3rd annual connference eha aug. 23, 2008 1 evaluation and development of ground water resources of...
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3rd Annual Connference EHA Aug. 23, 2008
1
EVALUATION AND DEVELOPMENT OF GROUND WATER RESOURCES OF ADA'A–BECHO PLAINS
FOR IRRIGATION PROJECT
Engida ZA*, Tilahun A*, Dr. Seifu K* and Dr. Yilma*
Client: Ministry of Water Resources
* - Consultant: Water Works Design Enterprise (WWDSE)
WATER WORKS DESIGN AND SUPERVISION ENTERPRISE
P.O.BOX 2561: Tel: 011- 6614501
Fax: 011-6615373 email: [email protected]
3rd Annual Connference EHA Aug. 23, 2008
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TABLE OF CONTENT
1. Location2. Objective and scope of the study3. Methodology
Geology and structures, Hydrology, Geophysics, Drilling of mapping wells
Isotope and water quality, Water quality monitoring, Hydrogeology
4. Main study output of the project Developing conceptual models (Inception
phase) Preparing hydrogeological map Preparing groundwater flow system of AB
Plains
3rd Annual Connference EHA Aug. 23, 2008
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TABLE OF CONTENT…
Evaluation of groundwater potential of Ada'a and Becho plains
Interaction of Debre Zeit Lakes with the groundwater system
Interaction of Awash river with the groundwater system
3rd Annual Connference EHA Aug. 23, 2008
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1. LOCATION OF THE PROJECT AREA • Central Ethiopia, in Oromia Regional State
in Upper Awash river Basin• Ada’a plain is found between elevation
1600 and 1900 masl and approximately between Co-ordinates 38050’E - 39015’E and 8030’N - 8053’N (T area-1641 km2 ,223km2M Net area of the plain1418 km2
• Becho plain is found between elevation 2040 and 2120 masl and approximately between coordinates 38008’E - 38036’E and 8038’N - 9000’N (T area 1414km2 seasonally inundated area117km2 net area 1297 km2)
Fig1
S6
3rd Annual Connference EHA Aug. 23, 2008
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Upper Awash
Abbay Plateau
ADAA PLAIN
Becho Plain
Lemi
Mulo
GolaGoja
Ambo
Mojo
Koka
Bu-i
Muger DuberDebra
Gorfo
Chobi ShenoShino
Bicho
Tefki
Dukem Ejere
BantuLemen
Degem FicheBiriti Deneba
Weberi
DaletiMinare
ChachaMekoda
Ketket
Wenoda
Aleltu
HolotaGinchi
SebetaGodino
Boneya
Dilela
Weliso
Ombole
Dinbaro
Mendida
Kachisi
AsagirtShikute
Inchini Chancho
Koremas
Sendafa
Adulala
Tarmaber
Ali Doro
Jemo Lefo
Muke TuriKembolcha
Adis Alem
Alem Gena
Tulu Bolo
Anchekorer Godo Beret
Welenkombi
Debre Zeyt
Kondaltiti
Debre Tsige
Addis AbebaChefe Donsa
Debre Genet
Debre Birhan
Shola Gebeya
Akaki Beseka
Gebre Guracha
Melka Kunture
Debre Libanos
400000
400000
450000
450000
500000
500000
550000
550000
600000
600000
9500
00950000
1000
000 1000000
1050
000 1050000
N
LOCATION MAP OF ADAA-BECHO PLAINS
8000 0 8000 16000 Meters
Fig1 LOCATION MAP OF THE PROJECT AREA
3rd Annual Connference EHA Aug. 23, 2008
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2. OBJECTIVE AND SCOPE OF THE STUDY
• Previous studies have indicated that there is a possible high groundwater potential, currently agriculture consists mainly of rain fed annual cropping. Crop yields are generally good in the project area, the high population growth has made the available land decreasing from year to year.
• Unless remedial measures are taken, the standard of living of the farmers will further decline, especially in view of the current rapid population growth rate of about 2.9 % per year. Since the rural population is expected to double in about 25 years, it is increasingly important to deal with these issues as soon as possible by implementing irrigation in the area.
3rd Annual Connference EHA Aug. 23, 2008
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2. OBJECTIVE AND SCOPE …
• Determine the hydrogeological condition of the Ada'a-Becho plains groundwater system
• Qualitative and quantitative evaluation of the groundwater resources of the plain and select potential well fields
• Carry out analytical and/or numerical model of the main aquifer of the area to recommended appropriate groundwater management
• Develop strategy of groundwater resources development together with cost estimates
3rd Annual Connference EHA Aug. 23, 2008
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3. METHODOLOGY• Data collection & review of previous works.• Geological & geomorphologic mapping• Hydrological survey and analysis • Hydrogeological investigation (water point
inventory, water quality survey, water quality monitoring, mapping well drilling & testing)
• Geophysical investigation (Resistivity and TEM)
• Isotope hydrogeology• Detail qualitative & quantitative groundwater
potential evaluation• Prioritization of potential prospective area for
Pilot well field development• Analytical Modelling SN
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECTA. Developing conceptual models (In. phase):
The hydrogeological and isotope data from Akaki catchment shows the following conditions• Most of the deep wells drilled in Addis Ababa
and adjacent areas are highly confined. Confining acidic volcanic and the aquifer basic rocks (basalt of different comp. and ages)
• The upper part of Akaki catchment is steep and composed of dominantly acidic volcanic rocks (which are practically impervious) it is difficult to assume that a recharge that occurred at the upper part of the catchment has formed a confined aquifer in the basalts at the central, eastern and western AA. The upper part of Akaki river catchment is merely runoff generator.
