Amibara Irrigation System Preliminary Report Summary

'SH
GOVERNMEN.
M)
VALLEY AUTHORITY
MELKA SADI and AM I BARA IRRIGATION SYSTEM LAYOUT
PRELIMINARY REPORT
rch 1568
S’TTALIA S.r.l.Imperial Ethiopian Government
AWASH valley authority
M £ L K A SADI and A M I B A H A IRRIGATION SYSTEM LAYOUT
PRELIMINARY REPORT
a n
-     CLIMATIC and HYDROLOGIC DATA
- IRRIGATION WATER REQUIREMENTS
march 1966 SEPITALIA - S.r.l.Inperlel Ethiopian Government AWASH VALLEY AUTHOR ITY
>C1XA SADI AND AMIBARA
IRRIGATION SYSTEM LAYOUT
PRELIMINARY REPORT
on
March 1968
SEPITALIA a.r.l.BUILDING MAT&UAL
fVJKQ IK THE VALiXT OF THE AWASH RI7ER: O? i'-itXAA SADI AND ME1XA WARAR
•f
£s?cLjgU®I faaturva of th* Valley of th* Awash river, al-
rs.j(-?-   ';   iv   Tefirad   la   th*   geollChoiogical   n»ap   (attached   to   the   General Rk-'T :   ’'■ r.oi'or «W) ahov r. sedimentary structure fomed by vol-
catth;
vtilcii have brought to light rock* of various types,
eisnb as: 'aeaelta, dolerites and Lav* effusLono.
Tho »^dlr-.entary structure presents a great variety of types of granulottiatrica, with a clear prevalence of clsyey-nsjddy aatarlal, which Is found all over the area concerned.
The rough toaterial, composed of gravel and pebbles la localised in the loop of the river Awash, where the derivations are errvlsaged
((Sepitalia solution), and in addition in an area ca.three Km. to North North-East of Melka Sadi. These deposits ar* fairly large, the itsaterfal can easily be extracted and is Ln excellent condition.
On closer investigation it will be possible to ascertain, on the
/ hiais of the percentage of the reject material of the quarries situ
ated at North North-East of Melka Sadi, If it would be more convenient I to instai the crushers near the areas uf exploitation and supply then
with uater from the Awash by Beans of pumping, or whether it would be better to place them near the river, taking there the materials from
the quarries.
For large lumps of stone, outcrops of basalt and doierite may be used with advantage, as they are found In the whole area (see geolo
gical nap attached to the General Report of October 1967); from these rocks all the sixes required for the building of th* various construe tions can be obtained, if, on the basis of financial calculations andgpctoolcdl     araolym.,     the     mplol     Cation     of     the     exlatl^     atlwvtai     gmrrtea ,, 3pt corn <.4erad *ui table.
Both th. frmhw. \plant for making sod screening the eatoriel*
frca the n ..» al t• vi*£ee) sad the plafit fur braaktag up the rock*, suet conelft' >t -soblle unite, so that they can be waved at will free ooe gtsrrr' jnatber. and placed <• near aa possible to the Wilder'*
▼orde.
Fro* >-.• 'ns been said, It oeaee that there are no problem
difficult
at the hu* 
be aada .
iflan as regard* the supply of large rocks, but only
«tage will the choice of the aoet econoedcal quarrla*
The problem if naintenanco and running coots of the eorks to be
built wtll Sa faced as soon at A.V.A. ha* cum to a AocUlcm on th*
program,- ’ c mlng Into farmland and dividing up the lead lo
question, „ wall «« on th. basil of the solution of the barrage, and
| Intakes.
Agards the coat of labour, hiring, mt.ri.i bro^r to the Elding alt. and the co.t of the complat^ work. Septtalla. s.r.U
obcatnad fr^ei specialist Hr®* *c A4dl“ Ab-b* krU* ****
Ethiopian Govommnt Administration, lists ot
•Ptltlly     uork^i     out     to     taka     l«<>     account     the     difficulties     of     asceta
“> th. .rm. 
th. 
U - be c.rrlad ** th. distance fr~
**“• AhaW i  .^t 300 km-, rhe l«t W of which ar. over tree *
9
fwT trBfflCf „pecUlly during. th. relay 
‘
If®»»0 N. 4
9 ) - Leveller                 above. 115 HP Cat.12
fb) -
to) -
Levellav «a above, 150 HP Cat.14 Motor cenwot mixer 4-6 cub.e capacity
Eth. 1 33.00 per hour
H                w                45.00    •1                W
tt
ri
24.00
II
II
11) -
Fixed cereewt mixer 0.5 cub.e.
11 n
11 •i
3.25
H
•1
12) -
13) -
14) -
Fixed c«ee«t mixer 1.00 cub.e.
8.40
N
H
Platon-driven welder 400 A. 50 HP                  motor   M                 ii
8.40
rt
11
Air    compvecaor    with    average    power 8 cub. m/1* 120 HP etc. aa above
of
11
ii                10.50    n                W
14b)-    Air     ca»fr,Baor     with     average     power 3 cub.n/l’               50 HP etc. aa above
15) -     Vibrator for c eaten t, seaLI, •*<» 16) -     Pump for draining water, fitted with
piston engine, medium type, 1000 l/l* H CM. 20 m.» 12 HP Jet 4” ate.
of
II
it
7.35    ii
II
•1
ii                 2.20    M               •1
II
it
3.30    tt               11
c) -
, drived fr<x  bcaalt material co be proceaaed on the
B
^*nri waah^d and ocreeled for reinforced
concrete
Eth. $
21       Sand for ro«d foundation ’* Rubble tur reinforced concrete
^etalifp^ far ro^j-beda
*
situiwi for masonry. quarries CtUn a radius of 5 kw. fro® the place
- u°rJ<-> Including transport: at Che rate <                Eth. $ O%25 per cub.rc. per km.
<• •»
site
per cub.™.
8.00-12.00
4.00- 6.00
10.00-12.00
7.00- 8.00
t>.00—    ■'•■?
j.50-5. OG
Ston*« Ur rt Md fe^
,.
"
° k he. t places
per
- < ♦.
i•
-L
f?r*"
‘ •i'
Ul v xnvl
.
?n
v.<- »•
ntorced ccnC
*
•*
11
I ■
1,‘
* >4 * 1
■ * • • >*•>»
fra
■      £.75
•      T* •
'
n-j 4 *• —-
’X i I*
trrf. I 1 .<•
v ?•<>
*
I
•*•
‘I’'
-rl0)
 . oil for en®inea
Eth.     $
1.60 per kg.
u)
 . Wood to        slgba pLeaks,            fixed measurements
IV               tt                 130.00  per    CUtoeB.
