Total Oxidant-Antioxidant Status Among Psoriatic Patients Attending At Alert Hospital, Addis Ababa

102 Pages·2016·4.72 MB·English

Interbasin Groundwater Transfer in Upper Rift Valley
Lakes and Upper Awash River Basins

By:
Bisrat Ayalew

Addis Ababa University
June, 2015
Addis Ababa University
Addis Ababa Institute of Technology
School of Graduate Studies
School of Civil and Environmental Engineering

Interbasin Groundwater Transfer in Upper Rift Valley Lakes
and Upper Awash River Basins
A thesis submitted to the School of Graduate Studies of Addis Ababa University in Partial
fulfillment of the Degree of Masters of Science in Civil Engineering under Hydraulic
Engineering.

By:
Bisrat Ayalew
Advisor:
Dr. Mebruk Mohammed

June, 2015
Addis Ababa University
Addis Ababa Institute of Technology
School of Graduate Studies
School of Civil and Environmental Engineering

Interbasin Groundwater Transfer in Upper Rift Valley Lakes
and Upper Awash River Basins
A thesis submitted to the School of Graduate Studies of Addis Ababa University in partial
fulfillment of the Degree of Masters of Science in Civil Engineering under Hydraulic
Engineering

By
Bisrat Ayalew Yifru

Approval by Board of Examiners

Dr. Esayas G/Youhannes ------------------
Chairman (Department of graduate committee) Signature

Dr. –Ing Mebruk Mohammed ------------------
Advisor Signature

Dr.-Ing. Asie Kemal -----------------
Internal Examiner Signature

Dr. Agizew Nigussie ------------------
External Examiner Signature
Certification
The undersigned certify that he has read the thesis entitled: Interbasin Groundwater

Transfer in Upper Rift Valley Lakes and Upper Awash River Basins and hereby
recommend for acceptance by the Addis Ababa University in partial fulfillment of the

requirements for the degree of Master of Science.

____________________________________ 
Dr. Mebruk Mohammed (Advisor)

_______________________________________ 
Date
ABSTRACT
Groundwater models are used to predict the groundwater flow processes using mathematical
equations based on certain simplifying assumptions. Numerical modeling method is used to
investigate the possibility of groundwater transfer (interbasin groundwater flow) between
Upper Awash River basin and Upper Rift Valley Lakes basin. Within the study the
hydrogeology is investigated from previous studies, a conceptual groundwater model is
produced and the numerical model is developed from this. The model conceptualization is
done by idealizing the study area into three models related to the surface water divide and the
main perennial Rivers and lakes. For these three basins the boundary conditions are identified
and incorporated into the models. The boundaries are Upper Awash River, Meki River, Ziway
Lake, and Koka Lake in addition to bottom and top surface of the aquifer in concern. The
models are three dimensional steady state by finite element method. All the study basins are
discretized according to finite element method into equal element dimensions. The elements
are three dimensional. The finite element model used in the study was TAGSAC. The
modeling process was towards estimating the hydraulic head in the model basins of the study
area by a means of finding the hydraulic conductivity of different geological classifications
and estimating surface recharge in terms of some percentage of the rainfall of the study area.
Finally the models are calibrated with the measured hydraulic head for each model basins.
The models results show that the groundwater divide and the surface water divide are not
coincident. There is a clear hydraulic head difference which can make groundwater to flow
from Upper Rift Valley Lakes basin towards Upper Awash basin in the middle of the study
area, along Ziway- Koka Lake and from Upper Awash to Rift Valley Lakes basin at west and
east part of it.
Key Words: Upper Awash River basin, Upper Rift Valley Lakes basin, Interbasin flow,
Groundwater flow Modeling, Hydraulic head, TAGSAK

i
ACKNOWLEDGMENTS
First of all, I would like to thank Ethiopian Road Authority (ERA) for giving me this
scholarship in Addis Ababa University. Most of all, my greatest appreciation goes to my
advisor, Dr. Mebruk Mohammed, who invested his time, knowledge and energy throughout
the whole research work. He is very supportive, willing and generally great. Furthermore, I
would like to express my warmest gratitude to Water Works Design and Supervision
Enterprise, Ethiopian Ministry of Water Resources and Energy, and National Metrological
Agency for their unprecedented collaboration during secondary data collection. Lastly I want
to thank my family and friends, who were encouraging and supporting me to finish this
research.

