j’aJ- AV*
6 f --
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^6
7 7 IMPERIAL ETHIOPIAN GOVERNMENT
AWASH VALLEY AUTHORITY
ADDIS AH ABA
••
MELKA sadi-amibara proposed
IRRIGATION PROJECT
FEASIBILITY STUDY
PART 11
STUDIES AND SURVEYS
VOL i - IRRIGATION ENGINEERING
I I xLCONSL I.T J Rome, |uly I960
/CONTENTS
PART 1 -
PART n -
GENERAL REPORT
STUDIES AND SURVEYS
VOL k - HYDROLOGY AND CLIMATOLOGY VOL. 2 - SOIL SCIENCE
VOL 3 GEOLOGY AND HYDROLOGY
VOL 4 IRRIGATION ENGINEERING
VOL. 5 AGRICULTURE AND LIVESTOCK
VOL, £ - ECONOMIC AND FINANCIAL ASPECTS VOL. 1 - SOCIOLOGICAL AND HEALTH ASPECTS
PART 111 OUTLINE OF THE PROJECTIMPERIAL ETHIOPIAN GOVERNMENT
AWASH VALLEY AUTHORITY
ADDIS AH AB A
MELKA SADI-AMIBARA PROPOSED
IRRIGATION PROJECT
FEASIBILITY STUDY
PART II
STUDIES AND SURVEYS
VOL i - IRRIGATION ENGINEERING
I I k L C r i N S II. T
Rome. July 1969A
CONTENTS
1,     introduction
2.       IRRIGATION PARAMETERS
2.1        IRRIGATION METHOD
2.2        CALCULATED WATER REQUIREMENTS
FOR EACH CROP
2.      3      EFFECTIVE      RAINFALL     AND      FIELD     IRRIGATION EFFICIENCY
2.4      FIELD      IRRIGATION      REQUIREMENTS      FOR      EACH CROP AND CROPPING PATTERN
2.4.1        Water Consumption in Irrigated Areas
of the Awash Valley 
2.4.2        Irrigation Test Work at the Melka Warar
Agricultural Research Station 
2.4.3        Conclusions
2. 5       WATER APPLICATION VOLUMES AND           IRRIGATION CALENDARS
2.6        PEAK IRRIGATION WATER REQUIREMENTS                    AND DAILY TIME OF IRRIGATION
2.7        IRRIGATION PLOTS 2.8        WATER MODULE 
3.      IRRIGATION WORKS
Page
1
3
3
4
8
12
13
13
15
16
26
29
33
35
3.1 
GENERAL 
35
3.2 
LAYOUT OF IRRIGATION NETWORK
38
3.3 
SURFACE AREAS - DEDUCTIONS - ALLOTMENT
OF LAND
38
3.4       NETWORK LOSSES
40Page
3.5       LINING OF CANALS
3,6       IRRIGATION CANALS - DESIGN CRITERIA 3.6.1        Discharges
3.6.2        Sections and Characteristics of the Irrigation Canals
3,7       OPERATIONAL CHARACTERISTICS OF THE NETWORK
3.7.1 Water Level Regulating Weirs
3.7.2 Measuring Flumes
3.7*3 Automatic Outlets
3.8     DIVERSION WEIRS
3.8.1 Melka Sadi Diversion Weir
3.8.2 Melka Warar Diversion Weir
4. DRAINAGE NETWORK
4.1       GENERAL - PURPOSE OF NETWORK
4.2      DESIGN CRITERIA
4.2.1 Rain
4.2.2 Irrigation Waters
4*2.3 Water Table Control
4.2.4       Freeboards
4.2.5       Geometric and Hydraulic Characteristics of the Drains
4.3      DESIGN OF THE SECTIONS
4.3.1 Field Drains
4,3.2 Unit Drains
4.3. 3 District Drains
4. 3.4 Main Drains
5. FLOOD PROTECTION
5.1      AWASH RIVER FLOODS
5.2      FLOODS FROM ALEIDEGHI PLAINS
43
44
44
46
54
54
54
55
56
56
63
71
71
72
72
75
75
77
77
78
78
80
83
83
95
95
100Page
6. ELECTRIC POWER SUPPLY
6.1       THE MARKET
6.2       THE SUPPLY: ALTERNATIVE SOLUTIONS
6.2.1        General
6.2.2        Diesel-unit Plants
6.2.3        132 kV Koka-Dire Dawa Power Line 6.2.4       Hydroelectric Plant
6.2.5        Conclusive Evaluation
tables
1   - POTENTIAL WATER REQUIREMENTS ON THE BASIS OF TURC'S FORMULA
2   - POTENTIAL CLIMATIC WATER REQUIREMENTS CALCULATED BY THE TURC, BLANEY-CRIDDLE, AND THORNTHWAITE FORMULAE
3   - CONSUMPTIVE WATER USE BY CROP (in mm) CALCULATED
BY THE BLANEY-CRIDDLE FORMULA AND CROP COEFFI CIENTS
4   - EFFECTIVE DECADAL RAINFALL AT MELKA WARAR
5   - FIELD IRRIGATION WATER REQUIREMENTS OF SOME FARMS IN THE AWASH VALLEY
6   - CALCULATED AND ADJUSTED FIELD IRRIGATION WATER RE QUIREMENTS FOR EACH CROP
7  - FIELD IRRIGATION REQUIREMENTS FOR EACH CROPPING PATTERN
8  - TYPICAL IRRIGATION WATER BALANCE FOR TEN-DAY PERIODS
9   - ONE-THIRD FIFTEEN ATMOSPHERE MOISTURE PERCENTAGES OF SOME REPRESENTATIVE SOILS10   - water application for certain crops
11   - FINAL INFILTRATION RATE IN mm/hour IN RELATION TO THE PERCENTAGE OF CLAY AND SILT
12  - AREAS AND DEDUCTIONS
13   - CHARACTERISTICS OF DISTRICT CANALS
14   - CHARACTERISTICS OF THE MELKA SADI MAIN CANAL
15  - CHARACTERISTICS OF THE AMIJ3ARA MAIN CANAL
16  - CHARACTERISTICS OF THE AMIBARA MAIN CANAL
17  - COORDINATES OF THE WEIR PROFILE
18  - CALCULATION OF THE JUMP RATING CURVE
19  - CALCULATION OF THE FORCES AND MOMENTS ACTING ON THE BODY OF THE WEIR
2 0 - STORABLE VOLUME UPSTREAM OF MELKA WARAR BETWEEN 737. 40 AND 738. 00
21   - COORDINATES OF THE WEIR PROFILE
22   - MELKA WARAR DIVERSION WEIR JUMP RATING CURVE
23   - CALCULATION OF THE FORCES ACTING ON THE WEIR BODY AND THE RELATIVE MOMENTS
24   - FIELD DRAINS
25   - UNIT DRAINS
26   - DISTRICT DRAINS
27   - MAIN DRAINS
28   - FLOOD ROUTING AT MELKA WARAR
29   - FLOODS FROM ALEIDEGHI PLAINSFIGUIL S
j  FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES - COMMERCIAL FARM - CROPPING PATTERN A/lfit
PERIOD
2    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES     -     COMMERCIAL     FARM     -     CROPPING     PATTERN     A/2nd PERIOD
3    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES     -     COMMERCIAL     FARM     -     CROPPING     PATTERN     3,/lsl PERIOD
4    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES     -     COMMERCIAL     FARM     -     CROPPING     PATTERN     B/2nd PERIOD
5    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES     -     COMMERCIAL     FARM     -     CROPPING     PATTERN     C/lst PERIOD
6    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TLMFS     -     COMMERCIAL     FARM     -     CROPPING     PATTERN     C/'2nd PERIOD
7    - FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS
TIMES - SETTLEMENT-CROPPING MODEL A
8    - FIELD WATER IRRIGATION RE JUIREMENTS FOR TEN DAYS
TIMES - SETTLEMENT-CROPPING MODEL B
9        -     CALENDAR        OF IRRIGATION   FOR SUMMER    TOBACCO
10         -     CALENDAR        OF IRRIGATION   FOR COTTON (1st stage)
1 1        -     CALENDAR        OF IRRIGATION   FOR COTTON     (2nd stage)
12         -     CALENDAR        OF IRRIGATION   FOR SUMMER    GROUNDNUTS
OidlTAM      <!. •tj . fltnv/
’ JC'in 
»! ’
1 3    - CALENDAR OF IRRIGATION FOR SUMMER MAIZE 14    - CALENDAR OF IRRIGATION FOR WINTER MAIZE
15  - CALENDAR OF IRRIGATION FOR WINTER TOBACCO16        - GALE. \R OF IRRIGATION FOR WINTER GROUNDNUTS 1 7 - CALENDAR OF IRRIGATION FOR VEGETABLES (TOMATOES)
18      - VARIATION OF INFILTRATION RATE WITH PERCENTAGE
OF CLAY
19      - irrigation plots
20      - irrigation drainage and road network - general LAYOUT
21      - IRRIGATION UNIT AND MINOR NETWORKS - TYPICAL ARRANGEMENT A
22      - IRRIGATION UNIT AND MINOR NETWORKS - TYPICAL ARRANGEMENT B
23      - INDEX OF CONSUMPTION AND NETWORK LOSSES
24      - MAIN AND DISTRICT CANALS GROSS INDEX OF CONSUMP TION
25       - MELKA SADI SUBAREA - DISTRICT CANALS - SCHEME 26      - DISTRP : T CANALS - TYPICAL CROSS SECT [ON
27      - MAIN CANALS - TYPICAL CROSS SECTION
28      - MELKA SADI DIVERSION WEIR - MEASURING FLUME - DISCHARGE RATING CURVE
29      - AMIBARA MAIN CANAL - MEASURING FLUME - DISCHARGE RATING CURVE
30      - DISTRICT CANAL INTAKE - MEASURING FLUME DISCHARGE RATING CURVE
31      - UNIT CANAL INTAKE - MEASURING FLUME - DISCHARGE RATING CURVE
32  - MELKA SADI DIVERSION WEIR - DISCHARGE RATING CURVE33     - MELKA SADI DIVERSION WEIR - TAILWATER AND JUMP RATING CURVE
34      - MELKA WARAR DIVERSION WEIR - DISCHARGE RATING CURVE
35      - MELKA WARAR DIVERSION WEIR - TAIL WATER AND JUMP RATING CURVES
36     - MELKA SADI SUBAREA - DISTRICT DRAINS - SCHEME
37     - DISTRICT DRAINS - STORED VOLUMES 3S - FLOOD ROUTING AT MELKA WARAR
APPENDICES1.     INTRODUCTION
In this volume the basic data are defined, the planning criteria described and the alternative soludons regarding the irrigation engineering discussed. The results are used in Part III to prepare the Outline of the Project, Chap ter 2 deals with irrigation parameter s. methods* water ratoB, daily time of irrigation, etc. Matters concerning the irrigation and drainage systems are contained in Chapters 3 and 4 respectively. Chapter 5 is concerned with protection works against both Awash river floods and the waters flow ing down from the Aleideghi Plains. In conclusion, electricity supplies to the Study Area are examined in Chapter 6,- 3 -
Z. IRRIGATION PARAMETERS
The following irrigation parameters must be determined:
l) Irrigation Method
Z) Calculated Water Requirements for Each Crop
3)      Effective Rainfall and Field Irrigation Efficiency
4)      Field Irrigation Requirements for Each Crop and Cropping 
Pattern
5)
Water Application Volumes and Irrigation Calendars
6)
Peak Irrigation Water Requirements and Daily Time of Irrigation
7)
Irrigation Plot
8} Water Modules,
2.   I IRRIGATION METHOD
In selecting the irrigation method, two systems have been 
examined; gravity and sprinkler.
Vis-^-vis       the       gravity       method,       sprinkler       irrigation       has       the       fol lowing disadvantages:
Costs of the irrigation network downstream the secondary Canals would undoubtedly be greater (by at least 60%), even considering that leveling although little would be required for gravity irrigation (none at all is required for the sprinkler m ethod).
Running costs would be higher because the water would be put under pressure; this would require some I, 500 kWh/ha per year.
It      is      calculated      that      irrigation      labor      requirements      would      be      about the same in both cases. Instead, as far as water requirements- 4 -
are concerned there would beaalight saving (of perhaps 10-15%)
in the main network with sprinkler irrigation, since this method permits more economic distribution. Whereas there are lower percolation losses on the one hand, there would be evaporation losses caused by wind on the other, unless it were decided to 
sprinkler irrigate only at night or in the morning. But, in that case, other disadvantages would have to be faced (see below, 
para. 2. 6).
Hence, taking all factors into account, gravity irrigation is by 
far the begt method to use in this case.
2. 2 CALCULATED WATER REQUIREMENTS FOR EACH CROP
The water requirements are estimated by first calculating the potential evapotranspiration on the basis of climatic data.
This evaluation provides the potential water requirement for each crop, and practical observations make it possible to determine the length of the effective irrigation season (2, 4). This season is al ways shorter than the total growing season (i.e. up to the time the product is completely harvested), and sometimes considerably so.
The only formula for calculating potential evapotranspiration for which coefficients are available for each crop is that derived by Blaney and Criddle. These coefficients were obtained in semi-arid zones of the U.S. j but they are considered to be suitable also for the middle Awash Valley.
The other formulae, such as Turc's and Thornthwaite  s only pro vide a "climatological" evaluation and there are no coefficients available for indivudal crops.
This notwithstanding, the potential water requirements have also been calculated on the basis of these. In the case of the Thornth waite formula, the potential water requirement is per month, while with the other two the period is decadal. The values derived by Turc's-formula are given in Table J; Table 2 compares the monthly values derived from all the three above mentioned formulae, and the values from Blaney and Criddle’s are set forthat the end of the paragraph in the table on water requirements for each crop(Table j).
15-
POTENTIAL WATER REQUIREMENTS ON THE 0A5I-S of TtJRC’S FORMULA (I) (mm per tan. day I |
l
1
Month1
1966-61
Average Relative
Hu mid My
%
-------------------------------
Total
RadlalLan (cal aq. cm/day)
---------------------- ------------------------------- 4- Temperature
5:1
Potent h i| Evapol rant pl ration
(mm)
1
LJcCad*1
n
□ecad*
in
Decade
I
Decade
n
Decade
111
□■E*da
I
Decade
11
Decaete
III
D< carle
Total
January
Fe brua ry
Ma rt h
April
May
June
July
Ai4gu.il
5eptrnibrr
October
Nove miw r
December
54
64
59
54
49
52
62
5a
55
5b
5«
59
63
s«
59
5Z
46
56
60
51
54
60
57
60
6l
50
56
46
49
59
60
52
53
61
57
576
6 09
636
6zi
632
621
58 n
565
60 L
600
571
580
20 6
23. 9
23*7
26. 1
26. 7
29. J
29. 5
26. 1
26.9
26.6
24.7
21.6
22. 1
23.2
24.9
26.1
27. 4
30. 1
28. 3
26, 3
27.4
ZS.6
24.1
2X. J
23. 1
21.15
25.9
26.4
28.1
29+7
27.5
26,7
27. J
24.6
ZJ. 0
22. 4
47
5a
ii
54
57
56
60
54
50
56
54
52
48
48
57
55
57
57
61
53
JI
56
53
51
4B
_________
54
46
* 62
57
67
60
5|
56
54
57
51
53
149
161
171
in
iso
112
165
157
168
164
154
149
(I) Ture'i; formula ll a* UoJIltfWtJ
ET^(rriim/d«cade) = (Eg * 50 J
where:
Ig = total radiation In email
(!♦
70
)
k*
cAlnrira wr Ifl. tfii
F              J* j
-rf>f •
I = iYcri|c dally Lampe Future aver thr cietide (°Cji
Hr relative humidity j thia la considered only alien thr t*1u« falli below 50 (daring the Liat decada of May and throughput
June, at M>Lha Wirir),Table 2
POTENTIAL CLIMATIC WATER REQUIREMENTS CALCULATED BY THE TURC, BLANEY-CRIDDLE, AND THORNTHWAITE FORMULAE
(mm/month)
1               Month                 '          Turc            it  Haney-C riddle
Thornthwaite
1
I January
1 February
149
161 -r
March                                        171
i April
1           171
1 May                                 1           180
i June
' July
August
September
I October
183
165
157
168
164
November                                   154
• December
| Year
149
1,972
149
141
165
168
182
186
186
157
170
166
151
147
70
80
111
134
168
210
186
142
151
122
93
68
1,986
1.535- 7 -
J
These net potential requirements are considerably higher than 
the real requirements of the crops (except in the case of peren
nial plants or polyannuals such as alfalfa or citrus). Indeed, 
most have an irrigation season of three months*or a little more, 
while evapotranspiration covers the whole 12 maltha of the year. 
At most, with two crops, the ground would only be irrigated 7 
months of the year.
As stated  earliert the Blaney  - Criddle formula is used  to  cal culate the requirements of each  individual crop.  The formula is as follows:
u — kf
where:
u = evapotranspiration in mm/decade
f - evaporation power, which is obtained with the expression:
*   where d is the percentage of daylight hours over the
period considered, compared with the total daylight
hours in the year and t_ is the average decadal tem perature (°F);
k = the crop coefficient which can be derived as a function of temperature on the baa is of experimental coefficients sup
plied by Blaney for some parts of the USA
k (1) can be calculated from kt x kc where kc is an exper
imental coefficient for the crop derived in the USA, while
kt is related to temperature through the expression:
kt = 0. 0173 t - 0. 314
where the average temperature t is in °F
(1) U.S. Department of Agriculture - Soil Conservation Serv ice. "Irrigation Water Requirements1 11 - Technical Release
No. 21, April, 1967.- 8 -
The water requirements have been calculated for decades or the like(11 days for the third decade of months with 31 days and 8 days for the third decade of February).
The crops ar^‘ considered on the basis of the effective sowing period planned. In point of fact, the growing season is the real growing season plus the period of time required for sowing (or transplanting). The exceptions to this are multi-annual crops such as alfalfa and citrus.
Consumptive Water Use figures are set forth in Table 3.
2. 3 EFFECTIVE RAINFALL AND FIELD IRRIGATION EFFICIENCY
The rainfall for the Mclka Sadi Amibara area is known for the
1 9^5-68•four-year period.
In view of the relatively short period involved, the decadal val ues derived can only be taken as indicative. However, compari son with rainfall at Awash Station for which figures are available for a ten-ycar period indicate that the averages for the four-year period do not depart greatly from those for the longer period.
In view of the smallness of the individual rainfall events it has been decided to deem only 60% of the total rainfall as being use ful. In addition, since evaporation accounts for the greatest los ses, this coefficient has also been applied to falls of less than 5mm because the greater losses through evaporation are com
pensated for by a rise in the relative humidity of the air, with a corresponding drop in evapotranspiration. Turc's formula takes relative humidity into consideration while the Blaney-Criddle formula does not do so explicitly. Since the consumptive water use requirements of each individual crop as mentioned above have been calculated by the latter method, it has been deemed advisable to consider large and small rainfalls in the same way.
In any case, even an approximate assessment of the smallest falls has but a negligible effect from the practical angle, when calculating irrigation water requirements.
Table 4 sets forth the useful decadal falls at Melka Warar.CONSUMPTIVE WATER USE RY CROP lu CALCULATED BY THE B1ANEY-CRIDDLE FORMULA AND CROP COEFFICIENTS
( figure. nr. by decade end for typical growing cyclo.)
Month
Decade
January
February
March
April
May
June
July
Crep
1
11
III
I
II
HI
I
II            111
:
II
1U
1
11
in
t
U
III
1
11
ill
Polrntlaj Evapotran.plralion
54. 2
51.0
MI
51. 7
51.2         59.9
56.2
62. 0
61.4
54.4
64. 7
Gon.umpU** Waler U.e
- Sammer Crop.:
Tobacco (1)
Groundnuts (2)
Colton (t month*)
Cetlon (5 month*) (J)
Malx.
- Winter Grope.
Mai..
Tobacco
Groundnut.
V.g.Uble. ( (omato.e)
Polunuual Crop. (4)
Alfalfa
Citrus
16
7
14
16
13
15
16
16
IN
14
37
21
14
21
41
21
20
4
17
2.
21
12
45
lb
28
1?
54
41
JO
19
44
44
36
2)
44
41
3b
22
32
55
55
»T
Jit
5?
62
47
63
71
61
56
61
60
51
5a
55
»4
47
.50
43
•
25
25
24
2B
>4
JJ
35
13
U
12
JO
26
41
14
46
17
56
43
55
40
57
41
6F
42
65
44
69
44
.4
54
• 1
50
83
52
•2
57
10
SO
74
la
So
(I)
(2)
TM crop coefficient* K through the growing
*°xTCeM
ppi 1*4 for tobacco with Ute tomato (irrigation Water Requirements USDA April 1467).
'""•*•••1 bT “* “* **k*
..
•« higher ouomU cJZcLt Bto^y
....
*a 7l.7,’ Lch*!*.
>>
le ir^ adopted are tho.e lor ooya (being a eimiUr plant providing oil eeedpJ.A long cyclo (150-day)
tor winter.
r *UU
**• considered lor cummer, and a ehorler-cycle variety such a. Red Valencia (I lOd
aye,
(3)
(<>
ZTaiomTLT* th. .hort.r cycle
CO      ar d wUh
necessari
ly implie. Larger daily water conaumjxion.
"”’  '        **— —M-d io. b-month cycle cotton. .me- It I.
felt that
m2rpo7
„?*,u‘,e"“a,‘
crop’<r< ,-poried- ‘h°u«h “*•*
-•» •••“ f‘—««*
•«-Table 4
effective decadal rainfall at melka warar
(in mm)
(average of I9S5-6B four  yeay period)
r
— ■-
Month
I
Decade
II
Decade
Ill
Decade
Average
for Month
January
February
March
April
May
June
July
August
Septembr r
October
November
Decembe r
Total
3
2
8
13
4
22
45
1 3
7
15
-
I
8
2
23
2
J
17
15
7
3
25
-
1
8
21
5
-
11
21
31
4
2
5
2
19
25
36
1 5
16
to
91
24
10
42
5
•»
-
-
345On the question of field irrigation efficiency, the particular irri gation method was the main point considered (it is a well known fact that furrow irrigation is much more efficient than border ir rigation or basin irrigation).
Most of the lands in the Area are loams, clay-loams or clay-sand' loams. The rate of infiltration in general is good and the field capacity is high (1). Hence, on the one hand, losses by surface seepage can be Limited by correct use and on the other, deep seepage losses arc limited by the good field capacity. Experience in similar environments indicates that the field irrigation efficien cy may be set at 0. 70  This means that the irrigation water re
r
quirements have to be increased by 4 3%. broken down as follows;
8% for direct evaporation;
1 0% for i r regular distribution;
25% for deep seepage.