it
11.)-
11b)-
llc)-
lld)-
4 ta.
If
125.00     •1
tt
V*                   3.00-3.50
It
♦1
2.00-2.50
1.00-1.50
at
at
ti
tt 110.00 If H
tt 105.00 tt w
lle)- Timber        cut          X  8 and     4x4;Length 4 m. Ilf)- Timber         (eltu) Is         4 a.      planks
• a at 95.00 ft
tv at 130.00 tt
ti
180.00     It
lit)-
1.00 -1.50 To all Lt under 11), 5.00 Eth.$ must
be ad*W pax quintal for transport froa ploc* origin to work area.
ft
tt
it                 130.00     tt
it
tt
it
tt
12) - Hallo
13) - Cement strength 300-400 from Addis
Eth.   $            0.65   P«r   k*. Ababa "         ta                    11.00   P«r   Cwts
14) -
'•
Ma ssai
at
i •                    10.10     •a
It
15) - Tubular roda  for
s-3,5
13a)- Orth^goM 1 untune
15b)- Small baaes
161  - Cement pipe 4 40
17) -.           n             tv
scaffoldings 0 48
Eth.   $                        1.98  per         .m.
tt
tt
II
tt
II
If
tl
tt
2.74   per    each
1.90     at
tt
6.50   per        .01.
tt                     12.60     tt
18)         -
»’
at
gQ
II
-
tt
19) -            ••            •<      lo0
)~*)Maoonry in hand-made bricks,
measuring 6x12x24
~b)PresBed bricks measuring 6x12x24
- Perforated bricks
11               ft                     30.00     at
t>
tt
at
ti
ti
ti
it
50.00    per eub.c
74.20       tt
90.00       tt
at
n ) with three holes
h) with six holes,
c ) with six holes,
<0 with six holes,
e ) special bricks,
It should be noted
for bricks apply to
, reeacuring   6x13x25
raeasurLng 8x12x25
it
ti
it
ii               120.00       at
raea curing   10x15x25         tt               tt              120.00       »• rr.«a surLng   12x20x25         H               at              130.00       ••
measuring
12x24x30         H               tt              170.00
n
tt
tt
tt
tv
tv
tiwt the pr
the Add!**
ices quoted
Ababa market.Thera are huwwr kilns In the neighbourhood
o f Nesereth, nemifacturing bricks at prices
1CJX lower; they are of a similar quality, but
it reoat be borne In mind that Nazareth Is
about 100 kat. nearer the work areas.
riBISXED
_ Excavation of asrsdy and muddy soil to a
depth of 4 •£. and transporting It for unload
Ing to & mttulrjura distance of 500 ra. Including every export casting and levelling of excavations a>d Mbar&jwfttt*
- Ac abov»*j, to « iwsjilKKwn depth of   8 a.
Eth. $ 3.00
11                4.50
- Excavation as mvAer item 1, but transport to & wwximura distance
- Excavation                  under item 1, but
soil by ripper
- Excavation as under itera  4,  but
rock
• Excavation auction required for
including every expenae; depth
in materiel of any kind
- Excavation is under item 5, but
6 ra.
•     Standard     mix     of     2     quintals     for including every expense
- Standcrd ralx of 3 quintals f-r foundations,
Including every expense for casting, tnvuldo,
with
of 3000 m.
in rocky
it
ii
II 4.00
11 3.30
in mine
it                  11                 5.50
foundations
to 3 «. and 11 11 7 .00
to a depth
ii
If
9.00
foundations       »
ii
n                 78.00
caaingB, etc.
°nd the iron
>  excavations for foundations
qxc 1 ukJed
ii
ii
109.20
As abuve for
elevation, including cfiluBvnc
and
fccaffolding
11 11
143 .CO
- As it<jau 9, but dosed for 4 quintals of
cement
~ « t ffiXidLavd mix at. 4 quintals uf ceaent for
•caffolding of bridges, including every estpatise as well ao csgIi'-S® end scatfuldxnja
iron
**      "* 162.50
” 203-20fogHo N. 7
U) _ Round steel rods for relnf Jrced concrete Aq 42 placed, includtt a end bindings
Eth
$
1.65
p«r
1x1  Ing dross
1Jb). A, above. but ^th tapruve<]
14) -
15) -
Aa Item
item
As
13b.teat of
fl
II
ft
fl
1.74
ft
l«
13 . b*-*t of
thg type
the type
Aq 50
Aq 50
II
1.68
If
•I
1.76
H
ia
11) - Wurk Ln
parapetfi  i
;
gyrnf’.led and tubular iron for
yy\>oves, staff angles, gully
grating?
'■call sluice gates, etc.,
placed t?-
kng two coats of paint
II
ft
2.88
II
w
17)  -Plastering
'xtth mortar, including every
expense
18) - Maeonry vl~h
II
If
5.20
per
sq.n
bricks       and       mortar, 
including
3caff0l.dk?•. '
and feeing
! cal bacalt material and
•I
II
117.00
per
cub.
19)  - Masonry ol
mortar, t»v
20) - Cewenc pl
o.dlng scaffoldings and facing for drain veils, pLaced
ii
ii
46.70
If
if
including waling of unions, excluding excavation £           40
*  As above,                60
u
• 1
14.00
per
.m
21)
•1
24 .00
II
f.
22)  •  Aa above, •£
8G
23)
24)
“ Aa above,              100
II
11
II
ft
-
II
••
II
33.20
11
ii
' Send, local
road foundations
rock material placed r-r
11
11
10.00
'• cub
25)
i
- bubble for road hod, obtained reck for road foundations
* kubble for road bed, obtained
r ock> placed
* Koilixig o£ road ma tert al Binding Band for closing ro<d
~ Mtuwinous mix for read paving,
tollingIng
front local
from local
•1
11
13.65
ii
ii
I
I
l»                 11                 16.20       ii
it
27)
28)
25)
If
O£
bed
including
11
11
0.12       •t           sp.
i
•’ 9.60 cuk
t» 55.00 !• i
*,
- Well
for
1
grating,,
” 
collecting         water,         fitted         with excavation excluded
-f at.,rxUrd »Lx
. . ■ •• -
1*                  1.     1C J
"SI
f ^tion Of uni ma •>£
thlckween at 2.0 ca«-
l-o
»-1 »
ioulfa K. g
One-atorey building for guard and offices,
fitted with oil conveniences inside and out
side: window frame, light and water instal
lation, including heat insulation of roof atui v
vail*•
from ground level to gutter frese
Eth.   $     85.00
per
33) -  ?aclr<a of . 
and slope* In general