Fig 2
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECT…A. Developing conceptual models (In. phase): The
hydrogeological and isotope data from Akaki catchment shows the following conditions• The tritium value from different sources Yves M.
Travi, Kebede S. (2000) shows Except few wells (probably shallow wells) the other wells both cold and thermal wells are depleted in tritium value in general
• Reconnaissance surveys at Muger and Abbay rivers gorges showed that the Mesozoic sedimentary formation is most likely dipping in SSE direction, which highly favors the Abay plateau groundwater flow to SSE direction into Awash River basin
• These observations led to conceptualize that the groundwater of Addis Ababa and in general Becho and Ada'a plains groundwater is recharged mainly from outside their surface catchments. The basalt plateau of Abay river basin that is found adjacent to Akaki and Awash rivers catchments could be the main recharge zone of Ada'a plain (as shown the figs 3and 4 below)
3rd Annual Connference EHA Aug. 23, 2008
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ABBAY RIVER BASIN BASALT
PLATEAU
Mt. Erer
Mt. Intoto
PROJECT AREA (APGW B)
Abay basalt plateau basin ,possiblymain recharge area of APGW B
Upper Awash river sub-catchments
Scale 1 : 700,000
Date:- January 2006
Fig.4.3Addis Ababa, Ethiopia P.O.Box 2561 Tel. 614501 610105
Fax:- 251- 1-615371 251-1-610898
e-mail w.w.d.s.e @ telecom.net. et
WATER WORKS DESIGN AND SUPERVISION ENTERPRISE
EVALUATION OF GROUNDWATER RESOURCES OF ADA'A PLAIN FOR IRRIGATION PROJ ECT
REGIONAL HYDROGEOLOGICAL SETUP OFADA'A PLAIN GROUNDWATER BASIN
10 0 10 20 KM
N
Legend
MINISTRY OF WATER RESOURCES
FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA
Roads
Towns
Lakes / Reservoirs
Schematic hydrogeological x-section lines(Conceptual)
#
#
#
#####
#
#
#
###
###
#
Alluvials
Basalts
Basalts
Acidic volcanic rocks
Basalts and scoria
Acidic VR
Basalts
Acidic VR
Ignimbrites
AVR
AVR
AVR
LS
BECHO PLAIN
Becho_Adaa section
AA_Adaa section
ADA'A PLAIN
MUKETURE
CHANCHO
Addis Ababa
Nazareth
Debrezeit
Modjo
TULU BOLO
WELISO
Ambo
Lake
Ziw
ay
Koka Reservoir
Lege DadiReservoir
Ginchi
3
4
5
6
78910
11
12
13
SO
UTH
ER
N R
IFT
VA
LLEY
BA
SIN
®®GROUNDWATER DIVIDE
400000
400000
450000
450000
500000
500000
550000
550000
900
000
9000
00
950
000
9500
00
100
000
0 10000
00
105
000
0 10500
00
FIG 4
Fig 2 CONCEPTUAL MODEL DEV.
FIG 3
Main output
3rd Annual Connference EHA Aug. 23, 2008
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§§
0 10km 20km 30km 40km
2700
2500
2300
2100
1900
FIG 4.5 CONCEPTUAL HYDROGEOLOGICAL X-SECTION ALONG ADDIS ABABA -ADAA LINE
ABBAY RIVER BASIN AWASH RIVER BASIN
RECHARGE
INTO
TO
ADDIS ABABA
AKAKI
DUKEMDUKEM
AD
AA
PLA
INA
DA
A P
LAIN
PO
SS
IBLE
GW
DIV
IDE
SPRING (T)
SPRING (C)
BASALTS OF DIFERENT AGE AND COMPOSITION
ACIDIC VOLCANIC ROCKS
FIG 3 CONCEPTUAL X-SECTION AP-AA-ADAA
3rd Annual Connference EHA Aug. 23, 2008
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§Springs
FIG 4.6 CONCEPTUAL HYDROGEOLOGICAL SECTION ALONG BECHO - ADAA LINE
ABAY RIVER BASIN
AWASH RIVER BASIN
PO
SS
IBLE
GW
DIV
IDE
SW
DIV
IDE
BECHO SWAMP PLAIN ME
LKA
KU
NT
UR
E
CO
NF
LUE
NC
E A
KA
KI &
AW
AS
H R
IVE
RS
ADAA PLAIN
2700
2500
2300
2100
1900
1700
1500
1300
0 10km 20km 30km 40km
Ele
vatio
n in
mas
l
BASALTS, DIFFERENT AGES AND COMPOSITION ( REGIONAL AQUIFER??)