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TABLE OF CONTENTS
ABSTRACT ............................................................................................................................ i
ACKNOWLEDGMENTS ...................................................................................................... ii
LIST OF FIGURES AND TABLES ...................................................................................... v
LIST OF ACRONYMS ........................................................................................................ vii
1 INTRODUCTION ........................................................................................................... 1
1.1 Statement of the problem ....................................................................................... 4
1.2 Objective of the study .............................................................................................. 4
1.3 Structure of the thesis ............................................................................................. 5
2 LITERATURE REVIEW ................................................................................................ 6
2.1 Interbasin flow ......................................................................................................... 6
2.2 Surface topography .................................................................................................. 8
2.3 Hydrometeorology ................................................................................................. 10
2.4 Geology and hydrogeology .................................................................................... 12
2.4.1 Geological setting ............................................................................................... 13
2.4.2 Hydrogeology ..................................................................................................... 14
2.4.3 Hydrology ........................................................................................................... 15
2.5 Groundwater .......................................................................................................... 16
2.5.1 Groundwater recharge ....................................................................................... 17
2.5.2 Groundwater flow model formulation ............................................................... 19
2.5.3 Groundwater flow equation............................................................................... 22
3 METHODOLOGY ........................................................................................................ 27
3.1 Location of the study area ..................................................................................... 27
3.2 Data collection ....................................................................................................... 29
3.3 Processing and analysis .......................................................................................... 29
3.4 Groundwater modeling .......................................................................................... 30
3.4.1 Discretization of the problem domain ............................................................... 30
3.4.2 Approximating equations ................................................................................... 33
3.5 Model Conceptualization ....................................................................................... 37
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3.5.1 Aquifer material properties ............................................................................... 37
3.5.2 Boundary conditions .......................................................................................... 38
3.5.3 Modeling approach and protocol ...................................................................... 39
4 RESULT AND DISCUSSION ...................................................................................... 43
4.1 Well inventory ........................................................................................................ 43
4.2 Rainfall distribution ................................................................................................ 44
4.3 Aquifer geometry ................................................................................................... 46
4.4 Hydraulic head and interbasin flow ....................................................................... 47
4.5 Model calibration and results ................................................................................ 51
5 CONCLUSION AND RECOMMENDATION ............................................................ 62
5.1 Conclusion .............................................................................................................. 62
5.2 Recommendation ................................................................................................... 63
6. REFERENCES .............................................................................................................. 65
APPENDIX 1 Wells used in Upper Awash River basin model ........................................... 68
APPENDIX 2 Wells used in Upper Rift valley Lakes basin model ..................................... 72

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LIST OF FIGURES AND TABLES
 Figure 2‐1Surface topography of Upper Awash River basin (UARB) and Upper Rift Valley 
Lake basin (URVLB) ................................................................................................................. 9
Figure 2‐2 longitudinal profile of the study area along the surface water divide (Awash ‐ Rift 
basin boundary from A to B in Figure 2.1) ........................................................................... 10
Figure 2‐3 longitudinal profile of the study area from Ziway Lake to Koka Lake (from ‘C’ to 
‘D’ in Figure 2.1) .................................................................................................................... 10
Figure 2‐4 yearly average rainfall distribution of the study area for some selected stations 
(from NMSA) ......................................................................................................................... 11
Figure 2‐5 Monthly rainfall distribution of the study area for some selected stations (from 
NMSA) ................................................................................................................................... 12
Figure 2‐6 General flow chart of numerical groundwater modeling process after (Anderson, 
1982) ..................................................................................................................................... 20
Figure 2‐7 Representative control volume (REV) ................................................................. 22
 Figure 3‐1 the three model basins of the study area (‘A’ is major basins of Ethiopia adopted 
from (Seleshi, 2007), ‘B’ is the study area showing the three model basins and boundaries)
.............................................................................................................................................. 28
Figure 3‐2 Upper Awash River basin, generated meshes ..................................................... 32
Figure 3‐3 Upper Rift Valley lakes basin, generated meshes ............................................... 32
Figure 3‐4 Upper Awash River basin – Upper Rift valley lakes basin generated mesh ........ 33
Figure 3‐5 Modeling protocol ............................................................................................... 42
Figure 4‐1 well location in the study area both in the URVLB and UARB ............................ 44
Figure 4‐2 constructed Thiessen polygon for the study area ............................................... 45
Figure 4‐3 Aquifer geometry used in the model .................................................................. 47
Figure 4‐4 Contour of simulated head potential and groundwater flow direction of Upper 
Awash River basin ................................................................................................................. 49
v
Figure 4‐5 Contour of simulated head potential and groundwater flow direction of Upper 
Rift Valley lakes basin ........................................................................................................... 50
Figure 4‐6 Contour of simulated head potential and groundwater flow direction of Upper 
Awash and Upper Rift Valley lakes basin as considered as one basin (Awash –Rift) ........... 51
Figure 4‐7 Geological classification of the area used in the model ..................................... 54
Figure 4‐8 Plot (regression graph) of measured head versus modeled head for Upper Rift 
valley lakes basin .................................................................................................................. 55
Figure 4‐9 Plot (regression graph) of measured head versus modeled head for Upper Awash 
basin ...................................................................................................................................... 56
Figure 4‐10 Plot (regression graph) of measured head versus modeled head for Upper 
Awash ‐Rift basin .................................................................................................................. 56
Figure 4‐11 Groundwater sub basins of the combined basins (Upper Awash – Rift) from 
simulated head potential and Surface water divide of UARB and URVLB ........................... 59
Figure 4‐12 Scatter plot of Upper Awash ‐ Rift basin. .......................................................... 60
Figure 4‐13 Scatter plot of Upper Awash basin .................................................................... 60
Figure 4-14 Scatter plot of the Upper Rift valley lakes basin .............................................. 61
Table 4.1 Mean annual precipitation of the study area ....................................................... 46 
Table 4.2 Geologic parameters of the study area for classified geological zones ............... 53 
Table 4.3 Summary of calibration errors .............................................................................. 58 

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