

3.2

3

Date of sampling

Tri

tiu

m c

on

ten

t (T

U)

WUR3 WUR5

WUR6 Dam

Al Matri A. S. 2008

Tawyeen Dam

Al Matri A. S. 2008

Schoeller-Berkaloff Diagram (Tw Basin )

0

100

200

300

400

500

600

Na K

Mg

Ca Cl

SO

4

HC

O3+

CO

3

Mean TW 2

Mean TW 6

Mean TW 8

Mean TW 9

Mean TW 10

Mean TW Dam

Co

nte

nt

(mg

/l)

Al Matri A. S. 2008

QuaternaryAquifer UAE

Characteristic stable isotope concentrations of some

major aquifer in the Gulf region and Middle East

20

10

0

-10

-20

-30

-40

-50

Seawater

Jabal Hafitaquifer UAE

LiwaAquifer

UAE

ShallowAquiferQatar

NeogeneSaudi Arabia

Umm er RadumaSaudi Arabia

Yarmok BasinBasalt AquiferSyria

Oxygen-18 (o/oo SMOW)

Deu

teri

um

(o

/oo

SM

OW

)

DammamAquifer Kuwait

Yarmok BasinMiddle AquiferJordan

Wadi Al BihAquifer UAE

-7 -6 -5 -4 -3 -2 -1 0 1 2 3

Al Matri A.S. 2008

Variation of 3H content in the Dam water and

observation wells in Tawyeen basin

0

1

2

3

4

5

6

7

8

2002.1

1.2

0

2002.0

7.1

1

2002.1

1.2

0

2002.1

2.0

6

2002.1

2.0

6

2003.1

0.1

4

2002.1

1.0

4

2003.0

7.2

8

2002.1

1.0

4

Date of sampling

Tri

tiu

m c

on

ten

t (T

U) TW2 TW6 TW8

Dam TW9 TW10

Al Matri A. S. 2008

18O / 2H Diagram of Wurrayah , Tawyeen

Dams and Observation Wells

-60

-40

-20

0

20

40

60

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

18

O (‰ vs SMOW)

2 H

( ‰ v

s SM

OW

) Wur wells

TW wells

Wur dam

TW dam

North UAE MWL

GMAL

OMWL

EMWL

Rain Avarage in UAE

Rain avarage in North UAEEvaporation line of the two

dams water, the Wur wells

water and the evaporated

rain in north UAE

Suposed position

of the EMWL

confirmed by the non

evaporated rain water

Evaporation line of the

TW wells

Isotopic composition of the

two dams waters before its

evaporation

Isotopic composition of the rain

water recharching the TW wells

before its evaporation

Non evaporated rain

waters

Al Matri A. S. 2008

Wur. Dam reservoir contribution

estimated by the isotopic balance

Dam reservoir

contribution ( % )

Average 18 O

43.2- 2.71Wur - 2

34.1- 2.53Wur -5

22.9- 2.32Wur - 6

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