cub.
ii
34)
with    baea$3    rubble    of    a    elnleue    thicknsas of 30 cm. '.*ic 1 vtding mortar
-  Storefront sliding, fitted with Iron window atx* d.>or frame® at cub. tn. empty for full r, 4-^ "Axrea»ntB as under item 32
14.GO
per     aq.n
n
is        51.CO
cub. F*-- 1 -
This      report      contains      the      principal      results      of      the      prell minniy      climatic      liydrologic      studies      perforned      in      order      to      indl vidurlizc       the       ch^rr.cteristics       nod       elements       necessary       for       the study    of    the    irrigation    eye    ten    at    Eelkn    Srdi    and    Amibara.    The study,    based    on    FAC’s    recent    report    (1)    find    on    information    eup plied     by     the     Awash     Valley     Authority,     has     been     subdivided     into 3 parts.
1)     The collection and elaboration of the climatic data re lative to the area to be irrigated,
2)     The estimate of irrigation water requirements for the preliminary dimensioning of the irrigation system,
3)     hreliminriry considerations on the inflows of the Awash River,
The study will subse juently be elaborated when the fi
nal project is presented and it will be completed with data
not yet at our disposal and with the latest available data.
With reference to the above, it Is pointed out that
the systematic gathering of climatic and hydrologic data be
gan at the end of 1964 and therefore the ulterior acq-ui ni t.5rp 
of .data and information could allow for anefficient conclusion 
of the investigations.
In November, 1964, the Awash Valley Authority began an accurate serico of climr.tclogic and hydrologic studies by 
means of the installation of relief stations all along the
Awash River basin. From the data provided by the A.V.A., was chosen that which would interest KeLka Sadi and Amibam more directly.
£l) FAG. Report on survey of the A.vush River basin. Rome 1965.- 2 -
For the climatologic studies, the measurements token at Melka Warar station, situated in the center of the territory, 
were utilized as wellas those of the Awora Melka on the Keasem River.
As for the data on the capacity of the Awash and of its tributaries, we examined the data gathered at the Awash st ac tion for the Awash River and those of the Arba, the Kessem and the Kebena River.
Since FAO provided a series of climatologic and hydro - logic measurements in 1962, 1963 and 1964, the data provided by A.V.A. from 1964A967 w«s integrated or compared where poa
sible, with those submitted by FAO's report of 1965.•
Awora Mrllia
ADDIS ABAB
•- 4 -
I - climatology
1 - Temperature
In    Table    1,    average    monthly    and    yearly    temperatures    are shovel    for    1965-196?    according    to    the    Melkn    Wamr    station.    By means    of    thia    data    and    referring    to    the    graphic    reported    tn    ta ble    3    the    existence    of    two    maxitnums    (in    June    and    September) are    noted    corresponding    to    the    monthH    that    precede    and    follow the rainy season.
The    monthly    mean    values    of    the    temperature    in    the    perial of     observation     does     not     differ     noticeably     from     the     individual monthly mean values.
The    general    annual    mean    of    26,4    °C    deviates    slightly    from the    monthly    maximum    and    minimum    means.    In    this    regard,    exami nation     of     the     monthly     temperature     coefficients     (table     6)     reve aled that the extreme coefficients vniy at 0,86 (January) and
1,13 (June).
Finally, it is noted that the mean value of the tempera ture concords sufficiently with that derived from the graphic report by FAO on page 28 of volume III (variation of mean an nual air temperature with height above sea level), when we consider the metereologic station under examination is situru) ted at 750 meters a.e.l.
Again referring to volume III of the FAO report, on pa-’ ge 29, the monthly temperature coefficients reported are obta
±ned from the Awora Ke lk a station situated at 805 meters a.s, 1. from 1962 to 1964.
These coefficients are shown in table 6 , together with those relative to Helka Warar, In comparing the data repor ted and considering the diverse period of observation, a clo se similarity can be observed between the two territories ,TABLE 1
Monthly air temperature, rainfull and relative humidity at X « 1 k a w a r a r
1 
air
■escape Future (°C)
1-------------
T
r----------------------- . —I
r  rainfall           (mm)
—
J----------------------- --
|      "65            "66 J-----
"6?
4---- ■■
1 mean    1 "65        | "66           1 "67
r   -----
! mean | "65
relative humidity            (°/°)
1
1  "66              "67         meiin
-4   —   ■ —
22,7           24,0
11
IJ
F —
21,5         22,7            9,5            0
50,1
4 —~--------------
1
1a.
22, 7
24,8
26,5
26,5
25,3         24,8        30,5    jl40,0         1 0
0 3.2 j 52,0 50,0 48,3
j---------
56,8
25,5
4-
l
25,6
33,5     I 33,5 j
89,5
50,4 67,6 45,9,
45,0 58, 2 61,2
1    A           25,6
II
26,5
28, 3
27,5        128,0 ___ _ .
| 28,5
8,5        55,0       1 62,6
[
45,1        59,4
54,6
54,8
55,7
r           |----- 29, 4
27,1
28,2
27,7
27  7
1  ’ i_ -t 4
0                      16,5           72,0    | 29,5         |     40,0            44,1        55,0            46,4
—
