Addis Ababa University

COLLEGE OF NATURAL AND COMPUTATIONAL SCIENCES

SCHOOL OF EARTH SCIENCES

Groundwater potential and Recharge zone mapping by using GIS

and Remote sensing Techniques in the case of Middle Awash River
Basins, Ethiopia

A thesis submitted to

The school of graduate studies of Addis Ababa University in partial

fulfillment of the requirements for the degree of masters of sciences in
remote sensing and geo-informatics

BY:By: BANE LAMMESA

(ID No: GSR/O463/08)
BANE LAMMESA
Adviser
(Id: GSR/0463/08)
Dr: BINYAM TESFAW
Advisor
Co- Adviser

Dr:AZAGEGN
Dr: TILAHUN BINYAM TESFAW

Co- Adviser Addis Ababa University

May 2017
Dr: TILAHUN AZAGEGN
 Groundwater potential and recharge zone mapping by using GIS
and remote sensing techniques in the case of middle Awash River
Basins, Ethiopia

A THESIS SUBMITTED TO

A THESIS SUBMITTED TO THE SCHOOL OF GRADUATE STUDIES FOR PARTIAL

FULFILLMENT OF THE REQUIREMENTS FOR DEGREE OF MASTER OF
SCIENCE IN REMOTE SENSING AND GEO-INFORMATICS

BY
BANE LAMMESA BANTI
(GSR /0463/08)

Addis Ababa University

May 2017
This is to certify the thesis prepared by BANE LAMMESA ENTITLED as “Groundwater
potential and Recharge zone mapping by using GIS and Remote sensing Techniques in the
case of Middle Awash River Basins, Ethiopia “is submitted in partial fulfillment of the
requirements for the degree of masters of science in remote sensing and geo-informatics complies
with the regulations of the university and meets the accepted standards with the respect to
originality and quality.

Signed by the Examining Committee:

Dr. Binyam Tesfaw __________________ _______/______/_______

Advisor Signature Date

Dr. Tilahun Azagegn ________________ _______/______/_______

Co-advisor Signature Date

Dr. ________________ _______/______/_______

Chairperson Signature Date

Dr.______________ _________________ _______/______/_______

Examiner Signature Date

Dr._______________ __________________ _______/______/_______

Examiner Signature
 ACKNOWLEDGMENTS
I would like to say thanks to my God before anything who gives me full health, peace, knowledge
and Wisdom to accomplish this thesis work.

My deepest feeling of gratitude goes to my advisor Dr. Binyam Tesfaw and Dr.Tilahun Azagen,
for their worthless advice, and constant encouragement helped me to complete this research work
successfully. I never ever forget their admirable patience, work quality, and attractive spirit of
friendship as unique personal possessions.

I would like to express my special and sincere appreciation to my instructor Dr. K.V
suryabhagavan and all Addis Ababa University, School of Earth Science instructors who support
in the Knowledge of Hydrogeology and Remote sensing and GIS. I extend my thanks to Samara
University for allowing me to pursue my postgraduate studies and helped me in financial support
for my research. I am thankful to water works and design construction enterprise, I am also grateful
to Ethiopia National Meteorological Agency, Ethiopian Geological survey, Mapping Agency and
Water Works Design Enterprise (WWDE) for providing me flow data, meteorology data, and
relevant documents, which helped me to carry out my research work.

I would like to express my deepest feeling to Prof. Tenalem Ayalew for his support, appreciation
and advise me in my works and I would like to express my special thanks to Wondosen Negasa
for his offering materials for my research . Really, I do not forget you where and when ever I go.

I have the pleasure to thank all my lovely Mother and Father, relatives, and supporters who have
been in my side encouragement and prayer, which made this true.

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 TABLE OF CONTENTS
Acknowledgments............................................................................................................................ i
Table of Contents ............................................................................................................................ ii
Acronyms ..................................................................................................................................... viii
Abstract .......................................................................................................................................... ix
CHAPTER ONE ............................................................................................................................. 1
Introduction ..................................................................................................................................... 1
1.1 Background ........................................................................................................................... 1
1.2 Statement of Problem ............................................................................................................ 2
1.3 Objective ............................................................................................................................... 2
1.3.1 General Objective ........................................................................................................... 2
1.3.2 Specific Objective........................................................................................................... 2
1.4 Research Question ................................................................................................................. 2
1.5 Significance of the study ....................................................................................................... 3
1.6 Limitation of the study .......................................................................................................... 3
1.7 Thesis organization ............................................................................................................... 3
CHAPTER TWO ............................................................................................................................ 5
Literature Review............................................................................................................................ 5
2.1 Definition Of groundwater potential and Recharge zone...................................................... 5
2.2 Groundwater in Ethiopia ....................................................................................................... 5
2.3 Factors Affecting Groundwater Potential and Recharge....................................................... 6
2.4 Role of GIS and Remote Sensing in Groundwater Potential and Recharge ......................... 6
2.5 Analytical Hierarchy Process Methods ................................................................................. 8
CHAPTER THREE ........................................................................................................................ 9
Materials and Methods .................................................................................................................... 9
3.1 Description of the Study Area ............................................................................................... 9
3.2 Population and Economic Activity ....................................................................................... 9
3.4 Wind speed and Relative Humidity .................................................................................... 12
3.5 Physiography and Drainage ................................................................................................ 12
3.6 Soil Type and Vegetation .................................................................................................... 13
3.1.6 Hydrogeology of the Study Area .................................................................................. 13
3.1.7 Aquifer Characterization of the Study Area ................................................................. 14

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 3.1.8 Groundwater Recharge ................................................................................................. 14
3.1.9 Groundwater Flow Direction ........................................................................................ 15
3.2 Methods ............................................................................................................................... 15
3.3 Data Description and Software ........................................................................................... 17
3.3.1 Software ........................................................................................................................ 17
3.3.2 Data Description ........................................................................................................... 17
3.4 Input Dataset ....................................................................................................................... 18
3.5 Identification Criteria for Groundwater Potential and Recharge Zone Mapping................ 19
3. 6 Reclassified Thematic Map of the Study Area................................................................... 21
3.6.1 Rainfall ......................................................................................................................... 22
3.6.2 Drainage Density .......................................................................................................... 23
3.6.3 Slope ............................................................................................................................. 24
3.6.4 Lineament Density........................................................................................................ 26
3.6.5 Soil Texture .................................................................................................................. 29
3.6.6 Land-use/Land-cover .................................................................................................... 31
3.6.7 Geomorphology ............................................................................................................ 33
3.6.8 Geology ........................................................................................................................ 34
3.6.9 Runoff ........................................................................................................................... 37
3.6.10 Curve Number ............................................................................................................ 37
3.7 Analytical Hierarchy Process .............................................................................................. 42
3.8 Weight Assessment and Normalization .............................................................................. 43
CHAPTER FOUR ......................................................................................................................... 45
RESULT AND DISCUSION ....................................................................................................... 45
4.1 Groundwater potential ......................................................................................................... 45
4.1.1 Weight Assessment....................................................................................................... 45
4.1.2 Weight Normalization .................................................................................................. 46
4.1.3 Principal Eigen Vector.................................................................................................. 46
4.2 Groundwater Recharge ........................................................................................................ 50
4.2.1 Weight Analysis ........................................................................................................... 50
4.2.2 Weight Normalization .................................................................................................. 51
4.2.3 Normalized Principal Eigen Vectors ............................................................................ 52
4.3. Validation of Groundwater Potential Zones....................................................................... 54

iii
CHAPTER FIVE .......................................................................................................................... 56
CONCLUSION AND RECOMMENDATION ............................................................................ 56
5.1 CONCLUSION ................................................................................................................... 56
5.2 Recommendation ................................................................................................................. 57
Reference ...................................................................................................................................... 58
Appendix ....................................................................................................................................... 65

iv
List of Tables
Table 3. 1: types of software used................................................................................................ 17
Table 3. 2: Data Used their Source .............................................................................................. 18
Table 3. 3 : Lithology and its aquifer characteristics ................................................................... 19
Table 3. 4 : Reviewed Geomorphology effect on groundwater potentials .................................. 20
Table 3. 5 : Lineament Density ................................................................................................... 20
Table 3. 6: Role of Slope for groundwater potential and recharge .............................................. 21
Table 3. 7: Drainage Density for groundwater potential and recharge ........................................ 21
Table 3. 8: Rainfall and its rank as per suitable for groundwater potential and recharge ............ 22
Table 3. 9: Drainage Density and its rank as per suitable for groundwater potential and recharge
....................................................................................................................................................... 23
Table 3. 10: slope value of and its rank as per suitable for ground water potential and recharge
....................................................................................................................................................... 25
Table 3. 11 : Lineament density and its rank as per suitable for groundwater potential and
recharge ......................................................................................................................................... 27
Table 3. 12 : Soil texture and their rank as per suitable for groundwater potential and recharge.
....................................................................................................................................................... 29
Table 3. 13 : land-use/land-cover and its rank as per suitable for groundwater potential and
recharge. ........................................................................................................................................ 31
Table 3. 14 : Geomorphology and its rank as per suitable for groundwater potential and recharge
....................................................................................................................................................... 33
Table 3. 15 : Geology and its rank as per suitable for groundwater potential and recharge ........ 35
Table 3. 16 : Hydrological soil group and its hydrological properties ....................................... 38
Table 3. 17 : Curve numbers for selected land use land cover and hydrological soil group ....... 39
Table 3. 18 : Runoff and its rank as per suitable for groundwater potential and recharge zone. 41
Table 3. 19 : Saatty’s, scale of intensity relative importance ..................................................... 43
Table 3. 20 : Random consistency index ..................................................................................... 44

Table 4. 1 : Relative weight for selected thematic layers ............................................................ 45

Table 4. 2 : Pairwise comparison matrix and normalized weight ................................................. 46
Table 4. 3 :Normalized Principal Eigen vectors .......................................................................... 47

v
Table 4. 4: Groundwater potential area and percentage of the study area. .................................. 49
Table 4. 5 : Pairwise comparison matrix...................................................................................... 51
Table 4. 6 : pairwise comparison matrix and normalized weight ................................................ 52
Table 4. 7: Normalized Principal Eigenvector ............................................................................. 52

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List of Figures

Figure 3. 1 Description Map of the Study Area ............................................................................. 9

Figure 3. 2 : Annual Mean Temperature of the Study Area ........................................................ 10
Figure 3. 3: Average Monthly Rainfall of the Study Area .......................................................... 11
Figure 3. 4: Correlation of Rainfall with Altitude ....................................................................... 11
Figure 3. 5: Physiography of the Study Area in In 3- D View .................................................... 13
Figure 3. 6 : Flow chart of Methodology ..................................................................................... 16
Figure 3. 7 : a) Drainage density map and b) Reclassified drainage density map ...................... 24
Figure 3. 8: a) Slope map and b) Reclassified slope map of the study area ............................... 26
Figure 3. 9: a) lineament density map and b) reclassified lineament density map of the study
area ................................................................................................................................................ 28
Figure 3. 10: a) soil texture map and b) reclassified soil texture map of the study area. ............ 30
Figure 3. 11: a) Rainfall map and b) Reclassified Rainfall map of the study area..................... 23
Figure 3. 12: a) Land-use/Land-cover map and b) Reclassified Land-use/Land-cover Map of the
Study Area. ................................................................................................................................... 32
Figure 3. 13: a) Geomorphology map and b) Reclassified Geomorphology map of the study area
....................................................................................................................................................... 34
Figure 3. 14: a) Geological map and b) Reclassified geological map of the study area ............. 36
Figure 3. 15: Curve Number map of the study area..................................................................... 40
Figure 3. 16: a) curve number map and b) Reclassified Curve Number of the Study Area ....... 42

Figure 4. 1: Groundwater Potential Zone Map of the Study Area ............................................... 48

Figure 4. 2: Groundwater potential zone Area Coverage of the study area ................................. 49
Figure 4. 3: Groundwater recharge zone map of the study area .................................................. 53
Figure 4. 4: Groundwater potential validation map of the study area ......................................... 55