ACIDIC VOLCANIC ROCKS
FIG 4 CONCEPTUAL X-SECTION AP-BECHO-ADAA
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECT…B.Preparation of Hydrogeological map and cross-
section: Phase I: Inv. and analysis:• Hydrogeological conditions of the area is a function of
geomorphology and tectonics, on the Plateau older Tertiary volcanic outcrops to the south the younger geological formation over lies the older volcanic unit
• The recharge condition, groundwater flow and aquifer parameters in the Adaa-Becho plains is highly governed by the general bedding of the sedimentary formation underlying the volcanic unit, the tectonic condition and the hydraulic properties of the different volcanic units that outcrops in the basin
• There are two basaltic aquifers in the Becho plain and along west-east direction from Becho-Legedadi section which are separated by ignimbrites and welded tuffs
HG-Map
BECHO
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECT…B.Preparation of Hydrogeological map and cross-
section: Phase I: Inv. and analysis:• Upper Basalt Aquifer
• composed of Quaternary of Weliso-Ambo basalts, Akaki basalts: scoria and spatter cones, and Tertiary-Neogene’s basalt of Addis Ababa basalts and Tulu ries basalts.
• one aquifer system in Ada’a plain (south of Dukem)• distributed in Upper Awash, where it outcrops at Central
Addis Ababa, Weliso and Akaki and it also overlain by ignimbrites and tuffs at Becho plaains, Legedadi area, in general where the ignimbrites and tuff outcrops
• Varies from more than 200 to 50 m thickness: TDS 400-700 mg/l
• by water balance method and chloride balance method the recharge of this aquifer is estimated to be 390 Mm3/year
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECT…B.Preparation of Hydrogeological map and cross-
section: Phase I: Inv. and analysis:• Lower Basalt Aquifer
• composed of tertiary Tarmaber basalt composed of dominantly scoraceous basalt and Amba Aiba basalt. These tertiary basalt formations occupy more than 75% of Abay plateau about 7,000 km2. .
• mapping wells drilling at Becho Plain, Holota, Melka Kunture, Legedadi areas penetrated at different depth this aquifer. The total confining head more than 220 meters
• The yield of the well was progressively increasing when the depth of penetration is increased in this aquifer. Water level varies from artesian condition to a depth of 67.5 meters
• The total annually recharge of the lower aquifer is estimated by different method is about 700Mm3/year.
Sn 24
3rd Annual Connference EHA Aug. 23, 2008
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BECHO PLAIN
ADAA PLAIN
T1
T2
T3
T4
T5
T6
T7
T8
T9
S1
S2
S3
S4
S5
S6
S7
S8
T1 1
T1 2
T1 3
T1 4
T1 5
T1 6
T1 7
T1 8
T1 9
T2 0
T2 1
T2 2
T2 3
S2 A
S5 A
S7 A
S1 0
S1 1
S1 2
S1 3
S1 4
S1 5
S1 6
S1 7
S1 8
S1 9
S2 0
S2 1
S2 2 S2 3
S2 4
S2 5
S2 6S2 7
S2 8
S2 9
S3 0
S3 1
S3 2
S3 3
S3 4
S3 5
S3 6
S3 7
S3 9
S4 0
S4 1
S4 2
S4 3
S4 4
S4 5
S4 6
S4 7
S4 8
S4 9
S5 0
S5 1
S5 2
S5 3
S5 4
S5 5
S5 6
S5 7
S5 8
S5 9
S6 0
S6 1
S6 2
S6 3
S6 4
S6 5
S6 6
S6 7
S6 8
S6 9
S7 0
S7 1
S7 2
S7 3
S7 4
S7 5
S7 6
S7 7
S7 8
S7 9
S8 0
S8 1
S8 2
S8 3
S8 4
S8 5
S8 6
S8 7
S8 8
S8 9
S9 0
S9 1
S9 2
S9 3
S9 4
VESB- 1
VESB- 2 VESB- 3VESB- 4
VESB- 5
VESB- 6
VESB- 7VESB- 8
VESB- 9
VESB- 6a
VESB- 10 VESB- 11
VESB- 12VESB- 13
VESB- 14 VESB- 15
VESB- 16VESB- 17
VESB- 18
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VESB- 21 VESB- 22
VESB- 23 VESB- 24
VESB- 25
VESB- 26
VESB- 28
VESB- 29 VESB- 31VESB- 32
MU
GE
R-B
EC
HO
SE
CTIO
N LIN
E
West-east section line along Abay Plateau
West-east section line along Upper Awash
Wen
oda_
Akak
i sec
tion
line
AdBh