30,0
29,8
| 29,7
r- ----- ------
0 J  l35,5             24,7        20,1              46,8           41,1        43,7           43,9
J           28, 5
not obc
erved
28.5         39,0
not obfi rerved
39,0              42,9
n* o*  n* o.
■
42,9
---------
A           26,8
i
--------- -
28,7 1
27,5
27,7 '         93,5 ,    141,5        218,5       151,2             54,0           56,7        60,0           56,9
S            26,4 1 4                 --- 1
----- |
30,0
29,0
~’1
.
0 1         24,7             27,3 ,          25,0 '     25,7          12,5           0 —         4
28,5         58,0          77,0           17.5         50,8             51.1           50,3        52,5            51,3 J                                                         — ---------
22,2        11,6
51,1
76,5
N J_     26,5
23,5 | 22,0
n. c-             25,0 | 74,0              0
n. o,
-1 n. o.
37,0       1    55,0           44,9
50,C
n . o .
-4
59,2
50,0
n. o < 1   ~ ~r
1
p
25,0 1
_____ L 25,9
23,5             0             0
40,6
_ 
-
26,4 |   478,5
-
_____ ,_J.
0                50,7 506,4             50,1
r J           -11
45,6
50,9Monthly            evaporation and veloc.
wind at            M e 1 k a 1# a r a r
evaporation           (m)
'      valoc.      wind (lo/sec, )
1
1
”65
"67           mean            "65              "66
1
J              265
"66
2 31
274
230
1,42          1,40
"67 mean
1,70 1.51
7 ;        317
239
296
284
1,50
1,50
0,90
1,10
2,10 1
—
n              337
T
1
A |        J16 j
■ "1
1,66 1 1,33
1,20 '
~ - 1
1.42
1,54
376
222
—
-
■J ! —
-
— w-
316     1     1,20
X1
307
—
342
354
1,30
1,76
-
J               354
1
1,30 2,10
-
0,30
1,30
1,99 
-
-- i
1
J
322
_
322            2,05
4               290 3       I 23&
0               199
!i       1     289 , ---
D       i 265 3.568
1
-
1 —-------
223
—
258
—
290
231
229
257
266
1,74
1,38
1,39
2,00      1 _ 1,10
-
225
267
1,44 1,76
1,40 1,36
-
2,05
1,02
1,69
rH
1,24 1,60
—
-4—
l,3t
4
1 
I -
3.426             1,50           *
*
1,49
1 —i
s u  m
■ m(e a n
L
1 .       ——•                 __  ___ -1TABLE 3
Variation of mean monthly air temperature
( o   ) at Me lk a Warar
c
---- 196 5
1966
1967
f
I
I
I
30°
i
1
1
:
I
II
I
26°
I 24 3
I
I
22°
20°Variation of monthly rainfall (mm) at Mellca War ar
i
00
ITABLE 5
Variation of monthly relative humidity (°/°) at
o/o
0
N
D
1 1 1 L
 _TAELE 6
k'OKTHLY     t eki ?;ra tu r e cc e?f i c i ent s
I
Height a. 8. L
805
750 ----- -
Station
Awora.v Melka
Melka Warur
J
0,90
y
0,98 0,94
M 1,04 0,97
A 1,03 1,04
M
0,86
1,07
1,05
J
1,11 1,13
J
1,03 1,08
A 0,97 1,05
S 1,03 1,08
0 0,98 0,97
N 0,95
0,95 -----I.l
D
0,91
0,89
- — MEAN
annual
0
temp   C __ 27,1 26,4
V J ?A0 - Vol. Ill Hejart- 29-and the possibility of integrating the data of one station, 
with sufficient exactitude, by those of the other.
2         - Rainfall
The rainfall regime is generally characterized by a chart rainy season (March, April, May) and by a main rainy season (July, August, September) with a main maximum in August. Tn 
the
months (January, February, May, June, November
and Dicember) the rainfall is generally minimal or completely absent.
Of the three years examined at Melka Warar (see Table 1), only 1965 is complete for the various months mentioned. In
1965 the rainfall as a whole amounted to 478 mm, the maximum occurring in April. It is not possible to furnish data about
on the total rainfall in 1966 and 1967 because the observations for the month of July are missing.
From Table 1 and from the graphic of Table 4, a consi derable difference is noted in the amount of rainfall in the various months of the three years under consideration showing some points which can be called exceptional (i.e. in February, 1966).
Again referring to Table 1, it is possible to note a complete absence of rain from October 1966 to February 1967 which is contrary to the corresponding period in 1965- 1966;
In conclusion, considering the brief period of observa— tion » the mean rainfall data cannot be considered sufficient representative. This justifies the corrections made in the
timate of the basic water requirements as stated in para graph II .
At the Melka Warar station, much information was gatho- elaborated upon relative to the duration and maximumintensity of the rainfall. This data is not.discussed in this
preliminary report but will be discussed in the second phase
of the studies .when drainuge and protection from external wa
ters for the territory will be reported.
3           Relative Humidity
The mean monthly humidity taken at Melka Warar from 1965 
to 1967 ie shown in Table 1 together with the air temperature
and rainfall during the same period. This allows for the tie-
ing-in of the three important climatic factors.
Table 5 shows the diagram of variations of the monthly 
relative humidity.
The mean value for 1965 is equal to 50,1°/°, while that
of the 3 year period (partial data incomplete) is 5O,9°/,< It
is not considered advantageous to establish a relation—ship 
between FAO* s report (Vol.Ill - page 57) on Awora Melka from
1962   to   1964   and   Melka   Warar   from   1965   to   1967   even   though   se veral     anomalies     in     the     rainfall     registered     at     the     latter     sta tion have already been noted in paragraph 2 .
In any case, it can be concluded that in May and June, as well as in November and December, the humidity is general ly lower than 50°/°, which agrees with that reported by ?A0 .