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 ACRONYMS

AHP Analytical hierarchy process

CN Curve Number

CSA Central Statistical Agency

ERDAS Earth Resource Data Analyze System

DEM Digital Elevation Model

FAO Food and Agricultural Organization

GIS Geographical Information System

GWP Groundwater Potential

GWR Groundwater Recharge

HSG Hydrological Soil Group

ITCZ Inter Tropical Convergence Zone

LU/LC Land use Land Cover

MCDM Multi criteria Decision Making

MER Main Ethiopia Rift

MoWR Ministry of Water Resource

OLI Operational Land Imager

RS Remote Sensing
USDA United States Department of Agricultures
USGS United State of Geological Survey
WIOA Weight Index Overlay Analysis
WWDE Water Work Design Enterprise

viii
 ABSTRACT
Groundwater is a valuable and important natural resource in the world and it is the most
fundamental for the growth and development of one country. However estimating the potential of
groundwater potential and its recharge zone has still uncertainty due to the nature of groundwater.
Therefore, this study aims to use the timely and cost effective remote sensing and geographical
information system (GIS) methods for delineating, classify groundwater potential, and recharge
zone in the Middle Awash River basin. Nine factors as a thematic map derived from Landsat 8
Operational Land Imager (OLI) Satellite image of the year 2016, Digital Elevation Models (DEM)
with 30 m and 1km spatial resolution and secondary sources were utilized in this research. These
were rainfall, slope, geomorphology, geology, lineament density, drainage density, surface runoff,
and Land-use/land-cover and soil texture. The methods to assess the potential and recharge zone
was using weight overlay analysis and Analytical Hierarchy Process (AHP) algorithm. All
thematic layers were reclassified based knowledge based analysis that was reviewed from different
kinds of literature. Then the weight for each factor was assigned according to their relative
importance as per suitable based on Saatty's scale of AHP. The important factors result show that
rainfall and slope have a higher weight and lithology has the lowest weight for identifying the
potential of groundwater potential and recharge zone in the study area respectively. The resulting
map of groundwater potential and recharge shows that 34 % and 32% of the area has very high
potential, respectively. The produced map of groundwater recharge zone reveals that the
northwestern and southeastern highlands of the study area are the most suitable areas. The result
also exhibits very high groundwater potential areas have a very low slope, alluvial plains, with
high lineament density and sandy loam soil textures. On the other hand, very low groundwater
potential corresponding to barrier landforms, structural hills, and high slope areas. High recharge
areas characterized by high rainfall, dense forest, and high drainage density. This result of
groundwater potential and recharge was validated and shows 0.88 correlations of high and very
high areas with that of existing water source and spring data. Therefore, this research demonstrates
a robust method of using GIS and remote sensing techniques, which is efficient and useful in
delineating and mapping groundwater potential and recharge zone.

Keywords: Groundwater potential, Groundwater Recharge, GIS, Remote Sensing, AHP

ix
 CHAPTER ONE
INTRODUCTION
1.1 Background
Groundwater is defined as beneath surface water that fills all the pore space of soils and geologic
formations below the water table. It flows in the aquifer layer towards the point of discharge, which
includes wells, springs, rivers, lakes, and the ocean. Water is the valuable and important thing used
for domestic use, livestock and industries in the world; it is the fundamental condition for the
growth and development of one country. Ethiopia is definitely the progressive fulfillment of its
urgent water needs as past and recent studies describe (Tamiru, 2006). According to Foster (1998),
groundwater makes up about 60% of the world’s freshwater supply, which is about 0.6% of the
entire world’s water.

The availability, accessibility, movement and occurrence of ground water depends on geology,
slope aspect, lineaments, drainage density, land- use/land-cover, Rainfall, surface runoff and
geomorphology of the area (Shaban et al., 2005). Evaluation, exploitation, exploration, site
selection/delineation and maps of groundwater need a serious caution, as it is cost and time
effective. Because it is out of our site and improper evaluation of ground water and site selection
is mostly expected to pose the problem (Tesfaye, 2012).

Geographical information system (GIS) and remote sensing (RS) is the optional methods to
provide all parameters which influence groundwater potential and recharge zone of one area and
it can access, manipulate and analysis the spatial and temporal data from satellite image (Kamal,
2017). Besides to this, (Gupta and Srivastava, 2010) Explain the several decision analysis
approaches such us Multicriteria Decision Making (MCDM), Analytical Hierarchy process (AHP)
and Fuzzy Logic to fill the gap of water scarcity and decision-making on ground water potential
and recharge zone evaluation and mapping. Analytical Hierarchy Process is useful methods for
complex decision-making. A serious pairwise comparison matrix used for checking consistency
ratio (Saraf and Choudhury, 1998). These decision makers use to reduce the bias in decision
making (Saaty,1980).This study was focused on the evaluation of groundwater potential zone in
Middle Awash river basin by the integrated approach of remote sensing and GIS techniques using
AHP modeling approach.

1
1.2 Statement of Problem
To investigate the groundwater potential of middle awash basins, a multi-disciplinary study
involving hydrogeology and geophysics have been undertaken by the Ministry of Water Resources
through the Water Well Design and Supervision Enterprise (Wakgari, 2010; WWSDE,
2015;Tilahun et al., 2015) by using Geophysical, hydrogeological methods that consume time and
cost. Besides to this, the groundwater potential and recharge zone are not delineated in previous
studies by using GIS and RS techniques separately. Since there is a limitation of previously
working done in the area of the potentials and recharge zone in details, the present study fills the
gap by applying GIS and remote sensing technique. These techniques are very easy to access,
identify groundwater potential, and recharge zone of large and inaccessible areas.

1.3 Objective
1.3.1 General Objective
The general objective of the study is to evaluate groundwater potential and recharge zone of the
Middle Awash River basin by the integrated approach of GIS and remote sensing techniques.

1.3.2 Specific Objective

 To prepare the thematic maps of the study area such as Lithology, Land use/cover, slope,
lineaments, soil texture, drainage density, and geomorphology and runoff depth.
 To identify the factors that more affects the groundwater potential and recharge zone.
 To Assess, evaluate and delineate groundwater potential and recharge zone of the area by using
remote sensing and geospatial data analysis.

1.4 Research Question

 Can lithology, geology, geomorphology, drainage density, rainfall, slope, and lineaments
be the main factors for an accurate result of the groundwater potential and recharge zone of
the area?
 What are the further advantage of remote sensing and GIS from other methods groundwater
potential and recharge zone identification?
 Are all the parameters have equal value to delineate groundwater potential and recharge
zone of one area?
 Is there high potential and low potential of groundwater potential and recharge in the study
area?

2
1.5 Significance of the study
Ethiopia is one of the countries in Africa known by abundant water resource but there is minimum
utilization to ground water for irrigation, domestic life, and lively wood. The main part of
Ethiopian rift valley are characterized by shortage rainfall especially lower and middle awash basin
areas have a shortage of rainfall and water scarcity due to a fluctuation of climate.
The population of Middle Awash River basins is used waters for drinking and other livestock
consumptions from ponds, surface waters and the others by going long travel to fetch the waters
from rivers. The decrease rainfall trend of dry zone and the increase of population size and
demands of water for irrigation and other livelihood requirement's calls sustainable exploitation of
the groundwater resources in the region. By considering the problem and the gap from the other
studies in terms of cost and time, increasing number of population density and fluctuation of
climate on water scarcity in Middle Awash River basins. This research analyzes, design and map
the spatial and temporal distribution of, groundwater availability, identify recharge areas and
factors for ground water formation for the study area.

1.6 Limitation of the study

The lack of the whole groundwater inventory data and unevenly y distribution of data point are the
major problem of this research.

1.7 Thesis organization

This research contains six chapters on ground water potential and recharges zone mapping by using
remote sensing and GIS techniques. Chapter one contains introduction and background of the
study, statement of problems and factors influencing s by these papers, significance of the study
and limitation of the study are, finally thesis organization. Chapter two contains reviewing
different papers done on the ground water potential and recharge zone mapping and related to the
titles and role of remote sensing and GIS on ground water potential and recharge from the other
methods. Chapter three contains methodology and material, types of data used in these research
and description of study area such us location, physiography, regional geology, local geology,
climate, population density, materials and methods, preparation of thematic maps and
reclassification according to the standard. Methods to integrate and analyze the various thematic
layers using a geographic information system (GIS) are given. Moreover, the steps to generate
groundwater potential zones using GIS presented in detail. The data sets include digital data such

3
as remote sensing images, digital elevation models. Chapter four contains results and discussion
of groundwater potential and recharge zone. Chapter five contains conclusion and
recommendation.

4
 CHAPTER TWO
LITERATURE REVIEW
2.1 Definition Of groundwater potential and Recharge zone
There are different definitions given to groundwater potential and recharge zone by different
authors in different time. According to Rashman (2016), groundwater is the most important natural
resources found beneath the earth surface stored in void space of geological stratum used in
economic development, domestic life, and any ecological diversity. Also, he concludes the
occurrence and flows system of groundwater is depends on geological characteristics of its
porosity and permeability and the formation of landforms such us high mountains, rift valley's and
flat areas and the role of landform on surface runoff and infiltration to the ground. Besides,
(Rajaveni et al.,2015) define Groundwater recharge; it is the percolation/ infiltration of water from
unsaturated zone to saturated zone through porosity and permeability of the earth materials above
the water table and finalizes precipitation, infiltration/ percolation of the surface water to the
subsurface influenced by geology and geomorphology.

2.2 Groundwater in Ethiopia

Awash River basin located within the main Ethiopian rift valley (MER). Concerning this area,
numerous reports were done in previous. For instance, previously hydrogeological and related
studies conducted in the Middle Awash River basin and its surrounding. Reys (2016) conducted
on groundwater potential evaluation and use trends in the upper awash basin. This study partly
discussed on the quantitative understanding of aquifer system and ground water conditions, how
to manage ground water potential and use of trends in order to increase its contribution.
In addition to the above authors, Pavelic et al. ( 2012) conducted on groundwater availability and
use in the sub-Sahara African country review of fifteen countries. He summarizes that the
hydrological conditions of sub-Sahara Africa are the major controller of under groundwater more
than other country and categorizes the hydrological aquifers parameters of sub-Saharan into
crystalline basement complex rock, consolidated sedimentary rock, unconsolidated sedimentary
rock, and volcanic rocks.
(Tamiru, 2006) done on the Groundwater occurrence in Ethiopia and describe the most important
factors governing the groundwater flow and storage in volcanic rocks. In addition, he summarizes
that the variation in mineralogy, texture, and structure of volcanic rocks cause the variation of

5
water bearing capacity of the area. (Seifu, 2010) conduct on the Groundwater occurrence in
Ethiopia, partly divide the source of groundwater recharge in Ethiopia under flood recharge, wadi
flood recharge, rainfall recharge and mountain block recharge, runoff from graben and summarize
the water isotope is the evidence. (Yitbarek et al., 2012). Describe type and distribution of
lithology in Ethiopia and they categorize sedimentary and Mesozoic sandstone to the southern,
karstic rocks to eastern and southeastern, quaternary volcanic rocks and unconsolidated sediments
in rift valley and low land depression area, fractured intrusive rocks, old Precambrian rocks and
metamorphic rocks to western part of Ethiopia and their aquifer characteristics.
Although, (Adetunji et al., 2011) conducted Water balance of upper Awash River basins based on
the satellite derived data /Remote sensing data on his MSc thesis, understanding the spatial
variations of water balance components of upper Awash River basins will provide full information
for the management surface and groundwater. The geology of main Ethiopia rift valley (MER) is
very complex, which are difficult to describe the hydrology of the area because of variability and
lateral discontinuity of volcanic rocks (Ernesto et al., 2015).

2.3 Factors Affecting Groundwater Potential and Recharge

Groundwater potential and recharge zone affected by different factors that control/facilitate this
process according to different previous works. As discussed by (Prasad, 2008) on deciphering of
the ground potential zone in hard rock water through the application of GIS. Partly he discussed
on the Lithology, geomorphology, lineament, slope soil, drainage pattern, land use and rainfall.
Finally, he summarizes, as those above parameters are very important factors in ground water
potential and recharge zone mapping. (Annesh and Paresh, 2015). Study origin of occurrence and
movement location of groundwater by using remote sensing data based on indirect analysis of
directly observable terrain features like geological structures, geomorphology, Land-use/land-
cover, Slope, Rainfall, drainage density, and lineaments.

2.4 Role of GIS and Remote Sensing in Groundwater Potential and Recharge
According to (Mukherje, 2008) GIS and remote sensing techniques, groundwater potential, and
recharge zone easily characterized. For example, conducted on Role of Satellite Sensors in
Groundwater Exploration, satellite sensors have the ability to emphasize the opened new
systematic and efficient exploration of ground water, landform mapping, geological mapping,
mineral exploration and geohazard studies. In addition, it helps to understand varies landforms,
which are not easily observed.
6
According to Semere (2003) Geographical information system and remote sensing is the most
advanced technology for much scientific application such us monitoring natural disasters,
landslide, earthquake, volcanoes and agricultural management, mineral and groundwater
exploration and can access large data at same time which are impossible to reach such us cliff,
mountains, and gorges.