The field efficiency in the sandy and sandy-loam soils has been 
put at 0. 60 in view of the higher permeability, but this type of
soil is unusual in the Melka Sadi Amibara area.
The figure can  be set at over 0,  70  but less than  0.  75  in  the case of clay  soils {*40% clay) because though  th*- deep  seepage losses are lower, the surface percolation losses are higher.
In any case, to be on the safe side when calculating the diversion capacities and the seasonal volumes of total irrigation water re- quiremi-nts. a field irrigation efficiency of 0. 70 has been taken for the clay soils too (which account for about 1 5 % of the total).
2 4 FIELD IRRIGATION REQUIREMENTS FOR EACH CROP AND CROPPING PATTERN
The field irrigation requirements have been calculated by ecnsi- de ring:
1) The water consumption figures calculated by the Blaney - C riddle method (para 2. 2);
(1) See also Vol. 2 (Part II): Soil Science Report.2)      Effective Rainfall (decadal average over the 1965-6B four- year period};
3)      Average field irrigation efficiency (of 70%);
4)       The effective growing period of each crop during which irrigation is required.
The latter factor was assessed on the basis of operations in similar irrigation districts nearby and within the Kielka-Ami- bara area (Melka Warar Research Institute Farm, Ambash Farm, along the course of the Awash).
2.4, J Water Consumption in Irrigated Areas of the Awash Valley
Field ir rigation water requirements on irrigated farms in 
the Awash Valley are often lower than the theoretical require ments of the plants through the whole growing cycle from sow ing (or transplanting) to harvesting.
This is especially true in the case of cotton and tobacco be cause after the first picking they are not usually -watered any more; naturally this shortens the effective irrigation period cons iderably.
For example, on the Tendaho Farm in the lower Awash Valley, cotton is irrigated four times (including pre-irrigation) within a period of less than 120 days, while the complete cycle up to the time the plants are removed is 1 80 days.
The Field Irrigation Water Requirements of crops on some farms in the Awash Valley, inside and beyond the borders of the Study Area are given in Table 5.
2 - 4. 2 Irrigation Test Work at the Melka Warar Agricultural Research Station
Systematic experimental work on the irrigation of the most im portant crops has been undertaken by the Melka Warar Agricul-FIELD IRRIGATION WATER REQUIREMENTS OF SOME FARMS !N THE AWASH VALLEY
Crop
Fa r m
AHLludr
m
a. 6. 1/
Average Water
ApplieaUcFi
(cu. m/ha)
No. of
Irriga -
linns
Volume
(nil. m/hl)
Irrigation
Method
Gotten
Nura-Era Aw*ra Mrlka Abdir Ambith TendAho
1.150
eos
950
750 160
1 T ooo
I, ooo 700
1. 500 2. 500(1}
6
7
10
.4-5 4
t
10, 000
6.000
7.000
7. 000
6-7.500
Sub me raion-inf lltr axion kibmcT«iDH -Inti ll rat w n Fu r r ow -1 rrlg* tion Borddr-Irriaillun
Bfciln- J rrigB-tion
T ubacco
NlirA -Era
1. 150
B00-900
5
4-4.500
Furro*-1 rrigatlcn
GruundnulB
Awara Me Ik a
BOS
1,000
5-6
5 6,000
Sabme re ion-Infiltration
Beant
Awara Mrlka
H05
1,000
6
6, OOO
Sub me r a 1 on - Inf 111 r ■ lien
Tematoei
Awht.I Ktelka
BOS
800
7-8
5.600-6,400
SubiTi r ri i on -1 nil ll; ration
Sugar Cane
Melrha ra
950
1,000
30
30, 000
■ Furrow ItrfagaEion
H,insnn ta
Awar* Melkn
fl 05
I. 000
10
JO. 000
Sasin lnfLIlraticn
Cl t ru B
Avrara Melka
nob
900-1. 000
1 S
16-IB.000
Infill ration by Ditches
Alfalfa
Awara Melka
BOS
1. ooo
20-25
20-25,DOO
Border Irrigation
Sudan Gra ■ >(2)
Melka Warar
750
1, coo
12 IS
tlE, 000
Jis; ooo
Border Irrigation
(j ) TMl high volume i* explained by the fact lhat ba bitl irrigation iff med. And eipecialiy brriyie al thr great iIee of Hie biBlBB (25 huh *hich . BinnngBt ether thing ■, results in heavy teepage IobbeB- at depth.
1
(J) A 10-month growing tyclr (*llh 5-6 cuti) from July Io April normally, ia conildfred useful.- 15 -
tural Research Station since the beginning of 1967. Most atten tion to date hag been given to summer herbaceous crops, but unfortunately checks on effective water consumption only start ed in 1968 which was a particularly rainy year. However, some of the results appear very useful, particularly as regards the irrigation period and the water consumption trends. Due account has been taken of these data in the considerations and conclusions set forth below.
2, 4, 3 Cone lusions
>
The decadal field irrigation water requirements have been work ed out on the basis of practical irrigation water consumption fig ures and of the theoretical values provided by the Blaney-Criddlc method. The practical indications are those regarding length of irrigation season, while the field irrigation water requirements during the course of the season considered have been taken as those given by the theoretical calculation (1),
The field irrigation water requirements for each crop and for each cropping pattern are get out in Tables 6 and 7 respectively. Those for the cropping patterns are also shown in diagrammatic form.
Normally the decadal field irrigation requirements are in excess
»  of 600-700 cu  m/ha. Since this volume corresponds to one water
#
ing, a ten-day interval between waterings is thus normal.
The field irrigation requirements for each cropping pattern, are also expressed in terms of a continuous discharge of so many liters per second per hectare, twenty four hours per day (see Table 7 and Figs. 1 to 8).
One of the water balances drawn up to determine irrigation re quirements is illustrated in Table 8.
(1 ) These calculated figures refer to the average year. It has
been seen that the average temperature variations were neg ligible over the 1965-68 period considered and so from the practical aspect it appears pointless to analyze theoretical decadal consumption for each year from 1965 to I968.- 16 -
Considering Cropping Pattern C/2nd for the Commercial Farms and Cropping Model B for the Settlement (1), and taking into account the irrigation network efficiency (see below Chapter 3). the total annual volume to be diverted is around T60 x 10^ cu. m.
2. 5 WATER APPLICATION VOLUMES AND IRRIGATION CALEN DARS
In determining the water application volumes, the basic con sideration has been the field capacity of the soils. Both loamy and clayey soils (vertisols) have a high capillary water capac ity (see Table 9).
The water and soil tests run in the laboratory indicate that on average it is possible to count on the available moisture being between 10% and 25% by volume, the lower value being for light soils (loams) and the higher for clay soils and for clayey silts, sandy clays and sandy-silty clays, largely.
In practice, apart from truly sandy soils in a relatively narrow strip along the Awash, it can be taken that the hydraulic con stants of the soil range from a minimum of 20% to a maximum of 55% of the dry weight of the soil, where the lower value is the 15 atmosphere percentage and the upper figure refers to the one-third atmosphere percentage measured with a Richards apparatus.
(l) See Vol. 5 (Part II).Wl»
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dOMO IDVI MOl tlhJHlHUlOia »|1»« wui.r..... -
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Table 7
FIELD IRRIGATION REQUIREMENTS FOR EACH CROPPING PATTERN
(in 1/ l*c/hi, every 10 days)
Month
Decade
January
February
March
April
May
June (I)
July
Aug al
September
October
November
December
C ropping
Pa lie rn
I
11
ni
1
U
QI
1
n
Hl
1
U
ni
1
11
U1
I
u
m
I
U
m
I
in
1
n
m
I
11
in
1
H
ID
1
11
in
COMMERCIAL FARM
Croppins Pattern A
let period
2nd period
Cropping Pattern B
0. 04
0. 34
0. 04
C. IB
0. 04
0. IS
0.04
0. 42
0. 03
0. 22
0. 02
0.20
0. 02
0. 49
0. 03
0. 50
0. 02
0.45
0. 02
0. 56
0. 01
0. 31
o. oof
0. 05
-
*
-
-
0. 145 0. 23
-
-
-
-
0. 04
o. ic
0. 16
0. 145 0. 18
0 145 0. 18
0. 145 0. IB
-
0. 05
0.16
0.26
0. 17
0.47
0. 34
0. 71
0. 68
0. 80
0. 68
0. 76
0. 84
0. 70
0. 85
0.53
0. 86
0. 25
0. 20
0. 12
0. 53
0. 03
0. 37
0. 08
0. 21
0 08
0. 20
0. 12
let period
2nd period
Cropping Pattern C
0. 24
0. 31
0. 32
0.41
0.32
0. 41
0.40
0.52
0. 46
0. 61
0.45 0. 596
0. 52
0. 69
0. 60
0.79
0.46
0. 61
0. 30
0. 39
0. 15
0.20
0. 06
0. 10
-
-
-
•
*
0. 06
0. 0*
0. 2 3
0.24
0.23
0. 24
0.23
0. 24
0. 20
0. 27
0. 13
0. 17
0. 07
0. 09
0. 21
0. 2K
0.33
0.37
0.61
0. 65
0. 73
0. 73
0 70
0. 67
0. 60
0 55
o. 41
0 40
0 22
0 21
0. 03
0. 03
0. 01
0 01
0. 03
0. 0 3
0. 10
0 12
0. 17
0. 22
0. 24
0 30
lai period
2nd period
SETTLEMENT FARM
Cropping Model A
0. 20
0 27
0. 25
0. 35
0.25
0 35
0. 14
0.45
0. >7
0. 52
0.45
0. 50
0.40
o. 5a
0. 41
0, 67
0. 37
0. 52
0 23
0 32
0 10
0. 15
0. 05
0. 06
-
-
-
-
-
*
0. t>4
0. 06
0. 20
0.21
0 20
0. 21
0. 20
0. 21
0. 18
0.25
0. 14
0. 17
0. 05
0. 07
0 14
0. 2-
1
0. 28
0. 31
3.46
3. 56
0. 60
0. 72
0. 70
0 74
0. 63
0. 66
0. 57
0. 55
0. 49
0. 37
0. 25
0. 14
0 07
0. 07
0. 20
0. 03
0. 19
0. |0
o. 21
0. 17
0 25
0. 25
C ropping Model B
0. 30
0. 12
0. 39
0. 12
o. 39
0 12
0. 54
0. 14
0. 66
0. 14
0 66
0. 14
0. 735 0. 14
0. 89
0. 27
0. 67
0.405
0. 39
0. 39
0. 15
0. 37
0 07
0.23
0. 12
0. 26
0. 08
0. OS
0. 26
0.23
0. 22
0. 23
0. 143
0.21
0. 23
0. 16
L
0. 37
0. 25
3. 67
3.41
0. 81
0. 51
0. 77
0.87
0. 66
0. 87
0. 46
0. 79
0.22
0. 62
0. 135 0. 46
-
0. 09
-
0. 28
0. 07 0. 185
0. 22
0. 09
0. 30
0 09
(l)ln the aecond decade, the value calculated is the average of two
(one lower and one higher) for the let and 2nd 5>day period.s
FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS TIMES*
8
*
FIELD WATER IRRIGATION REQUIREMENTS
FOR TEN DAYS TIMES
5 K3FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS TIMESI
I!
I
■I
i
it*
FIELO WATER IRRIGATION REQUIREMENTS
FOR TEN DAYS TIMES
COMMERCIAL FARM-CROPPING PATTERN 0/2nd PERIODFIELD WATER IRRIGATION REQUIREMENTS
FOR TEN DAYS TIMES
COMMERCIAL FARM-CROPPING PATTERN C/lstPERIOO
QFIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS TIMES3
field water irrigation requirements
for ten days times
SETTLEMENT - CROPPING MODEL A
SEASONAL VOLUME 10320 cum/haSlOii N
FIELD WATER IRRIGATION REQUIREMENTS FOR TEN DAYS TIMES
SETTLEMENT - CROPPING MODEL B41 -
i
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—      —                      4
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&        da             v
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1           Hi           i           H ft —=                “      1“
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11
ll   li J i < JCNE-THISUJ AND FIFTEEN ATMOSPHERE MOISTURE PERCENTAGES OF SOME REPRESENTATIVE SCHLg,
S*mple (I)
Depth
Mui «tu re  | %
at
0. 3 alm
Mei ilure %
at 15 atm.
Clay 0.002 mm
Sill
*0. 05
mm
Sand
Ca'«||orf
M
J4Z
604
190.
222
23B
10ft
E?5
336
563
Jib
5«0
0-fl
8-4%
10-75
0-30
0-25
is-m
o-zn
20-55
20-40
0-30
0-45
4 5-60
0-30
JO-05
0-2O
20-45
40-70
0-30
30-60
ft- 1 0
10-30
23.90
2S. 3
43.8
38. 7
48. 5
S5. 0
45. 6
47. 4
55. 7
41.7
23. 4
13. 7
3ft. 2
53. 2
37. 1
31, 6
45,0
37,0
35.0
JJ. 5
32. 0
f - 12.3
• 14, 6
. ’ 20.4
H I 5, ft
’’     30.6
•» ’ 38. 7
H 33.5
34. 8
’ * 35 ft
24 , 6
,r C 10 ft
r            23.2
21. ft
lfi.fi
r ‘* 26.5
\ 2i, a
•M 24. 2
u.e
1B.9
z 20. 1
i ’ 20, 1  |
14.0
15.5
51,9
44. 0
51.3
70.7
33. 0
6A. 2
30, 5
51. ft
21. ft
24. 3
13.2
17.3
60. 5
24 I
27.2
23.3
32.7
27.9
23.4
2ft. ft
27.5
20. 1
42.9
10,9
38.6
37. J
58.9
22.7
50.0                      39.2
61. 8
57. 3
44. 8
23, 3
20. 8
5.9
40. 4
6. 3
49.4
5. 5
59. 5
37, 1
49. 4
23. fl
16. fl
10. A
26.2
26. 7
26. A
34.8
31.2
49. 4                   23.9
493
41. 3
52.6
34.0
33.7
32. 0
20. 6
JI. 2
35. 1
fl} Seo Vol, £ fPar: E). fZJ L = Joam, C *
S; ’ tilt; S - toand.-23
However, considering that there is no great variation in moisture availability in most of the soils in the Area, it is considered that a single average value can be fixed. This value is the average of the available moisture values for the various types of soil (If
As can be seen from Table 9, the available soil moisture values found for some representative samples of the various soils (ex cluding sandy soils) run at around 16% by volume. Thus every 10 cm layer of soil can store 0. 16 cm depth of water, or 1 60 
cu. m/ha. 
| 
j + "!       , *A
?>-
From the water application  aspect,  this figure must be reduced by  at least 1/4  because the watering  must be done before all the available moisture has disappeared.
When calculating the specific watering volume for each crop, it is naturally necessary to consider the difference in root structure; this also applies in the case of any given crop too, through the course of its growing cycle. Furthermore, a cer~ tain variability of watering volumes also depends on the desira bility of adopting more or less equal turns during rainy and dry periods alike, for simplicity of operation.
In practice, the volume of water applied must remain below 120 cu. m/ha per 10 cm depth of soil. Taking due account of
the different crops and growth stages involved, net average water application volumes have been worked out for each crop. The effective water application volumes were then arrived at by assuming an average efficiency of 0,70 (see Table 10),
In considering the watering volumes, no account has been taken of the leaching requirement. Indeed, analysis of the Awash River waters (act Pari H  Vol. 1) indicates that the conductivity 
f
varies from a minimum of 0. ZZ to a maximum of 0. 38 mmhos/ cm at 25 C. On this basis, the leaching requirements envisage
(1} It might scum more advisable to use the minimum values but it should be remembered that the analyses relate to soils which have never been tilled, and without doubt the values found Will h,■ ex.d-d once the lands are cuRivated- 24
Tabic 10
WATER APPLICATION FOR CERTAIN CROPS
Crop
Irrigation
Method
Maxi mu m
Soil
Depth
(cm)
Field
Application
Volu me s
(cu. m/ha)
Maxi mum
Per missible
Volumes
(cu. nV ha)
Alfalfa
Cotton
Tobacco
Maize
Groundnuts
Vegetable*
border
furrow
furrow
fur row
border
furrow
I 00
100
80
80
70
60
900-1,200
700-900 (I)
700-900
700-900
600-800
600-700
l, 200
1,200
960
960
84 0
720
(1)A grealer volume could be considered, but since the growing season Cor cotton includes months when rainfall is quite high, it is as well
to limit the watering volumes so as to lessen the risk of useless and sometimes damaging waterings - in the case of clayey soils - causing hypersaturation of soils which must frequently be hoed and over which machinery often has to pass.<
- <>'
cd for the irrigation use of these waters in the extreme case oi very sensitive crops would be, respectively:
220 x 100
LR =
TH =
4. 000
580 x 100 4, 000
This signifies that even in the case of the highest salinity en countered in the Awash waters and the most sensitive crops, the increased quantity of water to be distributed for leaching, compared with effective crop requirements, would be less than 
10%. This is not a relevant figure a  far as current irrigation 
a
practice is concerned.
Irrigation Calendars (and frequency of irrigation)
The irrigation calendar is the operational tool governing the
application of water through the irrigation season. In practice, 
it is linked to the irrigation season and to the start and end of
waterings. It also indicates the times when the various waterings
should normally occur, and sets out the total number and fre
quency of such waterings.
The calendar must be suited to each crop and to the time of
year it is sown Sowing periods arc spread out over a certain 
length of time, but it is not possible to take account of this fact
when drawing up diagrams, so the irrigation calendars for the
crops refer to normal growing cycles and must be considered 
as representative of an average situation.
As      the      calculations      arc      made      for      ten-day      periods,      the      irriga tion     seasons     are     therefor*     all     multiples     of     ten     (sec     Figs.     9     to 17),
In relation to the peak field irrigation requirement of 0fc 85 l/ scc/ha (sec para. 6), the available daily volume is
0, 85 x 86400 1000This corresponds to a normal watering volume (for maximum watering volumes of 900 cu. m/ha, the average irrigation in
terval is
= 12 days approximately). Thus it would be
advisable to adopt a 1 0-day irrigation turn for distribution 
within the Irrigation Unit.
PEAK IRRIGATION WATER REQUIREMENTS AND DAILY TIME OF IRRIGATION
This problem has a different aspect depending upon whether
it is viewed from:
the design of the irrigation systems feeding the farms and the irrigation units;
the design of the main irrigation system and the ’’diversion capacity ’ at the Awash intake.
1
In the first case it is necessary to base the assessment on the water requirements of the most demanding crops without tak ing account of any rain which might fall at random, since it will be normal to grow just one crop (at any given period of
the year) within the irrigation unit, in view of the considerable size of the farms. In the second case, instead, it is necessary 
to refer to the most demanding cropping patterns net of any rain which might normally fall, since in a large district there are
many possibilities of striking a balance between the demands stemming from various parts of the same area.
In point of fact, as the peak requirements often occur when there is virtually no rain (end of September-October), the dif ference between peak irrigation requirements net of rainfall
and peak irrigation requirements including rainfall is practical ly negligible. Hence.it would be quite pointless to attempt to process the rainfall data to obtain frequency values.
From the calculations of water consumption by crop (without taking account of rain) it may be deduced that the crops with the highest peak water requirements (assuming an efficiency of 0. 70) are as follows:
cotton (short cycle: 5 months) 1.03 l/sec/ha (3rd decade Septemb‘ry
CALENDAR OF IRRIGATION FOR SUMMER TABACCO‘1J
(1) For earliest growing seasons the number of water application is 7
9 us
SEASONAL VOLUMEAPPLICATION VOLUMES
SEASONAL VOLUME
oAPPLICATION VO
SEASONAL VOLUME
CALENDAR OF IRRIGATION FOR SUMMER GROUDNUTSapplication volumes
seasonal VOLUME
E
o
CALENDAR OF IRRIGATION FOR SUMMER MAIZE
IRRIGATION SEASONapplication volumes
CALENDAR OF IRRIGATION
-
(l) for laifS|
growing stjsontjht n
application l5 7APPLICATION VOLUMES
SEASONAL VOLUME
CALENDAR OF IRRIGATION FOR WINTER TABACCOh)
eu.m/ha
tooo
900-
800 700* 600-
500 ■
100
IRRIGATION SEASON
(1) The latest sowing al th* ind of January requires 9 applicationsAPPLICATION VOLUMES
SEASONAL VOLUME
Q
63
o
CALENDAR OF IRRIGATION
FOR WINTER GROUNDNUTS
cu.m/ha 1000- 900 800 700 800- 500
CM. m/ha
►6SCID
•6000
IRRIGATION SEASONI
IAPPLICATION VOLUMES
SEASONAL VOLUME
CALENDAR OF IRRIGATION
IRRIGATION SEASONI27 -
summer tobacco I. 08 l/sec/ha (2nd decade August).
winter maize
I. 08 l/sec/ha (3rd decade March).
Consequently      the      irrigation      unit      network      has      been      designed on the basis of 1. 08 l/sec per net hectare.
On the other hand, regarding the peak irrigation requirements
on which to base the design.the main irrigation system and the Awash diversion, it will be seen from Tables 6 and 7 that the most demanding cropping pattern of those proposed is A/'I st (Q,84- 0. 86 l/sec/ha) with 90% cotton and 10% vegetables. It is high
ly probable that this pattern will be adopted, at least initially, though during the later stage more diversified patterns will probably be preferred.
The cropping patterns for the settlement scheme have peak re quirements in excess of A/l^t (0. 89 l/sec/ha in the second decade of March and 0. 87 in the third decade of September and the first decade of October). However, there is not a great possi^
bilily of these being adopted on a large scale outside the settle ment scheme. In any case, the differences are negligible and come within the degree of approximation of the calculation.
Thus, it is considered that the average between the two values for cropping pattern A/l may be selected, i. e. 0. 85 l/sec/net farm hectare (J
This unit discharge holds good for irrigating 24 hours per day during the peak period (virtually September 10th to October 31 st).
(I) The figure of 0, 86 which occurs in the first decade of November normally coincides with low or negligible water requirements for the other cropping patterns.- 28 -
Daily Time of Irrigation
The number of hours per day that irrigation water is applied 
is a decisive factor when designing the main irrigation net
work. The problem has been carefully examined on the basis
of experience gained in the existing farms and irrigation dis tricts of the Awash Valley.
