Groundwater Degradation and Sustainability of the Erbil

Basin, Erbil, Kurdistan Region, Iraq

By

RUBAR DIZAYEE

Bachelor of Science, 2010

Salahaddin University

Hawler, Kurdistan

Submitted to the Graduate Faculty of the

College of Science and Engineering

Texas Christian University

Fort Worth, Texas

in partial fulfillment of the requirements

for the degree of

Master of Science

August 2014

ii

ACKNOWLEDGEMENTS

This thesis would not have been possible without Becky Johnson’s support. I am grateful to her

for being my thesis supervisor. I thank Dr. Michael Slattery and Mrs. Tamie Morgan for their

contribution to my thesis. I am grateful to Dr. Helge Alsleben for his serious effort in providing

me with valuable feedback. I would also like to thank Dr. Steve Sherwood from TCU writing

center for his support in finishing this thesis. My gratitude goes to Mr. Mohammed Ahmad and

Dr. Imadaldin Hassan for providing me with information during my research. I also would like to

thank my friends Sebar Muhsin and Mahmood Mustafa for all the help they provided during this

research. My greatest appreciation goes to my parents for always believing in me and for their

continuous support.

iii

TABLE OF CONTENTS

LIST OF FIGURES ....................................................................................................................... vi

LIST OF TABLES ........................................................................................................................ vii

Chapter One: Introduction .............................................................................................................. 1

1.1. Overview of project ................................................................................................................. 1

1.2. Previous Studies: ...................................................................................................................... 5

Chapter Two: Geology, Hydrogeology, Climate, Soil, and Population ......................................... 7

2.1. Kurdistan Region ..................................................................................................................... 7

2.1.1. Tectonic Framework of Iraq and Kurdistan Region ............................................................. 7

2.1.2. Stratigraphy ........................................................................................................................... 9

2.1.2.1. Bakhtiary Formation ........................................................................................................ 11

2.1.2.2. Pleistocene units and Alluvium ....................................................................................... 11

2.2. Erbil Basin ............................................................................................................................. 13

2.2.1. Northern sub-basin (Kapran) .............................................................................................. 14

2.2.2. Central sub-basin ................................................................................................................ 15

2.2.3. Southern sub-basin (Bashtapa) ........................................................................................... 16

2.3. Challenges of the sub-basins and legitimacy of the distances between drilled wells ............ 16

2.3.1. Northern sub-basin (Kapran) .............................................................................................. 16

2.3.2. Central sub-basin ................................................................................................................ 17

2.3.3. Southern sub-basin (Bashtapa) ........................................................................................... 17

2.4. Climate ................................................................................................................................... 18

2.5. Soils........................................................................................................................................ 19

2.6. Population .............................................................................................................................. 20

Chapter Three: Objectives and Methodology ............................................................................... 22

3.1. Objectives .............................................................................................................................. 22

iv

3.2. Methodology .......................................................................................................................... 22

3.2.1. Manipulation of the Dataset ................................................................................................ 24

3.2.1.1. Survey Date ...................................................................................................................... 24

3.2.1.2. Well Locations and Coordinates ...................................................................................... 24

3.2.1.3. Converting Depths to Elevations ..................................................................................... 25

3.2.1.4. Estimate of Water Producing Formation ......................................................................... 25

3.2.1.5. Estimate of Aquifer Conditions ....................................................................................... 26

3.2.1.5.1. Aquifer Characteristics of the Alluvium and Bakhtiary Formation (confined, semi-

confined or unconfined) ................................................................................................................ 26

3.2.2. Creating Maps and Cross Sections ..................................................................................... 27

3.2.3. Climatic Data ...................................................................................................................... 33

3.2.3.1. Groundwater Recharge for Erbil Basin............................................................................ 35

3.2.3.2. Average Annual Decline of Water Table ......................................................................... 35

Chapter Four: Data Analysis and Results ..................................................................................... 38

4.1. Challenges of the sub-basins and legitimacy of the distances between drilled wells ............ 38

4.2. Well Data Analysis ................................................................................................................ 39

4.2.1. Elevation map ..................................................................................................................... 39

4.2.2. Depth map ........................................................................................................................... 42

4.2.3. Cross Sections ..................................................................................................................... 46

4.3. Climate Data .......................................................................................................................... 55

4.3.1. Groundwater Recharge for the Erbil Basin ......................................................................... 56

4.3.2. Precipitation ........................................................................................................................ 56

4.3.3. Evaporation ......................................................................................................................... 57

4.3.4. Calculations based on precipitation data............................................................................. 59

4.3.5. Scenarios based on future climate change .......................................................................... 61

4.4. Discussion and Interpretation ................................................................................................ 64

v

Chapter Five: Conclusions and Areas for Future Study ............................................................... 66

5.1. Conclusions ............................................................................................................................ 66

5.2. Recommendations .................................................................................................................. 68

5.3. Areas for Future Study ........................................................................................................... 70

Works Cited .................................................................................................................................. 71

Vita

Abstract

vi

LIST OF FIGURES

Figure 1: Location maps of the study area and projected drilled wells. ......................................... 2

Figure 2: Tectonic map of Kurdistan Region. ................................................................................ 8

Figure 3: Regional hydrogeological cross section (Choman-Erbil) ............................................... 9

Figure 4: Tertiary and Quaternary rock units in Iraq .................................................................... 10

Figure 5: Geological map of Erbil Basin with the sub-basins labeled .......................................... 14

Figure 6: Spatial distribution of average yearly rainfall in the study area. ................................... 19

Figure 7: Soil types in the Erbil Province. .................................................................................... 20

Figure 8: Location of the 36 wells on the Erbil Basin map. ......................................................... 31

Figure 9: Ground Surface Elevation Map of Erbil Basin. ............................................................ 41

Figure 10: Depth map of the Erbil Basin using all 36 wells. The map shows the deepening and

shallowing subsurface areas. ......................................................................................................... 43

Figure 11: Depth map for Alluvium aquifer ................................................................................. 44

Figure 12: Depth map for Bakhtiary aquifer................................................................................. 45

Figure 13: Location map of Erbil Basin showing alluvium profile along A-A’ and B-B’ ........... 49

Figure 14: NW-SE cross section along (A-A’) of alluvium aquifer ............................................. 50

Figure 15: NW-SE cross section along (B-B’) for Alluvium aquifer. .......................................... 51

Figure 16: Location map of Erbil Basin showing Bakhtiary profile along A-A’ and B-B’ ......... 52

Figure 17: NE-SW cross section along (A-A’) of Bakhtiary aquifer. .......................................... 53

Figure 18: NW-SE cross section along (B-B’) of Bakhtiary aquifer ............................................ 54

Figure 19: Map of the location of the meteorological stations in the study area. ......................... 55

Figure 20: Relationship between average annual temperature and average annual evaporation in

the study area. ............................................................................................................................... 58

vii

LIST OF TABLES

Table 1: Litho-stratigraphy of the aquifer systems in the Low Folded Zone of the Taurus- Zagros

series ............................................................................................................................................. 12

Table 2: Details about the 36 selected wells ................................................................................. 28

Table 3: Details about the 18 wells. .............................................................................................. 36

Table 4: Average annual precipitation for the years 2008 to 2012 ............................................... 61

Table 5: Results of the Calculations ............................................................................................. 62

1

Chapter One: Introduction

1.1. Overview of project

The Erbil Province is one of the most important agricultural regions in Iraq. The study

area contains the town of Erbil, the highly populated governorate in the region of intensive

irrigated agriculture area. People use groundwater annually for irrigation, agriculture, and

drinking. This water comes from drilled wells since groundwater is available throughout the

whole region. Surface water sources are very often unusable for human consumption due to a

lack of management and strategic planning. Consequently, groundwater plays an important role

for both irrigation and basic daily uses. Previous researches do not asses the sustainable use of

groundwater on a large scale; however, sustainability and contamination issues are major

problems in the Erbil Region. The study of the Erbil Basin was selected because 1) it contains

the highly populated Erbil City, 2) the water table has decreased sharply and a number of wells

have dried up in the last few years, and 3) desertification is increasing and precipitation is

decreasing in the area.

The Erbil Province is located in northern part of Iraq and covers an area of 15,074 km2

(3.5% of Iraq). It is the fourth largest Iraqi province after Bagdad, Basra, and Mosul (NCCI). The

province is bounded by Kirkuk to the south, Salah al-Din to the southwest, Ninewa to the west,

Dahuk to the northwest, and Sulaymaniyah to the east (Figure 1). The provinces of Kurdistan

Region (Erbil, Dahuk, and Sulaymaniyah) are geologically, hydrogeologically, and climatically

similar.

2

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3

The Zagros Mountains represent the main topography to the north and northeast of the

Kurdistan Region, reaching an elevation of 3,600 meters above sea level, whereas the Tigris

River plains (alluvial plains) are in the south of the region (Hameed, 2013). The vicinity of Erbil

province is comprised of mountainous uplands and fertile plains. Over 34% of the Kurdistan

Region is farmland used by people for agricultural purposes, while the rest consists of pasture,

forests, and urban land. In the Erbil province, 41% of the area is arable land and 59% is non-

arable land. The Erbil Basin is one of the most important basins in the Kurdistan region in terms

of adequate quantity and quality of groundwater as well as fertility of the land. The development

of the Erbil Basin has long been debated because there are unique features that separate it from

other basins, such as its geologic structure, stratigraphic relationships, and the geomorphological

setting of the region (Hameed, 2013).

Topographically, the Erbil Basin area is generally undulating with gentle to moderate to

very steep slopes. The plain of the Chai Siwasor, which stretches from Erbil to the Greater Zab

River, is an exception and is a nearly flat region without much topography (Ur et al., 2013). The

Erbil Basin is geomorphologically and geologically diverse, containing a range of river valleys,

flat alluvial plains, rolling gravel hills, and the Zagros foothill zones. Numerous large anticlines

and synclines with axis mainly oriented NW-SE parallel to the main Zagros orogen helped

producing the orientation of drainage patterns (Jassim and Goff, 2006). Also, the regional fault

systems are associated with intensive uplift. The Greater Zab River bounds the Erbil Basin to the

north-northwest, and Lesser Zab River bounds the basin to the south-southeast. The watershed

between the Erbil Plain and the Valley of Shalga River defines the eastern boundary of the basin.

The southwestern limit of the basin is the first long anticlinal hill that separates the Erbil Plain

from the Makhmur Plain, whereas the northeastern limit is the valley of the Bastora (Jassim and

Goff, 2006; Ur et al., 2013).