(Salwa, 2015) explain the application of GIS and remote sensing; compares GIS and remote
sensing applications on groundwater delineation with other methods such geospatial, numerical
modeling and geophysical methods. He concluded that the above methods are very expensive,
laborious, time-consuming and destructive. In contrast to the above methods, according to Tesfaye,
(2012) groundwater cannot observe directly by our eyes because of it is found beneath ground
there are many techniques which give information's about groundwater and recharge potential
zones such us hydrological investigation, geophysical and geoelectrical or geophysical seismic
refraction methods which is very expensive and time consuming. GIS and remote sensing are the
latest, time and cost effective technology for groundwater exploration by acquiring full
information and access all parameters of factors which controls groundwater potentials and
recharge zone areas by using different softwares easily.

A number of works done on the role of GIS and remote sensing on the groundwater potential and
recharge zone. From those, Chowdhury et al. (2009) conducted on integrated remote sensing and
GIS based for assessing ground water potential in west medinipur district India. Define when GIS
and remote sensing techniques have increased for using ground water potential and recharge zone
mapping. (Agrawal and Grag, 2016) conducted on groundwater potential and recharge zone based
on GIS and remote sensing and they identify different thematic maps for delineating groundwater
potential and recharge zones like drainage density map, lineament map, land- use land -cover map,
hydrogeology map and soil map, slope map.

Additionally, Lazarus (2014) done on evaluation of groundwater potentiality using the integrated
approach of remote sensing, geophysics, and GIS of Ojhala Sub-watershed, Mirzapur district,
Indian. In generalize different thematic layers like lineaments, slope, drainage and overburden
thickness used to integrate without considering aquifer thickness. This proves a broad idea about
the groundwater prospect of the area and the result of groundwater potential zones map generated

7
through this model verified with the borehole yield data to find out the validity of the model
developed which made the agreement with the result.

2.5 Analytical Hierarchy Process Methods

Different researchers use different weight overlay and decision making analysis methods; from
this (Sajikumar and Gigo,2013) Adopt thematic layers of elevation, Land-use/land-cover,
lineaments, and drainage gave accurate information about groundwater occurrence and generate
the result from Weight Index Overlay Analysis (WIOA) by employing analytical hierarchy process
methods. Finally, Conclude that analytical hierarchy process is the promising methods for
groundwater exploration.

8
 CHAPTER THREE
MATERIALS AND METHODS
3.1 Description of the Study Area
Middle Awash River basins are found in main Ethiopia rift between Latitude of 8o39'51″N−10o50'
0.13″ N and Longitude of 39o52'27″ E−41o14'38″ E with the total Area coverage of 30,464 km2 as
shown in Figure 3.1.

Figure 3. 1 Location Map of the Study Area

3.2 Population and Economic Activity

Middle Awash River basins dominated by various ethnic groups; Afar, Amhara, Oromo, Argoba
and Ethio- somale peoples. The most inhabitants of populations are afar population. Major of
them are Muslim followers and the others are Christian followers. Their economic activity are
depend on agriculture, pastoralists and nomadic life. Amhara, Oromo and Argoba peoples are

9
depend on agricultural practice. The Afar people are nomadic and pastoralists and recently they
start agriculture practice by irrigations along the rivers and low-lying riverine areas. According to
the central statistical agency of Ethiopia CSA (1998), the total number of male and female in the
study area are 465,492.

3.3 Rainfall and Temperature

The attitude variation of the study area causes temporal and spatial variability of rainfall. The mean
annual rainfall varies between 250 mm and 1200 mm. However high land areas to the southeast
and northwest of the study area have annual rainfall more than 1200 mm due to altitude effect
.The rainfall pattern in the area generally displays a bimodal type which is divide into two distinct
rainy periods in July and august as shown in Figure 3.2. As elevation increase the rainfall also
increase as shown in Figure 3.3, the northern and southern high lands get high rainfall and the rift
floor have low rainfall. Temperature also shows slight variation spatially in the study area. Rainfall
and Elevations have a direct relationship. Southeast high lands to the lowland and northwest to the
lowland from 23oC to 34oC and the maximum temperature are reaching more than 40oC in the
study area. In general, temperature values are maximum for months of April, May, June and July
in the Study area..
30

25
Temprature (oC)

20

15
27 28
22.7
10 19.4
15.2 14
13
5

0
Bedesa Gelemso Mi,eso Melka werer D/birhan S/gebeya Awash
Metrological Station

Figure 3. 2 : Annual Mean Temperature of the Study Area

10
 250
Rainfall (mm)

200

150

100

50

0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average monthly rainfall 2007-2015

Figure 3. 3: Average Monthly Rainfall of the Study Area

y = 1.3207x + 654.71
R² = 0.461
3000

2500
Elivation in m

2000

1500

1000

500

0
0 200 400 600 800 1000 1200 1400 1600
Rainfall in mm

Figure 3. 4: Correlation of Rainfall with Altitude

11
The general positive correlations between rainfall and altitude shows not very much high as
shown in Figure 3.4. Because of topographic effects on rainfall the southeastern plateau on the
windward side (Wakgari, 2010)

3.4 Wind speed and Relative Humidity

The seasonal variation of inter-tropical convergence zone (ITCZ) are influence the wind Flow
direction. The predominant wind direction during June to September is southerly to southwesterly.
The mean monthly wind speed in Awash and Amibara areas range from minimum value of 0.85
meter/sec or 28.4 miles/day in Dec. to max values of 2.4 meter/sec or 80.4 miles/day in July with
a mean annual value of 1.36 met/sec or 45.6 miles/day. From relative humidity, date available for
Amibara area the mean annual relative humidity in the area is around 61.3 %.

3.5 Physiography and Drainage

The Miocene massive geological process of the Ethiopia rift was cause to serious three distinct
slices of geomorphic series of plateau, escarpment and rift flooring. The physiographic
configuration of the area creates three distinctive river basins of abbey, awash and Wabishebelle
basins. The abbey basin located northwestern of the study area drains westward from northern
highlands, Wabeshebelle basins located southeast wards of the study area drained from eastwards.
The intermittent volcanic tectonic process of the rift form causes the landform deformation into
successive pieces of stratum land masses stacked one after the other. The land mass of middle
Awash River basin is categorized into three in Figure 3.5 which causes the physical and climate
variation, plateau covers about small part of the study area to the north and south of the study area,
escarpment covers small part of the area with moist climate of 16oc to 24oc and rift floor (Tewdros,
2011). These areas shares large amount of the study area with highest temperature of above 24oc
rain fall below 900 mm. The landforms of the rift floor area are flat plain with patch of volcanic
dome and caldera, alluvial landform, flat/flood plain, residual landform and structural landform.

12
 Plateau
Plateau
Escarpment
Escarpment
Rift Floor entent

Figure 3. 5: Physiographic classes of the Study Area

3.6 Soil Type and Vegetation

Soils are highly affects the movement and infiltration of ground water (Hornsby, 1986, Maurice
and Courteny, 1990). There are several major soil groups in the study area such as eutric
chambisol, eutric fluvisol, chromic cambisol, chromic vertisol and vertic cambisol. The most
dominant of the study areas are cambisols and leptosols According to FAO (1998) soil
classification. Depositional places and soil composition, thickness and soil textures can have a
significant role on hydrological process. Besides soil types, its texture and soil index properties
play great role on the runoff and infiltration rates of waters to the ground. The degree of
permeability and porosity are the principal factor in hydrogeology that indicates ground water
potential and recharge zone. The relative proportion of sand, silt and clay of the soil determines
soil textures, which categorized in to fine medium and coarse. The common types of vegetation’s
of the study area are julifora, Acacia, shrubs, thorny bushes, grassland and riverine woodland trees
are also found along the middle Awash River of floor plains. The crop production under irrigated
and rainfall farms among others are teff, Cotton, Maize and Vegetables like Tomatoes, Green and
Red Pepper and Onions.

3.1.6 Hydrogeology of the Study Area

Geological structure of fractures, joints, faults, folds and lineaments and physiography affects
hydrological process of an area (Wakgari, 2010). Crustal thickening and land disconnection are
takes place which is response to tensional force at the central rift produce various fissures size
13
aligned NNE-SSW as the main geological structures (Abebe et al., 2007). The presence of fissures
and volcanic activities in the several of the rift floor makes a partial change of the fissures in the
hydrological flow system, ground water and surface water interaction.

3.1.7 Aquifer Characterization of the Study Area

There are three types of aquifers data in the middle Awash River basins according to Ministry of
Water Irrigation and Energy report (MOWR) including; alluvial and lacustrine deposits,
Quaternary Pleistocene tuff, Miocene and welded tuff, Tertiary Pliocene, and basalt that associate
to shallow aquifer system and deep aquifer systems in the area. The above statement suggest that,
there is an understanding of hydrogeological patterns and lithological makeup of the area from this
data. Besides, from different shallow wells and open dug wells drilled on the riverbanks of Awash
(i.e. The shallow wells observed at Bilen, Sheleko, Melka worer and Melka Sedi) where a shallow
sand and gravel aquifer system are encountered at a depth of around 30 meters and below in a semi
confined nature. The water level in these well rises to a depth 10 − 15 meters. The shallow wells
of Melka Worer, Sheleko, Ambush, Melkasedi and Bilen indicate that the depth of around 50
meters.

3.1.8 Groundwater Recharge

Ground water recharge process is the percolation /the infiltration of water to the ground that, occurs
when any surface water flow to the groundwater table and infiltrate to the saturated zone. The
sources can be Precipitation, surface waters and irrigation losses through diffuse (direct) or
preferential (localized/indirect) and also Groundwater can be recharged from rainfall, surface
water storage, adjoining of watershed, infiltration through streams and rivers and artificial recharge
from ponds and reservoirs by direct and indirect mechanism (Lerner, 1997; Seifu, 2010). The area
characterized by deep non-expansive soil formation; rainfall events can give the significant
groundwater recharge. Specially, arid and semi-arid areas get natural recharge indirectly from
neighbor areas influenced by slope; recharge is less in high slope and very high in areas where the
discontinuities of rocks (fractures, joints and cracks) high and low slope. Mountain blocks, heavy
rainfall, floods from highlands, rivers and small streams are the major source of groundwater
recharge in the middle Awash River basins (Seifu, 2012). They influenced by several factors like
slope, land use land cover, lineament, soil properties and runoff. Those entire parameters map are
prepared and reclassified as suitable for the groundwater recharge zone according to the map of
the middle Awash River basins presented in Figure 3.15. Diffuse recharge mechanism refers to the
14
water added to the groundwater reservoir in excess soil-moisture deficits and evapotranspiration
by direct vertical percolation of precipitation through the unsaturated zone (Bisrat, 2015)

3.1.9 Groundwater Flow Direction

Both topography and geology plays a major role for the groundwater flow in the area. There is a
regional groundwater flow from the eastern mountain range towards North West /topographic
flows in the valley floor as observed from the Potentiometric head map constructed. This regional
flow most possibly controlled by the regional tectonics, which trend northwards following the
main rift trend. Local tectonics like the Wonji faults play major roles controlling the local flow
pattern where most hot springs emerges at the base of these local fault lines at Bilen and Meteka
areas.
From the conceptual flow, based on topographic setting three types of flow system observed in the
area of topographically undulation of the catchment creates local and intermitted flow system in
the area and that part with shallower and short flow paths known with local flow system. Small
permanent lakes in the upland portions of watersheds are usually discharge areas for local and
intermediate systems (Tenalem, 2008). Therefore, from this logical point of view, the presence of
small Permanent River indicates that, the local and intermediate flow systems in the eastern part
of the area. The groundwater flow system around Afdem and gewane area highly dominated by
intermediate flow system.

3.2 Methods
GIS and remote sensing techniques were applied to delineate groundwater potential and recharge
of the middle Awash River basins through analytical hierarchy process. The methods for this
research work includes the following stages: i) identification and evaluation of criteria; ii) data
collection; iii) preprocessing; iv) input dataset; vi) reclassified input layers; vii) Pair wise
comparison of criteria and give weight with Analytical Hierarchy Process(AHP); x)overlay
analysis with Weight sum overlay analysis in ArcGIS tools, Ranking the final value. The overall
methods are illustrated as shown in (Figure 3.6).

