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Chapter 24
Jezira Tertiary
Limestone Aquifer
System
INVENTORY OF
SHARED WATER RESOURCES
IN WESTERN ASIA
(ONLINE VERSION)
How to cite
UN-ESCWA and BGR (United Nations Economic and Social Commission for Western Asia; Bundesanstalt für
Geowissenschaften und Rohstoffe). 2013. Inventory of Shared Water Resources in Western Asia. Beirut.
CHAPTER 24 - JEZIRA TERTIARY LIMESTONE AQUIFER SYSTEM
Jezira Tertiary Limestone
Aquifer System
EXECUTIVE SUMMARY BASIN FACTS
The Jezira Tertiary Limestone Aquifer System RIPARIAN COUNTRIES Syria, Turkey
(JTLAS) comprises two Paleogene Formations:
an Eocene (main aquifer) and a Lower Oligocene ALTERNATIVE NAMES Turkey: Midyat Aquifer
Formation. It extends from the Jezira Plain on
RENEWABILITY Medium to high (20 - >100 mm/yr)
Syria’s northern border (Upper Jezira area)
into the south-eastern Anatolian Highlands in HYDRAULIC LINKAGE
Strong
Turkey. WITH SURFACE WATER

Large volumes of groundwater flow from ROCK TYPE Karstic
recharge areas in the highlands to groundwater
AQUIFER TYPE Confined
discharge areas along the Syrian border, where
many springs, most importantly the Ras al Ain EXTENT 14,000 km2
and Ain al Arous Springs, discharge from the
AGE Tertiary (Eocene to Oligocene)
aquifer system. Until approximately 2000, these
springs discharged a total volume of more than
LITHOLOGY Limestone
1,200 MCM and formed the principal source of
surface flow in the Balikh and Khabour Rivers, 200-300 m
THICKNESS
which are the main tributaries of the Euphrates ≥700 m in the east
River in Syria.
AVERAGE ANNUAL
3,000 MCM
ABSTRACTION
In recent years, there has been a significant shift
away from rain-fed irrigation to groundwater STORAGE 7,400 MCM
irrigation in the area and today almost 6,000
wells (around 2,000 in Turkey and 4,000 in Syria) Fresh (220-700 mg/L TDS)
WATER QUALITY
abstract about 3,000 MCM/yr of water from the to saline (1,400-4,700 mg/L TDS)
aquifer system. These high abstraction levels
WATER USE Mainly agricultural/domestic
have significantly affected the groundwater
regime and led to a dramatic decrease in AGREEMENTS -
springs discharge. Thus the springs at Ras
al Ain, which used to supply 87% of the total SUSTAINABILITY The springs which used to feed the Balikh and
discharge from the aquifer have practically Khabour Rivers have dried up
dried up.
562
INVENTORY OF SHARED WATER RESOURCES IN WESTERN ASIA - PART 2
OVERVIEW MAP
39°E 40°E 41°E
# Tigris
Karaca Dag Turkey
Atatürk Dam
Lake
4 Midyat
Derik
Mardin
A
Kiziltepe 5
Sanliurfa DSeoruikth-Meranr dLiinm Hit igohf Djirdjib .. .. 2 .. .. .. .. ..
37°N Khabour ne (A u Qamishli .. .. 37°..N ..
µ JHallabarran ( Ras al Ai3nCµeyBlanpinar ZergaB' (B(C Jagh Jagh .. .. .. .. .. .. .. .. .. .. ..
Ain al Arous Tell Abyad A Central Plains ..
6 ..
LebJaorndoannTuSrykreiay Iraq Jarablus-Tualal Abba High Balikh! ! J!ezira Plain! !SoUu!tphpeer!rn JLei!zmJieritab oe!lf Ab!del !Aziz#! 1!! A' !KhabHo!aursa!kah! ! ! ! ! ! ! ! ! 7! .. .. .. .. .. ..
Syria Iraq ..
36°N Saudi Arabia Bahrain 0 25 50 100km 36°N .. ..
..
..