Only the HVA Farms at Metchara and Wonji growing sugar cane irrigate forless thanJwe.nty four hours per day (they operate
12-13 hours). To achieve this, reservoirs have been built on the farms so that water diverted from the Awash can be stored during the night. This solution was necessary in the case of Wonji, since water has to be pumped up from the river and hence it was necessary to have stand-by capacity available in case of pump breakdowns. Where Metehara is concerned, ad vantage was taken of the fact that the lie of the land was fairly favorable for reservoir construction.
On other farms in the valley and on the Anbash Farm within the Study Area, irrigation is practised 24 hours per day, dur ing the peak periods, from Mid-September to the end of Octobe Experience gained on these farms has indicated that there are no particular difficulties encountered in irrigating at night. Nor, compared with daytime irrigation, has there been any appreciable increase in labor costs or any decrease in effi ciency.
It has been attempted to assess what the increase in costs would be for the MSA Area if irrigation were restricted to
14-16 hours per day, so that this increase could then be com pared with reductions which might occur in labor costs and improved efficiency. The increase in costs would derive from:
construction of reservoirs, should it not be possible to increase the flows from the river;
improving the conveying capacity of the irrigation net work.- 2? -
Reference to Part D, Vol. 1, Chap. 3 shows that it is not pos sible to increase the discharges from the Awash by 30-40<. Thus, the question of reservoir construction was examined. However, the lie of the land is very unfavorable. Therefore, as will be appreciated, the cost ofatorjm^waLer would far o up weight the resulting benefits, even as regards order of magni tude. In view of these findings, it would have been quite super fliious to calculate the increased costs of a larger capacity ir rigation network or the greater expense involved in operating such a system on a discontinuous basis.
1
2. 7 IRRIGATION PLOTS
As anticipated in para. 2. 1, the gravity metho d gf irrigation and in particular the furrow irrigation, has been selected for must uf the crops (cotton, maize, tobacco and vegetables), not least because this provides the highest iirrigation efficiency, which is an important factor since there ia only a relatively limited amount of water available. With the plots planned it will also be possible Lu adopt border irrigation for groundnuts a and some vegetables, by means of small ridges 10-2 0 meters apart and parallel to the rows, thus dividing the irrigation plot into 4-8 sections.
In the case of furrow irrigation, the size and the form of the irrigation plots depends partly on the irrigation parameters and partly on the physical and hydraulic characteristics of the soil,
The side at right angles to the furrows is taken as being the width of the plot. This width is a factor more closely bound up with the need for drainage Lhan for irrigation. In practice, a certain number of furrows is watered in turn, the number depending on the water module selected. This matter will be dealt with in the following paragraph (see 2, 8),
As will be deduced from Chapter 4, this w^hJjUimitod by. tji^drainafiejietwork, and is 75 m for most of the lands in the Area,30 -
The length  of the furrows and  thus of the irrigation  plot,  de pends instead  on  factors closely  bound  up  with  the way  irriga tion is operated on the field. These are mainly:
the nature of the soil;
the water application volume.
The nature of the soil has a direct bearing on the final infiltra tion rate of the water. In this respect, a scries of field tests
has been run using the double-cylinder Picker apparatus (1) with constant water level. Two checks have been made for each point in various parts of the Area.
Tests have also been run in the holes from which samples for laboratory analysis were taken. For these (27), therefore, physical soil data are also available and hence the infiltration rate can be tied in with grain size (see Table 11). Merely in the case of the clay component, the curves relating the various minimum and maximum infiltration rates to percent clay (see Fig.. 18) have been drawn up and a certain correlation* value (modest) has been deduced. These curves are merely of indicative value, inasmuch as it is not possible to deduce the behavior of all the particular soils in the Area from them.
The infiltration values indicate that there is a great variation in behavior, depending on grain size make-up (2).
(1)      F. Bonetti: Cons iderazioni sull'importanza dell’infiltra- zione dell'acqua nella teoria e nella pratica irrigua (Rivi- sta "L'irrigazione", Verona, Centro Internazionale Studi Irrigazione, No. 1-1966).
(2)      See Table 3, Vol. 2 (Partll) Soil Science Report.VARIATION
MINIMUM    VALUES
h
+4
+
+
-
so \          4-
+
X
-L.
\>+
+
- 50
4
♦
4-
■1h
A
0
50
co
70
70- 31 -
Table I i
FINAL INFILTRATION RATE IN mm/hour IN RELATION TO THE PERCENTAGE OF CLAY AND SILT
1
Poi Ilian
Studied
Final
Infiltration
Rate
(mm/hour)
Percent
Clay
Per cent
sin
M+M.
Mln.
44/l/E
si/*/E
VV*
04/? A
io..'i A
50/! A
50/5/W
IZ/B. M.
4i AA
54/2/E
2A
51/1 A
8/5/W
ai /3/w
45/14/E
4S/E
4>/4/W
6Z/13A
77/1/W
21/1/E
05/|./E
M. WAR AR
18/1 0/E
5Q/3/E
Aaada
io/6/w
45
BO
BO
220
LtO
90
zoo
190
120
35
00
100
40
180
105
35
90
130
70
BO
25
25
75
330
25
20
10
40 0)
110
130
105
115
50
75
1 30
120
35
40
90
40
45
105
25
90
B0
70
20
9
7
40
1Z
5
IZ
to
4. 3
13.2
14. 1
1 5. 0
15. 2
2 B. 4
IS, 4
19.4
31.6
23. 2
24. 0
24. 5
27. 6
30, 5
30. 5
31. 9
32.2
38. 8
42. 4
45.J
45. 1
45.3
52.9
50.9
68. Q
70. 2
14.2
71.6
52. 7
36.3
21, 7
S3. 9
33.5
21. 6
48, 9
j a. 9
45. 9
36. 5
113
35.8
54 S
28, 9
3B. fa
39. 4
38. f>
40. 5
34, H
3 9. 7
21, 5
34. 0
1 fa
27. 0
27.0
10, fl
1
(l) Figure not interpolated tn relation to clay content, becauae in thia rate it it linked largely with the ailt content.- 32
It     is     considered     that     three     soil     classes     may     be     blocked     out     for this parameter:
1)      Not very permeable soils
2      5      mm/hour      final      minimum
(average: 12. 5 mm/hoi^r)
infiltration rate
2)
Averagely permeable soils
25-75       mm
final
minimum
(average: 50 mm/hour)
infiltration rate
3)
Very permeable soils
75        mm/hour
final
minimum
(average 100 mm/hour)
infiltration rate
These infiltration rates are used to fix three different furrow lengths, since the watering volumes have not been differentiat ed on the basis of soils (only of crops).
“The optimuTrt" slope of the fiirfows _is between 0, 5 and~ 2^*, So for a good part of the land, the irrigation layout can be adapted 
to the natural grade,
In short, the slope of the furrows must be selected on the basis of the infiltration classes, while from the Crevat formula (1), the following lengths emerge:
1)       Land Class 1 (clay) Length of Furrow: 50-60 m
Land Slope
: 0. 5 - 1
2)       Land Class 2 (silt-clay or clay-loam or silt-loam) Length of Furrow: 2 5-30 m
Land Slope
: 2%o
3)      Land Class 3 (loam or sandy-loam) Length of Furrow: 10-15 m
Land Slope
(1) L (length) ■ - n
4K
: 2%# or slightly more.
where: i = .oil
) pe (metera per mater)
aO
K» Infiltration rate (m/aec)
<1 * depth of irrigation water (in meters) coefficient (20 for ungra.a.d .oil.)- 33 -
It is not advisable to greatly exceed 2%#in Class 3 because this would give rise to erosion. The furrow lengths are for limited watering volumes (700 cu. m/ha).
Each plot is separateJJr^^^nc^UengthwiseibyLan irrigation d’itxh which is rebuilt each year or each season by means of., a ditching plough. This ditch is not deep so water can easily penetrate into the furrows from which it is separated by small embankments 10-20 cm high that are broken down by hand at each watering (see Fig. 19).
The system proposed is a little costly as regards length of field canals but it has the great advantage of permitting unlimited variation in the length of the furrows to suit the crop and the watering volumes,simply by altering the dist ance between the irrigation ditches. The field canals are, however, permanent. This layout is similar to the one adopt ed at Abadir and to the irrigated plots at the Melka Warar Agricultural Institute.
As regards irrigation times for one hectare, it is felt that
by adopting a minimum turn of 10 days it will be possible to irrigate four hectares a day, one hectare being irrigated in 
6 hours. For an irrigation plot measuring 30 x 75 m =2,000 sq.m, there will be 1. 2 hours available per plot.
2. 8 WATER MODULE
The parameters on peak irrigation requirements have already been defined (para. 2.6) in relation to the design of the main network and the farm network (or rather that within the irri- gation unit).
The water module is the unit discharge to be distributed within the irrigation unit (see Chapter 3). This depends es sentially on the possibility (or otherwise) of making up groups of 2-4 people to handle the water module.- 34 -
It is possible to adopt fairly small water modules in the case
of furrow irrigation; indeed, in theory they can be equal to 
the discharge to be fed to one furrow (l.-l. 5 l/sec). Normal
ly a field-hand can handle a discharge of 10-20 l/sec, i, e. he
can follow 8-10 furrows at a time.
On the large commercial farms it is not difficult to make
available 2-3 hands per irrigation unit being irrigated. Thus
a group of hands could look after between 20-60 l/sec, the
average being 40 l/sec.
The unit canal serving the irrigation unit thus should have an 
average net discharge of around 40 l/sec. It must be large enough 
to take account of the peak discharges required by the most
demanding crop. Since the peak requirement is 1. 08 l/sec/ha, 
then with 40 l/sec it is possible to irrigate 40: 1. 08 = 37. 03 ha. 
To facilitate division of the area, the irrigation unit can be
rounded out to 40 ha net, and the water module will thus have
to average 40 x 1. 08 = 43. 2 l/sec.
Since normally  it will be necessary  to  apply  1.  0-1.  5  l/sec of water,  or a little more,  irrigation  will be performed  by introducing the water to 20-30 furrows at a time.
Usually, it is possible with an irrigation plot to irrigate a whole multiple divisor of the total number of furrows in the plot (variable from 75 to 1 50).FIG. 19
IRRIGATION PLOTS
---A
SECTION
No.27026I
‘l- 35 -
3. IRRIGATION WORKS
3 i               GENERAL
The purpose of this chapter is to discuss problems concerned with diverting the waters for irrigation.
Upstream of the Project Area, the Awash flows in a gorge
some few dozen meter deep and a hundred or so meters wide. When it enters the Project Area, however, the situation alters rather abruptly; the bed slope changes from more than 1 m/km
to about 20-30 cm/km, the river meanders and the low-flow
bed is some forty meters wide and 6-8 meters deep. At the present time, the flood bed covers the entire Project Area
and the right-bank plains. In general the top of the low-flow
bed banks is above the level of the surrounding plain, the lev ees often being several meters high (see Fig. 20).
The flooding problem is discussed in Chapter 5 ahead, though it must be mentioned here that land reclamation will entail the con struction of protective dykes.
In a first approach to the question of how to divert waters from the river, the possibility of installing pumping stations was ex amined. However, it is felt that quite apart from the question 
of cost and, especially, running costs such a solution would 
only be a feasible proposition for an irrigation area of a few hundred hectares and not for the whole Project Areav
In Vol. 1, it was seen that in some periods it is necessary to divert the whole of the flows from the Awash and its tributari e_s, and furthermore, a small quantity of storage is also required to compensate for daily fluctuations (and sometimes weekly fluctuations) in discharge.4
II a eerie* of pumping elation* were installed along the river, 
those upstream would certainly be able to draw water all the
time, but to ensure continuity of supply to those feeding the
northern part of the Area a_*eric9_of_weirs_would_be_needed. 
The cost of these would be high, and certainly in excess of
that involved in the construction of one or two Diversion W eirs„
Moreover, if it were decided to gave on capital costs by adopt
ing less cautious installation criteria, the weirs could be
damaged and perhaps destroyed by floods, and the saving on 
first cost would quickly be wiped out by high maintenance
costs.
Furthermore the stations would have to be protected from
floods which arc often unexpected and violent, though of short
duration. If the pumping stations were to be completely pro
tected the costs would be considerable and if they were not
protected properly then costs would not be merely limited to 
those involved m repairs, but also the cost of lost crops should 
irrigation be suspended for any length of time.
Hence, it emerged that the only feasible solution was that of
diverting the waters by__on<! or more weirs. In view of the
topography of the Project Area, there are two possibilities:
One      Diversion      Weir      (the      Melka      Sadi)      built      at      the      southern extremity for supplying the whole Area;
Two Diversion Weirs, one at the extreme south (Melka
Sadi Diversion Weir) and the other at Melka Warar Hill
(Melka Warar Diversion Weir) to supply the two sub
areas into which the Area is naturally divided by the re
striction at Melka Warar Hill.
The       following       considerations       led       to       the       second       alternative       be ing chosen:
To         copejyithjrrj^aticmi         requirements,         jt         is         necessary         in some periods to divert the discharges of the Kessem andDYKES
MAIN ROADS
TO BOCHAMO
AREA(FUTURE
WESTERN DYKE
MELKA WARi
DIVERSION V
LINK ROAD.
IMPERIAL ETHIOPIAN GOVERNMENT
AWASH VALLEY AUTHORITY ADDIS ABABA
IRRIGATION drainage and
ROAD NETWORK
04 HER AL LAYOUT'UK m
tw
- 37 -
Kebena     too;     these     join     the     Awash     downstream     of     the     Melka Sadi Diversion Weir.
Some small amount oi compensating capacity is
Because oi differences in bed slope, above and below Melka Sadi (20-30 cm/km downstream of and 1. 00 m/km up stream), by raising the Melka Warar Weir 60 cm above
the elevation required for diverting the waters, a reserve of about 700, 000 cu. m is provided for compensation. To achieve a "similar capcity upstream of the Melka Sadi Weir, the sill would need to be 4-m higher than necessary to simply divert the waters.
- The first solution would mean that if the Main Canal for
the Amibara subarea remained unaltered, that for_the Melka Sadi subarea would be 17 km long instead of 12km, with a discharge of between 30 and 35 cu. m/sec (1) in stead of 1 and 5 cu. m/sec. Taking account of the free board, the average cross-sectional area would need to 
be 85 sq. m instead of 1 0 sq. m, and the increase in vol ume would be about 1, 300, 000 cu. m. Considering struc tures too, the increase in costs would be around Eth. $ 2, 800, 000.
The difference between the total cost of the Melka Sadi and Melka Warar Diversion Weirs and that involving just the Melka Sadi Diversion Weir with the sill raised 4 m is of the order of Eth. $ 3, 000, 000. The difference in the overall cpst^fjhe two_ olution  (Eth, $ 200, 000) is small as a per
38
centage andin absolutejyalqe.s too, especially when'the“adT" vantages offered by the second solution are weighed.
(1) Account being  taken  of the fact that the Angelele and Bolhamo  Districts will have to  be supplied  at a later stage.JB -
LAYOUT OF IRRIGATION NETWORK
Each, of the two Diversion Weirs will supply its own subarea by means of a Main Canal.
In turn, each subarea is divided into Irrigation Districts which are supplied by District Canals taking off from the respective Main Canal.
The typical arrangement of each Irrigation District is as fol lows: (Typical arrangement A - Fig. 21).
The elementary area is the Irrigation Plot 800 m tong and 75 m wide (1).
8 Irrigation Plots form one irrigation Unit11 (600 m x 800 m or 48 hectares).
In  some cases (Typical arrangement B - Fig.  22) the Irrigation Units,  (always 600  x  800  m or 48  ha) are formed  by  tO frriga- tion Plots (600 m long and &0 m wide).
3.3
The borders of the Project Area have been fixed on the basis of the following topographic and morpholo
ctive
 con-TBACT
----------- FTG'TT
Pl STRICT ORAW------------------------------------------ BIOMT or WAV 1100
IRRIGATION UNIT
SCALE 1 AOOO
ETHIOPIAN GOVERNMENT
AWASH VAI.I.IY AUTHORITY ADDIS ABABA
IRRIGATION UNIT AND MINOR NETWORS
TYPICAL ARWANGEMFNT AVP|T - DRAW______________ j
unit CANAL
♦
I
■ oo
oisrwic’ J«o- IO • >00
f 00
■ fOMt
> p,i
•R<» MAIM-
Of «AV 1100
------------ A
4---------------- »0« 700
PH *
—
..    J -——!
u *»°° f-”f
4-
SECTION
JN'T TRAC*
5ECTION
____ FJBLDCAMAL *
SECTION
IRRIGATION UNIT
SCALI 1*000
IMPERIAL ETHIOPIAN GOVERNMENT
AWASH VALLEY AUTHORITY
ADDIS AMASA
MELKA SAOI-AMIBARA IRRIGATION PROJECT
IRRIGATION UNIT ANO MINOR NETWORS
TYPICAL ARRANOXHT B
ITALCONSULT
"Ct »• Kill
MABIBILITY btuoy- 39 -
to the north, by the Linda Bilcn swamp which separate^ the Amibara from J.he Angel el e Plain
to the east, by the Eastern Dyke which protects the Project Area from flood waters coming from the Aleidcghi Plains (this subject is also dealt with in detail in Chapter 5).
The dyke ha  been located at pointB where ground slope
5
changes occur (values of 2 give way to values of 6-10%#). This line is also more or less the dividing line between the Class 6 and better class lands. Naturally, it has not al
ways been possible to faithfully follow this dividing line and. so at least several dozen hectares of Class 6 lands are in cluded in the Project Area, while better lands have been excluded. From a purely technical aspect, these better
lands could have been irrigated by pumping up water to them, but as waler is the major (actor limiting the size
of the project Area in any case, it wa«a decided not to re claim these marginal areas (1),
The geographic area with the boundaries just described amounts io j 7j 770 ha, of which 1_7 3 ha are QCCJUpied by hills and rock outcrops.
Furthermore, a total of some 187 ha of marginal lands will nut be irrigated because their elevation would have neecs- sitated raising all the network*
(1) For the same reason, it is not planned to reclaim the belt an mainly Class 2 and 3) between the Western Dyke
and the Awash River. This could possibly be used for growing timber.- 40 -
The Project Area has been  supposed  divided  into  eight Commercial Fart* and  a Settlement Scheme Zone (or the nomadic pastoralists wh0 presently  inhabit the area,  and  for peasants from the Highland,. It is also planned to build a Township near Melka Warar Hill.
The       Farmsteads       on       the       Commercial       Farms,       the       four       villages of the Settlement Scheme and the Township will occupy 511 ha.
Thus, the Gross Arable Area is 16. 899 ha. or 95. 1% of the Geographic Area. Of this, 3. 090 ha are occupied by works
(see Table 12) and so the Net Arable Area is 1 3, 809 ha or
82. 6% of the Geographic Area. In this there are 226 ha of
Class 6’lands which have bee neon eider cd as irrigable when designing canals and assessing water requirements, though from the
economic aspect their return has been set at zero.
3.4 NETWORK LOSSES
Bearing in mind the nature of the soils in the Area, which derive from the decomposition of volcanic rocks, it has been, assumed that for an unlined network the seepage loss will be 150 liters/day and per square meter of wetter area (1).
This value, equivalent to 6 mm/hour, seems to accord well both with the permeability of the soils on the spot (10’^ cm/tf established during the geological and hydrogeological investif tions, and with those determined by the field infiltration tests with the double-cylinder method, especially if due account i® given to the fact that the latter are influenced by the test area which is only of one square decimeter approximately. Con sidering the length per hectare of the various classes of ca nals (2) and the relative average wetted perimeter, the wetted
(1)      SeeBauzil - Traits d’irrigation.
(2)     It has been considered that on average, in peak period’1 2 half the overall length of the Unit Canals and half the F‘ ' 
e
Canal for each Irrigation Unit will be under water.41
T>bl? U
AREAS AND DEDUCTIONS
Description
Length
( km )
Width
(m)
A ret
( ha )
Total
Arsa
( ba )
%
Geographic Arc*
Deduction! for:
-Rocky ion* a
-Elevated icrfi
-Villages, farm etc.
Total
Groee Arable Area
Dcducdloa« for;
-Dykes
-Main Canal*
-Main Drains
-Main Roads
-District Canal*
-District Drains
-Dlairlct Ro* di-
-Unit CanaJ«
-Unit Drains
-Unit Track■
-Field Canal*
’Field Drain*
Total
Net Arable Arei
17*770
100.0
173
187
511
871
4,9
■
•r
92
32
80
131
146
105
175
240
ISO
150
2. 300
2,400
16, 599
95. 1
900 0
zo
25
28
11
15
1J
«
6
6
7
2.5
4.5
154
64
22 3
144
2Z0
116
140
144
90
105
560
1. 050
3. 090
17.4
18. 4
13. BO?
82 . 6
81.6
^=T“4
- ‘1Z -
area has been calculated. This amounts to about 90 sq. m/ha of Gross Arable Area. Accordingly, seepage losses during the peak requirement period are of the order of 0. 1 5 1 sec*ha of Gross Arable Areju
To this value has been added that for handling losses (faulty handling, leaks past gates, filling or emptying of lhe canals operating intermittently), which on the basis of experience acquired with network having similar characteristics, has been taken to be 0. 06 l/sec per hectare of Gross Arable
Area.
During peak periods network losses, referred to the Gross Arabic Area, thus amount to 0. 2. lZl££xha.
During the periods in which the water requirement is lower the water levels in Main and District Canals will be near those of the peak requirement season; consequently the water losses too will be of the same order of magnitude,
It has therefore been assumed that the network losses will vary according to the water requirement between 0, 22 1/sec ha in the peak requirement period and 0, 1 1 l/sec t ha when the water requirement is near to zero.
ThO 8C
Cnr
values have been assumed in order to en- e    th a°t the network can be operated safely under all circum-
SUf  eB At the same time it >i thought that seepage losses
stance , 
won a ill, iccn p  ount oi uuu
be ap
re
p ciably lower than those calculated,
{act lhat a by no means indifferent part
the Area has soils containing an important percentage of
° and that the silts and clays carried by the irrigation 
Clay’ v.hen the rivers arc in flood, and which will be deposit-
^d7n the walls and beds of the canals, will exercise a further waterproofing effect.
it was seen that the aver,a^eJ.a;kXJil^onsumptiQ.n In ChaptCperiod is n- j/sec net to the field per hectare of- 4 3 -
The net to the field index of consumption per hectare of Gross Arable Area is:
0. 85 x CL 816 = 0. 69 1/sec* ha
Considering network losses, the gross index of peak consump tion at the Diversion Weirs, per hectare of Gross Arable
Area is:
0. 69       0. 21 - 0. 90 1/sec- ha
Thus the network efficiency is 77%. Fig. Z3 shows the relation ship which links network loss and gross indices of consumption it the Diversion Weirs to the net to the field indices of consump
tion.