This is not so for February and March where in 2 out 0- 3 years the humidity exceded 50°/° at Melka Warar. For July , the mean value transposed in Table 1 does not have any parti cular significance since it represents only one year of obs vation.
4    “ -Evaporation
Table 2 shows the mean monthly 
thlY evaporation at Melka Aa
ffiean
 an-
rar. The data 1b complete for
_ t-o for 1965 oaly 1
e are
 few u
.r
ew
 mean
nual total was 3568 mm. F°r values available.
b
_ nq66 I9 <»The maximum mean evaporation valUe8 Were
March and June 1965 and agree with FaO in 6 r6P°rted for
tion (Vol.Ill- page 67).                                                                6 
5   Winds
The mean monthly wind velocity, calculated at Melka Wa rar, is shown in Table 2. The mean for 1965 is 1,5 m/sec.
6  - Monthly data on Solar Radiation
The total solar radiation plays an important role in 
the determination of the basic water irrigation requirements. 
In the absence of solar radiation data at Melka Warar, FAO* s data from the Metahara Station (955 meters a.s.l.), Awo ra Melka (605 meters a.s.l.), and Gewani (650 meters a.s.l.), was taken into consideration for the period from 1962 to 1964; that is, those stations closest to the Melka Warar Station and situated at much the same altitude. From this data (Vol. Ill page 55) it is evident that the normal monthly intensity of to 
tai solar radiation does not differ greatly for the three eta
tion with-in the same month span. The diversity is very mode st reaching a maximum of 40 calories per sq. cm. per day in Au gust fnr Awora Melka and Gewani.
Previously, the close climatic analogy between Melka and Melka Warar was shown, particularly the m y  Perature coefficients (Table 6). There fore, the monthly da ta of solar radiation for the Melka Awora land# alre y Btered at Awora Melka will be considered.
Melka St?This
chapter
will
not
include
the
investi
gations
made
on 
land 
classific
ation 
for
the
choice
of
I
rritable
xonee
nor
tho
se relative to the prospective Land use in the irrigated area*.
They will be amply discussed In the second part of the
studies made.
It has not been possible to find information and data
of any importance at the experimental stations recently insti tuted at Melka Wsrur therefore stope wero taken to conduct an accurate verification of the studies made by FAO (Vol.Il ) on the prospective land use in the irrigated areas and on the po tential cropping pattern, rotutionu, arborlcolturo, etc. This verification wag then controlled by inveotlgutiono conducted dlroctly on the plantations neurost to the Molka Sadi and Ami bars* lands.
On the basis of the previously stated Verifications and investigations, the conolderutlons and conclusions reached by FAO (Vol. II - XVIII) cun be hold as fully acceptable and the refore the determining of the irrigation water requirements
will be based on crop rotation uchetaeu as suggested by FaO in Vol. II - puge 142, keeping in mind the poaslbllity of permanent plantations such uu sugar cane, fruit trees, etc. 
w
With reference to the aforementioned "absence of expe rimental data regarding crop water requirements" these will
be evaluated by calculations which Include climatological fa ctors.15 -
1           Calculation of potential evapotranspiration.
Many formulas exist for the calculation of potential eva potranepiration. Among the principal ones are those of Thorn- thwaite (based solely on climatic and geographic factors), Blaney-Criddle (based on climatic factors and coefficients, de pending on the crop), Penman, (based on the method of energy ba lance), Turc (based on temperature, humidity and solar radia tion), and Bouchet (balance of energy - evaporimeter Piche).
Turc' s method was chosen from these various formulas be cause it has already been applied and experimented with widely 
in Africa and in latitudes similar to the one under considera
tion. It is particularly noted that Turc's formula is indi -
pendent of the plant^ecies grown and therefore does not par ticularly limit the destination of crops on the lands.
Turc1 b formula
ETp - 0,4 t (Ig+50) (1 <■ 50 -hr )
t +15
where :
Ig = total direct and diffused solar radiation in small calories per square centimeter horizontal surface per day.
t = mean monthly air temperature in °C
hr = percent relative humidity (only taken in to account if less than 50°/°)
The basic climatical date used in applying Tore  s formu la are those previously examined. Thia data is reporte
Table 7 and while the Jl, .hr and_P (”^11 in mm) values wa re recorded at Melka Warar, _Ig was recorded at the Awor
1- 16 -
ka Station for the previously performed considerations.
The potential evapotranspiration values calculated with 
pure' s formula are shown in Table 7.
2  - Basic irrigation water requirements
The    basic    water    requirements    (Bi)    per    hectare    is    found    by subtracting        available        rainfall        (Pu)        from        potential        evapotranspl ration     (ETp)     and     dividing     the     difference     by     the     overall     irriga tion efficiency :
Bi = ETp - Pu
K
In accordance with the method indicated by FAO (Vol. II - page 155), it is assumed that Pu = 0,7 P for P >10 mm and 
Pu = 0 for P <10 mm.
Again in accordance with the method indicated by FAO, the irrigation efficiency (K) assumed is 70°/°.