15
 DEM Rainfall Data Landsa 8 Existing map

Preprocessing Preprocessing Lithology First stage

Drainage density
IDW
Interpolating Lineament LULC
Slope

Rainfall Soil Texture

Geomorphology

Project all layers in to the same coordinate system

Second Stage

Resampling in to common cell size

Reclasifying as per suitable for GWP

Soil Drainage Runoff Geomorph Lithology Lineam Third

Slope LULC stage
texture density Volume ology map Map ent

AHP Pairwise Comparision

Wightage Calculation Fourth stage

overlay

Groundwater potential and Recharge Zone Map

Figure 3. 6 : Flow chart of Methodology

16
3.3 Data Description and Software
3.3.1 Software
Table 3. 1: types of software used

No. Software used Version Description

1 ArcGIS 10.2 and 10.5 For image preprocessing and thematic map
generating

2 ERDAS 15 For image preprocessing, such us layer stacking and

for other uses

3 PCI Geomatica 17 For lineament generation

4 Surfer 14.3 For 3-D visualization of land surface

3.3.2 Data Description

Hydrogeological data used for ground water potential and recharge zone of the study area and the
summery of data descriptions are as follows.
 Metrology data obtained from Ethiopia Metrological Agency and Ministry of Water
Resources bureau for rainfall descriptions.
 Downloading Soil and rainfall Map from food and agricultural organization (FAO, 1998)
data website for land-use/land-cover mapping.
 Water sources inventory data from Afar regional state, Oromia and Amhara. Water
Resource Development Bureau and zonal water offices for validations of groundwater
potentials result.s
 Geological Maps prepared by Geological Survey of Ethiopia 1:250,000 Scale for
lithological mapping.
 Landsat8 (with path and row of 053/168, 054/167 and 054/168 scenes) from the year for
lineament map January 2016 image of 30 m Resolution.

17
  Digital Elevation Model of 1 km Resolution for generation of slope, drainage density and
geomorphology.

Table 3. 2: Data Used their Source

Data type source Output layer Resolution

Rainfall Metrological agency of Ethiopia Rainfall, Runoff Depth
Soil map Food and agricultural organization Soil texture
Geological Geological survey of Ethiopia Geology map
Map
DEM http://igskmncngs506.cr.usgs.gov/gmtd Drainage, slope 1 km
Landsat8 USGS Lineament 30 m

3.4 Input Dataset

The input layers were prepared for multiple variables such as thematic maps of Slope, drainage
density and geomorphology map generated from DEM data of 1km resolution. Lineament map of
30 m resolution from Landsat 8 and manually digitized from geological map of Ethiopia. Land-
use land-cover map from Food and Agricultural Organization, runoff joining of land-use land-
cover and soil texture and rainfall by simple empirical formula.
Lithology was prepared from geological survey of Ethiopia maps sheets of Wara Ilu, Ayelu Terara,
Debribrhan, Diredawa, Nathreth and Bedesa sheet by mosaicking and digitizing from 1:250,000
scale.

Rainfall map was interpolated in ArcGIS 10.5 from available Metrological data of ten years two
thousand six to two thousand fifteen from of twenty six stations of Abayater, Afdem, AliyuAmba,
Ankober, Arbabordade, Argoba, Asabae, Teferi ,Asebot, Ataye,Awashb Arba ,Awash sebat Kilo,
Bedesa, Kora, Kuni, Koreberte, Meteha Bila, Mieso, Mezezo, Shewa Robit, Shola Gebeya and
Gelemso. Rainfall data of 1km resolution from FAO (1998) used for preparation of layers as
parameters. Each factor map was prepared in a manner that can support to the overall goal of
groundwater potential and recharge zone mapping, the digitized vector layers and prepared input
layers were changed and resampled to raster layers of 1km cell size in order to make appropriate
for the overlay analysis.

18
To evaluate groundwater potential and recharge zone the necessary parameters were prepared for
each layer and resampling to a common spatial resolution as per suitable for overlaying, weighting
as per suitable for groundwater potential and recharge controlling capacity and each of thematic
maps was computed by AHP pairwise comparisons.

3.5 Identification Criteria for Groundwater Potential and Recharge Zone Mapping
Parameters influencing groundwater potential and recharge and their relative importance are taken
from previous literature. The exactly the same factors were combined and only representative
parameters were selected. The others uses lithology, geomorphology, land use land cover,
lineaments, slope, soil, drainage density, rainfall and runoff which affects groundwater potential
and recharge as the major parameters (Sajikumar and Gigo, 2013; Mahswaran et al., 2016).
Geology
The types geology that exposed to the surface are highly affect groundwater recharge by
controlling the percolation and flow of water to the ground Shaban et al. (2005) and geology plays
a great role in the occurrence and distribution of groundwater potentials zone. Each lithological
unit and their aquifer characteristics described in Table 3.3
Table 3. 3 : Lithology and its aquifer characteristics

Factors Lithological unit Aquifer characteristics

Lithology Sedimentary rocks Very high
Igneous rocks Moderate
Metamorphic rocks Low
Source: (Mwega, 2013)
Geomorphology
Geomorphology describes the landform and structural features including; hills, plateaus,
pediment/Pedi plain and rift floor that helps to understand the characteristics of the hydrological
formations of one area. The value of geomorphology vary in terms of their characteristics and
spatial distribution for groundwater potential and recharge processes as presented in (Table 3.4).

19
 Table 3. 4 : Reviewed Geomorphology effect on groundwater potentials

Factors Class Rank Groundwater potential

Factors hill 1 Very Poor
plateau 2 Poor
Pediment/Pedi plain 3 Moderate
Valley/flat 4 Good
Source: (Nagaraju, 2016)
Lineament density
Mogaji et al. (2011) Lineaments are the structural discontinuity of the earth surface such as faults,
foliations, joints, and bedding planes. also a mappable linear features present on the surfaces
indicates the zone of weakness and structural discontinuities it may be curve, linear and slightly
curve which is the most essential for the infiltration and movement of water to the ground as
described in (Table 3.5 )
Table 3. 5 : Lineament Density

Factors Criteria Value in km/km2 Classification

Lineament density 0 − 0.34 Very low
0.34 − 0.99 low
0.99 − 1.57 Moderate
1.57 − 2.11 High
2.11−2.69 Very high
Source: (Waikar and Aditya, 2014)
Slope
HsinFuYeh (2016). Slope is one of the factors controlling infiltration of water to the ground and
the indicator of groundwater potential suitability. A high sloping region causes more runoff and
less infiltration and have poor groundwater prospects compared to the low slope region. Low
slopping regions causes less runoff and high infiltration rate and have good ground water prospect
as shown in (Table 3.6).

20
 Table 3. 6: Role of Slope for groundwater potential and recharge

Factors Value (Degree) Classification Infiltration rate

Slope 0−1 Flat very high infiltration
1− 3 Gentle slope High infiltration
3 − 15 High slope Low infiltration
15 − 45 Hill Very low infiltration
Source: (Maheswaran et al., 1999)

Drainage density

Drainage basin is the natural draining of water runoff to lowland or to a common point. Drainage
density and type of drainage indicate the information of rock and soil permeability, infiltration of
water and surface runoff (Horton, 1945). There are several types of drainage network, dendritic
drainage, rectangular, parallel drainage and coarse drainage.
Table 3. 7: Drainage Density for groundwater potential and recharge

Drainage description Ranking in Ranking in words

density(km/km2 ) words
0 − 0.5 Low density Good 1
0.5 − 1.0 Moderate density Moderate 2
1.0 − 1.5 High density Poor 3
1.5 Very high density Poor 3
Source: (Salwa, 2014).

3. 6 Reclassified Thematic Map of the Study Area

Parameters influencing groundwater potential and recharge and their relative importance were
reviewed from previous literature and from hydrological experts. These study uses lithology,
geomorphology, land use land cover, lineaments, slope, soil, drainage density, rainfall for
groundwater potential and rainfall, runoff depth, slope, geomorphology, soil texture, drainage
density, geomorphology and lithology for groundwater recharge which affects groundwater
potential and recharge. In determining the value given to each parameters and in establishing the
level of desirability of each attribute, different measurements and ranges was used where most
applicable to existing national norms and standards.

21
3.6.1 Rainfall
Rainfall is the most factors for the formation of ground water potential and recharge. The rainfall
map of the study area is shown in (Figure 3. 7). The northwestern and southeastern part of the
study area receives very high rainfall of around 1030 – 1288 mm/year; the southeastern and
northwestern part receives high rainfall of around 847 – 1029 mm/year. The northwestern and
southeastern highland foot receives moderate rainfall 658 – 847 mm/year. The central rift floor
receives low rainfall 513.5 – 658 mm/year. The eastern rift floor part receives very low rainfalls
(343 – 513.5 mm/year as presented in Table 3.8. The high rainfall distribution along high slope
gradient in the northwest and southeast highland parts directly affects the infiltration rate
groundwater potential zones in the downstream central rift floor of the study area.
Table 3. 8: Rainfall and its rank as per suitable for groundwater potential and recharge

factors Value in mm Rank in word Rank in number

Rainfall 343 – 513.5 Very low 1
513.5 – 658 low 2
658 – 847 moderate 3
847 – 1029 high 4
1030 – 1288 Very high 5

a)

22
 b)

Figure 3. 7: a) Rainfall map and b) Reclassified Rainfall map of the study area

3.6.2 Drainage Density

Drainage density is the natural flowing of water runoff to lowland/ common point. It indicates
behavior of surface and subsurface formation, the information of rock, soil permeability,
infiltration of water and surface runoff (Mishra, 2013). The structural Drainage network used to
explain the characteristics of groundwater potential and recharge zone as shown in Table 3.9. The
area where High drainage density values have high runoff and indicates low possibility of
groundwater availability and hence higher weights are assigning to the low drainage density area
and vice versa. (Domingos et al., 2015, Agrwal and Grag, 2015).

Drainage density preparing from Digital Elevation Model (DEM) by line density tool ArcGIS 10.5
and reclassified into five categories as shown in Figure 3.8 ( a and b). Very high drainage density
recorded at the volcanic mountains and near the mountain foots and very low drainage density
recorded at the central rift floor area and some part of the high lands.
Table 3. 9: Drainage Density and its rank as per suitable for groundwater potential and recharge

Factors Km/km2 Rank Rank in words

Drainage Density ≤ 0.146 − 0.48 1 Very high
0.48− 0.63 2 High
0.630743 − 0.73 3 Moderate
0.73 − 0.84 4 Low
≥ 0.84 5 Very low

23
 a)

b)

Figure 3. 8 : a) Drainage density map and b) Reclassified drainage density map

3.6.3 Slope
Slope is the steepness or the change of elevation between two locations and it has a direct influence
on ground water recharge (Chowdhury, 2009). High slope regions have high runoff and low

24
infiltration rate that are not suitable for groundwater recharge, because of water cannot get enough
time to infiltrate to the ground (Chenini et al., 2010). The slope map of the study area was prepared
based on the Digital elevation model data using the spatial analysis tool in ArcGIS 10.5. Based on
these result, the slope of study area was divided in to five classes namely; flat, gentle, moderate,
high and steep slope. The generated map was reclassified and ranking depend on their groundwater
potential and recharge influence as shown in Figure 3.9. The highest rank was given to flat slope
because, flat area have ability to hold water which are very easy for infiltration of water to the
ground and the lowest rank was assigned for steep slope because they result to high runoff and
low infiltration which cause low groundwater recharge as shown in Table 3.10. About 88 percent
of the study area are categorized under very low slope/flat, 10 percent are medium slope, 1 percent
are under very steep slope.
Table 3. 10: slope value of and its rank as per suitable for ground water potential and
recharge

Factors Slope(Degree) Classification Groundwater Rank

infiltrate potentiality

Slope 0 Flat Very high 5

0−1 Gentle slope High 4
1−2 Moderate slope Moderate 3
2−4 High slope Low 2
4 − 10 Steep Very Low 1

25
 a)

b)

Figure 3. 9: a) Slope map and b) Reclassified slope map of the study area

3.6.4 Lineament Density

Lineaments are the structural discontinuity of the earth surface such as faults, foliations, joints,
bedding planes and mappable linear features present on the surfaces. It may be curve, linear and

26
slightly curve which is the most essential for the infiltration and movement of water to the ground
(Morelli and Piana, 2006). High lineament density area are good for ground water recharge and
low lineament density are less suitable for groundwater recharge and discharges. The lineaments
for this research are extracted from geological map of the study area aligned to south east to north
western which are understands from Figure 3.10 . The direction of lineaments of the study area are
towards the direction of the tributaries and wetlands, which suggests that the direction of aquifers
mostly tends to be aligned with the surface water bodies. The runoff from the points of lineaments
is towards the direction of the valleys cause for the high productive of groundwater recharge
(Abdullahi et al., 2013). The lineament density done by the line density in ArcGIS tools and
classified in to five categories 0 − 0.1, 0.11− 0.23, 0.23− 0.40, 0.40 − 0.46 and 0.46 − 0.54 km/km2
as presented in Table 3.11. The lineament density was relatively high in west and east of the study
area when compared with the other areas and very less at the west northern, north eastern, central
south eastern of the study area. The place having very high lineament density, the infiltration rate
of the ground water will be more and the place were low lineament density, the infiltration rate of
the groundwater will be less.
Table 3. 11 : Lineament density and its rank as per suitable for groundwater potential and
recharge

Factors Km/km2 Rank suitability

Lineament Density 0 − 0.0728 1 Very low
0.0728 − 0.1455 2 Low
0.1455 − 0.2183 3 moderate
0.2183 − 0.3639 4 High
0.3639 − 0.655 5 Very high

27
 a

a)

b)

Figure 3. 10: a) lineament density map and b) reclassified lineament density map of the study
area

28
3.6.5 Soil Texture
Soils are the most important factors for ground water recharge and its quality. The percolation or
infiltration rate of water to the water tables influenced by soil permeability. Soil texture of the
study area reclassified into five classes based on (FAO, 1998) shown in Figure 3.11 and their
hydrological soil group (HSG) properties are described by Universal Soil Data Analysis (USDA)
Class – 1 (clay, Soil group D): It covers small amount of highland of northern and eastern of basins
have hydrological properties of Highest runoff potential and very low infiltration rates have
mainly clay soil as described in Table 3.12.
Class – 2 (Sandy Clay, Loam, soil group C ): cover the western, eastern southern and central part
of the study area in small amount and have hydrological properties of low infiltration rates and
consists of chiefly of soils with moderate fine to fine textures.
Class – 3 (Sandy Loam, soil group A) Covers large part of southern, western and northern of the
study area have hydrological properties of low runoff and high infiltration rates consists mainly of
deep well excessively drained sand or gravels. Class – 4 (Loam, soil group B) covers small part of
the study area to the eastern and have hydrological properties of moderate infiltration rates of
consists moderately fine to moderately coarse textures and Class – 5 wetlands (soil group A)
Table 3. 12 : Soil texture and their rank as per suitable for groundwater potential and
recharge.