AMW1
AMW2
AMW3
AMW4
AMW6
AMW7
AMW8
AMW9
AMW5
AM_F
AMW13
AMW15
AMW17
AMW16
AMW14
AMW11
AMW10
AdBh648
AdBh660AdBh439
AdBh485
AdBh477AdBh474
AdBh734
AdBh403
AdBh002
AdBh236
AdBh355
AdBh339
AdBh126
AdBh340
AdBh263
AdBh318
AdBh116
AdBh038AdBh198
AdBh358
AdBh241
AdBh246
AdBh291
AdBh301
AdBh001
AdBh019
AdBh042
AdBh048
AdBh129AdBh130
AdBh152
AdBh182
AdBh293A
Kachise-Adaa P
lain section line
Lemi
Mulo
Gola
Goja
Mojo
Koka
Bu-i
Muger DuberDebra
Gorfo
Chobi ShenoShino
Bicho
Tefki
DukemEjere
BantuLemen
DegemFiche
Biriti Deneba
Weberi
DaletiMinare
ChachaMekoda
Ketket
Wenoda
Aleltu
Holota
Ginchi
Sebeta
Godino
Boneya
Dilela
Weliso
Ombole
Dinbaro
Mendida
AsagirtShikute
Inchini Chancho
Koremas
Sendafa
Adulala
Inewari
Tarmaber
Ali Doro
Jemo Lefo
Muke Turi
Kembolcha
Adis Alem
Alem Gena
Tulu Bolo
Anchekorer Godo Beret
Welenkombi
Debre Zeyt
Kondaltiti
Debre Tsige
Addis Abeba
Chefe Donsa
Debre Genet
Debre Birhan
Shola Gebeya
Akaki Beseka
Gebre Guracha
Melka Kunture
Debre Libanos
Segno Gebeya _Legedadi se
400000
400000
450000
450000
500000
500000
550000
550000
600000
600000
650000
650000
9500
00
950000
1000
000 1000000
1050
000 1050000
110
000
0
HYDROGEOLOGICAL MAP OF ADAA-BECHO PLAINS GROUNDWATER BASIN
Scale 1:700,000Date: April -07
Drawn by EZA
WATER WORKS DESIGN AND SUPERVISION ENTERPRISE
Preliminary Hydrogeological map of Ada'a - Bechoplains and their recharge areasTITLE:
PROJECT: Evaluation of the groundwater potential of Ada'a -Becho Plains
FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIAMINISTRY OF WATER RESOURCES
Scale 1:700,000
Meters8000400004000
N
Faults/lineaments
upper awash
Abbay Plateau
Adaa-Becho plains Groundwater basin and its recharge area
Groundwater divides
Groundwater flow-directions
HYDROGEOLOGICAL X-SECTIONS
Ñ VES POINTS
#YMAPPING WELLS DRILLED BY THE PROJECTAND WOBERI WELL BY OROMIA IRRIGATIONDEV. AUTHORITY
#Y EXISTING WELLS DEPTH > 150 METERS
II. MISCELLANEOUS
Out crops in the gorges, there may be a possibility to pentrate this formation at a great depth more than 450 meters At Abay Plateau
D. Mesozoic Sedimentary aquifers
Tertiary and Quaternary Rhyolitic and trachytic volcanic r idges and volcanic centers (QbgPr+QZqTy+NebRy +NCvTy) of Bede gebaba, Ziquala, Wechecha, Furu, Yerer,etc. localized aquicludes
C3. Localized aquiclude
C2. EXtensive and regional upper aquicludeRegional to Sub-regional lower aquiclude of Asahngi Basalt (PaaB), Blue Nile Columnar Basalts (PntbB) and Alaji Ryholites acts as regonal aquiclude between the lower basalt aquifer and Mesozoic sedimentary formations
Regional to Sub-regional aquiclude of Nazaret groups (NnuRI) welded ingnimbrites, Chefe donsa pyroclastics (NQcdPc) and Addis Ababa Ignimbrites (NadB), have low groundwater potent along fractrues andweathered zone. Separates the upper and lower basaltic aquifers
C1. EXtensive and regional upper aquiclude
C. Regional and local Volcanic aquitards
B2. Lower basalt AquiferLower Tertiary Volcanic aquifer : Tarmaber scoraceous basalt (PntbB) and Amba Aiba basalt (PaaB) high productive aquifer. Outcrops in Abay plateau and underlain by acidic volcanic rocks in upper Awash
Quaternary and Tertiary basalts, Bishoftu saptter cones and lava flows (QbiB), Weliso-Ambo basalt (QabB), Akaki Basalts and Scoria (NakB) and Addis Ababa basalts (NadB) moderate to high sub-regional aquifers
B1. Upper Basalt Aquifer
B. Fractured and Scoraceous basalt Aquifers
Alluvium of Abay plateau (Qal) and Debre Zeit area allluvium and lascustrine (Qal+Qld) aquifer of modertae to high productivity
A. Extensive aquifers with primary porosity
I. Aquifers Properties
LEGEND
Fig 6
Fig 7