4

The overarching goals of this study are to determine the feasibility of groundwater use

and its sustainability for the entire Erbil Basin. This study addresses the following questions: (1)

What is the geometry and physiography of the basin? (2) Does a groundwater deficit exist and, if

so, how does it affect the various sub-basins in the Erbil Basin? (3) What is the overall

sustainable use of the groundwater within the aquifer systems across the Erbil Basin? The

hydrogeological study of the Erbil Basin assesses the availability of the groundwater resources in

the Erbil Basin for the development of irrigation, agriculture and drinking purposes.

Furthermore, the study focuses on the characteristics of the two main aquifers (alluvium and

Bakhtiary Formation) throughout the whole Erbil Basin and its sub-basins. The study also

includes an attempt to quantify the sustainability of these aquifers within the sub-basins.

This research is based on raw well data for five consecutive years (2008, 2009, 2010,

2011, and 2012). Data include static groundwater levels, dynamic groundwater levels, ground

surface elevations, depth to water, total depths of the wells completed in the two main aquifers,

and soil types. In addition, a climate data set includes precipitation and evaporation data. These

data are used to investigate and better understand the groundwater availability across the entire

basin. The author used climate, water well, and formation data to conduct an analysis of

groundwater levels, aquifer storage, and aquifer recharge from precipitation, and compares

groundwater withdrawals to recharge rates to estimate sustainable groundwater use in the Erbil

Basin.

5

1.2. Previous Studies:

There is a definite lack of scientific study and papers for the Erbil Basin. Below are the

papers that the author depended on while conducting this study:

Jawad and Hussien (1988) studied the groundwater monitoring network rationalization in

the Erbil Basin by applying a multivariate analysis approach to rationalize a piezometric

approach on a network of fifteen wells monitored for about three years. The purpose of

their study was to measure the annual changes in the aquifer storage and understand the

aquifer conditions in terms of recharge and discharge, by dividing the aquifer into a

number of zones and analyzing the aquifer condition in each zone separately.

Hassan (1998) studied the groundwater conditions in the Erbil Basin. The author

proposed a method (maximum water surplus method) for calculating the average amount

of infiltration from precipitation, and surface runoff. The study also included an analysis

of hydro-chemistry and hydro-geochemistry of the groundwater in the region and

considered that groundwater in the area is very suitable for industry, irrigation, and

domestic purposes. Since in Erbil people depend mainly on groundwater for all aspects of

life, Hassan (1998) calculated water population balance in the area to find the water

demand per capita in winter and summer seasons.

Al-Tamir (2008) conducted a study on groundwater quality variation in the Erbil City by

applying principle components analysis technique (PCA) to define the factors responsible

for the variance in groundwater quality and pollution. The author concluded that the

variance in the groundwater quality is as a result of agricultural pesticides and herbicides,

human activities, and rock dissolution.

6

Hameed (2013) conducted a study on water harvesting in the Erbil Territory. The study

focused on identifying suitable sites for water harvesting by using geographic

information system (GIS) and multi criteria evaluation (MCE). The author suggested a

number of micro and macro catchments depending on data such as soil texture, slope,

rainfall data, land use/cover, and drainage network. The author concluded that suitable

sites for rainwater harvesting are 36% of the total area of the region.

7

Chapter Two: Geology, Hydrogeology, Climate, Soil, and Population

2.1. Kurdistan Region

2.1.1. Tectonic Framework of Iraq and Kurdistan Region

The Zagros Belt in Northern Iraq is an example of a geologically recent Tertiary orogen

with an earlier obduction-subduction tectonic history (Numan, 1997; Jassim and Goff, 2006).

The tectonic activity along the Zagros Belt has been long-lived and started in the Late-

Cretaceous time (Numan, 1997); however, the final geometry developed during Miocene-

Pliocene time. The Zagros Mountains formed as a result of the collision of the Arabian and

Eurasian plates, where the Arabian plate was subducting underneath the Eurasian plate until it

reached a collisional stage (Jassim and Goff, 2006). This collision created a fold-thrust belt.

The Zagros orogen in the Kurdistan Region of Iraq is divided into stable and unstable

shelves; the stable shelf has a thin sedimentary cover with no significant folding, whereas the

unstable shelf has a thick and folded sedimentary cover and the folding increases toward the

northeast (Al-Juboury, 2012) (Figure 2). The unstable shelf is divided into four NW-SE striking

tectonic elements (Numan, 1997; Jassim and Goff, 2006): Foothill Zone (Low Folded Zone),

High Folded Zone, Imbricate Zone, and Zagros Suture Zone (Figure 2) (Jassim and Goff, 2006).

8

Figure 2: Tectonic map of Kurdistan Region (modified from Jassim and Goff, 2006).

The Erbil Basin area lies in the Low Folded Zone of Northern Iraq. Buday (1980)

introduced the Low Folded Zone as a tectonic unit, which has limited tectonic activity.

Anticlines and narrow synclines are dominated by open folds that have wavelengths ranging

from 5 to 10 km. The areal extent of the Erbil Basin covers a wide syncline bounded by the

Permam Dagh anticline in the NE and by the Kirkuk anticlinal structure in the SW. According to

Buday and Jassim (1987), the synclinal area between these anticlines represents the middle part

of the Erbil plain, which consists of several sub-basins (northern, central, and southern) (Bapeer

9

et al., 2010). The Erbil Basin is getting deeper toward SSE, where the antiforms and synforms

disappear and the thicknesses of the formations are increasing. In contrast, the basin gets

shallower towards the NNE, where the antiforms and synforms are more abundant and

topography increases as does tectonic activity (Figure 3).

Figure 3: Regional hydrogeological cross section (Choman-Erbil). Modified from

Stevanovic and Iurkiewicz (2009)

2.1.2. Stratigraphy

The stratigraphy of the area is characteristic of Iraq’s Zagros belt (Figure 4) (Bellen et al.,

2005). The sedimentary succession is possibly more than 10 km thick and quite probably begins

with late Precambrian formations. This layer is overlain by a Palaeozoic–Lower Mesozoic

succession that is several thousand meters thick (Numan, 1997; Jassim and Goff, 2006). Steady

and slow subsidence throughout the Mesozoic allowed widespread deposition of shallow marine

sediments on a wide epeiric carbonate platform (Dunnington, 1958). From mid-Jurassic to Late

10

Cretaceous faulting formed intra-shelf basins with clastic input from the west. Cretaceous

deposition was periodically interrupted by nondeposition and erosion due to localized

reactivation of faults during the Zagros orogeny. During Palaeocene-early Eocene time, a NW-

SE-trending, deep open marine basin developed to the south through central and eastern Iraq in

which the clastics (mainly shale) of the Kolosh Formation were deposited. Shallowing of this

basin and its isolation from clastic input gradually introduced limestone into the upper part of the

Kolosh Formation, and further shallowing introduced red beds and marls in mid-late Eocene

times, when sedimentation was controlled by a shelf isolating this lagoonal area. The Pilaspi

Formation represents a lagoonal facies. The late Eocene unconformity at the top of the Pilaspi

Formation is the result of a marine regression.

Figure 4: Tertiary and Quaternary rock units in Iraq. Modified from Bellen et al. (2005)

AGES

11

During the late Miocene, the Lower Fars Formation, which is dominated by mudstone,

shale and sandstone, formed as a result of erosion of mud and sand from nearby hills in a

terrestrial environment (Al-Tamir, 2008; AL-Kubaisi, 2008). The remainder of the surface

geology comprised of fluvial sandstones and muds passing upward into the coarse fluvial

conglomerates of the Bakhtiary Formation (see below). The Pleistocene period was characterized

by coarse pluvial and fine inter pluvial pebbly sand and silty sediments (AL-Kubaisi, 2008) and

the deposition of recent alluvium (see also below) is also terrestrial.

2.1.2.1. Bakhtiary Formation

The Bakhtiary Formation crops out at the surface near the southern end of the Bastora

area, on the limbs of Permam anticline located in the north of Erbil Province, and both eastern

and western sides of the basin, which is close to the recharge and discharge zones of the study

area (Habib et al., 1990). It consists of thickly-bedded conglomerates, sandstones and shale and

is considered Pliocene age. The formation is overlain by Quaternary terrace gravels in the valleys

or alluvium (Bellen et al., 2005). The Bakhtiary Formation covers more than 80% of the study

area. The thickness of the Bakhtiary Group (Upper and Lower Bakhtiary) varies (Al-Tamir,

2008), but several studies have shown that the thickness of this formation reaches over 1,800

meters at the Erbil Plain (Jawad and Hussien, 1988).

2.1.2.2. Pleistocene units and Alluvium

The Quaternary deposits are common over a wide range of the Erbil Basin area.

Pleistocene deposits, which rest on a Pliocene Bakhtiary Formation (Table 1), consist mainly of

soils, gravels, and conglomerates with some sands, clay, and silt. The youngest deposits consist

of river terraces deposits, alluvial fans, slope deposits and flood plain deposits (Jassim and Goff,

12

2006). The thickness of these deposits varies; however, it can exceed 100 meters in some

locations across the basin. The nature of these coarse-grained, unconsolidated materials makes

them ideal reservoirs for groundwater. The coarse sediments of the alluvial fans play a vital role

in shaping and generating confined aquifers within the basin. The coarse alluvial deposits consist

of fine-grained clay interbedded with sandy silty layers that amalgamated with pebbly, gravelly

strata. Ghaib (2004, 2009) estimated the water table level and thickness of the alluvial deposits.

The thickness of the alluvium might reach up to 150 meters, especially at the Bastora area near

the northern boundary of the Erbil Basin.

Table 1: Litho-stratigraphy of the aquifer systems in the Low Folded Zone of the Taurus-

Zagros series (from Stevanovic and Markovic, 2004)

Age Formation Lithology

Thickness

(m)

Water bearing

characteristics

Quaternary Pleistocene

to recent Alluvium

Gravel, clay,

and sand 10-150

Hydraulically

connected;

from one

aquifer system

in the Low

Folded Zone

Neogene

Pliocene

Upper

Bakhtiary,

Lower

Bakhtiary,

Mukdadia

Conglomerates

and Claystone,

partly

Sandstone and

Siltstone

>2,500-3,000

Miocene

Upper

Fars,

Lower Fars

Mainly

sandstone and

Evaporites,

and some

Conglomerates

L. Fars:

400- 900

U. Fars: 500

Low

groundwater

yield with

acidic or salty

water

13

2.2. Erbil Basin

The largest reservoir for groundwater in the Erbil Province is the Erbil Basin, also known

as Dashty Hawler Basin. The Erbil Basin covers an area of 3,200 km2 and has a depth of

approximately 800 meters. This basin is one of the most important groundwater basins in the

Middle East because of its nearness to the surface, not to mention the quantity and quality of its

water (Ahmed, 2009). The groundwater within the Erbil Basin generally flows from northeast to

southwest. A groundwater divide within the basin directs flows toward either the Greater Zab

River to the north-northwest or the Lesser Zab River to the south-southeast. The groundwater of

the Erbil Basin contains small amounts of soluble salts and harmful ions that could have negative

impacts on human health (Internal report directorate of groundwater-Kurdistan Region, 2012).