Factors Classification Rank in words Rank in numbers

Soil texture Clay Very poor 1
Clay loam Poor 2
Sandy clay loam Moderate 3
Sandy loam High 4
Sandy and wetland Very high 5

29
 a)

b )

Figure 3. 11: a) soil texture map and b) reclassified soil texture map of the study area.

30
3.6.6 Land-use/Land-cover
Land-use/land-cover have a direct effect on the hydrological process of surface runoff,
evapotranspiration and groundwater recharge. Water body, agriculture land and the waterlogged
area are excellent sources of groundwater recharge, while the bare lands and exposed rock surface
areas are less important for groundwater recharge as shown in Table 3.13. The Land-use/land-
covers of the study area were taken from FAO (1998) data and the area highly covered by shrubs
and exposed rocks, bare land, built up area, forest, dense forest, grass land and cultivated lands.
The rift valley were covered by bare lands, exposed volcanic rocks and sandy soil sparse vegetation
While still to some extent the riparian vegetation occur along considerable stretches of mainstream
Awash river. The northeastern and southeastern escarpments are predominately shrublands,
croplands. Shrubs and grasses mainly cover the pediment slopes along escarpment margins as
presented in Figure 3.12.

Table 3. 13 : land-use/land-cover and its rank as per suitable for groundwater potential and
recharge.

Factors Classification Rankin Rankin

numbers words
Land-use/land- Bare land, rock outcrops, settlement and lava 1 Very poor
cover flow
Annual crop land 2 Poor
Sparse forest, open grassland and wood land, 3 Moderate
open shrub land, closed shrub land and closed
grass land
Dense forest and open grass land, 4 High
Wetland and water body 5 Very high

31
 a)

b)

Figure 3. 12: a) Land-use/Land-cover map and b) Reclassified Land-use/Land-cover Map of the

Study Area.

32
3.6.7 Geomorphology
The identification and characterization of various landforms and structural features in the study
area are very important from geomorphological study point of view. Which are mandatory for
groundwater potential and recharge zone (Shifaji and Nitin, 2014).The geomorphology reclassified
in terms of groundwater recharge and potential the geomorphology of the study area classified in
to five units: Structural hills, flood plains, residual landform, evaporate and volcanic land form.
Locationally, structural hills to the eastern and southern part of the study area, flood plain or flat
land to the central and northwestern of the area, volcanic landforms to the central and small part
to the eastern of the area, residual landforms to the southern and western part, evaporate small part
to the northeastern of the Study area. There is a maximum runoff associate with Landforms which
characterized by hills slope. This shows poor Potentiality for groundwater potential and recharge
possibility. However, there is a small portion of land, which has high elevation compared to local
surrounding land. By extraction of various classes of geomorphology, a thematic map for
geomorphology generated as shown in Figure 3.13. The rank assigned to the individual landform
classification according to its respective influence of groundwater occurrence, holding and
recharge, as presented in Table 3.14
Table 3. 14 : Geomorphology and its rank as per suitable for groundwater potential and
recharge

Factors Geomorphic units Ranking in word Ranking

Geomorphology Volcanic landform Very poor 1
Residual landform Moderate 3
Structural landform Poor 2
Alluvial landform Good 4
Flat or flood plain Very good 5

33
 a)

b)

Figure 3. 13: a) Geomorphology map and b) Reclassified Geomorphology map of the study area

3.6.8 Geology
The way of Geologic formation and genetic type is essential condition for ground water flow,
transport and mineral composition. Types of rocks determine peculiarities of hydrological cross-
section structure, type of porosity values, the nature of permeability, geological structure
geomorphology and character of spatial heterogeneity of flow and transport parameters.
Lithological stratigraphy of the middle Awash River basins investigated by the Ethiopian
Geological survey in different times as presented in (Figure 3.14). This area consists volcanic and

34
sedimentary rock units and the stratigraphic summary of the area described from the oldest to the
youngest as follows:
Table 3. 15 : Geology and its rank as per suitable for groundwater potential and recharge

Factors Classification Rank in word Rank in numbers

Geology N1-2n and Qwi Very low 1
Qdb Low 2
N1gg and N1a Moderate 3
N1n,Tab,N1-gg, High 4
Qal, Ql and Qwbh, Qbh, Tab Very high 5

a)

35
 b)

Figure 3. 14: a) Geological map and b) Reclassified geological map of the study area
Pre-rift basaltic succession (Qwbp); they are dominated by minor silica members (Jima volcanic
–Tertiary volcanic) that, well exposed on the low land areas of middle awash basin with unbroken
Succession and covers very small area. They also intensely jointed, hydrothermally altered and
spheroidally weathered basalt outcrops in the western escarps of the Lake Abaya graben
(Mengesha et.al, 1996).
Nazereth-Group (N1n, Nrn, N1gg, N1-2a) the name Nazeret Series was given to a thick
succession of welded ignimbrites with flame, pumice, ash and rhyolite flows and domes with rare
intercalations of basalt flows which occur in the Main Ethiopia Rift, rift margins and adjacent
plateaus (Meyer et al.1978 as cited Mangesha et al., 1996). In composition, the ignimbrites are
sub-alkaline rhyolites and trachyte with rare peralkaline varieties. The Nazereth formation widely
covered southern and western part of the study area.
Dino Formation (Qw, Qdp, Qw) these units are coarse unwedded pumiceous Pyroclastic mainly
of light tuff and ignimbrite outcropped in most part of low land of the southwest, west and north
of the study area. The ignimbrite outcropped contains coarse quartz grains with joints displayed
categorized under this formation
Quaternary ignimbrites (Qwi): This formation consist of Quaternary bimodal transitional
basalt/peralkaline felsic volcanic products of Wonji Group. The volcanic products of Wonji Group

36
are intimately associated with lacustrine sediments related to ancestral lakes in the rift floor (in the
fluvial periods of Pleistocene) covers small low land part of the study area.
Rhyolites (Qwa): The units mainly covers small part of study area; composed of ash and pumice
deposits, Trachytic lava flows from the volcanic centers near gewane area and exposed rocks of
light greenish gray, porphyritic trachyte which show cooling joints and more weathering near the
flanks of the shield.
Lower quaternary Basalts (Qwbh): It is basaltic eruptions with lines of scoria cones making
fault traces and the interstratified with the earlier succession of lake sediments exposed in the low
land of the study area.
Volcanic Lacustrine –Sediments (Ql): covers mainly the floor of the depression near rivers and
essentially lacustrine sediments of mainly volcanic origin and were related to the existence of large
lakes during Pleistocene times (Mohr, 1968). They are generally yellowish-gray colored,
horizontally bedded and poorly sorted with fragments of rhyolite, obsidian and basalt in a matrix
of ash and silt clay.
Alluvium and Fluvial deposits (Qal): fluvial deposits, lacustrine deltas and Colluvial outwash
debris found widespread in the study area particularly along the foothills of the major fault scarps
and low land areas. Recent deposits in the area include soils and alluvial sand deposits. The soils
are mainly residual weathering deposits, whose composition controlled more by the physical
condition of formations than by the type of rock from that they derived.

3.6.9 Runoff
Runoff is the over land flow of water that occurs when the excess storm water or other source are
flow on the surface.to calculate the runoff there is formula that requires some inputs Curve Number
(CN) which represents land-use /land-cover and soil textures and rainfall data.

3.6.10 Curve Number

The curve number of hydrological parameter used to describe the storm water runoff potential for
drainage areas and function of land use, soil type and soil moisture (Shereif et al.,2014) as well as
the empirical parameters used in hydrology for predicting direct runoff infiltration from excess
rainfall. The amount of infiltration of surface water or rainfall is determined by soil type and land
use land cover. Generation of curve number requires Hydrological soil group (HSG) map, land use
land cove map and drainage boundaries (Preston et al., 1998).The hydrological soil group and soil
relationship described in Table 3.15.Besides it is a dimensionless number and limited range 1-100
37
 Table 3. 16 : Hydrological soil group and its hydrological properties

HSG Soil content Property

A Sand, Loamy Sand Low runoff potential and high infiltration rate

B Silt Loam, Loam or Silt Moderate infiltration rate

C Sandy Clay Loam Low infiltration rate

D Clay Loam, Silt Clay Loam, Highest runoff potential and very low infiltration rates
Sandy Clay, Silt Clay or Clay
Water Bodies.

Source: (Hong et al., 2008)

Runoff depth is preparing the land-use /land-cover map and converting raster to polygon. Then
after joining the land- use land- cover with soil texture map Table 3.1

38
 Table 3. 17 : Curve numbers for selected land use land cover and hydrological soil
group

HSG
LULC A B C D
Dense Forest 100 100 100 100
Moderate Forest 36 60 73 79
Sparse Forest 45 66 77 83
Wood Land 45 66 77 83
Closed Grass Land 68 79 86 89
Open Grass Land 68 79 86 89
Closed Shrub Land 45 65 75 80
Open Shrub Land 49 69 79 84
Annual Crop Land 67 78 85 89
Wet Land 49 69 79 84
Water Body 100 100 100 100
Settlements 80 85 90 95
Bare Soil 77 86 91 94
Rock Out Crop 90 93 95 96
Lava Flow 90 93 95 96
Source: (United States Department of Agriculture, 1986; Soulis and Valiantzas, 2012)

39
 Figure 3. 15: Curve Number map of the study area
∑𝑛
𝑖=1(𝐶𝑁𝑖 𝑋 𝐴𝑖)
CNaw = ∑𝑛
Eq. (1)
𝑖 𝐴𝑖

Where CNaw = the area weighted CN for the drain age basins

CNi and Ai = CN area for each land use land cover and soil group polygon respectively.

n = number of polygon in each drainage basins

(𝑃−𝐼𝑎)2
Q= (𝑃−𝐼𝑎)
+S Eq. (2)

Q = runoff (mm) P = rainfall (mm)

S = Potential maximum retention after runoff begins

Ia = initial abstracts (mm)

Ia = 0.2s

Substitute the value of Ia in equation 2 for equation 3 results to calculate Q

(𝑃−0.2s )2
Q= (𝑃−0.2𝑆)
+S Eq. (3)

25400
S =254 (𝐶𝑁−10) Eq. (4)

40
Where, CN is curve number for the time.

Table 3. 18 : Runoff and its rank as per suitable for groundwater potential and recharge zone

Factors Value in mm Rank in word Rank in numbers

Runoff 116 - 431 Very low 1
431- 537 Low 2
537- 657 Moderate 3
657 - 833 High 4
833 - 1295 Very high 5

41
 a)

b)

Figure 3. 16: a) curve number map and b) Reclassified Curve Number of the Study Area

3.7 Analytical Hierarchy Process

The analytical hierarchy process (AHP) is a theory of measurement by pairwise comparison and
depend on the decision of experts to derive priority scales. The comparison was made on a scale
of numbers 1–9 which shows how many times a layer is important than the other (Saaty, 1980).