Jezira Tertiary Limestone Aquifer System
Selected city, town Ecocene; Oligocene outcrops of the aquifer system
International boundary Pre-Eocene Formation outcrops
Inventory of Shared Water
River Approximate subsurface extent of the aquifer system
Resources in Western Asia
Intermittent river, wadi Zone of agricultural development (selection)
Canal, irrigation tunnel A A'Hydrogeological cross-section Disclaimer
The boundaries and names shown and the designations
µ Spring .. Faults aucsceedp otann tcheis b my athpe d Uo nniotet dim Npalyti oonffsic.ial endorsement or
u Bore-hole # Mountain
Freshwater lake Specific features:
1Jebel Abdel Aziz Anticline
Direction of groundwater flow
2Qamishli Anticline
Groundwater quality zones: 3Ras al Ain Anticline
(
((ABC SFBrarealiscnhke is CNhaa -CCHalC-SCOOa3344C tlty ytpypepe e ww waatateetrerr 546MSTeoalulr dAthibn My Aaandrt diAcinnlin tFiecaliunlet Zone
7Sinjar Anticline
© UN-ESCWA - BGR Beirut 2013
563
CHAPTER 24 - JEZIRA TERTIARY LIMESTONE AQUIFER SYSTEM
CONTENTS
INTRODUCTION 566
Location 566
Area 566
Climate 566
Population 566
Other aquifers in the area 566
Information sources 566
HYDROGEOLOGY - AQUIFER CHARACTERISTICS 567
Aquifer configuration 567
Stratigraphy 567
Aquifer thickness 568
Aquifer type 568
Aquifer parameters 568
HYDROGEOLOGY - GROUNDWATER 569
Recharge 569
Flow regime 569
Storage 569
Discharge 569
Water quality 569
Exploitability 570
GROUNDWATER USE 571
Groundwater abstraction and use 571
Groundwater quality issues 571
Sustainability issues 572
AGREEMENTS, COOPERATION & OUTLOOK 573
Agreements 573
Cooperation 573
Outlook 573
NOTES 574
BIBLIOGRAPHY 575
564
INVENTORY OF SHARED WATER RESOURCES IN WESTERN ASIA - PART 2
FIGURES
Generalized hydrogeological cross-section along the Jebel Abdel
FIGURE 1. 567
Aziz-Mardin Anticlines
FIGURE 2. General stratigraphy of the Ras al Ain area 567
Monthly distribution of total groundwater abstraction in the Ras al Ain
FIGURE 3. 571
area in Syria (2000-2001)
TABLES
TABLE 1. Lithostratigraphy of the Jezira Tertiary Limestone Aquifer System 568
565
CHAPTER 24 - JEZIRA TERTIARY LIMESTONE AQUIFER SYSTEM INTRODUCTION
Introduction
LOCATION POPULATION
The Jezira Tertiary Limestone Aquifer System is In Syria, the Jezira Tertiary Limestone Aquifer
situated beneath a plateau area, which stretches System extends over the governorates of
from northern Syria into south-eastern Hasakah and Raqqah. A total of 1.2 million
Anatolia in Turkey. It extends across the Upper people live within the boundaries of the
Jezira Basin, in the area between the towns of delineated basin, of which 90% live in Hasakah
Qamishli, Hasakah and Tell Abyad in Syria, and Governorate.3 In Turkey, the aquifer system
Sanliurfa and Kiziltepe in Turkey as shown in the extends over the provinces of Mardin and
Overview Map (see also Figure 1). Sanliurfa. A total population of 1.8 million
lives in the districts of these provinces that fall
within the delineated basin, of which 62% live in
AREA Sanliurfa.4
The Upper Jezira Basin lies to the south of the
mountains of the Derik-Mardin High between OTHER AQUIFERS IN THE AREA
the Euphrates and Tigris Rivers. It comprises
plains at altitudes of 350-500 m asl, most In Syria and in the plains of Turkey, the Jezira
notably the Harran, Ceylanpinar and Kiziltepe Tertiary Limestone Aquifer System is covered by
Plains, which merge into the vast Upper Jezira aquiferous Miocene to Quaternary Formations,
Plateau. The mountain chain is dominated most notably the Upper and Lower Fars Aquifer
by the Karaca Dag volcanic massif (altitude: System (see Chap. 25). In the Kiziltepe Plain in
1,919 m asl), which is adjoined in the west by a Turkey, the main exploited aquifer is made up
zone of hills north of Sanliurfa, and in the east of Pliocene-Quaternary talus and conglomerate
to the highlands between Mardin and Midyat deposits.5 In the Syrian Jezira, the extensive
(altitude: 1,000-1,254 m asl). Various streams Pliocene-Quaternary Radd Aquifer adjoins the
flow south from the mountain area and converge Jezira Tertiary Limestone Aquifer System in the
in the Upper Jezira Plain to form the Balikh and east. Collapse structures which developed in
Khabour tributaries of the Euphrates River. the Miocene Lower Fars gypsum aquifer serve
as groundwater discharge funnels from the
The Jezira Tertiary Limestone Aquifer System underlying Jezira Tertiary Limestone Aquifer
covers an area of 14,000 km2, of which 8,500 km2 System.