Table 7 shows the calculated values of Bi (basic water re quirements) for the various months of the year. Considering that the value of Bi was calculated on the basi8 of c] lmatic factors recorded for a relatively brief period of time and ta king into account the particular aspect of the rainfalls (i.e. February 1966), it was thought opportune to round out to the excess the value of Bi according to the quantity indicated on the last line of Table 7.
Therefore, in the following, the basic irrigation water requirement shall be indicated by "Bi appl."
3  - Irrigation water requirements with crop rotation
On the basis of the considerations in paragraph 1, rota tions were taken into consideration, indicated by FAO
C -^ (see table page 142- vol. II) a
* ’ on line P, the perma
dTABLE 7
Climatological data used in the computations of the water requirements
Basic irrigation water requirements (Without considering crop rotations).
Months
J
F
M
A
M
J
J
A
S
0
N
D
YEAR
t (°C)
22,7
24,8
25,6
27,5
27,7
29,7
28,5
27,7
28,5
25,7
25,0
23,5
26,4
2
Ig (cal/cm -d)
580
610
635
620
630
620
580
565
600
600
580
580
600
1 hr o/o
46
44
43
46
P (mm)
3,2
56,8
52,2
55,0
29,5
20,1
39,0
151-.2
50,8
11,6
37,0
-
506,4
l , ETp (Turc) (mm
152
165
173
174
187
194
181
160
171
164
158
163
2042
Pu (mm)
-
40
36
38
34
14
27
106
35
8
26
-
364
ETp - Pu (mm)
152
125
137
136
153
180
154
54
136
156
132
163
1678
B i (mm)
217
180
196
194
218
257
220
77
194
223
188
233
2397
Bi a ppi. (mm)
220
1 200
200
200
230
270
220
80
200
230
200
240
2440IAUAiJS O
Requirements
(for crop rotations)
J 2200 2200 2200
, 1470
1 1930
| 1980
F
2000
1000 2000
—
1500
M
2000 500
M
2300
2300
2300
J
q
A
S
01
N
2700
800
2000
2000
D
2400 |
1000
1330
1530
1750
| 1800
1000
1800
A 2000 2000
1000 1330 1000 1800
1720
2070
2700 2700
1800 2350 2430
2200 2200 2200 1650 1930
800
1500
2300
0
1000
800
670 700
2000
1670 1000 1800
1150
1150 580
0 660 1000
2400
2400
1200
2100
I960
1992
720
738
2070
1800
1656     1610
Bi appl.  = Basic water A-B-C-D = Basic water
=  Basic water
1126
1426      1984
2396
1594
990
892
2160
2052
24.900
18.600
19.750
15-960
17.060
22.410
18.756
requirement per hectare applicated regardless of rotation requirement per hectare for rotation A-B-C- D requirement per hectare under virtually permanent
crops
Bi
=  Potential water requirement
per hectare for cropping plun.- 19 -
nent plantations.
The       estimated       irrigation       water       requirements       per       hectare were    computed    by    taking    the    arithmetic    mean    of    the    water    requi rements for all the crop rotation schemes :
bi - A > B t C4 F
5
The values of bi during various months of the year, cal culated in relation to the already recorded crop schemes, are reported in Table 8.
The maximum requirement per hectare is 2396 m /ba in the month of June. On the basin of this value, rounding out
the figure to 2400 mVha, the maximum value of the inflows to be deviated from the Awash River will be calculated as well as the dimensioning of the water intake. In regard to the dimen sioning of the distribution works, it will be calculated on the basis of the maximum basic water requirement per hectare regar dlees of rotation which assumes a value of 2700 m /ha in the month of June.
J- 20 III - STREAM               FLO'ff
AND SEDIMENT              LOAD
The     results     presented     In     the     FAO     report     (Vol.     HI)     „„ accurately     controlled     and     eiaaiced     also     on     the     taele     of     the     In formation gathered after 1964.
Particular     attention     was     given     to     the     following     4      recor ding stations :
-     AWASH River       at Awash Station             (st.   10)
-     KESSEM River      at Awora Melka              (st.   11)
-     KEBENA River     at the Gaugin Site           (st.   12)
-     AREA River on Miesso          Road               (st.   13)
Tables 9> 10, 11 and 12 (with available data from the end 
of 1964) show the maximum and minimum monthly inflows at the tbur
above-mentioned stations.
The Arba River mean and minimum monthly              inflows are nil or almost nil. The maximum inflows reach values of a certain impor
tance only in the months of August, September and October when 
the Awash River has an increased inflow, for which the contribu
tion from the Arba River is negligible with regard to irrigation.
The Kessem and Kebena River generally present a minimum in 2
flow during the dry months, inferior to 1 m /sec. The same mean inflow in the months of maximum irrigation utilization (May, June and December) generally result in smaller values for which an e ventual solution consisting of a single deviation of the Awash placed above the Kessem and Kebena Rivers could reduce the volu me of water which is already scarce.
Referring to the Inflow of the Awash River as shown in Ta ble 9 and eraninlng th. dally .ear Inflow (not Included In this
ble 9 and
preliminary report) the following data was derived relative
tothe duration of the minimal inflow.
Number of days with inflow inferior to 20 m /sec.
3
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
1964
2
-
1965
0
0
0
0
2
0
0
0
0
1
3
0
1966
0
0
0
0
1
6
0
0
0
0
6
0
1967
8
14
7
1
7
9
0
0
0
1
Number of days with inflows inferior to 30 mVeec
YEAR
J
F
M
A
M
J
J
A
S
0
N
D
1964
5
4
1965
0
0
3
3
6 •
1
0
0
0
6
8
1
1966
4
0
1
3
4
9
2
0
0
4
27
28
1967
31
19
26
17
18
24
2
0
0
14
The above-mentioned data could be useful in relation to the necessity of rwgulating the capacity of the Awash River with the irrigation process in the middle ans lower valleys.