42
(Table 3.18) represents the scaling used in AHP. If the matrix formed is equal to bij, aij = wi/wj,
where w is the weight of each parameters, i, j=1….n of every positive numbers entry to everywhere
and satisfy the reciprocal properties, bnij = i/bij which is called reciprocal matrices.

Table 3. 19 : Saatty’s, scale of intensity relative importance

Intensity of relative important Definition

1 Equal importance
2 Weak or slight
3 Moderate importance
4 Moderate plus
5 Strong importance
6 Strong plus
7 Very strong
8 Very, Very strong
9 Extremely importance
Source: (Saatty’s, 1980)

3.8 Weight Assessment and Normalization

The pairwise comparison matrix was carried out by using AHP techniques. To compute the
cumulative weight of the main criteria, the relative weight of their corresponding classes were
considered. Map Categorization and weight Assignment for groundwater potential and recharge
parameters selected for groundwater potential and nine parameters selected for groundwater
recharge potential zone. Categorization and weight Assignment for both Groundwater potential
and recharge zones. Normalization of Assign Weight using AHP, on the basis of Saaty’s scale,
considering two themes and classes at a time on the basis of their relative importance to determine
the Groundwater Potentials and recharge zone. Thereafter, pairwise comparison matrices of
assigned weights to different thematic layers and their individual classes are constructed using
(Saaty’s, 1980) AHP and weights normalized by eigenvector approach. Consistency Ratio (CR)
calculated to examine the normalized weights of various thematic layers and their individual
classes according to Saaty (1980). To compute CR of various thematic layers and their individual
classes, the following steps were carried out.

43
 𝑎𝑖11 𝑎12 … 𝑎1𝑛
⋮ ⋱ ⋮ 𝑎𝑖𝑗
A1[ ], aij. = ∑𝑎𝑖𝑗 for i,j = 1,2..n Eq.(5)
𝑎21 𝑎22 … 𝑎2𝑛
𝑎𝑛1 𝑎𝑛2. . 𝑎𝑛𝑛

The eigenvalue and the eigenvector calculated as:

𝑊1 𝑊1′
𝑛
𝑊2
] and Wi = 1𝑛 for all n=1, 2…n and W’ = [𝑊2′]
∑ 𝑎𝑖𝑗
W=[ Eq. (6)
⋮ ⋮
𝑊𝑛 𝑊𝑛′
1 𝑊′ 𝑊′ 𝑊′
λmax= 𝑛(= 𝑊1 + 𝑊2 ...𝑊𝑛) Eq.(7)

W: Eigenvector,
wi :Eigenvalue of criterion i, and.
λmax : Average eigenvalue of the pair wise comparison matrix.

CR is a measurement of consistency, of pairwise comparison matrix and it is calculated using

equation

Consistency ratio is the indication of acceptability of reciprocal matrix, which calculated as the
following

CI
CR= RI Eq. (8)

Where CI is consistency index and RI is random consistency index

λ max −𝑛
CI= Eq. (9)
𝑛−1

These matrixes have the property of consistency known as consistency ratio (CR).if the
consistency ratio of the matrix is greater than 0.1 the matrix should be re-evaluated.

Table 3. 20 : Random consistency index

Matrix size 1 2 3 4 5 6 7 8 9 10
RI 0 0 0.58 0.9 1.12 1,24 1.32 1.41 1.45 1.49

44
 CHAPTER FOUR
RESULT AND DISCUSION
4.1 Groundwater potential
The result of present work on the groundwater potential was done by the analysis of thematic
layers (rainfall, soil texture, slope, runoff depth, land- use/ land- cover, lineament, geomorphology,
drainage density and lithology) and the parameters values are given based on the saatty scale as
shown in (Table 4.1). Based on the pairwise comparison matrix, the relative weight matrix and
normalized Principal Eigenvector were calculated. The influence percentage of thematic layers
and the rank for its parameters was assigned based on the judgment of works carried out by
researchers or knowledge of expert gained through similar work on groundwater potential zone
mapping (Tesfaye, 2012).

4.1.1 Weight Assessment

The Relative weight for thematic layers(Rainfall, Slope, Geomorphology, Lineament density
,Drainage density, Soil texture, Land-use/Land-cover and lithology ) were assigned according to
their relative importance for each analyzed based on the judgment of works carried out by
researchers or knowledge of expert gained through similar work on groundwater potential zone
mapping (Tesfaye, 2012). To compare the importance of two layer maps show that one of them
has more influence to the groundwater occurrence than the other.

Table 4. 1 : Relative weight for selected thematic layers

parame
Rf Sl Gm Ln Dd St Lulc Lith
ters
Rf 1 2.00 3.00 5.00 6.00 4.00 6.00 7.00
Sl 0.50 1 2.00 3.00 5.00 5.00 6.00 7.00
Gm 0.33 0.50 1 0.50 2.00 4.00 2.00 3.00
Ln 0.20 0.33 2.00 1 2.00 2.00 2.00 3.00
Dd 0.17 0.20 0.50 0.50 1 2.00 3.00 4.00
St 0.25 0.20 0.25 0.50 0.50 1 3.00 4.00
Lulc 0.17 0.17 0.50 0.50 0.33 0.33 1 4.00
Lith 0.14 0.14 0.33 0.33 0.25 0.25 0.25 1
Total 2.76 4.54 9.58 11.33 17.08 18.58 23.25 33.00

Where Rf = Rainfall, Sl = Slope, Gm = Geomorphology, Ld = Lineament density, Dd= Drainage

density, St = Soil texture, Lulc = Land-use/land-cover, Lith = Lithology

45
4.1.2 Weight Normalization
The weights were normalized based on the equation five (5), which are calculated by averaging
the values in each row to get the corresponding ranking, which gives the results of normalized
weights of each parameter as presented in Table 4.1. From the result, observed rainfall has the
highest value rather than other parameters. Because, It indicate high rainfall have the possibility
of high groundwater recharge thus high groundwater potential zones, while low rainfall indicates
low groundwater recharge thus low groundwater potential zones. The main source of groundwater
in the area was the rainfall of the northwestern and southeastern highlands the study area due to
mountain block and slope.

TABLE 4. 2 : Pairwise comparison matrix and normalized weight

Rf Sl Gm Ln Dd St Lulc Lith Wt Wt (%)
RF 0.363 0.441 0.313 0.441 0.351 0.215 0.258 0.212 0.32 32
SL 0.181 0.221 0.209 0.265 0.293 0.269 0.258 0.212 0.238 23.8
GM 0.120 0.111 0.104 0.044 0.117 0.215 0.086 0.091 0.111 11.1
LN 0.073 0.073 0.209 0.088 0.117 0.107 0.086 0.091 0.105 10.5
DD 0.060 0.044 0.052 0.044 0.059 0.107 0.129 0.121 0.077 7.7
ST 0.091 0.044 0.026 0.044 0.029 0.054 0.129 0.121 0.067 6.7
LULC 0.060 0.037 0.052 0.044 0.019 0.018 0.043 0.121 0.049 4.9
LITH 0.051 0.031 0.035 0.029 0.015 0.013 0.011 0.031 0.027 2.7
TOT 1 1 1 1 1 1 1 1 1 100

Where, Rf = Rainfall, Sl = Slope, Gm = Geomorphology, Dd = Drainage density, St = Soil

texture, Lulc, = Land-use/land-cover, Lith = Lithology, Wt= Weight
4.1.3 Principal Eigen Vector
In order to check the weight assigned to each parameter in Table 4.2, the normalized principal
Eigen vector value (λmax) was computed depending on equation 6 and 7 to drive the formula of
consistency ratio ( equation 8). This was done by multiplying the weight of the first criterion (for
example, Rainfall = 32) as shown in Table 4.2 with the total value that was found in the pairwise
comparison matrix (for example, Rainfall =2.76) table 4.1. This was applied for the rest of seven
factors as per equation 8. Finally, the summation of these values gives the consistency vector
(λmax of = 8.84) as shown in Table 4.3 for calculating consistency index.

46
 Table 4. 3 :Normalized Principal Eigen vectors

Parameters Normalized principal Eigen vectors

Rf 0.894
Sl 1.082
Gm 1.064
Ld 1.196
Dd 1.317
St 1.250
Lulc 1.147
Lith 0.891
λmax 8.843

The consistency index was computed to overcome for the formula of consistency ratio and this
was done based on equation 9, which results CI = 0.120. Then, consistency ratio was computed as
per equation 8 and the computed result of CR = 0.085 that is less than 0.1and the given weights
was valid for further analysis. Groundwater potential zone map (GWPZM) was computed after
checking all criterion as follows:

GWPZM = 0.32 * RRf + 23.8 *RGm +11.1*RSl+ 10.5 *RSt + 7.7 *RLd + 6.7 * RDd + 4.9 *
RLulc + 2.7 * RLith.

Where, RRf: Reclassified Rainfall Map, RGm: Reclassified Geomorphology Map, RSl:
Reclassified Slope map, Rst: Reclassified Soil Texture Map, RLd: Reclassified Lineament
density Map, RDd: Reclassified Drainage density Map, RLulc: Reclassified Land-use/land-cover
Map and RLith: Reclassified Lithology Map.

Rainfall, slope, lineament density and geomorphology holds the highest value relative to the other
parameters. The weight assigned for Rainfall were greater than the weight of other, which
influence the occurrence of groundwater potential and recharge zone than others parameters
(Mwega, 2013; Kamal et al., 2016). The result for groundwater potential zones was classified in
to very high, high, moderate, low and very low Figure 4.1.

47
Figure 4. 1: Groundwater Potential Zone Map of the Study Area
The result of groundwater potential of the study area done by integration of all thematic maps to
delineate groundwater potential zones. The results categorized in to five categories namely: very
high, high, moderate, low and very low of groundwater potential zone Figure 4.1. Very low
groundwater potentials cover 2688 km2 of the study area, low groundwater potential covers 385
km2 at the central rift floor of Gewane area around volcanic mountain of Afdem, southeastern and
northwestern of the study area. Moderate groundwater potentials cover 6924 km2 at the foot of
northwestern and southeastern highlands and near horst and grabens. High to very high
groundwater potentials are covers 9890 km2 and 10575 km2, respectively to the main rift floor
lowland of the study area as shown in Figure 4.1.

48
Table 4. 4: Groundwater potential area and percentage of the study area.

No Groundwater Potential zone Area (km2) Area (%)

1 Very high 10575.6 34
2 High 9890.6 32
3 Moderate 6924.2 22
4 Low 2688.5 9
5 Very Low 385.3 1

12000
10000
8000
km2

6000
Area in

4000
2000
0
Very high High Moderate Low Very Low
GWPZ

Figure 4. 2: Groundwater potential zone Area Coverage of the study area

Based on the normalized weighting of the individual features of the thematic layers, very high and
high groundwater potentials was fallen in the alluvial plains in in the rift floors covers 34% and
32% percent respectively. Because of NE-SW, fault systems highly control the permeability of the
rocks in the basin apart from other Parameters, in which most of the springs, marshlands and
drainage lines following these weak zones that would support groundwater flow as shown in
Figure 3.12.
Moderate groundwater potentials were found in foothills to the northwestern and southeastern
highlands of the study area. Very low groundwater potential was found Northwestern,
Southeastern and volcanic landforms between caldera and cones near Afdem and were mountains
of gewane area, the northern and southern part of the study area.

49
4.2 Groundwater Recharge
The groundwater recharge zone investigation considers the analysis of thematic layers (rainfall,
soil texture, slope, runoff depth, land- use/ land- cover, lineament, geomorphology, drainage
density and lithology), which the same maps that were used for groundwater potential zone are
mapping. The parameters values was given based on the saatty scale as shown in Table 4.5. As per
the pairwise comparison matrix, the relative weight matrix and normalized Principal Eigen vector
were calculated for getting the relative weights of the variables. The influence percentage of
thematic layers and the rank for its parameters was assigned based on the judgment of works
carried out by researchers or knowledge of expert gained through similar work on groundwater
recharge mapping (Shifaji and Nitin, 2014 ).

Determination of the relative importance and the weight of each thematic map with another paired-
comparison matrix was done by saatty importance scale. In this pairwise comparison matrix, the
weight of consistency ratio value of groundwater recharge was computed and the result is less than
0.1 for all experts. This indicates that all experts' weightings are consistent and suitable for the
implementation.

4.2.1 Weight Analysis

The relative weight importance between criteria was assigned according to a numerical scale from
1 to 9, as shown in Table 4.6, and it is assumed that the selected parameters were equally important
or more important than others selected parameters. In this research, the relative Weight were
assigned for delineating and mapping of groundwater recharge of thematic layers(Rainfall,
Runoff, Slope, Soil texture, Lineament density, Drainage density, Land-use/land-cover and
Lithology).