Fig 5 Hydrogeological Map of ADAA-BECHO PLAINS
Fig 8Fig 9 Fig 10
Fig11
3rd Annual Connference EHA Aug. 23, 2008
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Fig 6 HYDROGEOLOGICAL X-SECTION ALONG BECHO PLAIN
3rd Annual Connference EHA Aug. 23, 2008
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Fig 7 Hydrogeological x-section along Kachise –Becho-Ada’a line
3rd Annual Connference EHA Aug. 23, 2008
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Fig 8 Muger-Holota-Becho
3rd Annual Connference EHA Aug. 23, 2008
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Fig 9 SEGNO GEBYA-LEGEDADI
Well log
3rd Annual Connference EHA Aug. 23, 2008
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Fig 10 Hydrogeological x-section along Plateau -Legedadi - Akaki section line
3rd Annual Connference EHA Aug. 23, 2008
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Fig 11 Hydrogeological x-section in Ada’a Plain (Southwest – Northeast direction)
3rd Annual Connference EHA Aug. 23, 2008
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3. MAIN OUTPUTS OF THE PROJECT…
B.Preparation of Groundwater flow system of AB Plains: Phase I: Inv. and analysis:
• Groundwater level elevation contour map was constructed for the regional basalt aquifer (lower aquifer) applying the data generated from drilling of mapping wells and existing bore holes identified to be representing the regional aquifer water level
• On the groundwater elevation contour map the following understanding is obtained• Entoto and Wechecha –furi and Bedegebaba ridges acts as
local barrier• The recharge at Abay plateau flows to Upper Awash through
two main direction i.e. through Becho plain and along Legedadi areas
• Almost 100% of Abay plateau is the recharge area of the lower basalt aquifer in Upper Awash basin
• Bore holes drilled along flow paths have yield and artesian if drilled at lower places
Fig12
Fig 12 sn30
3rd Annual Connference EHA Aug. 23, 2008
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Abb
ay P
late
au
Up
per
Aw
a sh
ADAA PLAIN
Becho Plain
Lake Ziway
Koka reservoir
Aba Samuel
AddisAbaba
Adama
Bishoftu
Modjo
Gu ra ge Hig h lan ds
Mt . We ch ech a
Mt . Yerer
Mt . Z iq ua la
Int ot o Rid ge
Mt . F ur i
Mt . Gu ji
Mt . Be de Ge ba ba
Lemi
Mulo
Gola
Goja
Ambo
Mojo
Koka
Bu-i
Muger Duber
DebraGorfo
Chobi ShenoShino
Bicho
Tefki
DukemEjere
BantuLemen
FicheDeneba
Weberi
Daleti
ChachaMekoda
Ketket
Wenoda
Aleltu
Holota
Ginchi
Sebeta
Godino
Boneya
Di lela
Weliso
Ombole
Dinbaro
Mendida
AsagirtShikute
Inchini Chancho
Koremas
Sendafa
Adulala
Ali Doro
Muke Turi
Kembolcha
Adis Alem
Alem Gena
Tulu Bolo
Welenkombi
Debre Zeyt
Kondaltiti
Debre Tsige
Addis Abeba
Chefe Donsa
Debre Genet
Debre Birhan
Shola Gebeya
Akaki Beseka
Melka Kunture
Fig 12 SIMPLIFIED GROUNDWATER FLOW PATHS IN AB
3rd Annual Connference EHA Aug. 23, 2008
26
Fig 13 Drilling at Holeta area
3rd Annual Connference EHA Aug. 23, 2008
27
Fig 14 DRILLING AT
ASGORI
3rd Annual Connference EHA Aug. 23, 2008
28
Fig 15 Melka Kunture Pumping test Q=36 l/s
3rd Annual Connference EHA Aug. 23, 2008
29
Fig 16 Artesian flow well drilled south of legedadi
3rd Annual Connference EHA Aug. 23, 2008
30
3. MAIN OUTPUTS OF THE PROJECT…
C.Evaluation of groundwater potential of Ada’a plains (ECGPAP):
• AQUIFER CHARACTERISTICS• aquifer composed of scoria, scoraceous
Basalt and fractured basalt unconfined extensive with high transmissivity
• groundwater recharge to Ada’a plain groundwater system is from three direction i.e.i) between Mountains Yerer and Guji, ii) between Bede Gebaba and Ziquala (Qgz) and from Mojo, Wedecha and Belebela catchment (Qmw).