As to maximum streams, on the basis of available data, your attention is called to the daily maximum values registered, at the Awash Station for the Awa9h, and for the Kessem, Kebena and Arba River :TABLE 9
AWASH at AWASH STATION (st.10)
- drainage area 18537,5 aq. km
19 6 4
19 6 5
19 6 6
1 9 6 7                             1
c} mux         Q mean        Q min
Q max
Q mean
Q min
Q max
Q mean
Q min
Q max         Q mean         Q min
I J 1
1F
-------------r-
1
IMi                      1
HA
1
I I V.                        1
J
1                             •   ------- _
1 I J
1 1 A
1 s
1 0
-
1
t ■
i____ _
N 49,59 37,86 16,12
P 66,32 l| 47,63 25,51
76,15
54,02
55,94
57,78
38,77 54,O2i
60,67 113,11 153,83
84,53
48,52
47,01
55,06 41,85 47,81 37,16 42,14 26,54 39,08 21,43 31,95 19,76
41,68 28,51
52,16        31,76
I 67,37        35,02
70,91        31,76
50,78       19,76
33,09       14,80
37,66       24,91
50,03         41.14         23,70 218,99       107,05  __ 35,76
80,64         55,14        27,05
92,14         59,97        20,30
72,05         40,89        16,46
101,58         41,19        13,70
162,32 62,23 28,51 151,61 95,10 66,83 154,15 99,19 38,02
82,18         45,93        21,40
-----  1
39,51 23,97 15.91 42,52 26,47 21,41
29,81             22,58            i3,7o_ 65,95           29 , 72        12,05
36,51             23,63 i      14,25
41,02              29,89         15,36 1
42,52             27,43         10,95 1
' 1
50,03             24,87       12,05
81,60             50,09       24,30 
158,51              90,63       51,00
167,69             87,22        40,80          1
176,87             52,55        19,75
i
1
Tot
• ■ ■ —
1497 x 106’ m3
1822  x 106 m3TABLE 10
KESSEM at AWORA MELKA (at.ll) - drainage area 3136 eq. km
FT
-------- .---------------- —
19 6 4
19 6 5
19 6 6
19 6 7
--------------------------- 1 ■ ■ 1---------------------------------------
j  Q max
------ F“
------------ r-
Q mean   i ---Q-- m---i-n--- "
Q max
------------- r
Q mean Q min
Q max        Q mean
Q min
Q max
Q mean        Q min
hT
1            4,85           4,07             3,55           1,50           1,04
0,60
n t     dr------1r      J   3,55           3,13             2,70         18,73           7,53           0,50
M 1             -              1   6,45          2,84             1,89           9,99           2,10 1     !      J  11,31          4,55              2,70        16.11           2,58
A        ------ ---- t
0,43
0,33
1 14
J
3,10 2,04
2,10 1,98
1,42 0,78 0,41 0,44
1,42 13,42 3,88 0,50
f
1 i
...
iL
r 1
j
J
A
s
0
1
11  ■
 -
’ 69,20       10,72             2,10     210,61         27,69           4,30
34,73
___ 6,67
i--------------
140,07
10fi,66 * • -
50,51            14,17  1 359,01
138,75          30,51
L1
340,00 107,42 j 46,42
•
•
I
I 205,10     24,25
1
17,51          4,87
I
H 7,4(> 6,08 5,46 15,92 3,05
D 6.7C) 5,45 4,86 2,08 1,62
2,30 138,90 32,67 1,38 0,75 15,92 2,05 0,51
— ——— 1
196^67
-
46,42 25,00
1
1,62
1,26 1
Tot
J
-TABLE 11
KEBE N A
GAUGIN SITE (at.12)
drainage area 1245 sq,. km
19 6 4
1 9 6 5       . .
19 6 6
19 6 7
Q max          Q mean
Q min
Q max        Q mean        Q min
Q max       Q mean
Q min
FT
Q max Q mean
Q min
1 J
6,00           4,44            3,54
1,69           1,12
0,76
7,40
2,12
1,14
4,29          2,75           1,74
25,73           6,19
0,89
67,80 |
12,28
L .
5,68          2,38
1,13
3,50          1,05           0,62
25,70               5,71 /
1,08 / 0,76      !
30,42
»
2,24 ' 26,54 53,09 33,02 56,74 52,07
2,65
11,02 1,60 4,24
35,00 13,96
9,70 8,52 2,05
256 x 10
3,12
0,72
0,89
1,87
5,31
3,86
3,86
1,17
1,53
5,72
0,61
1,67
0,06
0, 40 26,93
6,39
12,04
1,75
2,80
O, 72             0,56
29,81 105,16
20,01 5,72 1,40
1,40
4,75.
0,51
0,54
6,15
29,00
2,07 J 1,08
3,50 j o, 44
51,61            15,31             91,00               46,79    1   15,10
1,50
2,53
1,28
0,02 |      31,01 0,04               3,85
1,14
18,11              8,40
2,60 1,21 /
4,93
7,20
3,93
4,37
2,89
2,24
1,26
1,08
196 x 10TABLE 12
road (st. 13)
1 ------”----------------------------------- 1
19 6 4
19 6 5
- ------------------------------------------r
19 6 6                        1                   1 9 6 7                        \
Q mean
Q min
Q max       Q mean Q min                 Q max         Q mean      Q min
I1
1
1
1
Q max
Q mean
Q min          Q max
1
J
-----------
.
0
0
L0
-I
_________  J
F
10
1
0  1
i°
lr
1... •              ------------- L
0,65             0,05
— t
1,64
0
5,33
0,67
0,02
0,03
1,22
0,70lu
es
r
In thiB collated
the FAO part c sedim>
preliminary  report  it  can  be  concluded  that  the  v 
le<i      iC
“‘'Ona to
in 1965, 1966, 1967 agree with the report and thus will be used as the
of the irrigation system
J"
;j ika sadi
e
-lent loads and the maximum design M elka Utaa v/ —-arIahris. flood,- 27 -
will be adopted a  follows :
s
1100 mVeec at Melka Sadi
1150 mVesc at Melka Warar
Further        considerations        regarding        th,        relationship        between rainstorms     and     floods     in     the     rivers     have     n0        connection     with     the Mslka      Sadi      and      taibars      irrigation      system      studies.      Instead,      of notable      importance      is      the      relationship      of      rainfalls      and      drains in    the    area    to    be    irrigated    but    thie    problem    will    be    examined in the second part of the studies.