50
 Table 4. 5 : Pairwise comparison matrix
Rf Sl Ro Dd Ld Gm Lith St Lulc
Rf
1.00 2.00 3.00 4.00 5.00 5.50 6.00 6.50 7.00
Sl
0.50 1.00 1.50 2.00 3.00 3.50 4.50 5.00 4.50
Ro
0.33 0.67 1.00 1.50 2.00 2.50 3.00 4.00 4.50
Dd
0.25 0.50 0.67 1.00 1.50 1.50 3.00 3.50 4.00
Ld
0.20 0.33 0.50 0.67 1.00 0.50 1.50 1.50 2.00
Gm
0.18 0.29 0.40 0.67 2.00 1.00 0.50 1.50 2.00
Lith
0.17 0.22 0.33 0.33 0.67 2.00 1.00 1.00 1.50
St
0.15 0.20 0.25 0.29 0.67 0.67 1.00 1.00 1.50
Lulc
0.14 0.22 0.22 0.25 0.50 0.50 0.67 0.67 1.00
Tot
2.93 5.43 7.87 10.70 16.33 17.67 21.17 24.67 28.00

Where, Rf = Rainfall, Ro = Runoff, Dd = Drainage density, Ld = Lineament density, Gm =

Geomorphology, Lith = Lithology, St = Soil texture, Lulc= Land-use/land-cover

4.2.2 Weight Normalization

Weight normalization was calculated by averaging the values in each row to get the corresponding
ranking, which gives the results of normalized weights of each parameter as presented in Table
4.6. These calculated weights were considered the total weight. From result observed rainfall have
highest value and lithology have the lowest value. From the selected parameters, the weight
assigned for rainfall was higher than the rest parameters this happened because of

51
Table 4. 6 : pairwise comparison matrix and normalized weight

Parameters Rf Sl Ro Dd Ld Gm Lith St Lulc wt Wt (%)

Rf 0.34 0.37 0.38 0.37 0.31 0.31 0.28 0.26 0.25 0.32 32.00
Sl 0.17 0.18 0.19 0.19 0.18 0.20 0.21 0.20 0.16 0.19 19.00
Ro 0.11 0.12 0.13 0.14 0.12 0.14 0.14 0.16 0.16 0.14 14.00
Dd 0.09 0.09 0.08 0.09 0.09 0.08 0.14 0.14 0.14 0.11 11.00
Ld 0.07 0.06 0.06 0.06 0.06 0.03 0.07 0.06 0.07 0.06 6.00
Gm 0.06 0.05 0.05 0.06 0.12 0.06 0.02 0.06 0.07 0.06 6.25
Lith 0.06 0.04 0.04 0.03 0.04 0.11 0.05 0.04 0.05 0.05 5.00
St 0.05 0.04 0.03 0.03 0.04 0.04 0.05 0.04 0.05 0.04 4.00
Lulc 0.05 0.04 0.03 0.02 0.03 0.03 0.03 0.03 0.04 0.03 3.00
Tot 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 100.00

4.2.3 Normalized Principal Eigen Vectors

In order to check the weight assigned to each parameter in Table 4.5, the normalized principal
Eigen vector value (λmax) was computed depending on equation 6 and 7 to drive the formula of
consistency ratio ( equation 8) . This was done by multiplying the weight of the first criterion (for
example, Rainfall = 32.00.) as shown in Table 4.6 with the total value that was found in the
pairwise comparison matrix (for example, Rainfall =2.93) table 4.4. This calculation was applied
for the rest of eight factors as per equation 8. Finally, the summation of these values gives the
consistency vector (λmax of = 9.30) as shown in Table 4.3 for calculating consistency index.
Table 4. 7: Normalized Principal Eigenvector

Parameters Normalized principal Eigen vectors

RF 0.94
SL 1.02
RO 1.08
DD 1.14
LD 0.99
GM 1.10
LULC 1.10
ST 1.01
Lith 0.92
λmax 9.30
The consistency index was calculated based on the equation 8 and equation 9 to which results CI
= 0.04. Then, consistency ratio was computed as per equation 8 and the computed result was CR
= 0.03 that is less than 0.1and the given weights was accepted for further analysis. Groundwater
Recharge zone map (GWRZM) was computed after checking all criterion as follows:
52
GWPRM = 32 * RRf + 18.78 * RSl + 13.69 * RRo + 10.65 * RDd + 6.09 * RLd + 6.25 * RGm
+ 5.19 * RLulc + 4.09 * RSt + 3.27 * RLith
Where RRf: Reclassified Rainfall map, RSl: Reclassified Slope map, RRo: Reclassified Runoff,
RDd: Reclassified Drainage density map, RLd: Reclassified Lineament density map, RGm:
Reclassified Geomorphology map, RLulc: Reclassified Land -use/ land- cover, RSt: Reclassified
Soil texture, RLith: Reclassified Lithology

This study used nine major factors, which influence groundwater recharge potential zone (Runoff,
Rainfall, Slope, geomorphology, soil, land use land cover, drainage density, lineament density and
lithology).The result groundwater recharge of the study area was categorized into five classes
namely, very high, high, moderate, low and very low as shown in Figure 4.3. Very high
groundwater recharge dominate a large part of the study area, in rift floor relatively high slope,
northwestern and southeastern highlands and very low groundwater recharge cover small part to
the lowland of the study area.

Figure 4. 3: Groundwater recharge zone map of the study area

Very high groundwater recharge was located to the northern and southern highlands of the study
area and some parts of lowland in the rift floor. (Sumit et al., 2014; Agrawl and Grag, 2015)
follows the same methods and use similar parameters of (geology, drainage density, slope, and

53
soil) data's for groundwater potential zone, The result shows high groundwater potential in
Highlands which is similar to the present study result. Very low groundwater recharge are located
in the lowlands of rift floor of the study area. Very low and low groundwater potentials are falls in
the area of volcanic landform, bare lands, and rock exposure. The low value was assigned for these
parameters because of volcanic landform.

4.3. Validation of Groundwater Potential Zones

Delineation of groundwater potential and recharge zone by integrated GIS and remote sensing
techniques have a close agreement with the available point source inventory data as shown in
Figure 4.4. However, there is high yields of groundwater potentials in the some areas. This may
happen when the rift faults in the area have caused variable degrees of displacement on rock
formations coming to lateral contact to different rock types that have high permeability and as a
result, the lacustrine deposits to that areas. The spring observed in the study area are located in the
high groundwater potential following the same attitudes. In addition to this previous study, discuss
the occurrence of permeable rocks and high recharge rates in some highlands adjacent to steep
escarpments. For verification of resulted map Secondary field data collected in of 34 observation
wells, from these four wells fall in the low groundwater potential zone. The value with the depth
of 100-150ft and yields 2.4- 5.3 l/sec in low zone also three spring were used for validating, from
this three spring data three of them are fall in the very high groundwater potential zone. From
resulted map of groundwater potential zone 0.88 correlations shows high and very high areas with
that of existing water source and spring data.

54
Figure 4. 4: Groundwater potential validation map of the study area

55
 CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
5.1 CONCLUSION
In this present study, the result of groundwater potential and recharge zone by using GIS and
remote sensing techniques through Analytical Hierarchy decision methods were identified and
delineated based on the influential factors for groundwater potential and recharge zone. In this
research, nine parameters were selected which have more affects the occurrence of groundwater
potential and recharge zone prior to overlay analysis. By assigning quantitative weights, it is
possible to make important criteria that have a greater impact on the result than other criteria. In
The AHP, methods were adapted in Table 4.1 and 4.5 to give the value for each factor. This
approach allows decision makers to give the judgments in order to reduce complexity in decision-
making processes.
The results of consistency ratio in this study were 0.08 and 0.03 for groundwater potential and
recharge respectively. If the result of consistency ratios are greater than 0.1, the value is unaccepted
and it must be re-evaluated. In this case, the consistency ratio for both groundwater potential and
recharge zone was less than 0.1 and the value was accepted for further analysis.

The delineated Groundwater potential and recharge zone were classified into five zones namely,
‘very low’, ‘low’, ‘moderate’, ‘high’ and ‘very high’. Very low zone shows that the low suitable
area for groundwater prospect. Whereas very high zone indicates the most suitable area for
groundwater prospect. Very high potential areas present in alluvial plains, lacustrine sediments,
the Fracture valleys, and valley fills, which coincide with the low slope and high lineament density
of the study area. Very low groundwater potential falls in the area volcanic landform, bare lands,
high slope and high drainage density. The acceptable results were done by comparing the borehole
yield data with the Groundwater potential zone map of the study area.
The delineated Groundwater recharge zone of the study area has been also classified into five
classes; namely ‘very high', ‘high', ‘moderate', ‘low' and ‘very low' for recharge zone. Very high
groundwater recharge was identified to the northern and southern highlands of the study area in
high rainfall, high drainage density, high lineament density and structural landforms.

56
The effective parameters in the area for groundwater potential and recharge are rainfall, slope,
geomorphology, lineament density, drainage, density and drainage density in Pairwise
Comparison matrix analysis indicates that all parameters are significant.
Most of the area, around 34% zone under very high groundwater potential and the next very
Moderate groundwater potential zone where 32.47% covers, the third coverage of the area are
moderate groundwater potentials of 22.73% and the rest areas were categorized under high to very
low groundwater potential zone of 8.83% and 1.27%, respectively.

5.2 Recommendation
High potential groundwater recharge area was Based on the findings obtained and conclusions
reached the following recommendations were forward as follow:
 The same appropriate methods were recommended for complex areas to delineate
groundwater potential and recharge zone in the small area.
 The groundwater potential map along with other thematic maps forms serve as resource
information database that can be updated from time to time by adding new information.
 For further validation, field geophysical investigations on the potential well drilling sites
are recommended.
Identified to the northwestern part of the study area and low suitable for groundwater recharge was
present in eastern part of the study area.
In this research, integrated GIS and remote sensing techniques are very useful, time and cost
effective tool for the identification and delineation of groundwater potential and recharge zones
and analysis.

57
 REFERENCE
Abdullahi, J., Momoh, E., Udensi. (2013). Effect of Lineaments on Groundwater
Occurrence. 8(1): 22-32.

Abebe, T., Mazzarini, F., Innocenti, F. and Manetti, P. (1998). The Yerer-Tullu Wellel volcanic tectonic
lineament: A transtensional structure in central Ethiopia and the associated magmatic
activity. Journal of African Earth Sciences, 26(1), 135-150.

Adetunji, V., and Odetokun, I., A. (2011). Groundwater contamination in Agbowo community
Ibadan Nigeria: Impact of septic tanks distances to wells. Malayas J Microbiol, 7(3), 159- 166.

Agrwal and Grag (2015). Remote Sensing and GIS Based Groundwater Potential and Recharge Zones
Mapping Using Multi-Criteria Decision Making Technique.

Annesh and Paresh (2015). High Resolution Groundwater Prospect Mapping of Raichur, Karnataka
Using Remote Sensing and GIS. Imperial Journal of Interdisciplinary Research, 2(8).

Applicability of generalized additive model in groundwater potential modelling and comparison

its performance by bivariate statistical methods

Application

Asfaw, A. (2006). Hydrogeology of the Alaydegea plain and its environs middle awash valley, afar
region

Becht, R and Tenalem., A. (2008). Comparative assessment of the water balance and hydrology
of selected Ethiopian and Kenyan Rift Lakes. Lakes and Reservoirs: Research and
Management, 13(3), 181-196.

Bisrat, A. (2015). Interbasin Groundwater Transfer in Upper Rift Valley Lakes and Upper Awash River
Basins, AAU.

Central Statical Agency (CSA), (2007). Summery and statical report of population and Housing Census,
Addis Ababa, Ethiopia.

Chakraborti, D., Das, B., and Murrill, M. T. (2010). Examining India’s groundwater quality
management.

58
Chenini, I., and Mammou, A. B. (2010). Groundwater recharge study in arid region: an approach using
GIS techniques and numerical modeling. Computers and Geosciences, 36(6), 801-817.

Chowdhury, A., Jha, M. K., Chowdary.,V. M. and Mal, B. C. (2009). Integrated remote sensing
and GIS based approach for assessing groundwater potential in West Medinipur district,
West Bengal, India. International Journal of Remote Sensing, 30(1), 231-250.

Courtney, R. G., and Timpson, J. P. (2005). Reclamation of fine fraction bauxite processing residue (red
mud) amended with coarse fraction residue and gypsum. Water, air, and soil pollution, 164(1-4),
91-102.