lies in Syria and 5,500 km2 in Turkey. The
following main geo-physiographic features The Cretaceous Formation that underlies the
were used to delineate the aquifer system: the Jezira Tertiary Limestone Aquifer System
Balikh River in the west, the Jagh Jagh River in is found at great depth (≥1,200 m) and has
the east, the South Mardin Fault Zone and the hydrocarbon indications and saline groundwater,
southern limit of the Derik-Mardin High in the which limit its exploitation and means that it
north, and the Jebel Abdel Aziz Anticline in the cannot be considered a productive aquifer.6
south.
INFORMATION SOURCES
CLIMATE
Hydrogeological interest in the Jezira Tertiary
The southern part of the Jezira Tertiary Limestone Aquifer System developed mainly
Limestone Aquifer System lies in a semi-arid because of the discovery of one of the largest
climatic zone, while the northern mountainous karst springs in the world in the Ras al Ain
part reaches into more humid climatic zones. area.7 Hence most of the information collected
Average annual precipitation varies from around on the aquifer system over the past 50 years
300 mm in the south to 800 mm at the top of comes from this area. The Overview Map was
the Karaca Dag Mountains. A mean annual delineated based on various local and regional
precipitation of 450 mm may be assumed for the references drawn from both riparian countries.8
catchment area.1 Precipitation is concentrated
during the cool winter season (0°C-10°C). No
rain falls during the summer season when
temperatures rise between 30ºC and 45ºC. Mean
annual potential evaporation is 1,000-1,300 mm.2
566
INVENTORY OF SHARED WATER RESOURCES IN WESTERN ASIA - PART 2
Hydrogeology - Aquifer
Characteristics
AQUIFER CONFIGURATION Figure 1. Generalized hydrogeological cross-section along the Jebel
Abdel Aziz-Mardin Anticlines
The Jezira Tertiary Limestone Aquifer System
A A’
is exposed on the surface in the highlands in North South
the northern part of the catchment. The aquifer (cid:373)(cid:3)(cid:258)(cid:400)(cid:367) Turkey Syria (cid:373)(cid:3)(cid:258)(cid:400)(cid:367)
is covered by volcanic rocks in the Karaca Dag (cid:1005)(cid:853)(cid:1009)(cid:1004)(cid:1004) (cid:68)(cid:258)(cid:396)(cid:282)(cid:349)(cid:374)(cid:3)(cid:4)(cid:374)(cid:415)(cid:272)(cid:367)(cid:349)(cid:374)(cid:286) Jebel Abdel Aziz (cid:1005)(cid:853)(cid:1009)(cid:1004)(cid:1004)
(cid:4)(cid:374)(cid:415)(cid:272)(cid:367)(cid:349)(cid:374)(cid:286)
Mountain area and by Miocene to Quaternary Upper Jezira
sedimentary deposits in the plains to the south.