3. 5 LINING OF CANALS
Consideration has also been given to the possibility of reducing seepage Josses by partially or completely lining the canals. However, this would have involved a lining ratio of the order of 50 sq. m/ha of Gross Arable Area, even if lining were re stricted to the Main and District Canals.
Rearing in mind the frequent presence of swelling clays and the resulting need to adopt suitable measures to ensure satis factory preservation of the linings, the greater cost_of in vestment would be of the order of Eth, $ 800 per ha of Gross Arable Area,
Against this very high investment cost there would have been a reduction in the losses of the.prder of 0. 10 l/sec per ha of Gross Arable Area. i. e. a total of about 1. 7 cu,_m/'sec. With in the context of the Study assignment there appears to be a clear^lnd undoubted choice in favor of an 1 ined canals
The problem can perhaps be examined during the feasibility study regarding the reclamation of the Bolhamo, Angelele and Maro Gala Areas, a reclamation which almost certainly depends on the implementation of the Meky River Diversion Sc h em e,- 44 -
During thin phase it will be possible to compare the greater , investment entailed by the lining of the canals which for t| 
Melka Sadi-Amibara District should be performed at a late,  c with the investment cost of the above mentioned Scheme.
Moreover, at this time certain data should be available, and not only hypotheses as at present on the extent of the seepage losses in the Melka Sadi-Amibara networks. Already, how ever. even if no complete data are available, especially on the Compensation Reservoir, it appears that the orders .of magnitude of the. quantities involved are such as to exclude the solution with lined canals. The reduction of the seepage losses of the Project Area, amounting to 1. 7 cu. m/sec and to 50 cu. hm/year would entail a higher investment of the order of Eth. $ 13,000, 000, with a cost per cubic meter of stored water of the order of Eth. $ 0. 6 to 1. 0.
To support our choice it appears advisable to point out the
fact that in none of the areas al. ,        ,        “----- —;--------—aj-
of reclamation in the Awash Valiev u,. i ----------------------- TT------- ~ . V—
4iX sAgjcreclaimed or in progress
r
envisaged, except in some sections
—.-------------------- ------------ lining of the canals been
whe
mjibiUtiur where .he^jju myulved^Xl r„.
--------------------
T^-tfaere jg high j>er-
The lining of canals will thus be limited 
upstream and downstream of structure ° VCFy short atretches' may cause erosion and damage both  bere local turbulence
w
ture itself. 
0 thc canal and to the struc-
O
3. 6 IRRIGATION CANALS - DESIGN CRlTERlA 3. 6. 1 Discharges
a) Unit Canals and Irrigation M d,,i,. As stated in the paragraph 3. zt
down into Irrigation Units nor
ma ]v
i   . Ml k^
’
. 0, "'"ken ArableINDEX
ANO
OF CONSUMPTION NETWORK LOSSES
-
CONSUMPTION
SiI
I
I
I
11 'i
.1
) ' 'ii
•I
ii
•i
i2
- 45 -
Area of 48 ha. Each Irrigation Unit will be continuously supplied (during the peak period) with one Irrigation Mod ule.
Since deductions for works (canals, drains and roads)
amount to about 20 the Nel Arable Area of the Typical Irrigation Unit is thus 40 ha,
In view of the fact that the entire Irrigation Unit may be cultivated with the most demanding crop (tobacco) which during the peak period has a net to the field index of con sumption of 1.08 l/sec per hectare of Net Arable Area, 
the value of the Irrigation Module net to the Field is
1.08 x 40 - 43. 2 l/sec. The water losses in the Unit and Field Canals can be taken to be 7 l/sec (1 6%);the Irriga
tion Module at the Unit Canal Measuring Structure amounts in round figures, to 50 lj sec.
This seems to be a just compromise betwe€*n the two coun- terposed requirements; first, the need to make allowance
for the fact that al the beginning the farmers will not be
very familiar with irrigation techniques and hence will
not be able to handle large quantities of water on the field; and second, that once they have acquired the necessary 
skill they could use a sufficient discharge to guarantee
that labor costs do not account fur too large a proportion 
of total irrigation costs.
Referring the figure 50 l/sec to the Gross Arable Area of
the Irrigation Unit the gross index of consumption at the Unit Canal Measuring flume results:
50: 40 - 1.03 l/sec.ha of Gross Arable Area.
b) District and Main Canals
To facilitate mechanized farming and especially pest con trol measures using aircraft, it is probable that a number
of adjacent Irrigation Units will be put under the same crop.- 46 -
Hence the cross-sections in the terminal parts of the
District Canals must be Urge enough to carry the dis. 
charges for the peak requirements of the most demand^
crops.
The    corresponding    gross    index    of    consumption    is    1.03    I. per hectare of Gross Arable Area.
Going  back  toward  the Diversion  Weir it is probable that the proportions of the various crops will increasingly  ap proach that envisaged for the whole Area for which the
grosBjndcx of conaumpliop, as calculated it. par
i s 0. 90 l/aec _pe r hectare, of Gross Arable A tea.
The index of consumption to be assumed for the design d the various stretches of District and Main Canal in rela tion to the surface served by the stretch, is given by Figure 24, the index of congumption is equal to 1  03 
r
for areas of less than 250 ha and 0. 90 1/ e .ha for areas
Sc
of above 10, 000 ha while fOr areaB be[ween z5o and I 0, 000 ha the variation is linear
a)      Gene ral
As stated in paragraph 3*5 be urdined, jxccpt at_pointa g i ve rise to_ e r o si on. 
canals will
- -' _1q cal_t urhii I ence might
All the canals have been designfbd
35 for the Manning roughness <.L«MBXning a value of
K/.
n
The maximum allowed water
.
I! » - 6 • Cb'W
, r .Ji
on the basis Of the following f0 V been calculated for the design and construct^ q{ a^safull ad d Similar canals m various arCis
* — •'Q Cits
2 , Q0Q fl£
* yPt‘ ^ere SoilBX.
2000                  3000                  4000                  5000                    6000                   7000                   9000                  6000                 10000 GROSS ARABLE AREA COMMANDED- 47 -
were fairly similar to those in the Melka Sadi-Amibara area: V = 0.20 f 0  16 b
t
wher c:
V - maximum water velocity (m/sec)
h - water depth (m)
Whenever      possible,      the      minimum      water      velocity      has      been      check ed in order to keep sedimentation as low as possible.
The freeboards have been put at:
0. 15 m for the Field Canals
0. 20 m for the Unit Canals
0.     30     tn     for     the     District     and     Main     Canals     having     a     discharge lower than 5 00 l/sec
0.     40     m     for     the     District     and     Main     Canals     having     a     discharge frorn 501 to I, 000 1/ sec
0.     50     m     for     the     District     and     Main     Canals     having     a     discharge from 1, 001 to 5, 000 l/sec
0.     60     m     for     the     District     and     Main     Canals     having     a     discharge higher than 5, 001 1/bcc.
The above figures accord well with those suggested by the
United States Bureau of Reclamation, bearing in mind that the
Irrigation Canals cannot receive runoff waters and that discharge
regulating devices and automatic outlets have been envisaged.
b) Field Canals
The      Field      Canals      will      carry      water      periodically.      Hence      it      is reasonable     to     expect     that     a     few     months     after     they     come     into operation     the     bottom     and     the     sides     will     be     covered     by     grass, as happened in the Metehara Area.
Water velocity^ ther efor e  can be eyen_quite high, 31 p_t0__ 
t
0. 5 m/sec, without there being any risk of erosion. The
bottom gradient can range from 0. 5 to 2 m/km (extremelimits of slope after leveling). The depth for a discharge
of 50 1/sec will thus be included between 3 0 and 20 cm. whereas the velocity will vary between 0. 24 m sec and
0. 48 m/sec.
) Unit Canals
The Unit Canals will have to convey an Irrigation Module (50 1/sec); since their general trend is parallel to the contours the hydraulic gradient will have to be limited. A gradient of 0. 20 m/km has been assumed.
The bottom width has been fixed at 40 cm; the side slopes at 2/3.
The   depth   is   thus   35   cm   and   the 0. 17 m/ecc.
velocity of the water
d) District Canals
The area served by the various
District Canals ranges
from a minimum of % ha (two Irrigation Units) to a maxi mum of 1. 900 ha. The discharges thus vary from a mini mum of 100 1/bcc to a maximum of I, 730 L/sec.
Two hydraulic gradients have, been adopted: 0. 10 m/km in sections where the natural gradient of the land was slight or where the water level Was more ’han 50 cm above the ground; 0. 20 m/km in r* 
gradient of the ground was sufficient.
etions where the natural
Bearing m mind the object of the Study.   detailed design 
a
was made for the District Canals of the Melka Sadi sub area only (see Fig 25), Whereas for the AnUbara
only the alignments, the extent of the areft
elevations at the intakes from the H
un
 Can- I a
d
were determined. 
Table    13    sums    up    the    geometrical
.erl.tics of the various type„ ’ also Fig. 26). 
Can *“ derivation
‘ l'ydtaplip
Moptcd (nnr
MELKA SADI SUBAREA
DISTRICT CANALS - SCHEMEAp MI£ H ■ II
II
■jl27033
DISTRICT CANALS
O)Ji
*!
I
rCHARACTERISTICS OF DISTRICT CANALS
Geometric Characteristics
Hydraulic Characteristics
Type
of
1-0. 10 m/kiu
1-0. 20 m/kxn
Section                       a                      h                       f
b
Welled
Area
(sq. mJ
’A cited
Perimeter
(m)
Hydraulic
Radius
(m)
V
(m/sec)
Q
(l/sec)
V
(m/iec)
Q
U/«ec)
Max.
Velocity
’ m/ seel
60/ 40
60/ SO
t-0/ 60
60/ 70
100/ 70
100/ 80
100/ w
100/100
150/100
!50/110
150/120
150/130
150/140
150/150
0.60
0. 60
0. 60
0. 60
1,00
I. 00
1.00
1.00
1.50
1.50
1.50
1.50
1.50
1.50
0. 40
0. 50
0. 60
0.70
0. 70
0. 80
0. 90
1. 00
uoo
1. 10
1.20
1.30
1. 40
1.50
0* 30
0. 30
0. 30
0* 30
0. 30
0. 3/0. 4
0. 3/0. 4
0. 40
0. 4/0.5
0. 4/0. 5
0.50
0.50
0. 50
0. 50
L. 20
1.20
1.20
1.20
1.20
EZD
1.20
1.20
1.20
1.20
1.20
1.20
1.20
1,20
0. 4H
0. 6fi
0. 90
1. 15
I. 44
1.76
2.12
2. 5D
3. 00
3.46
3. 96
4.49
5.04
5, 63
2. 04
2.40
2.76
3. 12
3.52
3. 88
4.25
4. 61
5. 10
5.47
5.83
6. 19
6.55
6. 91
0. 24
0.28
Q. 33
0. 37
0.41
0.45
0.50
0.54
0. 59
Q.«3
0, 68
0.72
0.77
0. Bl
0. 13
0. 15
0. 17
0. 18
0. 19
0.21
0. 22
0.23
0.25
0.26
0, 27
0.2B
0.29
0. 31
63
101
149
20 8
275
363
465
582
7 36
B94
1. 071
1.266
I, 4B1
1.716
0. 19
0.21
0.23
a. 25
0.27
0.29
0. 31
0 33
0.35
0. 36
0. 38
0.40
0.41
0.43
6 9
142
210
293
38B
512
656
B2l
1.03B
1.261
1.510
1, 785
2. 08B
2. 420
0.26
C. 28
0.30
0. 31
0. 31
Q.33
0.34
0. 36
0, 36
0. 38
0.39
0.41
0.42
0.44
i
—JL
-
Table I 3) Main Canals
All canals which serve areas belonging to at least two 
Commercial Farms have been classified as Main Canals.
In    the    study    of    the    Amibara    Main    Canal    the    possibility    of using    it    to    feed    also,    at    a    later    stage,    the    Bolhamo    and Angelele     areas     has     been     borne     in     mind.     Through     want of    final    data    for    these    two    Areas    the    same    consumption indices     adopted     for     the     Project     Area     have     been     adopted. Account    has    been    taken    of    a    Gross    Arable    Area    of
6, 000 ha for Bolhamo,of 4, 500 ha for Angelele Area.
It has been envisaged that the increase in discharge to provide for feeding the other two Areas can be obtained for a first stretch (from Sta. 0 to Sta. 8, 830) through deepening the section, for a second stretch (from Sta.8,83C to Sta. 11, 560) through the lowering of the roughness coef ficient by lining the bottom and sides with concrete slabs; and for a third stretch (from Sta. 1 1. 560 to Sta. 1 7, 730) both by deepening the section and by reducing the roughness coefficient by lining.
U.I.;
map.
oJ Sla. U, 730 . „cw canal hivr be „ already
ooo
ch.» a teri.tic 'otl' h°
rc               1
1
P 'r  " °"al' 
',nd           3  1
 hy*' " *'
Main Coal (.„ al o
.
Table 15 sets out the oner t*
° ( MeIta
characteristics of the Amil*00*1 dlrnen«ional and hydrauh<- tion of the Bolhamo and An Main Canal, before reclama' the operational, dimensional h Area“' Table 16 indicate® of the Amibara Main Canal aft” bydraulic characteristics
Areas
-
Cr the reclamation of these■rtQWN
MAIN CANALS
TYPICAL CROSS SECTION
J
>CHARACTERISTICS OF THE MEL,KA $ADL MAIN CANAL
GEOMETRIC CHARACTERISTICS
1. m )
HYDRAL’OC CHARACTERISTICS
Trum Sts.
ta St*.
Comm
A tv*
(h*>
Di«l! barge
«
h
h
h
I
E
b
A
t
Welled
A re a
(»n. »*)
Wetted Perimeter
I TT. )
Hydraulic
HbiILus
{ m |
Hydraulic C radiant
( m/km |
Water
Velocity
( tn/tec ]
Diicharge
( l/.« 1
0
5.414
2,500                     r -
4, 931
S, b 05
3. 21L
6, 60S
2, 197
B, £ 10
Uil
9. r-W
1.052
11,540
3. 250
4, 000
1, 220
2.420
1,650
1. 0*0
2.50
2.00
2. 00
2. DO
1.50
1.50
2.00
2.0Q
L 60
1.40
1.15
0. 95
0.00
0. 60
o, to
0. 60
D.50
0.50
1,00
3. DO
3  00
+
3. 00
l,D0
1, oo
10,30
9. fiO
B 60
d, oo
6. 90
6.15
11.00
10.00
7.04
S. 74
4.2B
3.25
J
9. 71
9. 21
7, 77
7.05
6. 15
5.41
IU1
1.0!
0. 91
0. Al
0 70
0. 60
0. IB
0. 15
0 20
0. 20
0. 20
1
9.20
0.51
0, 49
0.46
0. 42
0. 39
1
0. M
5. 6)4
4. %i
1. 2t3
2,471
1.670
LlSO
1
J JCHARAGTERISTICS  OF  THE  AMIRARA  MAIN  CANAL tBefore rtdamutian of Bulhamu and Ar^rtala Ara**)
Ch* r*c*«ri«°**
Corrwrk.
Area
Diacharg*
Wa«’*4
Ar**
,*q- n*)
1.61° 4.210
4.410
6.510
7.710
0.110 10.10° |1.>6°
12.41° 1J.450 17. T>°
|0. 4«° 20.«<»
II.4*5 10.
to. no 4.165
6.  16< 7.474
7. JOO 9, 527
5. J 3° J, H»
Watt** P»ri«**,-r
| I 29 11    II 12     75 12 37 12. 21 12. 03
Hydraul^
Hydr*ulkc R*diU« (m)
a
B
2. 4/0 2. 040
' 4.440
' 5.JJ0
I     4.400
'      3.610
I 2.420
I 2.010
5. 00
1. 00
5. 00
5 00
3. 00
S 00
9. 00
J. 00
J 00
7. 00
1. 00
2 OO 1.50 1. »0
h
h
2. 30 2.21 2. 15 2. I® 2 00 1. 4» 1 40
j 00
1 05
1. 64
1. 40 1. io
1. 25 1. 10
0. 70
0. 63
0. M 0. 14
0. 16
0, 16
0. 16
0. 16
0 20
0. 20
0. 20
V*loc*,v im/ >
0. 53
0. 52
0 51
O. 51
0 50
O. 49
0 48 0. 4B 0. 47 0. 41 0 41 0. 40 0. 39 0. 32
10. 167
9. 918
9. 106
• . 706
7.911
?. 562 7. 200
5, 133 I 5. 055
4.023 2.918 2. 1 31
I. 641 i. 264
1 >CRARACTEFUSTICS GF THt AMZBAHA ^LALN CAXAL
(AHer the reclamation oE Flu LN* mu and Angelrl* Areas Groai Arable Are**! HolharnG &  DOO ha - Angelela 4,500 ha]
(
Geometric Gharactarlilics
Hydraulic Chara clarialhca
From Saa.
to Jt4,
ClffM
.Aral
{ha)
Ditehart c
(1/iec)
a
h
1
b
c
Welted
A rea
(■q- m)
Welled
Perimete r
(mJ
Hydraulic
Radius
(m)
Hydraulic
Gradient
Water
Velocity
(m/'flac)
Dtatha rne
U/flat)
RaufhnrtB Coefficient
K
0, DO
I. 100
1.870
4. 250
4. 470
6. 510
7, 71 0
a. Bj>0
|0r700
ll< Ho
12,410
13,430
17. 7J0
U.49Q
21, *65
L5, J4B
14. 610
13. 665
12.t>64
12. 479
n. m
10, 027
9.630
a, J«o
7, 420
6. 540
1. 603
10, 770
1 J, AID 1 J. ISC
12, 300
II.SID
11,230
1 0, 7 1 D
% «0
8,720 1
7, 740
6,960
6. 210
5. DO
5. 00
5.00
5. 00
5_0C
s. 00
5. 00
J. oo
3. 00
3. 00
3. 00
2. 00
3,20
-1.70
2. 60
2,55
*2,45
*2.40
M 2. 15
1.90
1,85
1.70
I, 60
*1.65
o. to
0. to
0.60
0. OU
0  bO
r
a. 6a
o. 6a
o. to
0. 60
0. to
0.60
0. to
2,65
3. 32
3h 32
J- 32
3. 32
3. )2
3. 32
4. 00
4. 00
3.92
3.70 i       5.48
16. 40
14, 90
14. 60
14.45
14. IS
14. 00
13. 85
10.50
10. 35
9.90
9,60
e 75
31, lb 16. 54 24, <4 14. 74 21. 14 14. 37 22. SO 14. 19 21.25 13. 93 20. 64 13. S3 20. 03 13.47 11. 12 9.15 10. 68 9.67
9, 44                       9.13
a. 64                       fl. 77
7. IB                        7.95
L. 90
L 66
1.61
1.59
1.54
1,54
1.49
1. 13
1. 10
1.03
0.99
0. 93
O. 14
0. 14
0.14
0. 14
0.14
0. 14
0, 14
0. U
0.16
0. 16
0.16
0. 20
0. 64
0. 62
0. 57
0. 56
0.56
0.55
0. 55
0. B5
0.45
0. 44
0. Bl
0. 64
19.900
14,150
is, ian
12.700
11.TOO
1 1. 240
10*790
9, 900
9. 390
7,930
7. 020
6.460
15
35
15
35
35
35
35
65
65
65
65
65
L
L
1
9T *fa’l3.7
OPERATIONAL CHARACTERISTICS OF THE NETWORK
a/
During  the initial stage of network  operation  the water bailiff, will not be very  familiar with  irrigation  techniques; thus it has been  thought advisable to  design  the irrigation  network  in  such a way as to ensure safe, ea_sy and_ flexible operation.
The Intakes to the District and Unit Canals will be equipped 
with discharge measuring flumes and control gates; water
level regulating weir5 are planned on the feeder canals (Main 
or District) immediately downstream of each Intake. Auto
matic outlets are planned along and at the end of Main and 
District Canals.
3.7.1 Water Level Regulating Weirs
The water level regulating weirs will be of the broad crested 
long-sill type.
The lengths of the crest are planned . ln 2-m steps - so that the
rated peak discharge will flow with a head of 20 cm fl 60 1/sec
per meter of crest) over the weirs on Mam Canals and of'
10   cm   (56   1/sec   per   meter   of   crest)   over   the   wcirs   on   District Canals.
For    discharges    running    50    to    150%    of    the    ratPd    u head varies from 13 to 27 cm for the weirs n
aF8e '
and from 7 to 1 3 cm for the weirs on Distri
In other words, a  discharge variation Of causes a  level variation upstream of the Mam Canals and + 3 cm in the District C
3. 7. 2 Measuring Flumes
Canals
r,cl Canals.
i $0% vis-a-vis rated, of + 7 crn
ana la.
The measuring flumes will be of the Venturi *ype to the model tests carried out at the Hydraulic in<1? C° Milan University,
rd jng
e of55
Figs.    28,    29.30    and    31    show    the    di    a    cha    rge-head    rating    curves of the various types of Measuring Flumes.
From the curve of the Unit Canal Measuring Flume, it will be
noted that with a head variation of + 3 cm (corresponding to a
discharge variation of + 50% of rated in the District Canal)
the discharge taken from the Unit Canal varies from 43 to
60 l/sec+
The     same     type     of     consideration     holds     good     for     the     Measuring Flumes on the District Canals.
3. 7. 3 Automatic Outlets
The Automatic Outlets consist of one or more steel syphons installed in such a way that they come into operation when the water level of the canal exceeds the rated level by i0 cm.
The intervals between outlets and the syphon sizes have been 
so planned that they can draw the excess of discharge what
ever be the number of intakes with gates shutted out the oper ation,
Each automatic outlet is also equipped with a manually-operated taildrain gate which will permit periodic emptying of the canal and emergency operation. All automatic outlets are connected to the nearest drain.
Automatic outlets are also planned at the end of all District and Unit Canals; these consist of a broad-crested long-sill weir with taildrain gate; those outlets too are connected to the drainage network.
J- 56 -
3.8
diversion weirs
3.8.1
Melka Sadi Diversion Weir
a) General
Thia Diversion Weir, sited at the end of the Melka Sadi Gorge, will divert the irrigation water for the Melka Sadi subarea. The discharge to be diverted is 5. 6 cu. m/sec while the elevation at which the water must be diverted is
748. 20 m a. s. 1. The final siting of the weir has been decided on the basiB of geologic considerations.
The 1.000-year flood has been\aluated at 1. 500 cu. m/sec (Vol. I).
t»i WatCr bed tbe river at the weir is approxima-
.. 