In general the Erbil Basin is divided into three sub-basins, which include the Northern

(Kapran) sub-basin, the Central sub-basin, and the Southern (Bashtapa) sub-basin (Figure 5)

(Habib et al., 1990). Researchers based this division on hydrogeological characteristics obtained

from deep wells, previous groundwater studies, and water quality (Ahmad, 2002). Sub-basins are

separated by minor surface and subsurface structures. Other areas in the basin include Shalga and

Bastura, but whether these belong to the Erbil Basin proper is debated.

14

Figure 5: Geological map of Erbil Basin with the sub-basins labeled. Modified from

Hameed (2013)

2.2.1. Northern sub-basin (Kapran)

This sub-basin has an area of 915 km2. The uppermost part of this sub-basin, which is

located near the foothill zone of the Zagros Mountains, consists of Bakhtiary Formation. A few

meters of alluvial deposits overlie the Upper Bakhtiary Formation in the lower part of this sub-

15

basin. In some locations, the thicknesses of alluvial deposits reach 50 to 60 meters. Both the

alluvium and the Bakhtiary aquifers are inter-granular and serve as groundwater-bearing units

(aquifers) with no aquitards or aquicludes between the two formations. According to records

from numerous deep wells, the Bakhtiary aquifers lithologically are composed of gravel, sand,

silt, conglomerate, and clay beds, whereas alluvium aquifers consist of interbedded sand, silt,

clay, and gravel (Ahmad, 2002).

Generally, Bakhtiary and alluvium aquifers are unconfined, meaning that precipitation

infiltrates directly into these aquifers, but in some parts of the study area, because of a covering

of thick clay, the aquifers become semi-confined or confined (Jawad and Hussien, 1988). In

normal conditions, the deep wells will be artesian. In the confined portion of the aquifers,

groundwater occurs at depths of approximately 40 meters below ground surface (bgs) and the

wells are not artesian. The total depths of deep wells drilled into the Kapran sub-basin from 1977

to 1989 ranged from 80 to 150 meters bgs, with total depths of more recent wells (1990 to 2002)

ranging from 160 to 200 meters bgs (Ahmad, 2002).

2.2.2. Central sub-basin

This sub-basin has an area of 1400 km2. The formations in this sub-basin are the Upper

and Lower Bakhtiary Formation and alluvium. The upper part of the Bakhtiary Formation

consists of gravel, sand, clay, and conglomerate strata. However, in some of the deep wells in the

lower Bakhtiary Formation consists of thin beds of gravel, sand, or conglomerate. The materials

of alluvium aquifers are the same as the Bakhtiary Formation, with the exception that they

contain silt in between the other layers instead of multiple clay layers. The discharge rates of

wells in this sub-basin range between 1 to 2 l/s (Ahmad, 2002).

16

2.2.3. Southern sub-basin (Bashtapa)

The Bashtapa sub-basin has an area of 885 km2 and is mostly dominated by the Upper

Bakhtiary Formation. Two different types of aquifer systems, the unconfined and semi-confined

aquifers, characterize this sub-basin. The semi-confined aquifers of this sub-basin consist of silty

materials (silty clay, sandy clay) that are interbedded with thin fine-grained sandstone strata,

amalgamated with clay layers, whereas the unconfined aquifers mainly consist of interbedded

clay beds with some silt or silty clay (Ahmad, 2002).

2.3. Challenges of the sub-basins and legitimacy of the distances between drilled wells

The regulatory principles of drilling water wells are not well developed in the region, and

the implementation and enforcement of the rules and regulations to foster production of water

resources still present fundamental issues in this region. Numerous studies have been done by

different organizations to address these issues; few of them have touched on the major problems

created by a lack of management. The lack of regulation has resulted in wells being drilled in

close proximity to each other, closer than new regulations permit, and the aquifer is also tapped

by numerous unpermitted (illegal) wells.

2.3.1. Northern sub-basin (Kapran)

According to a study done by the Furat Center and adopted by the Ministry of

Agriculture and Water Resources, the distance between wells in this sub-basin should not be less

than 300 meters and the number of drilled deep wells should not exceed 225 wells in the entire

sub-basin. However, the results of the Furat Center’s study show that the current distance

between wells is 450 meters, while the number of drilled wells is 1,074. Furat Center research

indicates that the distance between the wells is adequate, but the number of drilled wells far

17

exceeds the number recommended by the Furat Center. The 1,074 drilled wells also does not

include wells drilled by pile equipment: mechanical devices used to drive piles (poles) into soil

to provide foundation support for buildings or other structures and not for drilling water wells

(Internal Report Directorate of Groundwater-Kurdistan Region, 2012). To get control over the

illegal well drilling, the Kurdish Government forbade drilling wells by pile equipment on 22nd

August 2010 (zarikrmanji.com), aiming to make the aquifers more efficient and faster in

recharging the groundwater.

2.3.2. Central sub-basin

The studies done in this sub-basin by the Furat Center show that the distance between

wells in this sub-basin should not be less than 400 meters and the number of drilled deep wells

should not exceed 738 wells in the entire sub-basin. In fact, the results of the Furat Center’s

research indicate that the well distance in this sub-basin is 600 meters and the number of drilled

wells is 3,149, which exceeds the optimum number of wells supposed to be present by 2,411.

Most of the wells drilled for agricultural purposes are located in this sub-basin, which causes a

real possibility of groundwater contamination by fertilizers used for agricultural purposes

(Internal Report Directorate of Groundwater-Kurdistan Region, 2012).

2.3.3. Southern sub-basin (Bashtapa)

The maximum distance between water wells in this sub-basin, according to the Furat

Center, should not be less than 500 meters and the number of drilled deep wells should not

exceed 500 in the entire sub-basin. The results of the Furat Center’s research shows that the

distance between wells is 550 meters and number of drilled wells is 583. However, most of the

18

wells drilled by pile equipment (not counted in the 583 drilled wells) are located in this sub-basin

(Internal report directorate of groundwater-Kurdistan Region, 2012).

2.4. Climate

The Erbil Province generally has a varied climate and is classified into two climatic

regions. A Mediterranean climate region with an average annual rainfall of 600 to 800 mm

characterizes the north and northeast parts, whereas a warm climate region with an approximate

average annual rainfall of 500 mm characterizes the south and southwest parts of the Erbil

Governorate (Hameed, 2013). It is cold and snowy in the winter, and hot and dry in summer.

January is the coldest month in the region; the average winter temperature for the Erbil Province

is 7.9 °C (Hameed, 2013). The land topography varies from a mountainous and semi-

mountainous region to hilly and plain lands, all of which impact the influence of precipitation.

The plains are characterized by a semi-arid climate. Precipitation occurs from October to May,

and decreases from northeast toward southwest in the region, which means the northeastern parts

get higher amounts of precipitation than the southwestern parts. In the Erbil Province, the

quantity of rainfall is between 200 mm/year in the south and 1,200 mm/year in the north, with an

annual average of about 700 mm/year (Figure 6). Rainfall is one of the most important climatic

factors, and it changes within very short periods of time (UNDP, 2011).

19

Figure 6: Spatial distribution of average yearly rainfall in the study area. Modified from

Hameed (2013).

2.5. Soils

Based on the geographical location, soils in the area vary in depth. For example, soils are

shallow in the north and northeast (mountainous region), whereas the soils are deep and have

good texture in the south of the Erbil Province (the valley and plain lands). Soils in the southern

part of the area are some of the best soils for agriculture and include chestnut soils, dark brown

soils, and black soils. The semi-mountainous areas and most plains are covered with red and

brown soils. Overall, various zones with different types of soils have been identified in the Erbil

Province (Figure 7) (Hameed, 2013).

20

2.6. Population

According to the general Iraqi census, the population of Erbil was 770,439 in the census

of 1987. Starting in 1991, the Kurdish authorities in the three Kurdish provinces did a combined

census. The province’s population numbered 1,095,992 in 1997, 1,315,239 in 2003, and

1,542,421 in 2008 (Internal report directorate of groundwater-Kurdistan Region, 2012).

Population in the Erbil Province has now reached 1.9 million. The population increase indicates

that Erbil grows by 2.9 percent on an annual basis (Erbil Governorate, 2012).

There are significant differences when comparing data from the census and the water

resources management. Demand for water is twice as high as the demand in the 1980’s. Besides

the increase in population, water demand dramatically increased for industry, agriculture, and

Figure 7: Soil types in the Erbil Province. Modified from Hameed (2013).

21

domestic use. At the same time, drought has hit the region. The first drought period started in

1999 and lasted for four years until 2003, while the second drought period started in 2008 and

lasted into 2009 further training the water resources.

22

Chapter Three: Objectives and Methodology

3.1. Objectives

Datasets for water wells and climate from 2008 to 2012 were obtained from the Ministry

of Agriculture and Water Resources of the Kurdistan Regional Government, Iraq. The use of

these data was challenging since there was a lack of details that cover all of the overarching

objectives and to answer all of the questions (see below). However, to reach a certain level of

understanding to the addressed hydrological issues in the Erbil Basin, and to tackle and minimize

the concerns of water users in the Erbil Basin, including water resources deficits, drought,

groundwater overexploitation and mismanagement of the extracted groundwater used, several

objectives are proposed:

1. To obtain, compile, and analyze the available geology, climate, and well data for the

Erbil Basin. This is the first such study conducted in the region at basin scale. A large

portion of this work involved an intensive and complicated research effort to obtain

and integrate the data.

2. To document and quantify the rate of groundwater level changes in the Erbil Basin,

from 2008 through 2012 using the available well data.

3. To analyze the sustainability of the groundwater resources within the Erbil basin based

on the estimated rates of groundwater changes.

3.2. Methodology

Datasets for water wells and climate from 2008 to 2012 were obtained from the Ministry

of Agriculture and Water Resources of the Kurdistan Regional Government, Iraq. The water well

dataset contained the following information for most, but not all, of the wells:

23

Year that the information was collected (called “survey date” for the purposes of

this study)

Well coordinates (latitude and longitude)

Well location (name of basin)

Ground surface elevation

Total depth of the well

Depth to static and dynamic water levels

Name of producing formation (missing for the majority of wells)

Yield

Well names

The climate dataset contained the following information:

Monthly rainfall data (from 1941-2012)

Air temperatures

Relative humidity (in %)

Precipitation (both rainfall and snowfall)

In addition, the Ministry provided a dataset of 18 wells for which water level measurements were

obtained in the years 2001 and 2010. The following data for these 18 wells were available:

Water level data for 2001 and 2010

Well location (name of basin and sub-basin)

Well names

Several programs were used to perform the data analysis including Microsoft Exceltm

,

ESRI ArcGIS 10.1 (Geographic Information Systems), Blue Marble Geographics Global Mapper

13, Rockworks 15, and Adobe Illustrator CS6.