(cid:1009)(cid:1004)(cid:1004) (cid:1009)(cid:1004)(cid:1004)
The top of the aquifer system descends from
more than 1,000 m asl in the outcrop areas in
the highlands to 200-400 m asl in the border (cid:1004) (cid:1004)
area between Syria and Turkey.9 The aquifer
system again appears on the surface in the core
of the Jebel Abdel Aziz Anticline on the southern (cid:1009)(cid:1004)(cid:1004) (cid:87)(cid:349)(cid:367)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:882)(cid:89)(cid:437)(cid:258)(cid:410)(cid:286)(cid:396)(cid:374)(cid:258)(cid:396)(cid:455)(cid:3)(cid:38)(cid:381)(cid:396)(cid:373)(cid:258)(cid:415)(cid:381)(cid:374)(cid:855)(cid:3)(cid:116)(cid:258)(cid:410)(cid:286)(cid:396)(cid:882)(cid:271)(cid:286)(cid:258)(cid:396)(cid:349)(cid:374)(cid:336)(cid:853)(cid:3)(cid:286)(cid:454)(cid:393)(cid:367)(cid:381)(cid:349)(cid:410)(cid:286)(cid:282)(cid:3)(cid:367)(cid:381)(cid:272)(cid:258)(cid:367)(cid:367)(cid:455)(cid:3) (cid:1009)(cid:1004)(cid:1004)
margin of the Upper Jezira. However, this area in plains and wadi areas
is assumed to be situated outside the catchment (cid:104)(cid:393)(cid:393)(cid:286)(cid:396)(cid:3)(cid:75)(cid:367)(cid:349)(cid:336)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:882)(cid:68)(cid:349)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:3)(cid:38)(cid:381)(cid:396)(cid:373)(cid:258)(cid:415)(cid:381)(cid:374)(cid:400)
(cid:28)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:882)(cid:62)(cid:381)(cid:449)(cid:286)(cid:396)(cid:3)(cid:75)(cid:367)(cid:349)(cid:336)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:3)(cid:38)(cid:381)(cid:396)(cid:373)(cid:258)(cid:415)(cid:381)(cid:374)(cid:400)(cid:855)(cid:3)(cid:58)(cid:286)(cid:460)(cid:349)(cid:396)(cid:258)(cid:3)(cid:100)(cid:286)(cid:396)(cid:415)(cid:258)(cid:396)(cid:455)(cid:3)(cid:62)(cid:349)(cid:373)(cid:286)(cid:400)(cid:410)(cid:381)(cid:374)(cid:286)(cid:3)
of the Jezira Tertiary Limestone Aquifer System. (cid:4)(cid:395)(cid:437)(cid:349)(cid:296)(cid:286)(cid:396)(cid:3)(cid:94)(cid:455)(cid:400)(cid:410)(cid:286)(cid:373)
(cid:18)(cid:396)(cid:286)(cid:410)(cid:258)(cid:272)(cid:286)(cid:381)(cid:437)(cid:400)(cid:3)(cid:38)(cid:381)(cid:396)(cid:373)(cid:258)(cid:415)(cid:381)(cid:374)(cid:400)(cid:855)(cid:3)(cid:75)(cid:349)(cid:367)(cid:882)(cid:271)(cid:286)(cid:258)(cid:396)(cid:349)(cid:374)(cid:336)(cid:3)(cid:349)(cid:374)(cid:3)(cid:400)(cid:381)(cid:373)(cid:286)(cid:3)(cid:258)(cid:396)(cid:286)(cid:258)(cid:400)(cid:3)(cid:258)(cid:374)(cid:282)(cid:3)(cid:282)(cid:381)(cid:3)(cid:374)(cid:381)(cid:410)(cid:3)
(cid:272)(cid:381)(cid:374)(cid:400)(cid:415)(cid:410)(cid:437)(cid:410)(cid:286)(cid:3)(cid:258)(cid:395)(cid:437)(cid:349)(cid:296)(cid:286)(cid:396)(cid:400)(cid:3)
The lower boundary of the aquifer system (cid:38)(cid:258)(cid:437)(cid:367)(cid:410)(cid:400)
consists of an aquitard of marls and marly
Source: Redrawn by ESCWA-BGR based on FAO and UNDP, 1966.
limestones of Upper Cretaceous (Maastrichtian)
Note: The figure shows the position of the Eocene Formation (Jezira Tertiary Limestone Aquifer
to Paleocene age. The top of the aquifer system System) with respect to other formations in the Upper Jezira Basin.
is formed by the overlying volcanic rocks in the
Karaca Dag Mountain massif and by confining STRATIGRAPHY
layers of Neogene age in the plain areas. The
lateral boundaries are defined by: The Jezira Tertiary Limestone Aquifer System
consists of three formations as shown in
To the north, the South Mardin Fault Zone Figure 2: two karstic formations that constitute
and the southern limit of the Derik-Mardin the main aquifers and a massive formation
Uplift10 where outcrops of the underlying in the middle that is water-bearing, mainly
Upper-Cretaceous-Paleocene aquitard in tectonically active faulted areas. A brief
(Pre-Eocene on the Overview Map) are found description of these formations is given in
in some areas. Table 1.