V m ^de and & m deep. A few hundred meters above
 .
dozen meter' 
depth increa’es to 8everal
weir          -          Only          tworequircd                upstream          of          the
the hills of the Melka Sad r ** been set at approximately that^r The weir will consist of tw  ?n°
to c°nnect up with
° f the ®iU
o          f low’wat*r bed (40 m).
w ide gravel passes. The «iii 8P ® a.nd by two 3-m
an
a   8. 1. . l0 h/.eVatiotl *B planned to be at 748. 30 m  .
«sary for the diversion. gh'r than elevation nec-
b)
The profile of the weir will k
U bc of the Cr.
The head neceBBar„ to cna
(1. 500  cu. m/sec) flow, over'^?**  Hood
T *Pe-
calcuUted ..
of £«>.-
Q
■ 0 48-L- ‘ V7?T’1 ° ^ula:
-m lOn„ di8cJiarge
-‘R f 8 8,11 been
8f  rMELKA SADI DIVE measuring
FLUME
discharge
RATING
CURVE
27035
wattr uevei'
discharge:/
. .if**N. 27036 
[italconiult]
DISCHARGEDISTRICT CANAL INTAKE
' MEASURING FLUME
D i SC HA RG E R ATI N G C U RVE
w
w*TEfr tmt
Ne, 27037
DISCHARGE!
UNIT CANAL INTAKE
MEASURING’Fll>iE
discharge rating curve
S3■ ■■
■ ir
■: FIH-
N-.27O3B
DISCHARGE- 57 '
where:
Q - discharge (in cu. m/sec)
h = head (m)
L - weir length (m)
when:
L = 40 m and Q = 1. 500 eu. m/src (aee Fig. 32)
h = 6. 70.
The above calculations are obviously acceptable if there is no back up at the weir, i. e if the tailwater level is less than:
748. 30 4 0. 7 ho - 753. 00 m a. s. 1*
As it was not possible to have a tailwater rating curve recorded on site, this has been traced (Fig. 33) on the basis of the backwater curves in the Awash River (see Chapter 5). From this it emerges that, for a discharge of 1, 500 cu.m/sec the tailwater level is 754. 0 m a, s, 1.
The: sill submergence ratio is:
754. 0 - 748. 3 6. 70
0. 85
Bearing in mind the approximation inherent in the pro cedure with which the tailwater rating curve has been de termined (1) the caution which was used in assuming the roughness coefficient used therein (above all that relating to the high water bed) and the fact that, for sill submergence ratio of 0. 8. the reduction of the discharge actually flouring over the weir in comparison with that calculated with the above formula is of the order of a few per cent, it is felt
that the approximation of the calculation is sufficient and of the same order of magnitude as that of the other values concerned.
(1) See Chapter 5.The weir profile has been calculated for a design head of 6.70mty using the Creager-Scimemi formula:
1.80
where:
ho = design head (m)
x-y= coordinates of the weir profile (m).
Table 17
COORDINATES OF THE WEIR PROFILE
X
ho
JL
ho
X
(m)
y
(m)
0. 10                   0. 007
0.30                    0. 054
0.50                    0. 135
0. 70                   0. 248
0. 670
2. 010
3. 350
4. 690
0. 047
0. 362
0. 905
1.660
-Energy dissipation
In order to select the
J° dissipate the energX8tth8Uitable *ype of stilling basin the jump rating V*'
g over the weir
The ,           ,
The calculations are fltM rating curve has been n
8 been «lculated.
l ** Tablc
en plotted18 intnrt
nFl «. 33..
nd the lumpFIG.32
MELKA SADI DIVERSION WEIR
discharge rating curve
N.-27039
upstream water level
DISCHARGEMELKA-
SADI- DIVERSION
WEIR- -
tail water  AND JUMP
rating  CURVES
•3   ...
Hr:
Th
•
—
i-i-
f”
—1, —
• •*
r;
ii'^
l
—: 1 xr •:
-■ . 1
, 1 w- -
2 —..  , -I It •
r-
•
*
.. ■
—1-
.....
TH
;;
--I
—
_ L_ 7TTL..
ri izLx!::'
.
-J      !_
ii
4r 3a
13rH:’
!:!!.!,! .
_yn - ----------
i.
N. 270^0
500
>000 DISCHARGE
1SOO
2000 cu. tn/aee.t.
il ‘u ’ -- 59 -
Table l g_
OF THE
Z
( m )
0. I
0. 2
0, 3
0. <
0. 6
Q
'|iv, m/«e)
50
IDO
150
200
JOO
I,
( m J
0. 70
1. 10
1.   45
1.75
2.  bO
JUMP RATING CURVE FI
2 ( m J
( m )
J. 50 1. 90 4.25 4.55
5.   1 0
a.z
a. 5
a. a
9. 0
9. 4
( m )
Or 12
0.24
0. 34
0. 44
0. 64
7.5
5+5
4- a
4 + 1
3- 9
10. I 7. 3
*?. 4
5. 7
5, L
1.21 1.75 Z.  I  S 2. 44 J+26
9. 9
10.4
io. a
I 0]
1.44
I.05
2. 20
2.6S
J.  2
500
750
1. DOO
I.   250
J.  500
Jr 20
4.20
5. 20
5.   90
6.  70
6. 
1.5
2. 0
2.5
J. 0
7. DO
S.OD
0. 70
9. 40
I I- O
£1.2
tl
Z. 5
2. J
2. 2
4, 1
J. 6
.1. 1
Z. 9
2. 7
4.  14
5.  1?
5.  7J
6.  60
7.2560 '
The ju  p ratln, curve is always lower than .he
m
tai ,watlI
X« curve; in other words, the jump drowned 
the source; .he energy dissipated thereby m.nitnun,^
the dissipation occurs mainly downstream of the Weir a#. 
of its appurtenances, with probable erosion of the bott3rr
and banks of the river.
The advisability of arranging for the jump to be formed 
farther downstream, by using a sloping apron was con
sidered. However, the geometric and hydraulic con
ditions are such that the dimensions of the apron result
ing from this appear excessive in relation to the size
of the work. It has, therefore, been decide d to use a
dentated roller bucket, the dimensions of which have
been fixed as a first approximation, blit which will have
to be refined at the Final Design Stage through model
testa.
As    a    precaution,    not    least    in    relation    to    the    cost    estimate. It IS planned to have, downstream of a bucket, a series
an< l aide protections, whose roughness would gradually increase.
d ) Stability check
The geologic aspects , „ 
3; here, t
The two banks
e      xan^ined and digeusged in
^  * 
ocal conditions are summ<irized■
i
CWl! st 0, ,
ra
The permitted loading Tccent silts some 5-m thick, a bed of cLayey congl0m °*’ ^n^ath the ailts occurs
"Bht bank and
™s 5 
m
thick on the
The
right bank: thiB te_d vtrl,e a 7-m
Uv * •» * .-*■;» 
c  onglomerateB n
.
«u. o„ [he
kb
1
“’l,Inflt7r
CD »sl»m.rate..
----------------------------------------■ — / •- 61 -
A special check hag been made of the danger of undermining taking into consideration the most serious case which occurs when the water upstream is at sill elevation [748.30 m a, b.L ) while the downstream bed is empty.
Having set the foundation of the weir at 742. 50 m a. s. 1, with a cutoff down to 738. 50 m a. s. l. . Lane’s coefficient is:
t
6. 0 + 4. 0 + 10. 0/3 + I- 0 748. 30 - 743. 50
= jQ
In view of the nature of the clay which cements the con glomerates, this value appears more than acceptable.
Table 19 shows the calculations of the forces and moments acting on the body of the weir.
The weight of the structure is 89 T/m
Resultant of the uplift pressures is 19 T/m
Resultant of the horizontal thrust is 16 T/m
The overturning moment is 134 T, m/m
The righting moment is 517 T. m/m
The eccentricity of the resultant of the vertical forces is;
5. 00 -
517 - 114
89 - 19
-     0. 47 m
The unit loads on the ground are therefore:
89 - 19
1. 0 x 10. 0
(89-19) x 0. 47 x 6 
-         1. Ox 10. 0^
_ _ . ___ ______ 7. 0 + 2, Q T/sq. m
This means a maximum pressure of □. 9 kg/sq. cm
e) Siltation
Only fragmentary information covering a limited period of time is available on sediment transport (see Vol, 1), How ever, on the basis of experience with weirs on similar wa ter courses, provision is made for two gated gravel passes, 
. one on either side of each weir. The dimensions of these passes should ensure that sediment can satisfactorily be flushed downstream.- 62 -
lur I
1 '
t. vMelka Warar Diversion Weir
a) General
The Mclka \\Tarar Diversion Weir, sited at the Melka Warar Gorge, will divert the water for the irrigation of the Ami bar a subarea (1 0, 2 cu  m/sec) and later, also that for the Bolhamo 
t
(5. 4 cu. m/sec) and Angel ele (4. 0 cu. m/sec) areas. The wa
ters are to be diverted at an elevation of 7 37, 40 m a. s. 1.
There are large daily fluctuations in the discharge of the
Awash River, since during the months of low flow most of
it is returned to the River after having been stored in the
Koka Dam and released as required for power generation 
there. These fluctuations are of the order of 5 +■ 10 cu. m/sec;
and to compensate this a storage capacity of the order of 150-
200, 000 cu. m is necessary.
To cope even with brief water shortages, as has been stated 
in the Vol. i, it is advisable that this storage capacity be in
creased to about 600, 000 cu, m.
The    sill    elevation    has    thus    been    set    at    an    elevation    of    738.    00    m a. s. 1,
The storable volume upstream of the weir between elevations
of 738, 00 and 737. 40 m a. s. ). is calculated in Table 20 on the
basis of the cross sections of the low water bed of the Awash 
River.
The final siting  of the weir was decided  on  the basis both  of geological and  morphological considerations.  The geologic aspects are discussed in the Vol; 2.
The    low    water    bed    of    the    River    is    approximately    40    m    wide and     7     m     deep     and     cannot     carry     the     hundred-year    peak     flood discharge      (1,500      cu.      m/sec).      Since      a      protective      dyke      must be    built    between    the    two    weirs    (see    Chapter    5)    it    is    as    well Lhal    the    weir    should    be    as    long    as    possible    to    reduce    the    back up of water.M
STORABLE VOLUME UPSTREAM OF MELKA WARAR BETWEEN 737. 40 ANo
Section
L
M.
^*0. 6xL
(iq. rn)
(■q. m)
51
59
57
55
51
65
47
32
41
40
45
41
49
42
50
48
ED
36
14
17
39
38
29
19
29
30
I------ ----------------------
30, 6
35.4
34, 2
33, 0
3!. a
39.0
28, 2
It. 1
24 fc
24.0
27. 0
24.6
29.4
25. 2
10. 0
28, a
30. o
21. 6
20. 4
22. 2
IX 4
ZZ, 8
17. 4
23. 4
17. 4
18 0
-
L 120
1, 060
1, 020
1, 040
820
670
I. 140
1,020
1.450
550
450
I.5J0
990
760
i, +90
). Oto
1,210
1. 450
1.070
1. 040
1.7J0
1.200
2. J70
1
>*, 520
I3i *20 37.632
34,144 36, lOQ 34.944
19. 434
14,673
27,701
26.010 56. 894 14,. 510 12,284
41,674 29, 106 22. 344
Z4. 7*8 11. ZfO
23,217 27. 588 13, +95 21. 507 21,Z16
tt,3+“ al, no
674, niThus a weir has been designed 60 m long (three 20-m spans)
which, at peak Hood discharge produces a backwater curve
approximately parallel to the ground profile at the dyke align
ment.
Thus the overall width  of the weir including  the two  3-m gravel passes and  the four 1-m piers is 70  m.  The one section  which provides the following advantages hag been chosen:
- Acceptable geologic conditions
Wider-than-norma] low-flow bed
Strip     of     land     downstream     on     right     bank     suitable     for     Main Canal alignment*
The flood protection works upstream of the Melka Warar Diversion Weir were designed for the hundrcd’-year flood which - routed in the high water bed between the two weirs, at Melka Warar - has a peak discharge of approximately
1, 100 cu. m/scc.(l),_
b) Weir profile
The profile of the weir will be of the Creager Type.
The head necessary to overflow the hundred-year flood is
given by the formula;
Q =       0. 48'Li' h '
where:
Q - discharge (mm/sec) h = head
L = weir length (m)
For L = 60 m and Q = 1. 100 m/sec, h = 4. 20. (l) See Chapter 5,- 66 -
The above calculations (see Fig. 34) are obviously validif^ >, no tack up at the weir.i. e. if the tailwater level i, lo.,„
than:
738. 00 + 0. 7 ho = 740. 94
Since   it   was   not   possible   to   have   a   tailwatcr  rating   curve   re. corded on site, this has been traced on the basis of the back.
water curves (see Fig. 35 ).
It emerges from this that,  for a discharge of 1,  100  rnm/sec the downstream water level would  be 740,50  m a.  s.  1.  ,  i.  e. the sill is not submerged.
The  profile  of  the  weir  has  been  calculated  for  a  design  head of 4. 20 m using the Creager-Scimemi formula:
y 
wher e:
ho = design head (m)
. 1.80
X. y = coordinate of the weir profile (m) coordinates OF the WEIR PROFILE
Table 2J_FIG.
MELKA WARAR DIVERSION WEIR
DISCHARGE RATING CURVE
WATER LEVEi
IULCQ V.2
IFIG. 3567
c)   Energy dissipation
In order to choose the most suitable stilling basin to dissipate
the energy of the water flowing over the weir, first the jump 
rating curve was calculated and then compared with the tail-
water rating curve.
The     calculations     are     set     out     in     Table     22,     while     the     jump     rating curve is plotted in Fig. 35,
The jump rating curve is always lower than the tail water rating curve. In other words, the jump is drowned out at
the source; the energy dissipated by the jump would be mini mum. Dissipation would occur mainly downstream of the
weir and of the relative appurtenances with probable erosion of the bottom and sides.
The advisability of arranging for the jump to form further downstream using a sloping apron was considered; the geo metric and hydraulic conditions are, however, such as to 
call for an excessively long and high apron.
A dented roller bucket has thus been chosen. The dimensions of this have been designed in first approximation, and will, therefore, have to be refined in the Final Design through model tests.
Conservatively, not least lor the purpose of determining the costs, a series of bottom and bank protection works and sides with progressively increasing roughness have been planned for the stretch downstream of the bucket,
d)   Checking stability
The geological investigations show that the right half of the weir will be founded on a thick bed of basalt, whereas the left
half will be founded on compacted clay with good load-bearing characteristics. Undermining was checked taking into con
sideration the most serious case which occurs when the up stream water is at sill elevation (738. 00 m a. s. 1. ) whereas the down str earn bed is empty.
e )   Sjltati on
The criteria specified in para. 3.8.1 were adopted.68
melka warar diversion weir jump rating curve
JHaving planned the foundation of the weir at 728. 00 m, a.a.l. and two cutoffs reaching 725. 00 m a. s. 1. , Lane's coefficient will be:
6, 0 J- 4» 04 4.0_t 5. Ot 15, 0/3                                24       =
,
738. 00 x 729 
~9
This      figure      is      acceptable      in      relation      to      the      characteristics of the foundation soils.
Table    2    3    sets    out    the    calculations    of    the    forces    acting    on    the weir body and the relative moments.
The weight of the structure is 193 T/m.
The resultant of the uplift pressures is 80 T/m* The resultant of the horizontal thrusts is 50 T/m. The upturning moment is 805 Trn/mw
righting moment is 1,761 Tm/m. The
The
eccentricity of the vertical loads is therefore:
7 50 . -*>*
193-80 The unit loads on the ground are:
193 - 80
1. 00 x 15, 00             -
1.0 m
[193 - 00) x 1. 0 x 6 I, 00 x 15. OOZ 
„ _ , ~
- - _ 3. 0 T/sq
,
This means a maximum load of 1. 05 kg/sq. cm.• —
* *r •
rf *
rT W
-
>t » «r» >«r MVMfrt MCMWTTS
< <-*
<~f t
-U>M» ■ wM
i _-
r
f< it «
:,. • !®
tMt-W
«I
.>; i
c<
♦ ♦> i
Vt I
n> c1 < DRAINAGE NET
GFNFAAL - PtrRFTSJE V ^F-’WOK.K
th* Pr.'t^vr \r«M in <*nera{ S»< *
•*e-*kw^r<i« «?2g*
if      I?      5      rn      km.      Hcwfp         m      »om*      ;vi      rf      •      rht<      frMfith*
m t rk*tflv i*ul *v*n bn<»fTi»< rrti Ln th«M* -1 ««<
pond^
tion
■!>
hv *vvion vmf. infi-tttn
th**      -      Urn      itolotfiv      al      ihVMti|      itton*      (Vol      I      «h<Hr *hi* inipp’ MiM'ill of tbv* »«*<iipft 14 on th* b»w aid#.
do. >u»ivnv0p. wcqf
hna-zy
V     *     h*     <*     ?hu     4ifuMU>h     h.m     <iv*n     H«*     h.»     Httl*     -mi#*       ft»*     >** **n itn< * th® Ai5* i hi* hr*n ntn ulh va!*d i im| ♦ *
»nlr i f*w t?otT4i»iitlv h*tM*r«
fry
fltr" 4 *oh*i|H 11
!
ioh# (Vol 1} how* •HoWi* ffro? fthera - -j
i vim r ihh' it lteiw®®u 7 nyl IM m ?«*luw
i! » Hirh if® That th* **® r inrahi lit y of th*
fhoi It i « ht^hly liki'iy that arilb th* i«t p-mIim fion of frf<4 it< ■«i+ this vtmr fahlft vvouhl •tirt to ri** tow-iH* ground l®v*t o> »
I**-*! i’hny
• * v«er fr»w
f*w /mri, i nd
rhtftlngH tn I fop*. »nl*«* ♦mtnblo »r-»
f.iknti Ifrn. «. th** naiml fnr th** drainage
t' hi < will ha /* to
culLrtr* md rnnvry aw i? th* rain wih»f • *od tny augph «
4
i r r i (j a cion
preventing my wale rkigging,
caU«ict mil convey awiy euch if rig iti*>n watnr* >< nttight h« dischurgori through <it«< <■* «^ll* w« |u chn •irn^iga
nnr.wnrit* dim to
control th** water table t«•/*!■»
sn handling- 72 -
In principle, the drainage network forms a mirror image of the irrigation network, viz. there will be a field drain for every field canal, a Unit Drain for every Unit Canal, a District Drain for every District Canal and a Main Drain for every Main Cana], as shown in the Typical arrangements A and B (Figs.21 and 22).
Because of the topography of the Area, however, the two net works will not correspond exactly; whereas each Irrigation Unit is also a Drainage Unit, the surface area of the Drainage Districts does not always correspond to that of the Irrigation Districts.
4. Z DESIGN CRITERIA
4.2.1 Rain
Various methods and formulae could be used to calculate dis^ charges. However, they all require a thorough knowledge o the climatic conditions, and in particular of the rainfall of short duration and great intensity, of the agronomic and soil5 conditions of the Area, as well as of a series of coefficients found experimentally from the drainage networks of areas with similar climatic, soils, agronomic and topographic conditions-
Unfortunately, in the case in question whereas the soils and agronomic conditions of the lands as they will be after recla mation are known or can be assumed with a fair degree of approximation, the data available on the rainfall of short dura tion and great intensity are very fragmentary and cover only a limited number of years; moreover, the experimental coef ficients from similar areas are lacking.
Among the many methods in existence. it is considered best to adopt the Puppini Method (1). which has the advantage of being
(I) See: Le reti idrauliche - Pr f
o   n c .           01 G. Supino, p,,
• ^tron. Bologna,- 73 -
based on logical reasoning and of using parameters and coeffi cients which, in part at least, do not represent situations de fined by analogy, but the specific characteristics of the net work under study+
This method presupposes knowledge of the relationship linking 
- for the return period for which the network is to be designed - the depths of rainfall for the respective durations. This rela tionship is normally given by the equation:
h - atn in w hich:
r
h = depth of rainfall (in m)
t = duration of the rainfall (in days).
From the measurements made by raingauge at Awara Melka and at Mrlka Warar the following equation for the rainfall- depth duration relationship is to be assumed (l):
h = 0.0865 tf 3
The maximum unit discharge (in l/sec.ha) flowing through a section of the drainage network is given by the following for mula:
u^ =       (10 m +60) n (vq + v) “ (K a)
where:
uj = unit discharge flowing through a section (in l/sec,ha) m = coefficient linked to the hydraulic characteristics of
the section
a - coefficient of the rainfall intensity/dur axion. equation (0. 0865)
(1) Its return period may thus be considered of the order of 10 years (see Vol, i).. 74 -
n - coefficient of the rainfall intensity/duration equation 
(0.33)
v 0 = unit volume (cu. m/sq. m) of water remaining in the
fields and in the furrows during rainfall
v = unit volume (cu. m/sq. m) of water stored in the drain
age network upstream of the section under study
k = ratio between the volume of water reaching the network during the time of rainfall and the volume of rain falling.
For the Melka Sadi-Amibara area, taking account of the types
of section which will be adopted for the drains and the type of land preparation proposed, it is considered that the coefficients- m-and -v -can be given the value of 1.50 and 0.015 res pec lively. 
o
Taking into account the fact that the Area will be irrigated throughout the year and in particular during the two rainy sea sons, it is considered that the percentage distribution of the rainfall will be:
Water reaching the network during rainfall
Water reaching the network 
after end of rains
65%
15%
Water    evaporated    from    the    land    or    infiltrating in the soil
Total Rainwater
The coefficient K will thus be 0. 65.
The unit discharge will therefore be expressed by the formula: 7 x IO~3
U i 5               (0.015        v)2
The discharge will be expressed by
Q 1 = Uj A
where A is the area served (in ha).
20%
100%
...75 -
<
T rr j gat io n Wat ere
To determine the discharges which will even exceptionally 
rMch the d ra in a. g e network, from the irrigation network it
ia considered that all the irrigation discharge diverted at
the two barrages could reach the terminal section of the
Main Drain,
The      corresponding      discharges      have      thus      been      calculated      on      the basis of the following formula:
Q2 = i A
where:
QZ = discharge (l/sec.ha) flowing through a section i = peak index of consumption - 0. 9 l/soc, ha
A             area commanded by the section (in ha)#
4- 2, 3 Water Table Control
To determine the discharges that can reach the drainage net work from the aquifer, in accordance with what has been en visaged in determining both the water requirements and the characteristics of the irrigation network, the distribution of the irrigation waters diverted from the Awash is as follows:
Evapotranspiration from the soil and plants Evaporation from soil immediately after
irrigation
To aquifer by deep field infiltration
To drainage network through wrong field handling To aquifer through losses from irrigation canals To drainage network through canal discharges, gate losses, etc.
diverted from Awash River
54% 4%
13%
5%
20% 4%
100%To sum up, the drainage network will have to take from the
aquifer 33% of the diverted discharge from the Awash, i. e. a
unit discharge (1/sec. ha) equal to u  0. 33 x 0. 90 = 0. 301/sec-ha.