24

3.2.1. Manipulation of the Dataset

3.2.1.1. Survey Date

The well data measurements in the Kurdistan Region are collected only once per well

resulting in only one data point for use in this project. The provided well data had not been

sorted according to the survey date (period during which the information about the wells was

collected). The author sorted the wells according to their survey dates; the collected data

consisted of wells surveyed over five years 2008 through 2012.

Unfortunately, the water level measurements were not conducted on the same dates or

even the same years; therefore, the analyses of these data represent overall trends in water levels

for the aquifers, not a precise calculation for a specific date.

3.2.1.2. Well Locations and Coordinates

The Kurdistan Ministry of Agriculture and Water Resources provided a well data set that

consisted of 6,974 wells located in different basins in the province. Wells that did not belong to

the Erbil Basin according to the basin location data (which indicated location of each well) were

discarded; this process reduced the number of the wells from 6,974 to 2,050.

The Latitude /Longitude coordinates for each well were plotted for the 2,050 wells in the

Erbil Basin using ESRI ArcMap 10.1 to find their exact location in the basin. A number of the

wells had missing or inaccurate coordinates. Wells whose location did not plot within the Erbil

Basin were discarded.

Besides missing or inaccurate coordinates, the datasets for some of the wells were also

missing fundamental data for this research, including the survey date, depth where water was

25

first encountered while drilling, depth of water table, elevation above sea level, static and

dynamic water levels, characteristics of the aquifer types (confined, semi-confined, or

unconfined), piezometric surface of groundwater, and well yield. By discarding the wells for

which the required information or the latitude and longitude were lacking, the number of wells

included in this study was reduced to 995.

Using Blue Marble Global Mapper to plot the wells on a base map of the Erbil Basin

delineating the sub-basins (Al-Tamir, 2008), each of the 995 wells were classified according to

their location by sub-basin name. Documenting the sub-basin for each well location is important

as the drilling regulations differ in each sub-basin. Using Global Mapper, the distances between

wells were determined to compare the actual distances to the legally permitted distances in each

sub-basin. This documentation was used to determine the legality of the wells in the Erbil Basin.

3.2.1.3. Converting Depths to Elevations

The static to dynamic water levels were converted using the ground surface elevations

and depth-to-water measurements provided in the well dataset. The total depth of the well, depth

to static water level, and depth to dynamic water level were subtracted from the ground surface

elevation to convert depth measurements to elevations.

3.2.1.4. Estimate of Water Producing Formation

Among the 995 wells, only 409 wells had formation information provided in the dataset;

therefore, the author estimated the formation information for the remaining 586 wells by

applying two methods:

(1) Personal contacts with professors Kanar Hamza, Mohammed Ahmad, and

Imadaldin Hassan, who have knowledge about the formations of the area and their

26

approximate thickness. All of these individuals have done research on the Erbil Basin and

the Erbil Region

(2) Comparing the formation information of the surrounding wells that have

similar elevations above sea level and are located within the same sub-basin to those with

missing data.

Through these two methods, the author was able to estimate the well production for

which the ministry of Agriculture and Water Resources provided no formation data in the

dataset. Generally, the surface elevation of all the wells (with or without formation data) differs

from each other by 0 to 10 meters. Similarly, the distance between wells with and without

formation data is not large. The relatively close agreement of wells in terms of surface elevations

and distances from each other indicate the formation data of the wells do not differ significantly.

3.2.1.5. Estimate of Aquifer Conditions

3.2.1.5.1. Aquifer Characteristics of the Alluvium and Bakhtiary Formation (confined,

semi-confined or unconfined)

It is crucial to have an idea about the aquifer conditions (confined, semi-confined, or

unconfined) as they relate directly to the recharge patterns. For instance, unconfined aquifers get

recharged directly from precipitation infiltration into the subsurface, which means there is no

confining layer overlying the aquifer. The confined aquifer is the opposite of unconfined. It has

an impermeable layer (aquiclude) overlying the aquifer, which does not allow direct recharge.

Instead, the aquifer gets recharged where the impermeable layer ends. Semi-confined aquifers

are overlain by low permeability layers that allow limited recharge and discharge from the

27

aquifer (aquitard). The alluvium aquifers are generally unconfined, whereas the Bakhtiary

aquifers are primarily semi-confined to confined.

The dataset did not include information about aquifer conditions in each sub-basin of the

Erbil Basin, so the author depended on Ahmad (2002), who provided data about the static water

levels (water level before pumping) and dynamic water levels (water level during pumping).

Depending on Ahmad’s (2002) data and the aquifer’s static and dynamic water levels in the well

data set, in the present research the static water level was used to estimate whether a well was

drilled into a confined, semi-confined, or unconfined aquifer. The dynamic water level was

generally not used because of the variability due to pumping rates, pump and well sizes, and

changes in pumping rate. However, because of limited data for some of the wells, the author

used the dynamic water level in some instances. Even so, the aquifer conditions could not be

determined for a number of wells. Despite some uncertainties in the aquifer conditions, the

author used all of the wells for this research because the dataset was already limited. Discarding

any additional wells would have resulted in insufficient data for building a general understanding

of groundwater fluctuation and the legitimacy of the wells in the Erbil Basin, which is one of the

major problems facing the basin.

3.2.2. Creating Maps and Cross Sections

The assessment of the hydrogeologic conditions in the Erbil Basin was initiated by

constructing workable sets of cross sections and maps. Maps and cross sections were constructed

using Blue Marble Global Mapper and Adobe illustrator CS6, to demonstrate geometrical

distribution of the aquifers (alluvium and Bakhtiary Formation), groundwater level fluctuations

and the overall geometry of the Erbil Basin. For the maps and cross sections construction, only

wells for which all information were provided in the original dataset or wells whose conditions

28

could be determined with some certainty were included. Even though, well conditions were

estimated for all wells, conditions for some of the wells were more accurate than others. Higher

precision was largely based on communication with Mohammed Ahmad (personal

communication, 2014), who has extensive knowledge of the formations and conditions of the

aquifers in different parts of the Erbil Basin. Thirty-six of the wells, which are named for their

owners, included highly reliable information about the geology and well measurements including

total depth (TD), coordinates, well measurements, and subsurface information and were used to

produce the maps and cross sections of the Erbil Basin. The data for these wells and their

locations were mapped into Rockware software for analysis (Table 2 and Figure 8).

Table 2: Details about the 36 selected wells

Well

No.

Well Name Sub-

basin

Total

Depth

Producing

Formation

Aquifer

Condition

W01 Sawis Badel /17 Central 260 Alluvium Unconfined

W02 Daham Huseen Ahmed Bashtapa 300 Alluvium Unconfined

W03 Azez Abubaker Smael Central 277 Alluvium Unconfined

W04 Abdulmajed Abdulrahman Central 243 Alluvium Unconfined

W05 Idris Yosuf Khorshid Bashtapa 300 Alluvium Unconfined

W06 Abdulqadr Mhamad Smail Bashtapa 300 Alluvium Unconfined

W07 Najeba Osman Tahir Bashtapa 283 Alluvium Unconfined

W08 Shwan Smko Muhammed/2 Bashtapa 271 Alluvium Unconfined

29

W09 Ali Ibrahim Salim Central 228 Alluvium Unconfined

W10 Sabir Ismail Rasul Central 250 Alluvium Unconfined

W11 Khader Ali Khader Bashtapa 242 Alluvium Unconfined

W12 Luqman Aziz Hussien Bashtapa 243 Alluvium Unconfined

W13 Ary Husain Muhaideen Bashtapa 305 Alluvium Unconfined

W14 Omar Ali Taha Central 230 Alluvium Unconfined

W15 Sabr Muhammad Aly Central 252 Alluvium Unconfined

W16 Sabiha Muhammad Abdullah Central 300 Alluvium Unconfined

W17 Najmaddin Ali Hussein Central 251 Alluvium Unconfined

W18 Muhamad Ali Ahmed Central 212 Alluvium Unconfined

W19 Fawzia Mustafa Kader Bashtapa 220 Alluvium Unconfined

W20 Ali Ismail Omar Bashtapa 234 Alluvium Unconfined

W21 Nawzad Yahya Said Central 300 Bakhtiary Semi-confined

W22 Abdulrahman Qader Hamad Central 250 Bakhtiary Semi-confined

W23 Khalid Ali Haji Central 250 Bakhtiary Semi-confined

W24 Kompany Barani Projay Neshtajebon Central 300 Bakhtiary Semi-confined

W25 Kako Raof Omer Central 251 Bakhtiary Semi-confined

W26 Kompaniy Ask & Green land Projay Central 300 Bakhtiary Semi-confined

Heran City/2

30

W27 Omer Rahman Hmadamin Central 200 Bakhtiary Semi-confined

W28 Abdulrahman Fake Muhammad Central 232 Bakhtiary Semi-confined

W29 Sherzad Bairam Jamil Central 300 Bakhtiary Semi-confined

W30 Saber Ahmed Omer Central 250 Bakhtiary Semi-confined

W31 Naznaz&Shirin Omar Xdr Central 303 Bakhtiary Semi-confined

W32 Zrar Ahmad Omar Central 256 Bakhtiary Semi-confined

W33 Sulaiman Ali Diwary Central 286 Bakhtiary Semi-confined

W34 Mariwan Nur Aldin Bashtapa 300 Bakhtiary Semi-confined

W35 Jala Hassan Sharif Bashtapa 240 Bakhtiary Semi-confined

W36 Wahid Said Mustafa Bashtapa 207 Bakhtiary Semi-confined

31

Figure 8: Location of the 36 wells on the Erbil Basin map.

Using the elevation above sea level data for these 36 wells in the study area, an elevation

map is created showing the differences in the elevation across the basin. The elevation map is

color-coded with a specific scale to show the variations in altitude across the Erbil Basin. The

map also shows the steepness of the slopes and their geomorphological patterns across the basin.

Thus, the elevation map identifies the altitudes in the study area and the slope variations in which

the wells were drilled.

The depth maps of the Erbil Basin and the aquifers were created using the well

measurements of total depth (TD) of each represented well. The purpose of these maps is to

show geometry of the basin and identify relatively shallow parts and deeper parts of the basin.

Determining the geometry of the basin allows interpretations of the subsurface geology

32

throughout the entire basin. They show that subsurface geology is related to the surface geology,

which means surface and subsurface geology of the Erbil Basin are geologically linked.