To the south, the northern limit of the Figure 2. General stratigraphy of the Ras al Ain area
Sinjar Trough in Iraq,11 where fault-related
structures – most notably the Jebel Abdel B B’
North-west South-east
Aziz-Sinjar Anticlines – and the general
bedding of the geological formations
Turkey Syria (cid:18)(cid:381)(cid:374)(cid:302)(cid:374)(cid:286)(cid:282)(cid:3)(cid:449)(cid:258)(cid:410)(cid:286)(cid:396)
suggests groundwater flow towards the south
(see Overview Map and Figure 1). (cid:90)(cid:258)(cid:400)(cid:3)(cid:258)(cid:367)(cid:3)(cid:4)(cid:349)(cid:374)(cid:3)(cid:94)(cid:393)(cid:396)(cid:349)(cid:374)(cid:336)
µ
(cid:89)(cid:437)(cid:258)(cid:410)(cid:286)(cid:396)(cid:374)(cid:258)(cid:396)(cid:455)(cid:853)(cid:3)(cid:87)(cid:349)(cid:367)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286) (cid:38)(cid:349)(cid:396)(cid:400)(cid:410)
To the east, the Jagh Jagh River, where (cid:449)(cid:258)(cid:410)(cid:286)(cid:396)(cid:882)(cid:271)(cid:286)(cid:258)(cid:396)(cid:349)(cid:374)(cid:336)
(cid:104)(cid:393)(cid:393)(cid:286)(cid:396)(cid:3)(cid:68)(cid:349)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286) (cid:336)(cid:396)(cid:381)(cid:437)(cid:393)
the Paleogene sediments drop down to (cid:894)(cid:4)(cid:395)(cid:437)(cid:349)(cid:296)(cid:286)(cid:396)(cid:895)
(cid:104)(cid:393)(cid:393)(cid:286)(cid:396)(cid:3)(cid:68)(cid:349)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)
great depths,12 suggesting that the river (cid:894)(cid:4)(cid:395)(cid:437)(cid:349)(cid:410)(cid:258)(cid:396)(cid:282)(cid:895)
channel may represent a fault. (cid:68)(cid:349)(cid:282)(cid:282)(cid:367)(cid:286)(cid:3)(cid:68)(cid:349)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286) (cid:94)(cid:286)(cid:272)(cid:381)(cid:374)(cid:282)
(cid:894)(cid:44)(cid:286)(cid:367)(cid:448)(cid:286)(cid:415)(cid:258)(cid:374)(cid:895) (cid:449)(cid:258)(cid:410)(cid:286)(cid:396)(cid:882)(cid:271)(cid:286)(cid:258)(cid:396)(cid:349)(cid:374)(cid:336)
(cid:75)(cid:367)(cid:349)(cid:336)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286) (cid:336)(cid:396)(cid:381)(cid:437)(cid:393)
To the west, the Balikh River which also (cid:894)(cid:58)(cid:286)(cid:460)(cid:349)(cid:396)(cid:258)(cid:3)
(cid:100)(cid:286)(cid:396)(cid:415)(cid:258)(cid:396)(cid:455)
seems to represent a fault bordering (cid:62)(cid:349)(cid:373)(cid:286)(cid:400)(cid:410)(cid:381)(cid:374)(cid:286)(cid:3)
(cid:28)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286) (cid:94)(cid:455)(cid:400)(cid:410)(cid:286)(cid:373)(cid:895)
the Jarablus-Tual al Abba High.13
(cid:87)(cid:258)(cid:367)(cid:286)(cid:381)(cid:272)(cid:286)(cid:374)(cid:286)(cid:3)(cid:894)(cid:4)(cid:395)(cid:437)(cid:349)(cid:410)(cid:258)(cid:396)(cid:282)(cid:895)
(cid:18)(cid:396)(cid:286)(cid:410)(cid:258)(cid:272)(cid:286)(cid:381)(cid:437)(cid:400)
Source: Redrawn by ESCWA-BGR based on ACSAD et al., 2003.