3rd Annual Connference EHA Aug. 23, 2008
31
ADAA PLAINÊÚÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
#Y
#Y
#Y
#Y
#Y
#Y
ð
ð
ð
ðð
ðð
ð
ð
Lake chelelka
Lake Hora
Lake Kilole
Lake Bishoftu
Lake Hado
Lake Bishoftu Guda
Lake Kurif tu
1864
1884
1856
1870
Koka reservoir
Belbela reservoir
1590
1930
Mt. Ziquala
Mt. Guji
Mt. Bede GebabaAMW5
AMW21
AMW25
AMW12A
AMW12B AMW22A
AMW22B
AMW24A
AMW24BMojo
Koka
Dukem
Ombole
Adulala
Alem Tena
Debre Zeyt
Akaki Beseka
Tede
Dire Well
Gafat well
Dukem MBI
Shimbira MedaWell
Air force well
Awash River at
155
0
190 0
1800
1650
1800
1650
1950
1900
1600
1750
1650
1850
1700
2100
1800
1600
2000
1750
1800
1950
1850
1700
1800
1750
480000
480000
490000
490000
500000
500000
510000
510000
9200
00
920000
9300
00
930000
9400
00
940000
9500
00
950000
9600
00
960000
9700
00
970000
9800
00
980000
GROUND WATER LEVEL ELEVATION CONTOUR MAP OF ADAA PLAIN GROUNDWATER BASIN
Groundwater Level elevation contour
Mapping wellsð
Groundwater flowdirections
Water Quality monitoring Bore Hole#Y
All-weather roads (asphalt)
All-weather roads (gravel)
Railway
LEGEND
A B Hydrogeological x-section
3000 0 3000 6000Meters
N
Scale 1:250,000
A
B
3rd Annual Connference EHA Aug. 23, 2008
32
Fig 11 Hydrogeological x-section in Ada’a Plain (Southwest – Northeast direction)
3rd Annual Connference EHA Aug. 23, 2008
33
3. MAIN OUTPUTS OF THE PROJECT…
C. ECGPAP: ESTIMATED RECHARGE APRecharge Direction
Weighted transmissivity (Tav), m2/day
Width of flow (L), m
Average flow gradient (I)
Recharge estimated in MCM/year
Remark
Yerer –Guji Zone
1200 10,800 0.02 94.6
Bede Gebaba – Ziqual
10,200 13,460 0.01 532.0
Modjo+Wedecha +Belebela
153.0 Vol. II chap 7.3
Total 779.6 MCM/Year
3rd Annual Connference EHA Aug. 23, 2008
34
3. MAIN OUTPUTS OF THE PROJECT… ESTIMATED EXPLOITABLE GWR OF AP Analytical
method
• Excluding the recharge from Becho plain due to the maximum exploitation of the groundwater resource in the plain the net available exploitable ground water potential is estimated about 1,046MCM/year or 2.9MCM/day or 33 500 l/s
3rd Annual Connference EHA Aug. 23, 2008
35
3. MAIN OUTPUTS OF THE PROJECT… PRIORITIZING GROUNDWATER PROSPECTING SITES IN AP
Prospective site
Prioritizing Criteria Ranking
Area, ha
GWD range, m
T,Range, m2/day
EC,range, μS/cm
A 23,425
Dominantly from 60-120
5,000-10,000 in some part >10,000
Dominantly 500-750
2
B 19,760
< 30 5,000-10,000
Dominantly 500-750
1
C 5,540 60-120 5,000-10,000
500-750 3
D 3,316 30-90 200-1,000 500-750 4
Fig 17
3rd Annual Connference EHA Aug. 23, 2008
36
jj
j
j
j
j
j
j
Mojo
Koka
Dukem
Godino
Ombole
Adulala
Debre Zeyt
Akaki BesekaMt. Yerer
Mt. Ziquala
Mt. Guji
Mt. Bede Gebaba
A
BC
D
Koka reservoir
Belbela reservoir
Lake chelelka
Lake Bishoftu
Lake Hado
Lake Bishoftu Guda
River Awash
480000
480000
490000
490000
500000
500000
510000
510000
9200
00
920000
9300
00
930000
9400
00
940000
9500
00
950000
9600
00
960000
9700
00
970000
9800
00
980000
GROUNDWATER PROSPECTIVE SITES IN ADAA PLAIN
GROUNDWATERPROSPECTIVE SITES
Debrezeit lakes
Rivers
Townsj
LEGEND
Reservoirs
Main Roads (Asphalt)
Rail Way
N
4000 0 4000 Meters
Scale 1:250,000
Table
3. MAIN OUTPUTS OF THE PROJECT… C. ECGPAP: Fig 17 Prospective groundwater potential sites
3rd Annual Connference EHA Aug. 23, 2008
37
3. MAIN OUTPUTS OF THE PROJECT…
C. ECGPAP: Parameters considered• The groundwater system as extensive
unconfined aquifer.• Average transmissivity of the confined
aquifer Tavg = 5000m2/day • The specific yield of the aquifer is
estimated to be about 0.25.• Thickness of Aquifer 300 m• 100 wells 1km apart in grid
3rd Annual Connference EHA Aug. 23, 2008
38
#Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y#Y #Y #Y #Y
#Y#Y #Y
#Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y #Y
#Y #Y #Y #Y #Y #Y #Y #Y
#Y#Y
((
496000
496000
498000
498000
500000
500000
502000
502000
504000
504000
506000
506000
508000
508000
510000
510000
512000
512000
514000
514000
9620
00
962000
9640
00
964000
9660
00
966000
9680
00
968000
9700
00
970000
9720
00
972000
FIGURE 18 PROPOSED PRODUCTION WELLS DISTRIBUTION IN THE MOST PROSPECTIVE SITE OF ADAA PLAIN
N
200 0 200 400 Meters
Scale 1:50,000
CENTRAL WELL
Productionwells (proposed)#Y
Legend
C. ECGPAP: Fig 18 Proposed PW in prioritized sites
3rd Annual Connference EHA Aug. 23, 2008
39
C. ECGPAP: Calculated Max DD in the WF for different scenario of Abstraction rate and duration of pumping
Scenari
o
Well discharge
No. wells
Total discharge
Calculated maximum drawdown at the center of the well field for
different period of exploitation
l/sm3/ day l/s
m3/day
500 days
1000 days
2000 days
5000 days
8000 days
10000 days
1.4
2.7 5.513.