New subsurface cross sections were constructed based on data from the 36 wells. These

data were used to estimate the hypothetical thickness of the aquifers in the alluvium and

Bakhtiary Formation. In addition, possible contacts between these two aquifers are estimated in

the cross sections since the alluvium overlies the Bakhtiary Formation. The regional correlations

between these wells allow evaluation and documentation of significant changes in interlayering

within the alluvium and Bakhtiary Formation and their depths across the Erbil Basin. The

ultimate purpose of creating these cross sections is to identify the geometric distribution of the

aquifer systems, determine the groundwater levels, and delineate the shallowing and deepening

successions in the subsurface of the Erbil Basin.

To create the cross sections, the well with the highest elevation among selected wells in

the Erbil Basin was used as reference (datum). The elevation of each of the other wells is

subtracted from the reference well. Therefore, the depths have been calculated using their total

depths (TD) for the wells related to the reference well that is used as a datum. The cross sections

across the Erbil Basin were extrapolated from the chosen wells. In addition, cross sections show

the groundwater level in each aquifer system. This has been calculated based on the static and

dynamic groundwater levels in these wells. The lack of complete data for these wells caused

considerable problems. Tops and bottoms of the aquifers were not clearly identified from the

dataset; however, after constructing cross sections, the contacts of the aquifers are clearly

defined and can be distinguished in each constructed section. Although the observations are

based on only 36 wells throughout the whole basin, they provide a basic understanding of the

topography and subsurface geology of the entire basin.

33

The cross section data for the aquifers have been divided into two different types. Each

type represents a specific aquifer. For the alluvium aquifer, several wells were chosen to

construct two different profiles: Profile A-A’ and B-B’, which have different orientations. Profile

A-A’ is oriented NNW-SSE and includes the following wells: W01, W02, W03, W04, W05,

W06, W07, and W08 (see Table 2 for well names). Profile B-B’, which is oriented NW-SE,

includes the following wells: W09, W10, W11, W12, W13, W14, and W15 (Table 2).

Two different profiles with different orientations were also constructed for Bakhtiary

aquifer. The A-A’ profile is oriented NE-SW and includes the following wells: W23, W24, W25,

W26, W27, W28, W29, W30. Profile B-B’, which is oriented NW-SE, includes these wells:

W31, W32, W33, W34, W35, W36 (Table 2).

A soil map for the Erbil Basin was acquired from Hameed (2013). The map was modified

using Adobe Illustrator CS6 (Figure 7). This map shows a range of soil types, which were

grouped and categorized hydrologically into 10 categories to cover the entire basin and the Erbil

Region as well. Also, a map from Al-Tamir (2008) showing the sub-basins within the Erbil

Basin has been modified using Adobe Illustrator CS6 (Figure 5). Other maps such as a location

map, map of precipitation rates, rainfall map, and a river and lake map, have been compiled and

modified in the same way as the two previous maps. In addition, a generalized cross section of

Erbil and Northern Iraq has been modified.

3.2.3. Climatic Data

The Kurdistan Regional Government, Ministry of Agriculture and Water Resources

provided a dataset of monthly rainfall and snowfall for eight meteorological stations within the

Erbil Basin. Only four of the eight stations had the required data of precipitation, temperature,

and relative humidity for this study. The meteorological stations are located within the Erbil

34

Basin. The station names are: Qushtapa, Ankawa, Khabat, and Grda Rasha, which are 24 km to

the south, 9 km to the north, 40 km to the west, and 8 km to the south of Erbil City, respectively.

The monthly precipitation data was totaled to acquire an annual precipitation amount.

The snowfall in each station was converted to liquid using a ratio of 10:1 as the snow to liquid

equivalent ratio, because it is considered as the average value of the snow/water ratio (Dubé,

2003). This indicates that 10 centimeters of snow would produce only 1 centimeter of liquid

precipitation and it is applicable in the region as the climatic condition allows it. The produced

amount of liquid from snowfall was added to the annual liquid amount in each station. The

resulting annual precipitations for all of the four stations was added together, and divided by four

to get an average annual liquid precipitation for all the stations across the entire basin.

Temperature and relative humidity data were collected and provided on a daily basis.

These data were averaged to a monthly average, and the monthly average data totaled and

averaged to get annual measurements for temperature and relative humidity at each station. The

resulting average annual temperature for all stations were added together and divided by four to

get an average annual temperature. The same calculations were done to estimate the average

annual humidity for all of the four stations.

The temperature and relative humidity data were used to calculate the evaporation

amount in the area. The author used the Ivanoff equation for the evaporation calculation:

E= 0.0018 (t+25)2

(100-a) (equation 1)

where E= Monthly probable evaporation (mm), t= Mean monthly temperature (C°),

a= Mean monthly relative humidity.

35

3.2.3.1. Groundwater Recharge for Erbil Basin

In order to understand the water pumping and recharge conditions in the Erbil Basin,

climate data, the total area of the basin, and the average annual water use in the Erbil Basin were

used. The average annual water use was calculated by multiplying the average decline in water

table by the basin area. The calculations started by establishing the units of the variables. To

understand the recharge system at the Erbil Basin, the author first calculated the volume of

precipitation over the basin for each year for all of the four stations (Qushtapa, Ankawa, Khabat,

and Grda Rasha) and then totaled the amount for all of the stations and divided by four to get an

average annual volume of precipitation over the basin.

According to Hassan (1998), 24.23% of the precipitation infiltrates into the subsurface to

recharge the groundwater. The rest of the precipitation either evaporates or runs off on the

surface. Based on the infiltration rate given by Hassan (1998), the average annual recharge from

precipitation is calculated; the author calculated the average annual water use and

overexploitation of the basin as well. Overexploitation or “mining” of groundwater occurs when

the volume of water used exceeds the volume being recharged.

3.2.3.2. Average Annual Decline of Water Table

Determination of the average annual decline of the water table is based on data provided

by the Ministry of Agriculture and Water Resources as a separate data set for only 18 wells. No

latitude or longitude data was available for these wells. Therefore, they could not be mapped or

located and could not be used for constructing the maps and cross sections. The wells have two

years of collected data, the first reading was in 2001 and the second reading was in 2010. The

decline in the water table is calculated for each sub-basin by subtracting the first reading from

36

the second reading, and then taking the average of the numbers to get the average decline in each

sub-basin (Table 3). Groundwater decline is probably related to recent drought.

Table 3: Details about the 18 wells.

No. Basin Sub-basin Well Name

First reading

in 2001 (R1)

in meter

Second

reading in

2010 (R2) in

meter

R1-R2

in meter

1

Erbil

Basin

North

(Kapran)

Jadida Zab/3 39.26 43.98 -4.72

2 Barbiangicka 19.8 27.56 -7.76

3 Sebirany Gawra/ 6 28.83 37.3 -8.47

4 Kawer Gosk / 1 28.68 35.06 -6.38

North (Kapran) Sub-basin Average Change 6.83

5

Erbil

Basin

Middle

(Central)

Aziana 20.34 23.75 -3.41

6 Peerdawood 18 22.95 -4.95

7 Nawroz /13 32.98 44.12 -11.14

8 Shorsh /8 66.41 78.2 -11.79

9 Shadi/1 35.75 50.83 -15.08

10 Bahar /4 36.8 48.5 -11.7

11 Kundak 46.58 59.8 -13.22

12 Shawis /4 34.82 52.17 -17.35

13 Gird Azaban 9.88 14.41 -4.53

14 Darato/30 45.85 57.2 -11.35

Middle (Central) Sub-basin Average Change 10.452

15

Erbil

Basin

South

(Bashtapa)

Qultapa Yaba 36.43 38.44 -2.01

16 Qurshakhlo 17.11 21.2 -4.09

17 BstanyGawra 26.01 42.2 -16.19

18 Dorabakra 34.83 36.62 -1.79

South (Bashtapa) sub-basin Average Change 6.02

37

Finally two case scenarios are presented. Case scenarios evaluate the possible impacts of

a 10% decrease or increase in precipitation on the basin. These values were chosen to show

potential changes if precipitation increases or decreases. The calculations establish how much

more or less precipitation would be needed to increase or decrease precipitation by 10%. Results

also show the effect on the average annual water table decline.

38

Chapter Four: Data Analysis and Results

4.1. Challenges of the sub-basins and legitimacy of the distances between drilled wells

As mentioned previously, according to the Furat Center, the distance between the wells in

the Central sub-basin should not be less than 400 meters, and in Bashtapa, it should not be less

than 500 meters. However, using spatial analysis and Global Mapper, the author created maps

which show the distance between the wells in each sub-basin indicate that the distances are

variable and not according to the regulations of the sub-basins. In the Central sub-basin, among

the 595 wells located in this sub-basin, 25.2 % of the wells do not meet the regulations. In most

cases the distance between them is less than 400 meters, and in some locations the distances are

even less than 100 meters. In the southern (Bashtapa) sub-basin, among the 387 wells located in

this sub-basin, 20% of the wells do not meet the regulations because the distance between the

wells is less than 500 meters. However, based on the maps for both sub-basins, in some locations

the distances between the wells is much more than the legally required distance. This finding

may have resulted from the lack of data and inaccurate coordinate information for some of the

wells that had to be deleted from the database and, therefore, could not be used in this research.

The wells with very large distances from others might have other wells between them, but the

author was unable to plot them on the map and find out their real location or the actual distance

between them and their neighboring wells. The limited data included only a few wells located in

the Kapran sub-basin. Thus, the author could not provide any general information about the

legality of wells in the whole sub-basin.

39

4.2. Well Data Analysis

To map the study area in the Erbil Basin, 36 out of the 995 wells were selected.

Approximately half of the selected wells terminate and produce from the alluvium, while the

other half penetrate through the alluvium and produce from the Bakhtiary Formation (Table 2

and Figure 8).

4.2.1. Elevation map

The highest areas are located in the northern part of the basin, where the Kapran sub-

basin is located (the boundaries between the sub-basins is marked by a red line) (Figures 8 and

9). The northern part of the Erbil Basin area is characterized by high to medium altitudes ranging

from 480 to 680 meters. Several wells, for instance, W01, W02, W24, and W26 have been

drilled in that area. In this part of the basin surface runoff water flows down from the uplands,

settling and accumulating in the lowland areas toward the south. In contrast, the lowest to

moderately elevated areas, in which altitudes range between 280 to 440 meters, are located in the

central and southern parts of the basin, where the basin flattens and moderate to low relief areas

dominate the topography. Most of the wells (e.g., W08, W09, W11, and W15) are located in

these low-lying areas. The area farther to the southeast represents the lowest area in the basin

(Figure 9).

One purpose of an elevation map is to show the steepness of the areas across the study

area. Very steep slopes surround the Erbil Basin to the north and northeast. Besides these steep

slopes, slope angles generally decrease from north to south across the basin (Figure 9).

Topography often reflects the distribution and textures of underlying rocks. Therefore, if these

slopes follow existing structural patterns throughout the basin, they may predict dips of the

bedding planes and might depict the aquifers’ dip direction. In addition, the map shows the flow

40

paths of surface runoff. Water naturally flows towards flat areas, avoiding the uplands, where

water cannot settle. Water likely accumulates in flat areas, where it infiltrates and finally

becomes a groundwater recharge source.