567
CHAPTER 24 - JEZIRA TERTIARY LIMESTONE AQUIFER SYSTEM HYDROGEOLOGY - AQUIFER CHARACTERISTICS
Table 1. Lithostratigraphy of the Jezira Tertiary Limestone Aquifer System
PERIOD LITHOLOGY COMMENTS
Sandstones and limestones with Exposed widely in Turkey and in the Ras al Ain
Helvetian
some dolomites; commonly Anticline area where it was tapped by shallow
(Middle Miocene)
fissured and karstic. wells.
Massive and marly Usually not water-bearing but locally acts
limestones with some as part of the aquifer system near faults and
Oligocene
dolomites and marly folds, especially in a narrow belt along the
dolomites. border from Qamishli to Ras al Ain.
Main water-producing formation commonly
known as the Jezira Tertiary Limestone;a
Karstic limestone with original
denominated as the Midyat Formation in
Middle to Upper Eocene fissures and secondary
Turkey, where it comprises massive
dolomitization.
limestones at the base, followed by marls
and chalky limestones at the top.
Source: Geyh, 2004; ACSAD et al., 2003; FAO and UNDP, 1966.
(a) Elsewhere in Syria, the Middle to Upper Eocene Formations are known as the Jadala and Sinjar and are placed in the Palmyra Group
(Burdon and Safadi, 1963).
AQUIFER THICKNESS AQUIFER PARAMETERS
The thickness of the Jezira Tertiary Limestone The large water volumes that used to
Aquifer System is generally around 200-300 m discharge from the Jezira Tertiary Limestone
in Turkey.14 In Syria, the thickness of the Aquifer System in some springs indicate high
formations generally increases towards the transmissivities in the karst aquifer. However,
south (Figure 1) and east where about 570 m these high transmissivities are limited to a small
of Eocene was penetrated in the Qamishli radius around the group of springs comprising
bore-hole (see Overview Map).15 The Helvetian the Ras al Ain Springs where transmissivity
Formation usually has a thickness of 50-60 m.16 values of 3 and 4 m2/s were recorded.18
Transmissivity values generally decrease
significantly away from the spring discharge
AQUIFER TYPE zones toward the east and south where they
are most commonly in the range of 0.012 to
In Turkey, groundwater in the Sanliurfa- 0.04 m2/s.19 A value of 5x10-2 was given for
Harran-Ceylanpinar area was under artesian storativity.20
conditions until about 1970 when the pressure
began to drop significantly following intense
abstraction. The aquifer system at Ceylanpinar
is now unconfined in every location.17 In Syria,
the Jezira Tertiary Limestone Aquifer System is
confined in the plain areas in the southern part
of the basin, with artesian spring discharge.
568
INVENTORY OF SHARED WATER RESOURCES IN WESTERN ASIA - PART 2
Hydrogeology -
Groundwater
RECHARGE water in storage within the aquifer system is
likely to be significantly higher. However, it is
The main recharge areas of the Jezira Tertiary not known how much is stored within the Jezira
Limestone Aquifer System are the Derik- Tertiary Limestone Aquifer System alone.
Mardin Mountain chain where relatively high
precipitation over Quaternary deposits and
fractured limestone and basalt outcrops provide DISCHARGE
favourable conditions for rainfall and runoff
infiltration. Most of the recharge occurs during The importance of the Jezira Tertiary Limestone
winter and spring when precipitation can Aquifer System is reflected by the discharge
infiltrate. In the absence of precipitation data, it volume of several large springs such as Ras
was assumed in the 1960s that average annual al Ain and Ain al Arous (within the boundaries
precipitation in the catchment area was in the of the delineated basin) and Ain al Arab (west
order of 450 mm, and that as much as 150 mm of the Balikh River).28 The total discharge
of this rainfall would infiltrate over limestones of these springs used to exceed 52 m3/s,29
and basalts in the catchment of the Ras al Ain but has recently decreased dramatically to
Springs, mainly in Turkey.21 Furthermore, it was about 3 m3/s.30 The Ras al Ain Springs used to
concluded that a recharge area of 8,100 km2 is discharge 45 m3/s, or 87% of total discharge
required to replenish the annual discharge of from the aquifer system, have disappeared
the Ras al Ain Springs,22 which was calculated completely since 2001 (see also Chap. 2).31
at an average of 1,219 MCM/yr for the period
1943-1959.23 Using recent available information, On the Jagh Jagh River, springs with a 2-3 m3/s
annual recharge in the catchment area24 is discharge occur at the south-western foot of
estimated to fluctuate between 9x10-1 BCM the Midyat Plateau in Turkey, upstream from
(for a dry year with 500 mm precipitation) Qamishli.32 Two large karst springs, the Beyazsu
and 1.77 BCM (for a wet year with 800 mm and Karasu Springs, discharge 4.25 m3/s and
precipitation).25 This means that the catchment 4 m3/s respectively from the Midyat Aquifer
area would receive about 92 mm of recharge north-east of the Kiziltepe Plain.33
during dry years and 180 mm during wet years.