Diary Ali, M and Lanja, F. (2015). Groundwater potential mapping using remote sensing
and GIS-based, in Halabja City, Kurdistan, Iraq
Domingos, P and Sangam, Sh. (2015) Delineation of groundwater potential zones in the Comoro
watershed, Timor Leste using GIS, remote sensing and analytic hierarchy process (AHP)
technique.
Ernesto, A., Piero, B and Mario. S. (2015). Geology of Ethiopia: A Review and Geomorphological
Perspectives

FAO, (1998). World reference base for soil resources. World soil resources reports, 84, 21-22.

Foster, S. (1998). Groundwater: assessing vulnerability and promoting protection of a threatened resource.
In Stockholm, water symposium (79-90).

Gosavani, V and Tamilmani, D. (2009).Remote sensing and GIS applications for artificial recharge of
groundwater 4(1).

Gossel, W., Sefelnasr, A., Ebraheem, A., and Wycisk., P. (2008). A GIS-based flow model for
groundwater resources management in the development areas in the eastern Sahara,
Africa. Applied Groundwater Studies in Africa, on Hydrogeology.

Gupta, M., and Srivastava, P. K. (2010). Integrating GIS and remote sensing for identification of
groundwater potential zones in the hilly terrain of Pavagarh, Gujarat, India. Water
International, 35(2), 233-245.

Hasin. F., Yung- S., Lin, H. I., & Lee, C. H. (2016). Mapping groundwater recharge potential zone using
a GIS approach in Hualian River, Taiwan. Sustainable Environment Research, 26(1), 33-43.

59
Hong, Y., Adler, R. F., Tian, Y and Pierce, H. F. (2010). Evaluation of a satellite-based global
flood monitoring system. International Journal of Remote Sensing, 31(14), 3763- 3782

Hornsby, A. G. (1986). A microcomputer-based management tool for chemical movement in

soil. Applied agricultural research, 1(1), 50-56.

Horton, R. E. (1945). Infiltration and runoff during the snow‐ melting season, with forest‐
cover. Eos, Transactions American Geophysical Union, 26(1), 59-68.

Jeffry Swingly Frans, S and Koichiro, O. (2012). Analysis on Curve Number, Land Use and Land
Cover Changes and the Impact to the Peak Flowin the Jobaru River Basin, Japan.

Kamal, K. (2017). Delineation of groundwater potential zone in Baliguda of Kandhamal District,

Odisha using geospatial technology approach.

Lerner, D. N. (1990). Groundwater recharge in urban areas. Atmospheric Environment. Part B. Urban
Atmosphere, 24(1), 29-33.

Maheswaran, M., Ali, S., Siegel, H. J., Hensgen, D., and Freund, R. F. (1999). Dynamic mapping of a
class of independent tasks onto heterogeneous computing systems. Journal of parallel and
distributed computing, 59(2), 107-131.

Maurice, D. R., and Courtney, T. H. (1990). The physics of mechanical alloying: a first
report. Metallurgical Transactions, 21(1), 289-303.

Mishira, Sh. (2013). spatial analysis of drainage network for ground water exploration in river basin
using GIS and remote sensing techniques: a case study of tons river in Allahabad, India. Journal
of environmental research and development 7(3).

Mogaji, K. A., Aboyeji, O. S., and Omosuyi, G. O. (2011). Mapping of lineaments for groundwater
targeting in the basement complex region of ondo State, Nigeria, using remote sensing and
geographic information system (GIS) techniques. International Journal of water resources and
environmental engineering, 3(7), 150-160.

Mohamed, M. (2014). Groundwater potential modelling using remote sensing and GIS: a case study
of the Al Dhaid area, United Arab Emirates Geocarto International.

60
Mohr, P. A. (1968). The Cenozoic volcanic succession in Ethiopia. Bulletin of Volcanology, 32(1):5-
14

Morelli, M., and Piana, F. (2006). Comparison between remote sensed lineaments and geological
structures in intensively cultivated hills (Monferrato and Langhe domains, NW
Italy). International Journal of Remote Sensing, 27(20), 4471-4493.

Mukherje, A., and Fryar, A. E. (2008). Deeper groundwater chemistry and geochemical modeling of the
arsenic affected western Bengal basin, West Bengal, India. Applied Geochemistry, 23(4), 863-
894.

Mwega, B. W., Mati, B. M., Mulwa, J. K., and Kituu, G. M. (2015). Application of electrical resistivity
method to investigate groundwater potential in Lake Chala watershed. International Academic
Research for Multidisciplinary, 3(7).

Nagaraju, A., Sreedhar, Y., Thejaswi, A., and Dash, P. (2016). Integrated Approach Using Remote
Sensing and GIS for Assessment of Groundwater Quality and Hydrogeomorphology in Certain
Parts of Tummalapalle Area, Cuddapah District, Andhra Pradesh, South India. Advances in
Remote Sensing, 5 (02), 83.

Pavelic, P., Giordano, M., Keraita, B., Ramesh, V., and Rao, T., (2012). Groundwater
availability and use in Sub-Saharan Africa: a review of 15 countries. International Water
Management Institute.

Prasad, R., K., Mondal, N. C., Banerjee, P., Nandakumar, M. V., and Singh, V. S., (2008).
Deciphering potential groundwater zone in hard rock through the application of
GIS. Environmental geology, 467-475.

Preston, S. Chow, A. T., Dornseif, B. and Corrado, M. (1998). Pharmacodynamics of levofloxacin: a new
paradigm for early clinical trials. Jama, 279(2), 125-129.

Rajaveni, S. P., Brindha, K., and Elango, L. (2015). Geological and geomorphological controls on
groundwater occurrence in a hard rock region. Applied Water Science, 1-13.

Rashman (2016) Identification of Groundwater recharge potential zones in Thiruverumbur block,

Trichy district using GIS and remote sensing./

61
Reys, Asfaw. (2016). Ground Water Potential Evaluation and Use Trends in Upper Awash Basin with
Special Emphasis to Koka-Becho area (Addis Ababa University).

Saaty, T. L. (1980). Marketing applications of the analytic hierarchy process. Management

science, 26(7), 641-658.

Sajikumar, N., and Gigo, P. (2013). Integrated Remote Sensing and GIS Approach for Groundwater
Exploration using Analytic Hierarchy Process (AHP) Technique. International Journal of
Innovative Research in Science, Engineering and Technology, 2, Special Issue 1, December 2013.

Salwa. F. (2015). An overview of integrated remote sensing and GIS for groundwater mapping in
Egypt. Ain Shams Engineering Journal, 6(1), 1-15.

Saraf, A. K., and Choudhury, P. R. (1998). Integrated remote sensing and GIS for groundwater
exploration and identification of artificial recharge sites. International journal of Remote
sensing, 19(10), 1825-1841.

Seifu Kebede, 2010 Groundwater in Ethiopia Occurrence, drought proofing and technology options.

Seifu, Kebede. (2012). Groundwater in Ethiopia: Features, numbers and opportunities. Springer Science
and Business Media.

Semere, S. (2003). Remote sensing and GIS: applications for groundwater potential assessment in
Eritrea (Doctoral dissertation, Byggvetenskap).

Shaban, A., Khawlie, M., Abdallah, C., and Faour, G. (2005). Geologic controls of submarine
groundwater discharge: application of remote sensing to north
Lebanon. Environmental Geology, 47(4), 512-522.

Sheriff, M. (2014). Delineation of potential sites for groundwater recharge using a GIS-based
decision support system. Environmental Earth Sciences, 72(9), 3429-3442.

Shifaji, G., and Nitin, M. (2014). Identification of groundwater recharge potential zones for a watershed
using remote sensing and GIS. International Journal of Geomatics and Geosciences, 4(3), 485.

Shifaji, P., Nitin, M. (2014). Identification of groundwater recharge potential zones for a watershed
using remote sensing and GIS. International Journal of Geomatics and
Geosciences, 4(3), 485-498.

62
 Structures at alidege plain, south afar, Ethiopia.

Sumit, D., Bindu, B and Janak, P. L. (2014). Groundwater suitability recharge zones modelling in GIS

Tamiru, A. (2006). Groundwater occurrence in Ethiopia. Addis Ababa University, Ethiopia.

With the support of UNESCO.

Tenalem, A. (2008). The distribution and hydrogeological controls of fluoride in the groundwater of
central Ethiopian rift and adjacent highlands. Environmental Geology, 54(6), 1313-1324.

Tesfaye, T. (2012). Ground water potential evaluation based on integrated GIS and remote sensing
techniques, in bilate river catchment: south rift valley of Ethiopia (AAU).

Tewdros, T. (2011). Geophysical investigation for groundwater potential assessment and mapping

Thomas, C. (1995). Relation of streams, lakes, and wetlands to groundwater flow

systems. Hydrogeology Journal, 28-45.

Tilahun, A., Asfawossen, A., Tenalem, A., Seifu, K (2015). Litho-structural control on interbasin
groundwater transfer in central Ethiopia. Journal of African Earth Sciences.
U SDA. (1986) Urban Hydrology for Small Watersheds TR55, United States of America.

Waikar, M.and Nilawar, A. P. (2014). Morphometric analysis of a drainage basin using geographical
information system: a case study. International Journal of Multidisciplinary and Current
Research, 2, 179-184.

Wakgari, F. (2010). The hydrogeology of Adama-Wonji basin and assessment of groundwater level
changes in Wonji wetland, Main Ethiopian Rift: results from 2D tomography and electrical
sounding methods. Environmental Earth Sciences, 62(6).

Wondimagegn, W., and Mnalku, A. (2012). Selected physical and chemical characteristics of soils
of the middle awash irrigated farmlands, Ethiopia. Ethiopian Journal of Agricultural
Sciences, 22(1), 127-142.

Yitbarek, A., Razack, M., Tenalem, A., Zemedagegnehu, E., and Tilahun, A. (2012).
Hydrogeological and hydrochemical framework of Upper Awash River basin, Ethiopia:
with special emphasis on inter-basins groundwater transfer between Blue Nile and Awash
Rivers. Journal of African Earth Sciences, 65, 46-60

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64
 APPENDIX
Borehole data of the study area
site name Code x y Depth yield
BurkaMisra BH-35 696722 1018866 123 8
Tutuftu BH-36 685854 1009743 196 5.6
Daga dhaba BH-37 681409 1009313 151 5.6
Sabaka BH-38 676209 1005803 150
Ufe/Negib farm/ BH-39 681160 1014332 118 1.5
Kurfa Jarti BH-40 676671 1014620 267
Hayo BH-41 668814 1001716 228 3
Fugnan Ajo BH-42 668234 1011339 272 0.4
Awa. Dudub BH-1 626351 999671 129 1.5
Kessem BH-2 606466 1011563 100 5.3
Kebena BH-3 611283 1022078 100 5.6
Awash BH-4 618963 1023518 100 5
Kurkura BH-5 632047 999422 91.08 4.6
Kurkura BH-6 632412 998041 242 4
arba BH-7 628900 1008000 80
Gonita birk BH-8 637070 1017019 85.72 3.5
Awa. Arba BH-9 628683 1008918 126 2.1
Awa. Arba BH-10 629018 1008158 52
arba wonz BH-11 628898 1007914 148 2.5
lalib.Cons.arba BH-12 632471 1008252 194 5
Arba mil. Ca BH-13 628311 1007852 117 6.2
Kerensa BH-14 624548 1017845 81 2.95
odeelise BH-15 639503 1028950 117 6.7
Elfora BH-16 643277 1025555 120 2.6
Andedo Deep Well 646560 1040111 120 5.6
Andedo BH-18 647560 1039522 88 3.8

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melka sedi BH-19 623270 1023044 105
melkas.agr BH-20 624705 1021649 70
serkemo BH-21 632337 1031448 84 2
serkemo BH-22 632988 1031094 6.5
berta well BH-23 633197 1027266 82 5
Worer BH-24 629485 1031634 41 0.6
Wore2 BH-25 629045 1030474 72 6.2
Ambash BH-26 630511 1043228 48 7.9
Sheleko BH-27 628562 1038760 50 5.6
gelsa BH-28 638732 1072353 140 4.2
Halidebi BH-29 641074 1068549 66 3.5
Belen HSP-1 644235 1046853
Hassoba BH-30 635843 1045364 100 4.8
buremedaitu BH-31 663409 1102863
Ouref BH-32 673286 1119646 120 6.7
gewan town BH-33 681441 1126215 88 2.4
gewa.town BH-34 680061 1120521 113 4.2
Berta Deep Well 633107 1027266
Undelisea Deep Well 639500 1028942
Buremedatu Artesian well 668700 1102550

66