41

Figure 9: Ground Surface Elevation Map of Erbil Basin.

42

4.2.2. Depth map

The subsurface geology of the Erbil Basin is interpreted using the total depth of each

drilled well to the appointed aquifer. The maps show several areas of upwarping and

downwarping across the basin (Figures 10-12). Overall, these inferred depth maps illustrate the

deepening and shallowing in the Erbil Basin.

The three depth maps (Figures 10-12) show different subsurface geologic features and

multiple shallowing and deepening trends. This geometry is noticed most significantly on the

composite map of the entire Erbil Basin (Figure 10). The alluvium depth map represents the

wells that were likely drilled into the alluvium. The map clearly shows areas with shallow depths

in the western and southwestern part of the Erbil basin: mainly in the Bashtapa sub-basin and

western part of the Central sub-basin. Overall, the basin is deepest in the east and the center of

the Central sub-basin (Figure 11). In contrast, the Bakhtiary depth map, which represents the

wells drilled into the Bakhtiary Formation, is geometrically different from the overlying

alluvium. This map shows deep areas in the northeastern and western parts of basin. The central

area of the Central sub-basin shows shallower depth to the Bakhtiary Formation. Other shallow

areas are located in the southern part of the map (Figure 12).

43

Figure 10: Depth map of the Erbil Basin using all 36 wells. The map shows the deepening

and shallowing subsurface areas.

44

Figure 11: Depth map for Alluvium aquifer

45

Figure 12: Depth map for Bakhtiary aquifer

46

The changes in the shallowing versus deepening locations appear local, belonging to the

Erbil Basin itself. The interpretations for all depth maps (Figures 10-12) are consistent with the

general surface geology and suggest that the basin was not immune from local tectonics and

overall, these changes in the basin are most likely due to the tectonic activity, which caused

deformation including faulting and folding to the north and northeast of the basin.

4.2.3. Cross Sections

The author constructed two cross sections for each aquifer. Cross sections delineate the

approximate distribution and thickness of the alluvium and Bakhtiary aquifers in the subsurface

and estimate the geometry of the entire basin. These cross sections show the correlations

between the selected wells across the entire basin. Although the lithofacies and their physical

properties such as porosity and permeability control the ability to hold and transmit groundwater,

the cross sections show how the geometrical distribution of these two water-bearing aquifers in

the subsurface strongly affects the groundwater flow in the study area.

The author used physical measurements to construct 2D profiles, using the selected 36

wells, which helps in understanding the groundwater flow direction, as well as the geometrical

distribution of the aquifers in the alluvium and Bakhtiary Formation.

Four cross sections, two for alluvium and two for Bakhtiary Formation, are constructed

illustrating uplift in the northern part of the basin. Uplift is likely a result of large-scale

deformation caused by regional tectonics where deformation in fault blocks is associated with

folding, which creates elevated areas. Similarly, folding creates areas of downwarping, which

can be seen towards the southern end of the basin.

47

Profile A-A’ through the alluvium is oriented from NNW to SSE and includes eight wells

(W01, W02, W03, W04, W05, W06, W07, and W08). This profile shows the distribution of the

alluvium aquifer for the correlated wells in the subsurface where the top of this formation can be

picked at various depths from 110 to130 meters in the north, 70 to 170 meters in the center, and

200 to 220 meters in the south of the Erbil Basin (Figure 13 and 14).

The B-B’ profile through the alluvium is oriented from NW to SE and includes seven

wells (W09, W10, W11, W12, W13, W14, and W15). This profile shows the distribution of the

aquifer in the subsurface which is different from Profile A-A’. Here, the top of the alluvium can

be picked at 60 to 80 meters in the north, around 70 to 90 meters in the center, and 100 to 110

meters in the south (Figures 13 and 15). These variations of the top of alluvium aquifer represent

the deepening and shallowing of the basin.

Profile A-A’ of the Bakhtiary Formation is oriented from NE to SW and includes eight

wells (W23, W24, W25, W26, W27, W28, W29, and W30). This profile shows the distribution

of Bakhtiary aquifer in the subsurface, where the top of the formation can be picked at depths of

70 to 120 meters in the north, 130 to150 meters in the center, and 200 to 250 meters in the south

of the Erbil Basin (Figures 16 and 17).

The B-B’ profile of Bakhtiary Formation is oriented from NW to SE and includes six

wells (W31, W32, W33, W34, W35, and W36). This profile shows the distribution of Bakhtiary

aquifer in the subsurface, where the top of this formation can be picked at depths of 170 to180

meters in the north, 160 to170 meters in the center, and 200 to 220 meters in the south of the

Erbil Basin (Figures 16 and 18).

Overall, the cross sections show similar geometries for both aquifers. The depth of these

aquifers changes through the basin as a whole. This in turn effects on the presence of the

48

groundwater within these aquifers, which generally is located at greater depth to the south of the

basin than to the north.

The author used total depth to estimate thicknesses of the aquifers. Thus, these estimates

do not represent the actual thicknesses because the drilling was stopped at these depths, and no

contacts, lower and upper, have been defined or picked. Although thickness estimates are prone

to errors, wells W02, W05, and W06 on the transect map (Figure 13) and in cross section (A-A’)

(Figure 14) have the thickest alluvium. Alluvium is between 100 and 300 m thick. Similarly, the

thickness of the Bakhtiary Formation is not precisely measured.

Regardless, the cross sections can give the depth interval for each of these aquifers and

allow estimating the thickness in the subsurface and predicting the water table within these wells

precisely. The water table can be estimated at depths of 200 to 300 meters in the north, whereas

in the south the water table is estimated at depths of 330 to 370 meters (Figure 14). In contrast,

the water table is between 130 to 150 meters in the same aquifer but in a different transect and

profile (Figure 15). This variation in the water table zone could be due to several factors such as

thickness variations, pressure of groundwater, and deepening and shallowing of the basin. In the

Bakhtiary aquifer, the level of the potentiometric surface is estimated at depths of 40 to 120

meters in the northern part of the basin, whereas to the south it is estimated at depths of 220 to

250 meters (Figure 17). Furthermore, for the same aquifer but in a different transect and profile

(Figure 18) the potentiometric surface is between 80 to 180 meters, which indicates a noticeable

variation of the groundwater level across the entire basin due to the shallowing and deepening of

these aquifers relative to the ground surface in each well location.

49

Figure 13: Location map of Erbil Basin showing alluvium profile along A-A’ and B-B’

50

Fig

ure

14

: N

W-S

E c

ross

sec

tion

alo

ng (

A-A

’) o

f all

uviu

m a

qu

ifer

51

Fig

ure

15

: N

W-S

E c

ross

sec

tion

alo

ng (

B-B

’) f

or

All

uviu

m a

qu

ifer

.

52

Figure 16: Location map of Erbil Basin showing Bakhtiary profile along A-A’ and B-B’

53

Fig

ure

17

: sh

ow

ing N

E-S

W c

ross

sec

tion

alo

ng (

A-A

’) o

f B

ak

hti

ary

aq

uif

er.

54

Fig

ure

18

: N

W-S

E c

ross

sec

tion

alo

ng (

B-B

’) o

f B

ak

hti

ary

aq

uif

er

55

4.3. Climate Data

Hassan (1998) considers one of the most important hydrological subjects to be the water

balance estimation. According to the climatic conditions of the study area, there are different

methods used for calculating the water balance. Data from four different meteorological stations

were used to determine the average annual temperature, relative humidity, and precipitation of

the study area (Figure 19).

Figure 19: Map of the location of the meteorological stations in the study area.

56

4.3.1. Groundwater Recharge for the Erbil Basin

The main source of recharge in the Erbil Basin is precipitation. The recharge rate to

unconfined aquifers from precipitation is 24.23% (Hassan, 1998). However, Hassan (1981)

estimates variable infiltration rates from precipitation in this area from 22.8% to 24.9%. Here,

Hassan’s (1998) method is used to calculate the amount of recharge, as it is the more recent

study and is considered a more precise fit for the current climatic conditions in the study area.

4.3.2. Precipitation

In order to understand the water pumping and recharge conditions in the Erbil Basin, the

author analyzed climate data. Analysis began by calculating the average annual precipitation and

converting the precipitation into a volume for the years 2008 to 2012. This gives the volume of

precipitation over the basin.

Obtaining knowledge of the volume of precipitation over the basin is important. In fact,

for the Erbil Basin, the precipitation is the most crucial factor because it is the main source of the

basin recharge. However, the total amount of precipitation will not infiltrate into the subsurface,

some of the precipitation evaporates. The rest of the precipitation runs off the surface. The

calculations started by calculating the volume of precipitation over the basin.

Volume of precipitation over the basin (m3/year) = average annual precipitation

(m/year) * basin area (m2)

Data from the four stations show an average annual precipitation of 400.0284 mm

(0.4000284 m). The total area of the Erbil Basin is 3,200km2

(3,200,000,000 m2). Based on these

values, the average volume of precipitation over the basin is 1,280,090,880 m3

/year.

57

4.3.3. Evaporation

Evaporation is an important element to rely on when calculating the water balance.

However, evaporation is not a constant factor, but is variable and depends on several factors,

such as temperature and humidity. According to Hassan (1998), the best method for evaporation

calculation in Iraq, based on climatic conditions in the area, is called Ivanoff equation:

E= 0.0018 (t+25)2

(100-a) (eq. 2)

where E= monthly probable evaporation (mm), t= mean monthly temperature (C°),

a= mean monthly relative humidity.

Thus, the Ivanoff equation was used to calculate the average annual evaporation rates for each

year of the five-year research period. The average annual temperature and precipitation were

calculated from the available climate data from four different meteorological stations (Figure

19). In the Erbil Governorate, most of the precipitation takes place during the winter season and

the area very rarely gets rain during the summer. This is important because evaporation and

temperature are directly proportional. The evaporation rate increases with the temperature

increase and decreases with the temperature decrease. These relationships are important

indicators for the water balance within the basin (Hassan, 1998) (Figure 20).

The volume of evaporation over the basin is calculated by:

Volume of Evaporation over the basin (m3/year) = average annual evaporation

(m/year)* basin area (m2)

The results of the calculations show that the average volume of evaporation over the basin is

707,968,000 m3

/year, which is 55% of the total precipitation.

58

The calculation of the evaporation did not involve in the whole calculations for

estimating water balance because a constant rate of 24.23% of precipitation infiltrates into the

subsurface. The Evaporation is used for surface run off calculation only.

From infiltration and evaporation rates the surface run off in the Erbil Basin could be

estimated by the following calculation:

Average runoff = Average annual precipitation (100%) – infiltration rate (24.23 %)

– evaporation rate (55%)

This calculation shows that 20.77% of the average annual precipitation runs off on the surface.