7 21.927.4
1 20 1728 120 240020736
0 2.3 4.6 6.9 9.9 11.4 12.2
2 40 3456 120 480041472
0 4.6 9.113.
719.
8 22.9 24.4
3 50 4320 120 600051840
0 5.711.
417.
224.
7 28.6 30.4
4 70 6048 120 840072576
0 8 16 2434.
6 40 42.6
5 100 8640 1201200
010368
00 11.422.
934.
349.
4 57.2 60.9
3rd Annual Connference EHA Aug. 23, 2008
40
C. ECGPAP: Estimated EGWP of prioritized area
• The estimated exploitable groundwater resource (safe yield) is about 378MCM /Year or 1,036,800 m3/day or 8, 640 l/s by 100 wells each discharging 100 l/s.
Calculated Drawdown for Diffrent Scenario Abstraction Rate and duration T = 5000 m2/day
0.0
20.0
40.0
60.0
80.0
100.0
120.0
0 2000 4000 6000 8000 10000 12000
Exploitation Period in days
Calcu
lated
Dra
wdow
n, m
Q=207,360 m3/dayQ=414,270 m3/dayQ=518,400 m3/dayQ=725,760 m3/dayQ=1,036800 m3/dayPermissible DD
3rd Annual Connference EHA Aug. 23, 2008
41
C. ECGPAP: IMPACT ON THE LAKES
Lake Name
Distance from
the well field, m
Discharge of the wells in m3/day and drawdown after 5000 days
207360
414720
518400
725760
1036800
LakeBishoftu Guda 3025 2.68 5.36 6.69 9.37 13.39
Lake Hora 2663 0.89 1.79 2.23 3.12 4.46
Lake Bishoftu 3650 0.89 1.79 2.23 3.12 4.46
3rd Annual Connference EHA Aug. 23, 2008
42
C. ECGPAP: IMPACT ON THE LAKES
• The result of analysis shows that the maximum drawdown created on the lakes is less than 14 meters on the nearest lake Bishoftu Guda. Here it is found possible to shift further to the east the well field by two kilometers and the draw down on Lake Bishoftu Guda decrease similar to the other lakes.
• Further Numerical modeling shall be conducted to verify this analytical calculation in the final report. The estimated exploitable resources is estimated about 378 MCM/year on site B.
3rd Annual Connference EHA Aug. 23, 2008
43
C. ECGPAP: NEXT STAGE
• Drilling of 5 pilot wells each well discharge 100 l/s
• Detail design of 500 ha Pressurized irrigation
• Ground water modelling• Feasibility design of 10, 000 ha
pressurized irrigation
3rd Annual Connference EHA Aug. 23, 2008
44
MAIN OUTPUTS OF THE PROJECT…
D. Interaction of Debre Zeit Lakes with the groundwater
• Hydrogeological method of analysis• Water quality monitoring• Monthly water balance of DZ lakes
(hydrologic method
3rd Annual Connference EHA Aug. 23, 2008
45
MAIN OUTPUTS OF THE PROJECT…
D. Interaction of Debre Zeit Lakes with the groundwater
• Hydrogeological method of analysis• Constructing a groundwater level elevation
contour: two groundwater flow regimes within Ada’a plain caused by Debre Zeit lakes and Mountain Bede Gababa which they act as a groundwater divide and Barrier to the ground water system (fig 19)
• Water Quality monitoring (fig 20)• Lake Water balance of DZ lakes (fig21)
F1
3rd Annual Connference EHA Aug. 23, 2008
46
Fig 19 Groundwater flow paths at DZ lakes area
ÊÚ
ÊÚ
#Y
#Y
#Y
#Y
Lake chelelka
Lake Hora
Lake Kilole
Lake Bishoftu
Lake Hado
Lake Bishoftu Guda
Lake Kuriftu
1864
1884
1856
1870
1930
Mt. Guji
Mt. Bede Gebaba
Mojo
Dukem
Debre Zeyt
190 0
1800
1900
1750
1850
2000
1950
1850
1700
1750
Dire Well
Gafat well
Shimbira MedaWell
Air force well
485000
485000
490000
490000
495000
495000
500000
500000
505000
505000
510000
510000
515000
515000
520000
520000
9550
00
955000
9600
00
960000
9650
00
965000
9700
00
970000
9750
00
975000
Water Quality monitoring Bore holes#YGroundwater level elevation contour
All-weather roads (asphalt)
Motorable tracks (status uncertain)
Railway
LEGEND
1800
Groundwater f low directions
GROUNDWATER FLOW DIRECTIONS AT DEBEREZEIT LAKES AREAAND MONITORING WELLS