3
The corresponding discharge is given by the formula:
Q3 = Uj A
were:
A = area drained (in ha).
Aquifer control will be effected by the field drains, the direc
tion of which will in general be parallel to the main general
slope of the land, and the length of which will in general be
about 800 m.
Taking into account the envisaged crops, the nature of the soils
and the discharges to be drained, it is considered that a mini mum cultivation freeboard (unsaturated layer) of 40 cm will be
acceptable (in the peak irrigation periods).
It would  also  seem acceptable to  have drains with  a bottom width  of 40  cm,  an  average depth  of 1.40  m,  bank  slope of l/l and average depth of water of 10 cm.
Hoghoudl s formula has been used to determine the spacing:
=
Kd Ah
N
where:
I     =     center-to-center     distance     between     drains     (in     m) k = soil permeability (in m/day)
d = equivalent depth of filtering aoi] (in /\ h = drawdown of the aquifer (in m) N - discharge to be drained (in m/day).
.z
Considering   local   conditions,   a   K   value   of   0.   240   m/day   (equal to about 10 mm/hr) has been assumed; for d, the value of
8. 38 m was taken, corresponding to a filtering layer of 25 m;- 77 -
for Zlh, a value of 0. 90 m aod corresponding to 0. 30 I/sec x ha. Thia
g ves:
i
*
" 5,571
V>
]2   -  * 
=
8                            240 x 8. Jfl x Q, go 0,0026 
1 = 74. 5 m, rounded out to 75,
^2.4 Freeboards
The drainage network sections have been designed in the first instance to be able to convey the discharges drawn from the aquifer (U3 “ Uj A), ensuring a minimum freeboard between the g round level and the water surface in the field drains equal to 1.30 m.
The operation of the drainage network has also been checked during rainfall; taking account of its limited duration, it is probable that irrigation will be suspended on the field while the irrigation network remains in operation, thereby making 
it necessary to open the outlet gates or to operate the spill ways .
In this case the flowing discharge of the drainage network will ber
a = Qi + q2
Taking the shortness of the heavy rainfall events into considera tion. it is thought that in this case the freeboard could even be cancelled.
The two conditions dealt with above are considered as being extremes. Also, the intermediate case of the drainage net work handling only rain water has been examined and discuss ed.
1           5 Geometric and Hydraulic Characteristics of the Drains
For the whole drainage network open earth canals will be pro vided.
iFor the Field Drains a Blope gradient of l/l has been a.., whereas for the Unit, District and Main Drains a side slope Of 3 horizontal to 2 vertical has been assumed. The hydraulic calculation of the sections has been made by using Manning's formula with a roughness coefficient, K of 30.
DESIGN OF THE SECTIONS
Field Drains
As already stated in paragraph 4 2. 3. the Field Drains will be spaced 75 m apart, will have a depth of 1.40 m below ground level, a bottom width of 40 cm and side slopes of l/l.
A typical case has been considered of a drain about 800 m long, which will therefore serve an area of 6 ha.
The rainfall discharge at the end of the Field Drain has been calculated by the formula:
Q________L-- 10' , A
1 ■ (0. 015 + v)i A
using the trial and error method.
The calculations are set out in Table 24,
A value of 0. 006 cu. m/sq. m has been taken for coefficient v
of unit volume of water stored in the drain during the rainfall and the corresponding discharge (95 1/ ec) has been calculated.
3
B
From this, the hydraulic dimensions of the drain and the cor responding value of the coefficient v (0. 0051) have been worked onto.
On the basis of this value we then calculated the corresponding discharge (104 l/sec), the hydraulic dimensions of the drain and the corresponding value of the coefficient v (0. 0055).- 79 -
Table 24.
FIELD DRAINS
IThe    discharge    obtained    from    this    value    is    equal    to    the    p
re .
vious and the calculation was thus stepped down.
In the case of rainfall discharge, if the field drains can freely discharge, the water depth would be 42 cm and the freeboard 1.08 m; in effect at the end of each field drain there is a cul vert under the Unit Track, whose diameter has been set at
30 cm; the presence of this culvert will cause a head loss of the order of 5 cm; furthermore, the water levels in the down stream drains (Unit - District or Main) will be such that water would back up in the field drains. Consequently, in the design calculations of the Unit and District Drains it is assumed that the water depth in the field drains during the rain is, on aver age, equal to 0. 90 m and that consequently the unit volume of water stored there during rain amounts on average, to 0. 0156 cu. m/sq. m.
Unit Drains
Usually the Unit Drains serve an area of about 48 ha and run parallel to the contour lines.
The typical case of a Unit Drain 525 m long and having a bot tom gradient of 10 cm/krn has been considered.
The discharge it must dispose to control the water table is: Q} = 0. 3 x 48 = 14 1/sec
The hydraulic characteristics of the section are as follows:
Bed width Water depth W etted area
r
Wetted perimeter
0.40 m
0. 25 m
0. 19 sq.m
1.30m
Hydraulic radius
0.15m
Hydraulic gradient
0. 1 0 m/km
Water velocity
0.08 m/srcThe rain discharge flowing at the end of the Unit Drain is de termined by the trial and error method as described for the Field Drains and assuming as a first approximation that the unit volume of water stored in the Unit Drain during the rain is 0. 002 cu. m/sq, m
The calculations are set out in Table 25+
The case of rain discharge was then considered added to the discharge coming from the irrigation network which, in the case of the Unit Drains, amounts to an Irrigation Module, i. e to 50 l/sec.
The discharge to be disposed of is therefore:
Q = Qj + Q  = 316 4- 50 = 366 l/sec
z
The hydraulic characteristics are therefore as follows:
Bed width
Water depth
Wetted area
0. 40 m
1. 00 m
I.90 sqrm
Wetted perimeter
4. 00 m
Hydraulic radius
0. 47 m
Hydraulic gradient
0. J 0 m/km
Water velocity
0. 1 8 m/sec
The Unit Drains will have bed widths of 40 cm, side slopes
of 2:3, minimum bottom gradient of 0< 10 m/km and minimum depth below ground level of i. 55 m. The freeboards thus will
be;
!♦ 30 m in the case of water table control
0. 60 m in the case of rainstorm discharge (l )
0, 50 m in the case of rainstorm plus irrigation discharge
(J) Provided that water does not back up into the Unit Drains from the District or Main Drains into which they flow.UNIT DRAINS
Length: 600 m
Slupe : 0. lOm/km
Volume itorcd:
- in the field drain! - on the field
ha 48 x 156 cu. m/ha = 7,488 cu.m
ha 48 x 1 50 cu. m/ha = 7, 200 cu. m
7, 688 cu. m - 0, 0 306 cu. ni iq.a
1            Description              J           Unit
1st Trial
2nd Trial
3rd Trial             4th Trill
«1
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
l/iec.ha
l/eec.
■q.m
• q. m
0. 0306
0. 0020
6. 60
315
40/?5
1.73
1.038
0. 0106
0. 0022
6. 60
.315
40/95
Unit volume
cu. m
cu. m/sq. m
cu. m/'sq. m
cu, m/sq. m
0. D326
0. 032A
J- 83 -
3  District Drains
4. J -------------------------
for the design of the District Drains the procedure followed is
similar to that discussed for the Unit Drains.
First, the discharges for water table control and the correspond
ing hydraulic dimensions of the cross sections were calculated*
stretch by stretch. The minimum freeboard with respect to the
lowest points to be drained hag been set at 1. 30 m.
Subsequently  the discharges from rain (Qj = Uj x  A) were cal culated using  the trial and error method as discussed previous^
iy.
Finally the case of rain discharge added to discharge coming from the irrigation network through the Unit Canal outlets was considered, stretch by stretch. Ln this hypothesis the minimum freeboard with respect to the lowest points to be drained has been fixed at 0*
Calculations have been made for the District Drains of the Melka Sadi subarea (see Fig. 36); the relative results are summed up
in Table 26* whereas the detailed calculations are set out in
Appendix 1.
These calculations indicate that, in general, the most serious condition is that of water table control. Fixing the freeboard at I. 30 m in this condition, the residual freeboard in the last two cases is, in general, a few dozen centimeters*
Only in the final sections of some District Drains, when the
*rea served is of the order of 1, 500 ha, the two extreme con ditions (water table control and rains plus irrigation discharge) become equivalent or, the latter, more serious*
4
- 3- 4 x< .
MginPjains
For the design of the Main Drains, a similar procedure has be en followed to that already described for the Unit and Dis-
lrict Drains,district drains
R*ln«torm
T row
Su
to SU
Water Table Control
Ulnimum Ground
Lovol
Longlh
(n»)
Bed
Slap#
Bed
Width
(m)
Bed
(m)
Drained
Area
(ha)
Discharge (1/ooc)
Water
Depth
(m>
Water Elevation
(mJ
Stored Volume
(«u. m/
•q m)
ul
(!/••* ■
hr)
Q|
(!/••<)
Water
Depth
(m)
A.
J
0
a Do
740. 20
7»9.70
R00
0. 6
0. 4
738 h>
7JB 15
82
25
0. 25
738. 88
718. 40
0.0327
6. 50
930
0. 80
800
0.6
0. 4
130
39
0. 25
0. 0336
6. 12
900
I. 00
I. 600
739. JO
717 67
737. 92
1 000
o 6
0. 4
717 5?
737. 0$
226
60
0. 35
L. 4L0 L’ftin A.j
0. 0342
6. 00
7J0. 10
I. 350
1. 20
737 44
»
4
1
4U0
740. JO 739 80
«O0
0. 6
0 4
736. 55
738 07
96
29
□:z5
738. 60
738. 32
0.0337
6 15
590
0. 85
BOO
O. 6
1.600
0. 4
739.20
n«. 02
717. 54
192
5a
0. 30
0. 0H0
6. 05
737. B4
1, 160
1. IS
600
1
737. 49
O.fc
0. 4
66
I
0. 35
1
0. 0344
5. 90
1. 700
A. 3b!
59‘t
II "4
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]QJ|UO3 -iqwx J»|VA4-
Riinltorm   4 Irrigation
F rotn I Su
to Sta
*»hinvAmi Ground
1*941
Water Tabla Control
(m)
B.d
Slop,
Bed Width
("»)
Bad
□ •villan (m)
Drained
Area
(ba)
Diecbar«e (l/dec)
Water
Depth
(m)
Water Elevation
(m)
Stored V olume (eu. m/
44 m)
Water Elevation
(m)
Ml •
Depth
(m)
Q
u2
Water
Depth
(m)
Water
Eltvatioh
(m)
|          500
741.50
739. 79
740. 14
741. 19
1     1.400 i.zoo
741.10
741.40
BOO
BOO
0. 10
0. 20
0. 4 0
0.40
739. 69
719. 61
719. 4*
220
Jib
66
95
0. 45
0. 45
740. 06
739. 90
739. 75
718 47
0. 0145
0. 0 149
5. 89
S. It
1.290
I. 820
I. 70
I. 70
741. >1
6. 79
b. 62
1.490
2. 090
1.80
I 80
a O(i
J. <0
0 40
1. ooo
164
109
0. 30
739. 90
0. 0149
5. 72              2. 080
I. 20
6. 62
2. 140
1. 30
400
0. 90
0. 40
J.fOG
| 789. SO iPx*ut c.
718. |7
TIB 07
737. 7?
460
130
0. 40
0. 0151
5. 70              2.650
I. 60
74 0. 65
739. 37
739. 67
739. 37
6. 60
738. 17
3. 04 0
741. 24 741.49 741.41
741. 25 740. 75
739. 47 739. 77 739. 47
0
•oc
741,40
740.10
•00
0.60
0. 40
0. 0)36
400
L        1.200
’♦0. 70
0. 40
739. 80
719. 32
719. 4?
719. 07
160
48
0. 30
740. 10
739.62
6 20
990               I. 10
0. So
232
10
0. 35
0. 0132
739. 42
740. 90
74 0. 42
740. 57 740. >7
740. 95
740. 47 ^O. 6 7STI
I
♦
Irrigation
Ralnatorm
Water Table Control
F rom ’
Sta. 1
to Su. 1
Minimum Ground
Level
Length (m)
Bed
Slope
(m/km)
Bed
Width
|m)
Bed (□evation
(m)
Drained Area
(he)
DI aeharge
(l/aec)
Waler Depth
(m)
Water Elevation
(m)
Stored
Volume
(cu. m/ eq. m)
“1
(l/eec a
hr)
Q|
(!/••<=>
Water
Depth
(m)
Water
Elevation
(m)
♦
RUnetorm Q
u2
Water
Depth
(m)
Water             | Elevation
(m)
[
5. »*0
6. M
R, 170
b. oB
4. 350
196
0. 55
0. 0J4H
5. 78
3. 760
1. 90
1. 4U0
0. 30
0. 40
652
740. 58
?)». oe
739. 23
740 aO
719 00
738 »4
7)8.44
7)7. 80
5»3*0
1. 90
b. b*>
b. zoo
600
0. 40
2. ou
732
4
ao
0. 40
0. G349
5 7«
740. 20
2. 05
1,600
0. 40
2. 00
731 44
7)7 94
7)7. JO
6. 700
740. 14
739. 99
7 39. 35
b 40
7. aoo
1.2 ZD
366
0. So
0. 0357
5. 50
m. so
7)8. 30 '       too     1 751- >0
SIBILS
000
0. 10
0.40
736 40
7)6.31
04
25
0. 30
736. 70
736. 62
0. 0148
5. 80
487
1. 15
7)7. 55
737. 47
6. 70
5b)
0
130
Mi.30
740. aw
ADO
0. 60
0. 40
IK 60
739. 11
140
59
0. 30
739. 90
7)9. 42
0. 0)30
6. 41
1.270
1. 20
740. 80
740. )2
740. 22
7. It
1,450
1
1
1Water Table Ceetrol
MktUmum
Greead I
Level
U»|(h
(rn)
Slop*
T
width
(m)
Bed
Elevation
M
Drained
Area
(■»•)
Diaehargw (l/eec)
Waler
Depth
(m)
Water Dovatloe
(ml
Dr*m G
0        no. «o
100
J. 50
0. 40
144
43
O. 30
BOO
?m <o
no. io
111. 10
73*. 60
737. 40
000
0. 70
0. 40
240
I. 400
731. 70
th. »j
m.i6
72
0. 10
737 12
7)6. 56
600
0. 70
0. 40
J. JOO      737. JO
arain »
735.11
735. 45
zoo
46
0. 35
736 00
0 l
400
7J< JO
737.00
600
0. 10
0. 40
H
25
0.25
737. 00
736 B2
too
1. GO
1.400         n?
0.40
7)6.75
736.57
736.52
735.72
210
63
0. 30
7 36. 02
kR.ln.lorm »
Ralnetarm
Water Table Control
--------------------
Q
F   tom   | Su          1
to SU
Mt nt mum 3round
Level
Leafth
(m)
Bed
Slope
(m/km)
Red
Width
(m)
Bed
□•veil an (m)
Drained Area (Ha)
1 Recharge (l/eac)
Water Depth
(m)
Waler Elevation
(m)
Stored Volume (cu. m/
eq. "»)
(l/oec ■
(!/••«)
Water
Dept* (m)
Waler Elavatier1
(m)
tt l ♦
“2
Water Dept*
(m>
Waler Elevation
(m)
733. 35
2
7)0. 04
a 5.520 7.120
11, JOO 14.Soo 11. iso
24, 4*30 3x«m_JL
0 2,4™
1   4.200
1 Praia 4
a
5. $20 I. 60D 4. iao J, 200 1, 7*0
4.210
0.40
0. 40
0. JO
0. 45
0. 4»
0. 20
J. 0
5.0
5.  0
5.0
5. 0
5. 0
731, 45
724.   14
724k 00
724.   >4
725.   08
721. 85
72 J. 78 722. >4 721. 94 720. 24 714. 14 718. IO
1.  502 2,464 2.  955
5, 42 5
5. 149
6. 410
450 740 440
1, 14$ 1.540
1, 930
0. 40
0. 40
0. 50
0. 55
0. 65
0. 90
711. 85
7 za. M
727. 20 726. 24 725. $4 724.JJ
722. 49
722. 59
720. 89
0. 0364
0. 0173
0.0395
0. 0406
0. O4O9
0. 0429
5. 15
5. 00
4.50
4. 25
4.20
3. 80
7. 750 12.400 1 >. too 16,200 21.800 24. 500
1. 80
1 85
2. 35
2. 30
2. 75
3.50
733. 2$
729. 94
728. 75
72 7. 69
72 7. 4 3
726. IB
726. 08
724. 64
724. 69
722. 99
722. 84
721. 60
6 05 5. 90
5. 40 5. 15
5. 10 4. 70
9. 100
14.550
IS. 800
19. 700 26. 4 00
30. 200
1.90
2. 05
2. 55
2. 60
3. 00 3. 90
728. 95
727. 89
727. 63
726. 38
724. 94
72 3. 24
7Z0. 24
71 9. 00
722. 00
2,400
1. SOO
0. 24
0. 15
2.0
2. 0
724. 43
725. 74
722. 86
722. $9
561 1.060
155
0. 30
724. 75
724. 06
O. 0360
5. 40
2. 780
1. 50
725. 93
725.26
6. 30
3. 26C
1 60
726. 03
725. 36
>10
0. 55
723. 41
72). 14
0. 0 365
5.22
5. 560
2. 35
725. 21
724. 94
6. 12
6, 500
2. 50
725. 09
2. 400
1 727.24
s
0. $0
1.00
727.58
415
125
O. 30
728 68
0. 0 357
5. 50
2. 270
1.40
6. 40 
1
2. 660
<
728. 8 1 /
zW*l*r Tnblr Control j
Rain«taim
'
R^lnblorm * IrH^nUon
- ■» -
Lib lrj7 (Cfrnt. 2)It is thought
, ■ Me to poin< out to'- P'°“,n8 thC vol”»«<
stored in the Distric the calculations made corresponding draine
ion. «F‘»“ * 'M ‘°rmal
ins daring the rains, as resulting ftw
S adi 6ubarea, against (he
fig J?) ther
e
ia good C0„eU
v = O.O33O(—)
„ „„ A 0.035
where:
v    =    unit    volume    of    water    stored    upstream    of    the    Distric Drain outlet during the rain (cu. m/sq. m)
A = area drained (ha).
The calculations for the Main Drains of the Amibara subarea, 
where the District Drains were not designed, (1) were also 
made on the basis of (his relationship.
The   results   are   set   out   in   Table   27,   while   the   detailed   calcula tions are shown in detail in Appendix 1.
For the Main Drains the most serious condition is that of rain storm plus irrigation discharge. In the case of rain discharge only, the freeboard is generally between 10 cm and 30 cm whereas in the case of water table control it is always more than 1. 30 m.
(1)   Since, taking into account the aim of the study the approximation required, it was not considere essary to extend them to the entire Area.
of necFIG. 37
DISTRICT drains
STORED VOLUMES
DRAINED AREA’95-
5. r LOOP PROTECTION
AWASH RIVER FLOODS
A calculation of the discharge which the low-water bed of the Awash can carry in the stretch between the Melba Sadi Gorge and the Angel ele Plain indicates values of a few hundred cubic meters per second. This is not surprising even when compared with the very much higher flood discharges recorded for the Awash at the Awash Station, for the Kessem at Awara M elka and for the Kebena. The vast plains in the terminal part of both the Kessem and the Kebena Valleys, the very regular profile of the lip of the low-water bed of the Awash and the
fact that the low-flow bed of the Awash Riy_er_i_3 almost con stantly above the level of the surrounding ground lead to the supposition that very short, sharp floods are extensively rout ed in the valley reaches of the Kessem, the Kebena and on the M elka Sadi and Amibara Plains where the waters leave the low- flow course and spread out over the plains.
However, with the inception of commercial farming and the formation of human settlements, following the reclamation of the Melka Sadi-Amibara area first and those of Awara Melka, Bolhamo and Angelele later.it is not possible to permit such uncontrolled flood routing: protection works will have to be provided.
The Kessem and Kebena Plains are not scheduled for reclama tion on the short term and can thus continue to effectively route the floods. The same is true of the Bolhamo Plain on the left bank of the Awash downstream of M.elka Warar Gorge.
A  1:100, 000 map of the areas where the flood waters spill out onto the plains and of all the zones surrounding the Area had been requested by Italconsult (1), but unfortunately this has not been forthcoming.
0) See Inception Report dated December 1968*C- effort has been made to cautiously assess the desired 
Xr« of dkk'5 l° C°nUin the n°°din8' In
^instance it ’ha. been assumed (lor the purpose ot caleula. 
that the dyke would be built on both sides of the river; then 
has been ascertained on the basts of available data to what
e«enl the right-hand dyke may be lowered >£ that on the left „
not built immediately.
First and foremost the alignment of the dykes both on the right bank and on the left bank have been determined on the basis of the following criteria:
Minimum   distance   of   100   m   between   the   dyke   and   the   edge   of the low water bed of the river.
Width of the high water bed in the stretch included between
Melka Sadi and Melka Warar Diversion Weirs between
1,000 m and 2, 500 m.
Width   of   the   high   water   bed   downstream   of   the   Melka   Warar Gorge between 1, 000 and 2, 000 m.
term    n    discharge    curves    for    various    sections    were    then    de-
of 20 M
formula with a roughness coefficient
°
o
° ~ i
b 'd and 5
hl
«  *«'r sou.. (.1-
h
and    asst/    OcJuPied      by    a    thick    vegetation    of    trees    and    bushes) and assuming a hydraulic gradient of 2Q cm/km
* re summed UP in Tablefi and
tO determine thc flood profiles the hundred-year event
s a en into consideration referred to the Melka Warar see-
lion.
take     Into     re^onccrncdi     it     has     not     been     deemed     advisable     to take ,0.0 co„.,d„.Hoo flood.
«>' 'Xk.. ar. or.c.od on 
the left bank, a stretch will k^ j j , 
11  be constructed so that it can be ,
overflowed and demolished in tk- < , 
occurring than that considered c
.       ... 
,n  event of a more serious flood
Such a flood would thus be rout- , 
j
*.
ed in the lower part of the Awara Melka area.- 97 -
The characteristics of the hundred-ycar flood are as follows:
Peak discharge
Runoff volume
Duration
1, 600 cu. m/s ec
277 cu. hm
96 hours.