So, of total amount of precipitation 55% evaporates, 24.23% infiltrates to recharge the

groundwater, and 20.77% runs off to surface water

Figure 20: Relationship between average annual temperature and average annual

evaporation in the study area.

59

4.3.4. Calculations based on precipitation data

To measure the sustainable water use (pumping) in the Erbil Basin, the author calculated

the average annual potential recharge of the basin by:

Average annual recharge (m3/year) = (Volume of precipitation over the basin (m

3

/year)* infiltration rate in percent) / 100

Based on the result of the average volume of precipitation over the basin and an

infiltration rate of 24.23% (Hassan, 1998), the average annual recharge volume of the basin is

around 310,166,020 m3/year.

Table 3 shows the water level decline in each sub-basin, 6.83 meters, 10.45 meters, and

6.02 meters decline in Kapran, Central, and Bashtapa sub-basins respectively. The decline in

water table, based on the eighteen wells that have repeated measurements, is 0.78 meter/year.

This decline is mainly due to drought and the number of wells in each sub-basin, which highly

exceeds the legally permitted numbers. This decline is calculated by adding the average decline

in each sub-basin and dividing the result by three, so this gives the average decline in ten years,

dividing it by 10 gives the average decline in a year. Multiplying the 0.78 m/year decline by the

basin area gives the average volume of annual water used in the basin, which is 2,496,000,000

m3/ year. The annual water use volume subtracted from the recharge volume gives

overexploitation volume in the basin, which is 2,185,833,980 m3/ year.

Dividing the volume of average annual overexploitation (2,185,833,980 m3/ year) by the

basin area gives 0.68 m/year water table decline due to overexploitation in the basin. All of the

calculations are based on a 0.68 m/year decline. The author recalculated the volume of annual

water use and overexploitation based on a 0.68 m/year decline.

60

To get more accurate results on the groundwater conditions in the Erbil Basin, the author

calculated the volume of the annual water use in the basin by making following calculation:

Volume of the annual water use (m3/year) = Average annual decline in the basin

(m/year)* basin area (m2)

The resulting calculations suggest that the volume of annual water use in the basin is

2,176,000,000m3/year. This number helps characterize the volume of water being overexploited

within the Erbil Basin making the calculations below:

Volume of overexploitation (m3/year) = Volume of water used (m

3/year) – recharge

volume (m3/year)

Therefore, the volume of the overexploitation in the Erbil Basin is 1,865,833,980 m3/ year.

From the numbers shown above, the author concluded that, of the total water being

pumped only 14.3% is met by the recharge using the following calculation:

Amount of pumped water that is recharged by precipitation = (Recharge volume /

volume of water used)* 100

To reach to sustainability, the recharge would have to increase by 85.7%. In order to have this

increase in recharge, the area would have to get approximately 605% more precipitation.

The sustainable pumping volume for the basin is equal to the average annual recharge of

the basin, which is 310,166,020 m3/ year. This volume represents what should be extracted from

the Erbil Basin instead of 1,865,833,980 m3/ year. Furthermore, because the Erbil Basin is facing

a serious degradation in groundwater levels, the author also calculated a recovery pumping rate,

which requires that a portion of the average annual recharge would not be pumped from the basin

61

so that the basin could start to recover and the water table would slowly rise to earlier levels. The

author suggests that 10% of the total amount of recharge be left in the basin and not pumped.

The sustainable recovery pumping rate is then calculated by:

Sustainable Recovery pumping (m3/year) = (Volume of average annual recharge

(m3/year) * 90%)

The results of this calculation indicates that, in order to keep 10% of the recharge in the

basin for the purpose of basin recovery, the sustainable pumping of the groundwater from the

Erbil Basin is 279,194,418 m3/year.

4.3.5. Scenarios based on future climate change

Finally, the author assumed two case scenarios to predict and estimate hypothetically

how future climate change might affect the groundwater within the Erbil Basin. These scenarios

are based on the average increase in precipitation from 2008 to 2012 (Table 4), which is equal to

13% increase. This increase does not mean that the area is not experiencing drought, it only

means that drought conditions are not as severe as in the previous years.

Table 4: Average annual precipitation for the years 2008 to 2012

Year Average Annual Precipitation

(mm)

2008 359.867

2009 232.204

2010 387.161

2011 444.11

2012 576.8

62

In the first scenario a 10% increase in precipitation was used to see how it would impact

groundwater conditions within the basin. A 10% increase in precipitation would increase the

volume of average annual precipitation to 1,408,099,968 m3/ year. The average annual recharge

would increase from 310,166,020 m3/ year to 341,182,622 m

3/ year. Assuming constant water

usage (no increase or decrease in usage), a 10% increase in precipitation would decrease the

overexploitation volume to 1,834,817,378 m3/ year and the average annual decline of water

table in the Erbil Basin would be 0.57 m/year.

The second scenario involves a 10% decrease in precipitation, which would negatively

impact the groundwater conditions. This means the volume of precipitation over the basin would

decrease to 1,152,081,792 m3/ year. This assumption presumes a decrease in the annual recharge

volume to 279,149,418 m3/ year. So a 10% decrease in precipitation would increase

overexploitation to 2,455,149,418 m3/ year and the average annual decline of the water table in

the Erbil Basin would increase to 0.77 m/year.

Table 5 below summarizes all these calculations.

Table 5: Results of the calculations

Average annual precipitation (m) 0.4000284

Basin area (m2) 3,200,000,000

Volume of precipitation over the basin (m3 /year) 1,280,090,880

Recharge volume (m3 /year) based on 24.23% (Hassan) 310,166,020

Water table decline (m/year) as measured in 18 wells 0.78

Volume of annual water use (m3/year) based on 0.78

m/year decline 2,496,000,000

63

volume of overexploitation (m3/year) based on 0.78

m/year decline 2,185,833,980

Water table decline (m/year) (based on ten years

decline in water table (table2)

Water table decline (m/year) based on calculated

overexploitation

0.78

0.68*

Volume of annual water use (m3 /year) 2,176,000,000

Volume of overexploitation (m3 /year)

(water table decline – recharge volume)

1,865,833,980

(85% of total use is

overexploitation)

Total of the pumped water met by recharge 14.3 %

Sustainable recovery pumping (m3/year) (recharge

minus 10%) 279,194,418

Volume of Evaporation (m3 /year)

(55% of total precipitation) 707,968,000

Surface run off rate (%) 20.77 %

Volume of precipitation over the basin (m3 /year) + 10

percent increase

Assume 24.23% infiltration for recharge of (m3/year)

Overexploitation decreases to

1,408,099,968

341,182,622

1,834,817,378

Volume of precipitation over the basin (m3 /year) + 10

percent decrease

Assume 24.23% infiltration for recharge (m3/year)

Overexploitation increases to

1,152,081,792

279,149,418

2,455,149,418

* volume used for remaining calculations

64

4.4. Discussion and Interpretation

The Erbil Basin is genetically related to regional tectonics and places within the basin

vary topographically due to the presence of structural features in the subsurface. The deepening

of the basin is related to subsidence, which is likely created by tectonic loading, whereas the

elevated areas are generated due to either uplift of fault blocks or folding in the subsurface.

In the elevated areas, the rivers constantly modify their channels and the surrounding

landscape. As a result of the potential energy that derives from the gravitational force and the

water’s kinetic energy, derived from its movement downslope, the river carves vertically into its

channel, making pathways through narrow valleys. This process initially creates a deep channel,

due to hydraulic process of water movement and abrasion. Some of the flowing surface runoff

becomes the source for groundwater recharge as it infiltrates through the pores in the rocks, and

then accumulates in the aquifers in the low-lying areas. The elevation map elucidates that some

of the selected wells, particularly the ones that have been drilled in the topographically high

areas, might have limited groundwater production rates due to the steepness of the terrain in

which they were drilled. In steep terrain water from precipitation runs off the steep areas faster

than the flat areas, this is not favorable for groundwater accumulation. Also, the dip and dip

direction of the aquifer in the subsurface affect the groundwater accumulation and water well

production. The higher the dip angle, the faster the water will drain, which directly affects well

production. The groundwater accumulates and moves from high pressure areas to the low

pressure locations. This occurs because of the presence of fluid pressure, dip direction of the

deformed aquifer, lithology and rock fabrics.

To manage groundwater sustainably, several things must be known including 1) the

amount of recharge, 2) the amount of discharge and 3) changes in the groundwater depth below

65

the surface. Changes in groundwater levels should be monitored carefully through well tests

(pumping tests). This information can be obtained from the drilled wells to determine the amount

of groundwater being consumed, and the depth from which water can safely be withdrawn

because this impacts the quantity of the pumped groundwater from the wells, and in turn, it

affects the hydrogeologic cycle. Predicting the hydrogeologic system within the Erbil Basin is

dependent on the amount of recharge, which has to be equal or greater than the amount of

withdrawal for the area to meet the requirements of sustainable groundwater. If water is being

consumed at a greater rate than the recharge to the system, groundwater continuity would be

threatened as is the case in the Erbil Basin.

66

Chapter Five: Conclusions and Areas for Future Study

5.1. Conclusions

The nature of the aquifers varies geologically across the basin. Changes are likely

controlled by the deformation in the region. These geologic variations control the groundwater

quantities in the basin as noticed by the variations of the water levels across the basin. Therefore,

the results of this study indicate that geologic location is one of the most important factors

affecting groundwater quantity within the Erbil Basin.

The northern sub-basin is located in the topographically high areas, whereas the central

and southern sub-basins are located in moderately flat areas. The central and southern sub-basins

tend to collect more precipitation than elevated areas because water from precipitation runs off

the elevated surfaces towards flatter areas. According to the geological and geographical location

the central and southern sub-basins, are considered as a favorable place for groundwater

accumulation.

The idealized cross sections for each unit allow a basic interpretation that describes most

of the basin. The four cross sections illustrate and provide detailed information about the uplifted

northern part of the basin. Uplift may have occurred as a response to the local tectonic activity in

the region. Related to these depth changes is a noticeable variation of water table level across the

entire basin.

The climate data analysis shows that the present usage of groundwater in the Erbil Basin

is unsustainable and of the total amount being pumped only 14.3% is met by recharge. Based on

this recharge, the estimated water table decline is 0.68 m/year. In the current climatic conditions

the sustainable pumping volume for the basin is 310,166,020 m3/ year, which would require

reducing the current usage by 85.7%. A recovery pumping volume of 279,194,418 m3/ year or

67

10% less than current recharge would allow groundwater levels to rise again. Given the current

pumping volume, the precipitation amount would have to increase an unlikely 605% to reach a

sustainable use of water in the Erbil Basin. Assuming future climatic changes in the area, a 10%

increase in precipitation would result in an average annual water table decline of 0.57 m/year. If,

however, the basin gets 10% less precipitation, the average annual water table decline would be

0.77 m/year in the Erbil Basin.