The groundwater regime of the Jezira
Tertiary Limestone Aquifer System has been
FLOW REGIME significantly altered over recent decades.
Intensive groundwater pumping through a
The prevalence of a complex tectonic setting large number of wells in Syria and Turkey has
characterized by a number of folds and faults resulted in a dramatic drop in the water level
intruded by basaltic flows interferes with the in this aquifer system, which has in turn led to
development of a regional groundwater flow a lower total discharge from karst springs in
direction across the basin.26 Hence, groundwater an area of 2,000 km² to the south of the town of
generally flows from high areas in the north and Ras al-Ain.34 During the last 20 years, intensive
south to the low-lying central plains and wadi pumping from wells for irrigation has placed
channel beds (see Overview Map). heavy pressure on groundwater supplies in both
Syria and Turkey.35
STORAGE
WATER QUALITY
The volume of water stored in the aquifer system
that feeds the Ras al Ain Springs comprises The chemical and isotopic compositions of
the majority of the groundwater in the Jezira groundwater in the aquifer system show
Tertiary Limestone Aquifer System and has been important variations with respect to increasing
calculated as 7,400 MCM, or the equivalent of six depth, progressive confinement from north to
years of discharge at the average natural rate.27 south, and the geological facies changes.
Considering that there are several more springs Three main types of groundwater were identified
that discharge from the system, the volume of (see Overview Map):36
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CHAPTER 24 - JEZIRA TERTIARY LIMESTONE AQUIFER SYSTEM HYDROGEOLOGY - GROUNDWATER
Fresh Ca-HCO-type water: Found in springs EXPLOITABILITY
3
and shallow wells close to the unconfined-
confined limit with a Total Dissolved Solids The following criteria were used to delineate the
(TDS) value of 370-720 mg/L and exploitable areas of this aquifer system:
temperatures of 19°C-22.5°C. This type of
water occurs in the northern part of the basin Depth to top of aquifer: The average depth
(Zone A) where the water percolates and flows to the top of the aquifer ranges between
in short and shallow paths as in the main 100 m bgl and 200 m bgl with the greatest
spring at Ras al Ain. The isotope data depth occurring in the southern areas
suggests that this group of water is essentially near the Jebel Abdel Aziz Anticlines
recent meteoric water and that the increase in (Figure 1). Hence drilling depth is not a
TDS is related to the evaporation effect. limiting factor to exploitability.
Saline NaCl-CaCl-type water: This Depth to water level: Depth to
mineralized (1,400–4,700 mg/L TDS) thermal groundwater is about 5 m bgl near the
(30°C-38°C) water (Zone C) is drawn from Ras al Ain-Qamishli Anticlines and
deep wells that tap the confined zone of Jebel Abdel Aziz, rising to 40-55 m bgl
the aquifer system. It is derived by mixing in the intermediary central plains37 and in
groundwater from the Jezira Tertiary the Kiziltepe Plain to the north. This indicates
Limestone Aquifer System with water from the that groundwater is shallow enough for
underlying Upper Cretaceous Formation. This exploitation.38
is essentially paleo-recharge water, which
entered the aquifer system about 10,000 Water quality: Less than 10,000 mg/L
years ago. and hence not a limiting factor.
Brackish CaSO-type water: Admixed Hence the entire area of the aquifer system as
4
water which exhibits medium salinity delineated in the Overview Map is considered to
(700-3,750 mg/L TDS) and temperature be exploitable, although the existence of saline
(25°C-31ºC) and is formed by the mixing of Paleo water in the southern areas of the basin
the groundwater in Zones A and C. This type of (Zone C) may limit exploitation of the aquifer
water is found in both unconfined and confined system in the future.
zones (Zone B) and represents recharge water
from both the Pleistocene epoch and recent
times.
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