The relative hydrograph is shown in Fig* 38. The rating line
□ f the flood flow over the sill of the Melka Warar Diversion Weir, is shown in Fig* 34. On the basis of this diagram the water levels upstream of the w‘eir have been determined for discharges of 100, 200, 250, 300, 400, 500, 600, 700, 000, 900, 1, 000,
1, 05 0, and 1, 100 co. m/sec.
From these levels the backwater curves upstream of the weir and the relative storage volumes have been calculated, on the basis of the water level discharge curves of the various sections. The results of these calculations arc summed up in Appendix 2. The calculation relating to flood routing was then made on the basis of the equation:
( °Fi + QFi~l )
fQ
+ Q
j
wi
wi-1 f
2
2
AV
At
where:
Qp = Value of the flood discharge (cu. m/sec)
□w = Value of the discharge flowing over the weir (cu. m/sec)
Z\V = Variation of the volume of water (cu.  m) stored upstream
of the weir in the time
(sec).
Since the discharge Q . varies on a linear basis against time,
t
then:
Q Fi = Qpi.j + o. 0180 Zit
Q Fi = QFi J - 0.0062 Z\t
when L < 24 hours
when t > 24 hours4
- 98 -
and, taking into account the preceding equation’ 0.0185              +
0. 0062
4t-2AV=0
when t < 24 hours when  > 24 hours
Since     the     values     Qpi.p,     Qwi_j.     and step, it has been possible to calculat
t
Av     are     known e the values of
s tep by
At.
The results of the calculation
Fig. 38.
are shown in Table 28 and in
From this diagram it emerges that the value of the flood dis
charge at the Melka Warar Diversion Weir is about 1, 1 00 cu.n)/sec.
The backwater curves were calculated also for the Awash River
reaches downstream of the Melka Warar Diversion Weir for discharges of 200, 400. 600,800, 1,000, and 1, 100 cu. m/sec.
Ln this case, too, Manning’s formula was used with a roughness
coefficient K taken as equal to 20 for the low water bed and
for the high water bed. The calculations are shown in Appcr.
dix 2.
The basic criteria underlying the design of the dyke alignrn
were set out at the beginning of this paragraph. Of cours »
provision has only been made for building the one on the ng*
at the moment. This will consist of two stretches: the
between the two Diversion Weirs, and the second from t
Warar Diversion Weir to the Angelelc Plain.
Mention has already h
maps available with k™ made on the fact that there are no 1 eft-bank plains betw*?^.48’'8’ th® routing cHect oi the
the elevations of the
in such a wav 
in relation to the ba ’
e ^ka Sadi and Melka Warar. Thus, crest the first stretch have been fixed
minimum freeboard of one meter
tion that dvkes ^KA’lter curve determined on the assuinp- 111 be built on both sides.FIG, 38FLOOD ROUTING AT M3LKA WARAR
T
(hour*)
°F
(cu. m/»*c)
Qw
(cu.
2Qf
(cu. m/icc)
Qwi+Uwi-1
(cu. m/tec)
zo .
r
-(QWl’Owi-l) (cu. m/.cc)
V
(I0  cu. m)
3
23 V
(103   m)
eu
zav
(IO  cu. m)
3
AT
(••c)
At
(hour*)
0
2. 72
4. 95
11. 21
16. 11
19. 45
21. 67
24. 15
26. 84
29. 01
31. 97
14. 07
j«. 19
42. 19
47* 19
0
Ml
330
748
1,075
1,290
I, 445
1. 600
1.533
1. 484
i, 424
1* 178
1. 284
1. 196
L090
0
50
100
200
250
300
400
500
600
700
BOO
900
I. 000
1.050
1.070
0
362
660
1,496
2, 150
2. 580
2,890
3,200
3,066
2. 968
2, 848
2. 756
2.568
2, 392
50
150
300
450
550
700
900
1.100
1. JOO
I. 500
1,700
1.900
2,050
2,150
-50
112
i 3 60
1,046
1, 600
1,880
1. 990
2* 100
1, 766
1,468
1, L4B
856
518
242
0
639
1.6B5 '
10, 631
22,367
33, 370
40, 7 30
50.JB8
60. |55
66. 949
73, 913
79,935
85, 842
88, 897
90, 337
619
1,046
8,946
11.736
11.003
7, 360
9, 658
9.7 67
6, 804
6,974
6,002
5,907
3,055
1,440
1.278
2.092
17. 892
23.472
22.006
14,720
19, 316
19, 534
13,608
13,948
12, 004
11.814
6, no
2.880
9. m
8.040
22, 600
17, 300
12. 000
7, 960
8, 900
9.700
8. 550
9, 900
IL 100
14.800
14, 350
18, 000
2. 72
2.2 3
6. 26
4. 90
3. 34
2. 22
2. 48
2. 69
2. 37
2. 76
3. 10
4, 12
4, 00
S. 00- 100 -
For the second stretch, on the other hand, since detailed 
were available of the Bolhamo area (the reclamation of which is not planned at present) account has been taken of the fact
that the flood waters of the Awash River, after having reached the edge of the low-water bed, will continue to flow, as has occurred up to now, towards this Area,
The elevations of the top of this stretch of dyke have therefore been set so as to ensure a minimum freeboard of 1 m with re
spect to the backwater profile of the hundred-year flood in a first stretch where the Awash River flows along the last slopes of Mount Dofan, whereas downstream the elevations have been set at about 1. 50 m above the edge of the left bank.
Obviously, when the Bolhamo area is reclaimed and the dyke erected,alBO on the left bank the second stretch of the right bank dyke will have to be raised to the final elevation. How ever, since the reclamation of the Bolhamo area is not plan ned for the near future, there will be at least the advantage
of deferring a part of the investment.
The second stretch of the dyke is prolonged for about ' km beyond the northern boundary of the Area, so that the Awash waters, discharging on the Angelele Plain, do not have to over come the elevation of 722 m a. s. 1. , so avoiding the flooding of the southern part of the Area.
The dyke will be 5 m wide; the side slope towards the river 2/3, and the side slope towards the Area 1/2. Under the ton. towards the Area, a sand and gravel filter. 50-cm thick and 3-m wide, is provided.
5 2 FLOODS FROM ALEIDEGHl PLAINS
A. .he                    «">e .he
Melk. 
par , oj
• 
\
at the Plain as runoff.
< V "" 
b'd
by
other, arriveWhen they reach the Melka Sadi-Amibara Plain, the waters spread out over it, thereafter flowing towards the Angejele plain along the tai w eg that runs along the eastern limit of the Area,
We have not considered it advisable to collect and transport these waters by the drainage network, whose discharge would be increased by several tens of co. m/sec; furthermore these waters probably carry considerable amounts of solid loads which would in large part be deposited in the drains, com promising their proper operation and involving heavy mainte nance costs.
The waters will therefore be intercepted at the eastern limit
of the Area by means of a dyke which will thus delimit, together with the extreme slopes of the Aleideghi escarpment, a sort of large canal in which the waters can flow towards the Angelele Plain*
To determine the discharge this large canal must convey, the contribution of the hundred-year flood has been taken into con sideration* This contribution has been determined on the basis of the discharge measurements registered for the Arba River (244 1/sec* per sq.km) (l)
On the basis of the 1:40, 000 photomosaic the alignments of the creeks coming from the Aleideghi Plains, the extension of the respective catchment basins and the resulting discharges have been identified.
The hydraulic characteristics of the various stretches of the drainage canal have then been calculated using Manning’s for mula with a roughness coefficient K assumed to be 20*
The results of these calculations are summed up in Table zq*
The alignment of the Eastern Dyke extends immediately east of the Melka Sadi Main Canal and of Main Drain No. J* In view of its height, generally less Chan   m and of the short duration
°f the floods coming from the Aleideghi Plains, estimated at
2FLOODS KROM ALClDEGJtl PLAINS
i\about 24 hours or slightly more, the width of the dyke top has been set at 3 m and the side slope towards the Area at 1:2 and that of the external side at 2:3.
The elevations of the top of the dyke have been set so as to ensure a minimum freeboard of 70 cm with respect to the level of the flood waters in the drainage canal.}
I
i
N- IQS -
6. ELECTRIC POWER SUPPLY
THE market
An examination has been made of the envisaged structure in
the two zones earmarked for "Settlements’1 and ’’Commercial
Farms11 respectively, and of that of the village of Melka Warar
from the standpoint of the market for electrical energy.
The electricity requirements have been evaluated assuming
the farms to be fully developed and considering this will pro
bably be the case about 1980. The demand for energy in the
years immediately preceding, this, i. e. as from the start-up
of the planned agricultural activities has consequently been
estimated as equal to 50% of that under full development, in
1973, and to 80% of this in 1977.
The following types of uses have been considered for the 1Z
villages included in the Settlement Area, assessing the rele
vant demand (see Part in):
a)       Families (2. 400)
100    W/family;    utilization:    1,    500    hr    /year;    demand diversity factor: 2.
♦        Total peak demand: 120 kW
*        Total yearly consumption: 360. 000 kWh
■b)     Local offices (12)
250     W/office;     utilization:     I,     000     hr     /year;     demand diversity factor; 1.
- Total peak demand: 3 kW
Total yearly consumption; 3. 000 kWh-106-
c )      Central office (1)
350 W; utilization: 1, 000 hr /year; 350 kWh/year d)     Central workahop (1)
5 kW; utilization: 1. 500 hr /year; 7, 500 kWh yea
e)     Street lighting
'.i •
On the basis of 1,000 m of street lit per village and suming 1 W/m (fluorescent lamps) of demand with a^' diversity factor of 1 and the overall utilization of 4, 000 hr /year (about 12 hr /day), we obtain:
Total peak demand: 12 kW
Total yearly consumption: 48, 000 kWh
f)   Pumping water
Considering that each village will have a well able to
supply a few liters per second of drinking water,
the depth of the water table is 50-1 00 m, there will
average power of about 4 kW per well.
Hence on the basis of 50 kW in all, used 1 2 
the    consumption    of    energy    throughout    the    Sett    e will be:
50 x 12 x 365 = 219. 000 kWh/year.
Area
For the 8 villages in the area of the farms, the yP ^ ve
_     . __eS of
a
and the respective requirements of electrical energy
been assessed as follows:
a ) Houseb for managers - 1 familv oer house (120
250 W/family for lighting. 1. 75 kW /family f°r dcfnand appliances; overall utilization 2. 000 hr /year: diversity factor: 1.4.- 107 -
Total peak demand: 170 kW
Total yearly consumption: 480, 000 kWh
Houses for skilled personnel - 1 family per house (562
families)
100 w/familyi utilization: 1. 500 hr /year: demand
diversity factor: 2,
Total peak demand: 28 kW
Total yearly consumption: 84, 300 kWh
c )       Ho use 9 for unskilled personnel - 1 family per house
(3, 200 families)
100 W/family; utilization: 1, 500 hr /year: demand
diversity factor: 2.
Total peak demand: >60 kW
Total yearly consumption: 480, 000 kWh
d)       Dormitories - Total 10.462 rooms
40     W/room;     utilization:     500     hr     /year:     demand     diversity factor: 1.
Total peak demand: 420 kW
Total yearly consumption: 210. 000 kWh
c ) Local offices (8)
350      W/office:      utilization:      1.000      hr      /year;      demand      diversity factorrl.
Total peak demand: 2. 8 kW
Total yearly consumption: 2. 800 kWh.General office (I)
1. 5 kW; utilization: 1, 500 hr /year; 2, 250 kWh/year
Local workshops (8)
7 kW/workshop; utilization: 1, 500 hr /year; demand
diversity factor: 1.4.
Total peak demand: 40 kW
. Total yearly consumption: 84,000 kWh.
Tobacco driers (8)
200 W/year; utilization : 1, 500 hr /year; demand
diversity factor: 1.
. Total peak demand: 1.6 kW
. Total yearly consumption: 2, 400 kWh.
Stores (24)
200     W/store;     utilization:     1,500     hr     /year;     demand     diversity factor: 1.
. Total peak demand: 4. 8 kW
. Total yearly consumption: 7, 200 kWh.
Street lighting
On the basis of 4. 000 m of street lit per village. asS^ a 1 W/linear meter (fluorescent lamps) of demand, ** diversity factor: 1, and for an overall utilization o br /year (about 12 hours a day), we obtain:
Total peak demand: 32 kW
Total yearly consumption: 128, 000 kWh.Regarding the village of Melka Warar, the following data have been considered, in consideration of the appreciable urban and commercial development:
Peak demand: 24 kW
Yearly consumption: 76, 000 kWh.
These figures also include the amount consumed for pumping drinking water.
In the whole of the Study Area, when full development has
been reached (1980),
follows:
.         Settlement
villages
Farm villages
Village of
Melka War a r
Total
requirements will therefore be as
190: 3 5 kW
8r>0. 70 kW
24. 00 kW
637. 850 kWh/year
1,4S0. 950 kWh/year
76. 000 kWh/year
1,075, 05 kW                     2. 194, 800 kWh/year
I
Finally, assuming a further demand diversity factor of 1.4
among the various transformer cabins (medium to low volt
age), to supply the individual villages or farms, we obtain:
 Overall Peak Demand = approx. 770 kW
Overall Yearly Consumption = 2, 194, 800 kWh
In reference years 1973 (start-up of agricultural activity)
and 1977 (completion of program), the abovementioned
(net) requirements are estimated as:
■1973 Overall Peak Demand - approx. 385 kW
Overall Yearly Consumption -• approx. 1.100,000 kWh 1 977- Overall Peak Demand - approx. 615 kW
Overall Yearly Consumption - approx. 1,760,000 kWh- 110 -
the SUPPLY: ALTERNATIVE SOLUTIONS
6. 2. 1 General
The electrical energy required could be made available jn various alternative solutions, an overall evaluation of which has been made from both the technical and the economic point of view.
An initial solution envisages the installation of one or more Diesel-power units. These permit variable operation, ac cording to how much energy is taken off during the different hours of the day, but they have the drawback of high produc-| tion costs, due essentially to the market price of Diesel oil and gas oil.
Such power units would thus be best used for emergency serv ices or to supplement other plants during the peak demand periods.
A second solution consists in making a link to the existing 132 kV Koka-Dire Dawa power line. In view of the modest power requirements of the Study Area, it would however not seem convenient to set up a sp-ecial transformer substation (e.g. 132/15 kV) with MT line to the area in question. On the other hand, it is of interest to study a link (e. g. 1 $
with the existing transformer station at Metehara, locate about 45 km from toe barycenter of the Melka Sadi-Amiha
area.
Obviously, as the Metehara substation is supplied Dire Dawa power line, a comparative economic study o solution must, among other things, take into account t value of the energy made available in the HT network o terconnected system.
A third solution consists in setting up a sghlll
making use of the possible head of water downs of the Melka-Sadi Diversion Weir.- Ill -
pig sei -uni t Plant &
On the basis of the overall net demand for 1980 (770 kW peak = Z, 194. 800 kWh/year). it can be estimated that, in terms of gross production (i. e. including local distribution network losses, assessable as about 1G% for the peak power and as 6. 5% approx, for energy) the following amounts must be sup
plied:
Maximum load
Yearly energy 
855 kW
2. 350, 000 kWh,
The Diesel station could therefore conveniently be equipped
with Z 600-kVA units* able to supply a total of some 960 kW.
with a load factor of some 0. 8.
Costs may be assessed in the following way:
1)      Capital costs (interest and amortization)
The cost of two 600-kVA units complete with accessories
and assembled in situ, is of the order of 260, 000 Eth. $.
Assuming prudentially a life of 10 years and capital in
terest of 5%, the overall annual cost (sinking fund) is
1 2. 95 % of the investment, i, e. 33, 670 Eth. $/year.
2)       Opera, ing and maintenance costs
Assessable    as    some    20    Eth.    $    per    kVA    installed    per    year, with a total cost of 24, 000 Eth. $/year.
Fuel costs
The price of Diesel oil in the Meki Bridge area is present, ly 0. 385 Eth, $/liter, including taxes of 0. 205 Eth. $/liter Since, even for electricity undertakings, the above tax is applied, the calculation of the fuel costs has assumed a price of o. 400 Eth. $/liter in the Study Area, correspond^ ing to about 0. 450 Eth. $/kg.Assuming an average specific consumption of n kWh. a cost of about 11 Eth. cents pcr
;           ' 25° kg j>.
fuel      alone,      and      of      13      Eth.      cents      per      kWh      incf°- consumption.     In     short,     for     an     annual     output     of'?     lubri«»ct
the unit cost of the energy would be:                                             Z
’^ °-000]tr.
5
IL. 6~0 < 24.000 2. 350. 000
♦     0.13 = 15. 45 Eth. cents/kWh
This cost is formed essentially of the fuel cost. and excluding the abovementioned taxes, it is easy to ded'”
the cost would drop to under 10, 0 Eth. cts/kWh
132 kV Koka-Dirc Dawa Power Line
The distance between the Metehara transformer station and
the barycenter of the area of villages in question is of the order of 45 km. Thue, to transport a load of 800-1.000 kW it is as sumed there would be a double-circuit 15 kV line with 3 5sq.mrn copper conductors (about I. 870 kg of copper per km of line steel section poles.
With reference to the cost of medium voltage distribution lm in Ethiopia, it has been estimated that the double c ircuit in question would cost about 9, 250 Eth. $/km.
However, in order to make a concrete comparison witb1 solution outlined in para. 6. 2. 2 (Diesel unit in centra tion), it must be borne in mind that the Diesel unit uOU any rate have to be connected to a dorsal singlerCUl jjenc« line arranged longitudinally across the Study Area. an having a length of 40 km.
Therefore, the link with the Metehara station requir respect to the Diesel solution. 25 km of double circU1 a), line (from Metehara to the nearest limit of the Study and a further 20 km of 1 5 kV line, again double circu» \o indicatively only chargeable for half the cost, in ordcr golu- double the longitudinal line (also existing in the Dieee tion) as far as the barycenter of the Study Area.
res *‘th115
comp-iratieconomic evaluation of the solution iavohrtcg
the link with the Metehari substation must therefor* h* ba»-d
on:
£5    km    of    double-circuit    i5    kV    line    with    15    iq.mm    copper conductors (9, 250 Eth + $ km)
20    km    of    double-circuit    15    kV    line    with    }5    sq.mm    conductors (50** of the cost chargeable. i.s. -5.625 Eth. $/krtl).
The total cost of these lines is 325. 000 Eth. 5. thl» also includ ing the terminal equipment.
The annual operating cost for the Lines ts
Capital Costa (5% interest. 30 years of amortization)
6. 505% of 325. 000 Eth. S
O PA* e_a 11 n^t •> nd ma i ntrna nc e c oats I. 5% of 325. 000 Eth. $ 
21, 141 Eth S/ye>r
4* B75 Eth. $/ye*r
Since the energy tosses duo to transport from Met eha r a Substa tion to the barycenter of the area (vi/.. from the local I 5 kV sys tem). may be put at about 3. 5%, the quantity of energy to be sup plied from said substation will bo:
2, \50, 000
0, 965
2. 440, OOQ kWh. approx.
In the light of recent studies and technical reports on the EELPA Interconnected System, it would appear realistic to assume a mr“irkct value of about 2. 50 Eth. eta for thr kWh available on the HT network. This value would however appear to be bound to decrease in the earning years subsequent upon the coming into operation of new and highly convenient hydroelectric plants
Therefore, taking a cost of 2. 50 Eth.ct» per kWh for thr energy to be suppled from the Metehara substation, there will be an annual cost of:
0. 025 x 2, 440. 000 = 61.000 Eth. S/year.F
. !I4 -
.apply the distribution network in the IP short. ‘“TT'.-ical energy from Melehara. the annual
Sud. M«
c ”'^'?o»‘“-M0”7'(,ltE,h$/ve"
. .  o.< to •*« 
c
.......... button netuorb. « .Ma.n:
»«iUble “ in'ake 01
87.016 Eth. S / 2^ ‘
u
. 
,50.000 kWh = 3.70 Eth.cenl./kWh.
2. 4 Hydroclcc trie Ph nt
This plant could exploit the head of water created by the Melka
Sadi Divernon Weir.
The waters would be diverted al the above -mentioned Diversion Weir. The first section of the Melka Sadi Main Canal, whose align
ment should be shifted a few hundred meters to the cast, would carry both the water required for irrigation of the Melka Sadi subarea (about 5 cu.m/iec) and the waters necessary for the hydroelectric plant (some 10 cu.m/sec). which should be local ed at the progressive distance of 5. 000 m. The latter wa
ters would then be discharged into the river along a canal approx. 5 km in length. In order to prevent flooding of thc irrigation area, the Western Dyke (sec Part III) should be continued along both sides of the Canal for a length of 2 * 5. 0 km. with an average height of 5 m.
The average head available would be of the order of 1 0
Considering a discharge of 10 cu.m/sec, which would e^ ^en 800-850 kW to be produced with the I 0-1 I m head, it 3 n an noted that this would be available for 85% of the time. woUid annual basis, while in the most critical month this f>gu drop to 46%.
It is therefore clear that if the station in question is
be boil1
coul^
to     supply     the     Study     Area,     the     Area's     energy     requirern^olljd
only be met until about 1975, whereas subsequently all events be necessary to have a supplementary sour units or link with Mctehara substation), to which to riods of shortage.
(pie*el•115*
An evaluation of the coiti af vetting up the hydroelectric na tion in question has. however, shown it not to be convenient, mainly du® to the large investments called for by the embank-
m ent works. These costs, based on An 1. ooo kW. are roughly as follows:
Conveyance canal (increased cost of
Melka-Sadi Main Canal from progres
installed power of
sive distance 0 to 5. 000 m)
135. 000 Eth. S
Hydroelectric plant (civil works and
machinery)
650. 000 Eth. 5
Discharge canal and embankments
3. 330. 000 Eth. $
Total
4. 1 15. 000 Eth. $
Assuming  a  rate of Interest of 5%,  60  years amortisation for the hydraulic works and 40  years amortisation for the hydro  - plant the following capital costs lire obtained:
Conveyance      and      discharge      canals,
embankments 5. 28% of 3. 465, 000 Eth. $
Hydroelectric plant
5. 83% of 650. 000 Eth. $
Total
182. 952 Eth,lyear
37. 895 EZth.S/year
220. 847 Eth.tyrar
The annual operating  and maintenance costs have been assessed a "  25  Eth,  J/kW  for the hydroplant and as 1%  of the investments for the hydraulic works. Hence:
Hydroel
ectr c p ant
ii
Canals and embankments
Total
'T K
e  overall yearly cost (capital + operation and maintenance) * Ould be a, fallow.;
220. 847 + 59. 650 = 280, 497 Eth.S/year.