< <

Summery

Document Overview

This preliminary report from March 1968 by SEPITALIA S.r.l. for the Imperial Ethiopian Government's Awash Valley Authority examines the Melka Sadi and Amibara irrigation system layout, focusing on climatic/hydrologic data, irrigation water requirements, and building materials available in the region.

Key Sections

1. Building Materials in the Awash River Valley

The report details the geological features and available construction materials:

Sedimentary structure formed by volcanic phenomena with basalt, dolerite, and lava effusions
Clayey-muddy material prevalent throughout the area
Gravel and pebbles located near river loops and north/northeast of Melka Sadi
Recommendations for mobile crushing plants to process materials near construction sites

2. Price Lists for Equipment and Materials

Detailed pricing information is provided for:

Category	Examples
Equipment Rental	Bulldozers, graders, cement mixers, air compressors
Construction Materials	Sand, rubble, steel bars, cement, pipes, bricks
Finished Work	Excavation costs, concrete work, masonry, road construction

3. Climatological Data

Key findings from Melka Warar station (1965-1967):

Temperature: Annual mean of 26.4°C with peaks in June and September
Rainfall: Short rainy season (Mar-May) and main season (Jul-Sep) with August peak
Humidity: Mean annual relative humidity around 50.9%
Evaporation: Annual total of 3568 mm (1965 data)
Wind: Mean velocity of 1.5 m/sec

4. Irrigation Water Requirements

Calculations using Turc's formula for potential evapotranspiration:

Parameter	Value
Basic Water Requirement (Bi)	Calculated monthly values ranging from 800-2700 m³/ha
Irrigation Efficiency (K)	Assumed at 70%
Maximum Requirement	2700 m³/ha in June (used for system dimensioning)

5. Stream Flow Data

Analysis of four key river stations (1964-1967):

River	Drainage Area (km²)	Key Characteristics
Awash at Awash Station	18,537.5	Mean annual flow ~1500-1800×10⁶ m³
Kessem at Awora Melka	3,136	Highly variable flows (0.33-359 m³/sec)
Kebena at Gaugin Site	1,245	Annual flow ~196-256×10⁶ m³
Arba on Miesso Road	1,107.5	Mostly dry except Aug-Oct

6. Design Flood Values

The report recommends adopting:

1100 m³/sec at Melka Sadi
1150 m³/sec at Melka Warar

Conclusion

This preliminary report provides foundational data for the irrigation system design, including available construction materials, detailed cost estimates, climatic conditions, water requirements, and hydrological characteristics of the Awash River basin. The findings will inform the final project design, particularly regarding water intake structures and distribution systems.