N
2000 0 2000 4000 Meters
Scale 1:150,000
3rd Annual Connference EHA Aug. 23, 2008
47
Fig 20 EC versus time monitored BH (WQM)
TREND OF ELECTRICAL CONDUCTIVITY OF BORE HOLES AROUND DEBRE ZEIT LAKES FROM JANUARY 2006 TO DECEMBER 2007
0
200
400
600
800
1000
1200
1400
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Time, months 2006-2007
EC
, mic
roS
/cm
MBI well-AdBh0038 Air force well AdBh0068
Tede Well -AdBh0040 Gafat well-AdBh0081
Dire Well-AdBh0296 DZ-Shimbra Meda Well-AdBH0064
3rd Annual Connference EHA Aug. 23, 2008
48
Fig 21 Time series of groundwater Inflow-outflow (1000 m3)
3rd Annual Connference EHA Aug. 23, 2008
49
MAIN OUTPUTS OF THE PROJECT…
D. Interaction of Debre Zeit Lakes with the groundwater
• All the methods (Hydrogeological, water quality monitoring and Water balance of DZ lakes showed method the lakes except Kurftu lake acts as groundwater divide (recharge boundary) and Bede gebaba ridge as a barrier.
3rd Annual Connference EHA Aug. 23, 2008
50
MAIN OUTPUTS OF THE PROJECT…E. Interaction of Awash river
with the groundwater• Awash river monitored two stations
(upstream at Melkakunture and down stream at Ombole river gauging stations) far apart more than 50kms. From July- September, the EC at the two stations are nearly similar (about 100µS/cm). During dry season the electrical conductivity value measured at the two stations shows larger gap (400µS/cm at Melka Kunture and 600-650µS/cm at Ombole respectively). The conductivity of the regional groundwater of the area between Melka Kunture and Ombole vary from 600 to 650 µS/cm. The higher EC value measured at Ombole site verifies the fact that the river is being recharged by regional groundwater and the base flow from November to June at this station is from the regional groundwater
Trend of Electrical Conductivity and Bicarbonates of Awash river at two Stations
0
100
200
300
400
500
600
700
800
900
1000
Jan
Feb
Mar
Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec Ja
n
Feb
Mar
Apr
May Ju
n
Jul
Aug
Sep Oct
Nov
Dec
Time,month- Jan 2006 -2007
Par
amet
ers
EC
in m
icro
S/c
m a
nd
HC
O3
in m
g/l
HCO3- R. Awash @ Ombole
HCO3- R. Awash @ Melka Kunture
R. Awash @t Ombole - Downstream
R. Awash @ Melka Kunture-Upstream
SN19
3rd Annual Connference EHA Aug. 23, 2008
51
Fig 22 Interaction of Awash with the groundwater
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
ÊÚ
#·
#·
#·#·
#·
#·
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y#Y
#Y#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y
#Y#Y
#Y #Y
#Y#Y
#Y
#Y#Y
#Y
#Y
§
§
§§§
§
Aba Samuel2047
Mt. Ziquala
Mt. Guji
AMW4
AMW5
AMW12A
AMW12B
AMW24A
AMW24B
Dukem
Lemen
Boneya
Ombole
Adulala
Kondaltiti
Melka Kunture
1800
2100
1850
1650
1950
1900
1900
1750
2050
1650
1850
1700
1800
2050
2100
2000
1750
2000
1800
1950
2100
1700
1800
455000
455000
460000
460000
465000
465000
470000
470000
475000
475000
480000
480000
485000
485000
490000
4900009250
00
925000
9300
00
930000
9350
00
935000
9400
00
940000
9450
00
945000
9500
00
950000
9550
00
955000
9600
00
960000
9650
00
965000
9700
00
970000
9750
00
975000
Contours of elevation of groundwater level, masl
MAIN RIVER
RIVER
Reservoirs
LEGEND
Reservoirs
Zone grounwater dicharge to Awash river
N
4000 0 4000 8000 Meters
1:200000
3rd Annual Connference EHA Aug. 23, 2008
52
TEM Interpretation at Inchini
3rd Annual Connference EHA Aug. 23, 2008
53
Segno Gebeya
3rd Annual Connference EHA Aug. 23, 2008
54
Sululta
3rd Annual Connference EHA Aug. 23, 2008
55
Chancho
3rd Annual Connference EHA Aug. 23, 2008
56
THANK YOUFOR YOUR ATTENTION!!