The number of water wells far exceeds the desired number of wells as determined by

water resource management authorities and the central sub-basin has the highest number of

illegal wells; the distance between most of the wells in each sub-basin does not meet the legally

permitted distance between the wells. According to findings in this research, a significant

percentage of the wells are illegal based on measured distance between the wells. For instance,

of the 595 of the wells located in the central sub-basin 25.2% were found to be illegal. The

southern sub-basin included 387 wells of which 20% were determined to be illegal. Due to a lack

of data (only thirteen wells) in the northern sub-basin the author could not decide on the

legitimacy of the wells in this sub-basin.

This research shows that the central sub-basin is the sub-basin most impacted by drought

and illegal wells. Over ten years it has an average water level decline by 10.45 meters, whereas

the decline in the northern and southern sub-basins is 6.83 meters and 6.02 meters, respectively.

68

5.2. Recommendations

There are several recommendations based on the results of the current study. These

recommendations include:

1. Installing a network of observation wells in the area to observe the groundwater

level in the basin. This network could be started by obtaining latitude and

longitude coordinates for the eighteen existing wells that have two years of

measured data. All wells in the network should be located with accurate

Latitude/Longitude coordinates mapped and maintained in a GIS model database.

2. Construction of discharge stations is a necessity in the area for calculating the

exact amount of surface runoff and harvesting the runoff water to use during dry

period or using for artificial recharge of the aquifers.

3. Despite groundwater’s importance to the region, the aquifers in the region suffer

from overexploitation and mismanagement because of the perception (mainly by

local residents) that groundwater will always remain (Directorate of groundwater

resources –Erbil). Interventions should particularly target decreasing the number

of wells. The government should start by counting all wells in each sub-basin

including the wells that have been drilled by pile equipment. Based on the wells

used in this research, the author thinks that currently most of the wells drilled in

the Erbil Basin are illegal. The government should take restrictive and very quick

actions regarding illegal wells. This could be started by closing all the wells that

have been drilled illegally by pile equipment. However, for the current condition

of the Erbil Basin, this alone might not be enough. In order to ensure the

continuity of water availability in this area, the government should assign

69

withdrawal limits (i.e. quotas per water well) to limit waste and overuse of water

resources and to ensure future availability of sustainable groundwater reservoirs.

4. More dependency on surface water (rivers and streams) is recommended to

reduce dependency on groundwater. However, any policy interventions that target

usage of groundwater resources should take into account alternative sources for

farmers and other users of groundwater resources in case of limiting access to

available water wells. In the same way, any policy that targets using more

available surface water should pay particular attention to the effect this will have

on downstream communities.

5. Because better data collection results in better conclusions, a minimum set of data

points should be collected for the existing wells and new drilled wells:

Latitude and longitude coordinates for the wells

Survey date

Depth to water level

Depth to static water levels and collecting it once per year

Formation information, their actual thicknesses, and top and bottom of the

formations

Aquifer condition (confined, unconfined, and semi-confined)

Elevation above sea level

Purpose of the well (well use)

Fixing the missing data in the current dataset

And finally keeping all the data in a GIS data base.

70

5.3. Areas for Future Study

Bakhtiary aquifers are important water bearing units in the Erbil Basin. However, as a

result of data limitations including the top and bottom of the formation, aquifer condition, and

actual thickness of the formation in the area, the author could not do a complete research on this

formation and has to leave it for future study.

Conducting a study that shows the groundwater decline in the Erbil Basin and comparing

it to the results of this research to get an idea on whether the decline is still in the same rate

(stable) or it has increased or decreased

71

Works Cited

Ahmad, M. A. (2002). Brief references on hydrogeological characteristics of Erbil basin.

Ahmed, M. R. (2009). Ground water quality of selected wells in zaweta district, Northern Iraq.

Tikrit Journal of Eng.Sciences,17 (1), 28-35.

Al-Juboury, A. I. (2012). A Combined Petrological-Geochemical Study of the Paleozoic

Successions of Iraq. Mosul, Iraq: Research Center for Dams and Water Resources, Mosul

University, 169-198.

AL-Kubaisi, Q. Y. (2008). Groundwater chemistry of the Plio-Pleistocene aquifer of Erbil

hydrogeologic basin, N.Iraq. Iraqi Journal of Science,49 (2), 140-148.

Al-Tamir, M. A. (2008). Interpretation Of Ground Water Quality Data variation in Erbil City,

Nortern Iraq. Mosul, Iraq. Al-Rafidain Engineering, 16 (2), 24-30.

Bapeer, B.G., Sordashi, M.A, & Kareem, M. (2010). Infilteration rates of Soil in some locations

within Erbil Plain, Kurdistan Region, North Iraq. Iraqi Bulletin of Geology and Mining,

127-137.

Bellen, R.C., Dunnington, H.V., Wetzel, R., & Morton, D.M. (2005). Stratigraphic lexicon of

Northern Iraq. Gulf petrolink, 0310 asie (Iraq), 239.

Buday, T. (1980). The Regional Geology of Iraq. V.I., Stratigraphy and paleoecology,

Kassab.I.I.M., and Jassim S.Z., (eds.), Baghdad, 455.

Buday, T., & Jassim, S.Z. (1987). The regional geology of Iraq, 2, Tectonism, magmatism and

metamorphism. S.E. Geol. Surv. And Mineral Invest, Baghdad, 352.

Dunnington, H.V. (1958). Generation, Migration, Accumulation and Dissipation of Oil in

Northern Iraq, In: Weeks,. L.G.(ed). Habitat of oil. AAPG Symposium, Tulsa, Oklahoma,

1194-1251.

Dubé, I. (December 2003 ). From mm to cm... Study of snow/liquid water ratios in Quebec .

Quebec region.

Erbil Governorate Accessible at:

http://www.krp.org/english/ndisplay.aspx?sm=5yBwBg+oqQY=

Ghaib, F. A. (2004). Geo-electrical Investigation in Harir Plain Northeast of Erbil City. Iraqi

Journal of Earth Science,4(2), 31-43.

Ghaib, F. A. (2009). The Assesement of Erbil Aquifer Using Geo-electrical Investigation (Iraqi

Kurdistan Rgion). Journal of Applied Sciences in Environmental Sanitation, 43-54.

72

Habib, H. R., Al-Saigh, N.H., and Hassan, Z.M.. (1990). Geochemistry of under groundwater in

Erbil City,Iraq. Mosul, Iraq: Mosul University, 173-188.

Hameed, H. M. (2013). Water harvesting in Erbil Governorate, Kurdistan region, Iraq.

Detection of suitable sites using Geographic Information System and Remote Sensing.

Sweden: Department of Physical Geography and Ecosystem Science Lund University,

58.

Hassan, H. A. (1981). Hydrogeological conditions of the central part of the Erbil basin.

Baghdad, 179.

Hassan, I. A. (1998). Urban hydrology of Erbil city Region. Iraq, 119.

Internal Report, Directorate of Ground water in Kurdistan Region, 2012, Erbil, ministry of

agriculture and water resources, General Directorate of Water Resources.

Internal report, to ensure water and food security in the Kurdistan Region. (n.d.). Erbil: ministry

of agriculture & water resources in Kurdistan region- general directorate of water

resources.

Jassim, S. Z., & Goff, J. C. (2006). Geology of Iraq. Czech Republic: Dolin, Prague and

Moravian Museum, Brno, 341.

Jawad, S. B., & A.Hussien, K. (1988). Groundwater monitoring network rationalization using

statistical analyses of piezometric fluctuation. Hydrological Sciences - Journal - des

Sciences Hydrologique, 181-191.

NCCI. (n.d.). Erbil NCCI governorate profile. Iraq:

http://www.ncciraq.org/images/infobygov/Erbil_Governorate_Profile_NCCI.pdf

Numan, N.M.S. (1997), A plate tectonic scenario for Phanerozoic succession in Iraq. Iraqi

Geology Journal,30(2), 85-110.

Stevanovic, Z., & Iurkiewicz, A. (2009). Groundwater management in northern Iraq.

Hydrogeology Journal, 367-378.

Stevanovic, Z., & Markovic, M. (2004). Hydrogeology of northern Iraq, climate, hydrology,

geomorphology and geology, Spec.edn. (Spec. Emerg. Prog. Serv.),1, FAO, Rome, 122.

UNDP. (2011). Drought Impact Assessment, Recovery and Mitigation Framework. Iraq.

Ur, J., Jong, L. d., Giraud, J., & F., J. (2013). Ancient cities and landscapes in the Kurdistan

region of Iraq: The Erbil Plain Archaeological Survey 2012 season. Iraq 75:89-118.

73

zarikrmanji.com. (n.d.). (not active) Accessable at:

http://www.zarikrmanji.com/kon/index.php?option=com_content&view=article&id=124

4:2010-09-20-07-48-44&catid=100:2010-02-04-05-05-42&Itemid=252. Erbil.

Software:

Adobe Illustrator (Version CS6) “Computer Software”, San Jose, Ca, USA: Adobe Systems

Incorporated

ArcGIS (Version 10.1) “Computer Software”, Redlands, CA: Esri

Global Mapper (Version 12.00) “Computer Software”, Hallowell, Maine: Blue Marble

Geographics

Microsoft Excel (Version 2010) “Computer Software”, Redmond, WA: Microsoft Coropartion

Rockware (Version 15) “Computer Software”, Golden, Co, USA: Rockware Inc.

VITA

Personal Background

Rubar Dizayee

Erbil, Kurdistan

Education

Diploma, Private Nilufer College, Erbil, 2006

Bachelor of Science, Geology, Salahaddin University, Hawler, 2010

Masters of Science, Geology, Texas Christian University, Fort Worth, Texas, 2014

ABSTRACT

GROUNDWATER DEGRADATION AND SUSTAINABILITY OF THE ERBIL BASIN,

ERBIL, KURDISTAN REGION, IRAQ

by Rubar Dizayee, MS, 2014

Department of Geology

Thesis Advisor: Becky Johnson, Professor of Professional Practice

Development stages of the Erbil Basin are poorly understood and the sustainable use of

groundwater in the basin is uncertain. This study characterizes water sustainability and its

significance through demonstrating the overexploitation and deficit rates of the groundwater

supply, whereby describing hydrologic conditions of the basin. Various data sets like climate,

soil, well measurements, and geology of the aquifers are compiled to understand current and

future conditions of the basin. The lithology, geometry, water level, and thickening and thinning,

of the two main aquifer systems are described across the basin. The natural groundwater flow,

groundwater level oscillations, and nature of hydrologic units for the basin are determined by

using subsurface mapping and cross sections.