25. 000 £th,$/year
34. 650 Eth.iyear
59, 650 Eth Syear-116-
Taking into account on the one hand the limited dischar
available in low-water periods and, on the other hand,
limited effective head in periods of flood, an average pr
live capacity of the order of 5. 8 million kWh/year may be °
sumed, and the corresponding cost of production would be- '
280. 497 Eth. $/5. 800, 000 kWh = 4. 85 Eth. cts/kWh
However, the energy required by the Study Area in 1980 will
be 2, 350, 000 kWh, about 70-80% of which could effectively be
covered by the hydroelectric station, due to the deficit periods
The    cost    of    the    amounts    of    energy    effectively    placed    would    thus be much higher, in the region of 16. 0 Eth. cts/kWh.
6.2.5 Conclusive Evaluation
The examination of the three alternative solutions illustrated above shows that it is convenient to supply the Study Area by making a link with the Metehara substation. Modification of a number of common parameters (especia the capital cost, which Bhould realistically be increased from the 5% level as sumed herein) accentuates the convenience of this solution compared with the other two.
The energy supplied in this manner, apart from being far more economic than that which could be produced in a local Diesel unit, is more convenient than the hydropower that be obtained from a small local power station, even on the ou side assumption that the entire productive capacity of sal ork. station, considerably irregular, could be placed in the net*APPENDICES1APPENDIX 1
DRAINAGE NETWORK CALCULATIONSDISTRICT DRAINSriv
Oft I
0*4 ' I
5f I
001 'I
ftftEO '0
5E '0
It
m
!          ft '0
9 0
OOH
m
ft! Ifi
69 »U
11 651
76 IH
0* M I
4ft in
W
ft« 151
0? 'I
fiT*1
56 9
51 ’1
091 ‘I
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or 'o
•5
761
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th ‘Hl
Oft ‘0
51*
SO £
n
045
5) *9 irro :o
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57 0
67
96
K £11
70 *WU
10 ’IU
45 ’ll
009 * t
ft *0
90
OZ 6d
00 •
I
ol IQ
ft '0
9 '0
001
DI ’0*1
1
'III
IB RW 71 111
07 6fl 00 *M1
ftft lit
oi r
07 I              OSt I              00 9               Jftfo 0
9 -o
DOB
76 *IU
60 tri
it irt
19 £51
09 «U
009
0
rv^iwc
flflft‘7
09s. '1
Ob 9
U '0
tl
97?
ft 0
01 611
00* ’ 1
50 ‘I
?0 ‘1
OOF
Oft 1
ft? Bft
It 9U 19 'If!
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00 1
71 '9
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on
ft 0
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009
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ocs
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1750 U
Oft '8C1
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57 ’0
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(“J 1 non»A*|3
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p*fl
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1 *"/     J     r»*»7             nsoj
pimOJ£> I        v>£ I Lnturu’jtf/ i      UOJJ
UHOjiLlUy
| QJ|UO^ »jq»l >•»•*
P’B-
F ram Sta.
to Sit
Water Table Control
Minimum Ground
Level
Length (rn)
Bed Slope
|m/km)
Bed
Width
<■")
Bed Elevation
(m)
Drained
Area
th*)
LXecharge (!/••<)
Water
Depth
(nn)
Water Elevation
(m)
2. 4 CO
1
L_L_   A 0
200
7J0. 70
7J7. 01
737. 36
736. 60 7Jfl. »0
200
0. I
0. 4
736. 4*
736. 91
92
2a
o. 35
600
0. 1
2. 0
600
711, 50
736. 76
736.70
366
iio
0. 35
60U
0. 1
2. 0
462
in
0.4:
1,400
736. 70
736.55
736.49
zoo
0.1 I       2. 0
766
1,600
-
i Drain B \0
\
7*6. 50
735. 99
735.97
2)0
0.55
737. 26
737.26 717. II
737. OS
736. 95
7*6. 89
7*6. 54
736. 52
1
1
I 741.60
739.65
740. 20
600      \ 0. 10              I 0.40
*7
0 15
\
rWatar Tabla Clairol
Kainfttorm
1
KtlMlOttn * IttIv»Uo«Water Table Control
n.d
Slope (ft/km)
Bed Width
(m)
Bed Elevation
(ml
Drained Ares (ba)
R slnetorm ♦ Irrigation Water
Di a charge
Water
Depth
(m)
Waler Elevation
(m)
Stored Volume
(cm. m/
■ q m)
*1
(!/••< M hr)
Rainatorm
Qi
(!/••«)
Water
Depth
(m)
Water Elevation
(m)
U| ♦
“2
Q
Depth
(m)
Waler Elevation
(m)
I. 50
0.40
7 39. 70 734 50
24
0. 3C
740. 00
73B.80
0. 0331
6. 30
605
0. 7U
140. 40
735. 20
0. 75
740. 45
739. 25
I. 00
0. 40
745.50
742.70
28
0. 30
74 1. h0
743. 00
0. 0331
6 40
540
0. 80
I 00
a. 40
182
55
0. 10
I). <3 3 3-4
6. 30
I. 140
I. 05
741.30
741.25
741. 60
0. 40
326
9M
0. 35
0. 0335
6 23
2. 04 0
I. 35
741. 04
139
0.45
0. 0141
6. 00
2. 780
1. 55
740. U8
740. Ot
744. 30
743.50
743. 75
742.35 742.60
742. 04 742. 14
741. IS 741. 18
1W«t«r Tablr Ccnlrol
Riinilorm
I
kikrLilorm * Irrk^wAktmWater Table Control
Rainstorm
Rainalorm ♦ Irrigation
F rom
SU.
to Sia
Minimum Ground
Level
Length
(rn)
Bed
Slap*
(m/km)
Bed
width
<m)
Bad
Elevation
(m)
Drained
Area
(ha)
LX. or herge (l/aec)
Wata r
Depth
(m)
Water Elavatlon
(m)
Stored Volume
(cu. m/
■ R- m)
•I
(l/oec a hr)
Qi
(</••*)
Water
Depth
(m)
Water Elevation
(m)
“1 ♦
u2
a
Water Depth
(m)
Waler Elevation
(tn)
800
1.40
0. 40
246
74
0. 30
0. 0337
6. IB
1.520
I 10
7, 08
1. 740
1. 15
1.600
7)9. 6C
738. 00
738.JO
7)9. 10
739.15
800
I. 5©
0. 40
342
101
0. 30
0. 0140
6. 10
2. 080
). 20
7 19. 20
718. 00
7. 00
2. 390
I. 30
2. 4 00
ns. so
7J6,80
716. 60
736.ZB
7J7. 10
739.30
738. 10
800
0. 40
0. 40
436
146
0. 50
0. 0)42
6. 00
2. 916
1. 80
3. 200
Pr^nJ.
0
BOO
1.600
738 40
?>• 0ft
6, 90
3. 360
1.90
756.20
736.76
7)8. 50
738. IB
800
0. 60
0.40
7 19. 06
738 58
I
1
1
1
740. 50
740. 00
738. 70
800                    L. 50 1         0. 40
7 IB. 76
73B. 28
737 08
150
Z46
45
74
0. 30
0. 10
0. 0336
0. 0)39
6. 20
6-10
910 I. 5 00
1.05
1.05
739. 61
739. 13
738. 13
7. 10
7. 00
i. 160
1. 10
1. 720              1.10
«
717. J8
800                  0.60      I       0.40        1
1 716.50
1   716.45 \ eoo          \ 0.60              I a. 40
1
736.98
M2
101
1
0.40
0. 0144
5.91
2. 020
1. 45
738.43
7)7. 95
6. 61
2. 330 1         1.50        /
7«9. 86 719. IB 1 718. 13 1
1
738. 46 /
I
1    2.400      I 7)6.30
736.90
/
738. 00
\
\
/  776. 10 /
\
\
418
1)1                 0. 45
0. 034?
5 81
2. 550
1. 55
736. 00 717. 52
/
6. 71  / 2. 940 / J. 6*  /
/>
\     3,200 \          118. 20 \
\    7)5.97
1
736. 42
/
/
/zJ*. 62 / "*r
■,
Water Table Control
> FfC^ri      i A£irJnium[ 4
/ a“d
1
I Ground l SI ape
i 1 <M
1 fled i Bed r Dr a lined
|         Width   | Elevation     r Area
' ro Sr*     l" Level
J fm/fcrnj
I fffl)               J
(h>)
I M ■t’hirg* (■/••e)
1 Water Depth
(taj
Water Elevation
(m)
JI
(!/•*< x
hr)
Q|
0/mcJ
w*ur 1
□apth       | (mj
Waler 'i Elavition 1
(m)          |
uS +
u2
Wiiit
Depth (mJ
/
Drain Cl 1
O          739, A0
ion          735. 4t>
(
I
Stored Volume (cu. m/
■ q in]
A 00
1. 50               0. 40
710, 3 0
7J7. 10
144
41
0, 30
736. 60
73?. 40
0. 0JJ3
6. 3G
010
g5
739, 15
737. 95
7. 20
1.070
0. 90
900
0. 70               0. 40
736. 02
736.26
240
72
o. W
1,600          7JA. 70
717 12
lib 5b
0. 033b
6. 20
I, 4 60
1.25
7 3 0. 07
717. 41
7 L 0
I. TOO
I. 10
a oo
0. 70              0. 4 0
715 21
735. fe5
2 HU
B6
<i. J5
0, UH4
5.95
1,710'
1,50
d. Mi
I. 970
L 4(1
3. 230          737.JO
£r*in_H
?!4 JQ
too            jit. ao
736 00
716. 95
719, 2
718. 0 7J8, t
737. 5 737- 6 7J?. 05
Ou u
□ . ]0              0. 4 0
1H. 74
736.5?
96
29
0. ZS
737, Du
736. 62
C- OJ37
ti. Au
595
1. QD
TIT. 75 1 TJ7, 5?
7. 10
690
1. io
117. A5 7J7, t?
a 00
1. O0            CL 4 0
U.0139
6 IO
t, 28Q
J, 05
1,460         747
716,52
735. 72
21 Q
6)
0. 30
7. 00                1. 470             1. 15
7It. 02
736. 77L
DRAIN: A. I
From ata. 0
to ata.      800
Length: 800 m
cu. m/ha * 13. 600 cu. m
Sloped. 60 m/km
Stored volume:              ha        42    X           325
ha        40    X           306       cu. m/ha -         12, 200             cu, m
ha X
ha X
ha        82
cu. m/ha -
cu. m/ha •
cu. m
cu. m
25. 800             cu. m      - 0. 0315 cu. m/gq m
Item
Unit
lit Trial
2nd Trial
Tri.1
yl
u2
u
Q
Type ol aection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/»»e
•q. m
cu m
cu. m/eq. m
cu. m/aq. m
cu. m/eq. m
6.01
3rd Trial
6. 50
0. 0315
0. 0025
496
40/80
1. 28
1. 030
0. 03150
0. 00125
530
40/80
1. 28
1. 030
0. 0340
0. 03275
From eta. 800
to ala.
1J600
Length: 800m
Stored volume:
ha
82    X
327      cu. m/ha ■
26, 800
cu. m
ha
48     X
325      cu. m/ha =
15. 600
cu.  m
ha
X
cu. m/ha =
cu.  m
ha
X
cu. m/ha ■
cu. m
42.400
cu. m «
Item
Unit
lai Trial
2nd Trial
3rd Tri*
“1
y2
u
Q
Type of taction
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/iec x ha
l/aec x ha
l/«.c
aq. m
cu. m
eu. rn/aq. m
m/aq. m
cu  m/aq. m
6. 20
612
o. 01260
0. 00100
810
40/100
1. 90
1. 520
0. 03260
0. 00117
000
40/10°
0. 03360
0. 03377A1-1 0
^°D    ro
2< 40D
Length:    800m
Slop*: 0. 60 m/km
ha
130      X
33&
cu, m/ha •S'
44. 000
CU. tn
ha
96      x
325
cu. m/ha
31.200
Cu. m
ha
K
eu. m/ha  3'
c’L m
ha
ha
K
cu. m/ha  3
Cu. m
75, 200 cu. m = o+ Qjjj cu, tn/aq m
Hum
Unit
l.t Trial
2nd; Trial
3rd Trial
4th Trial
U]
*2
a
a
Tfp* oi a action
trtid area
Velum*
Uhis volume
Unit volume
Unit volume
l/aec k ha
l/*»c x ha
l/aec x ha
l/aec
sq. in
cu. m
cu. m/aq. m
cu. m/aq. m
cu, m/aq. m
5. 95
6. 00
0. 03330
0, 00! 00
1. 340
40/120
2. 64
2, 112
0. 03330
0. 00093
1,350
0. 03430
0. 03423
Pram m
I "" *  volum,;
,d
to ata.
Length: m
cu, m/hi < co.  m/ha  = cu.   m/ha   - cu_ m/ha -
Slope;                m/km
ha
ha
X
ha
Unit
lit Trial
cu. m
cu, m
cu. m
cu. m
Cll m
2nd Trial
cu. m/aq. m
3rd Trial
4 th Trial
1/ioc * ha
l/icc x hiTrr» •** C
SU»»4
•e >U   •0C
L»r«<h 800  m
”**•=•.60 mAw
ha     H      ■       >25      cu. m 'ha »          >1.200            cu. m
w                w                          cu m/ha •
a*
I
c«. m/ha «
cu. m
cu. m
hi
■
cu. m/ha ■
cu. m
ha
H
>1.200
eu m «• «/.,. m
Item
Unit
lai Trial
2nd Trial
•1
•2
Q
Type cZ tflctlor.
Vetted area
Volume
Unit velum*
Veil volume
Unit volume
l/fltc x ha
l/nc > hl
l/flec ■ ha
!/••(
•q m
cu m
cu m/aq. m
cu m/aq. m
cu. m/aq. m
6. 20
3rd Trial
6. 15
4th
** • r-a.
0. 0525
0. 0010
600
<0/85
1. 42
1. 136
0. 03250
0. 00118
590
40/85
0. 0335
0. 0116B
I
Fram eta. BCO
to el*. 
600
Length- 800 m
Slope-0. 60 mA™
Stored volume;
ha
96
X          33?
cu. m /ha =
32,300
cu. m
ha
96
X          325
cu. m/ha ■
31,200
cu. m
ha
X
cu. m/ha »
cu.  m
ha
X
cu m/ha -
cu. m
ha 192
61,500 cu.m -
Item
Unit
iat Trial
*1
“2
u
Q
Type of flection
Welled area
Volume
Unit volume
Unit volume
Unit volume
1/,.C * hl
l/aac x ha
l/aec x ha
l/aec
aq. m
cu. m
cu. m/flq. m
cu. m/flq. m
cu. m/flq. m
2nd Trill
6. 05
0031° co. «n/M "
3rd Trial
6. O5
0. 03300
0. 00100
1. 160
40/115
2. 44
1. 952
0. 01300
0. 00102
0. 03400
0. 03402W at*-
Z^OD
Lanfth: 9OH m
5>Wa: g, 40 mZhm
jrt*
„ I.400
M
192      *
J4 0
cn, rn /h* t
55b in
cu. tn
ha
q£ x
J25
cu. m/ba »
Ik. JOO
n. m
M
■
ta. m/ha >
cu. m
h*
1
ctL m/h* *
C’l. m
ha
29A
H, 40Q
ra_ m
• 0.
eu. rr»/aq m
|tam
Unit
lit Trial
IM Trial
3rd Trial
4th Trtol
*1
»1
1
Q
&f ttctian
W*t!id area
VflJuma
ffsit return*
UrII volume
Osdt return a
l/ste x ha
1/aec x ha
l/a»c x ha
5. M
5.
aq. m
eu( m
cm. m/aq. m
cu. m/aq. m
CH, m/aq. m
0. OJJSO
0. 00100
L W
40/135
k 20
2.624
0. 0> Jio
o. 00 H l
I. TOO
40/1JS
0, 03450
0. 01441
itlL
Lanjlh:
Tn
5lop*:
rn/km
**** ’alum.
cu.  m/h*  ■
cu. m
Cu.  m/h*  ■
ciA- m
cu. m/ta ■
cu. m/b* ■
cia. m
cu. m
ca. m ■
«l tn/aq. m
Unit
Ui Tri*)
2nd Trial
3rd Trial
4th Trial
l/aec   x   ha
l/aac ■ha
L/aac x ha
l/iac
aq, tn
cu. tn
cu.  m/aq,  m
tu.   m/aq.   m
cu. m/aq. mI
■
DRAIN: A
From iU. 0 Stored volume:
to Ila. LW
h* n
Length: 200 m
X 325 cu. m/ha • 29.500 cu. m
S,op’:<>- >0 m/krn
hi
«
hi X
ha X
cu. m/h* ■
cu. m/ha ’
cu. m/h> «
cu. m
cu. m
cu. m
29. 500 cu. m = o. 0325 cu.
m tq m
/
Item
Unit
lit Trial
2nd Trial
3rd Trial
6. 42
6. 40
“2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/iec x ha
l/iec x ha
i/iec x ha
l/iec
aq m
cu. m
cu. m/iq. m
cu. m/iq. m
cu. m/aq. m
0. 03250
0. 00050
590
40/125
2. 84
568'
0. 03250
0. 00062
588
40/125
0. 03300
0. 03312
from eta. 200 Stored volume:
to ata. BOO
Length: 600  m
SI ope: 0.10 mAm
ha 92         X      331        cu. m/ha »     30, 070            cu. m
h* 226      X       342       cu. m/ha ■     77, 300            cu. m
ha 48         X       306       cu. m/ba «      14,700             cu. m
ha X
ha 366
cu. m/hi «
cu. m
122,070 cu. m = 0. 0334 cU- n'/',q ”
2nd Trill
5. 90
3rd Trial
Type of lection Wetted area Volume
Unit volume Unit volume Unit volume
l/iec  x  ha
l/iec x ha
l/iec x hi
l/iec
iq. m
cu. m
cu. m/aq. m
cu. rn/iq, m
w. m/iq. m
0. 03340
0.00100
0. 03440
2.170
200/170
7. 73
4,638
0. 03340
0. 00126
0. 03466Al-14
«□
1.400
Length: 600
m
SI opt to, io m/km
h»
366 *
347
cu. m/ha =
126,700 
nm
h*
48      «
32 5
cu. m/ha ■
15.600 
„.m
ha
48       *
306
cii. m/h* «
14, 700 
cu m
hA
X
cu. m./ha «
««. m
bA
462
I57j 000 cu. n
o
a 0, 0340 cu- ffl/iq. m
Unit
1 at Trial
>od Trial
3rd Trial
4th Trial
r                    Itcm^
MJ
u2
Q
Typa of iflcLion
Wetted are*
Volume
U nit volume
Unit volume
Unit volume
l/iee X ha
l/t«c x ha
l/aae x ha
l/sec
nq. m
cu. m
cu. m/aq, m
cu. m/aq. m
cu, rn/aq. m
5. 71
5. 69
0. 03400
0. 00100
2.640
100/18$
a. as
3,298
CL 03400
0. 00115
2, 620
zWias
0. 03500
0. 01515
r (4=, lta_ lt4D0 to
5t0,t|l ’Olqm-;
■ ta.  I, 600
Length: 200   m
Slope:0. 10 m/kra
ha     462       X            351         cu. m/ha ■        162. 100           tu. m
ha
2SS
X
344
cu. m/ha =
99.DOO
eu_ m
ha
16
X.
306
cu. m/ha -
4. 900
E Ur m
ha
X
cu. m/ha -
cu, «
ha
766
266, 209
Eii. m =
0. 0349 eu. m/aq. m
Unit
1st Trial
2nd Trial
3rd Trial
4th. Trial
5.61
oi t.
4t, «^
’’lurr,
l/aec   x   ha
l/aee   x   ba
l/i«c x ha
1/aac
•q. rn
cu. tn
cu. m/aq. m
cu. m/aq. m
cu„ m/aq, m
5. 69
0, 03480
0. 000*0
4. 300
200/ZJO
12.54
2.508
0. 03490
0. 00033
4. J5O
200/ZJD
0, Q353O
0. 03513drain d
From ata 0
to eta.  600
Length: 600  m
Slop«:0. |q     "»Am
Stored volume             ha    76        X         325         cu. m/ha •         24,700              cu. m ha    48        X         306        cu. m/ha =         14,700              cu. m
ha
ha
ha 124
X
X
cu. m/ha «
cu. m/ha ■
cu. m
cu. m
39.400              cu. m       = 0. OJIBOcu, m /•q. m
Item
Unit
let Trial
2nd Trial
Ird Trial
Tnji
UL
u2
u
Q
Type of icction
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/iec x ha
l/iec x ha
l/iec x ha
l/iec
■q. m
cu m
cu. m/aq. m
cu. m/iq. m
cu. m/aq. m
6. 50
6. 21
0. 03180
0. 00100
805
40/H0
3. 50
2. 100
0. 03180
0. 00170
775
40/140
0. 03280
0. 03)50
From eta. 600            to eta.  1.400
Length: 800   m
Slope 0. 10 m/km
Stored volume:
ha
124     x      335
cu. m/ha >
41.500
cu. m
ha
48      X     325
cu. m/ha *
15. 600
cu. m
ha
48      X     306
cu. m/ha s
14. 700
cu. m
ha
X
cu. m/ha -
cu. m
220
cu. m/iq-
Item
Unit
lot Trial
2nd Trial
3rd Trial
“1
u2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/iec x ha
l/tec x ha
l/iec x ha
l/iec
•q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
5.95
5. 89
0. 03270
0. 00150
1. 320
40/170
5. 02
4. 016
0. 03270
0. 00183
1.290
0. 03420
0. 03453Al-16
t 40°
CO fit*’
2, ZOO
Length' SOO  m
SlopaO. 20   m/km
ha 220 X 345
h> 40 X 325
cu  m/ha =
r
cu  rn/ha =
r
75. aoo co. m
IS. SOO cu, m
ha        4B      X        306       E.UL m/ha =        14,700           c-j. m
h>                   X
cu. m/ha -
ha
316
CU m
106.100 m. m '0.03360 eu. m /•<L m
1
Unit
lit Trial
2nd Trial
3rd Trill
--------------------------- 4th Trial
5. Bl
“1
*2
Q
fyjHB of ItcHofl
Wrtted are*
Yolama
Ualt vslum«
tTniiL volume
Unit volume
l/acc x ha
l/«ec x ha
l/iec x ha
l/«ec
• q. m
cu. m
cu. m/vq. hts cu. m/iq. m cu. m/aq. m
5. 72
0. 03360
0. 00100
1.040
<0/170
5. 02
4. 016
0. 03360
0, 00127
LB20
40/170
0. 03460
0. 03487
n&m«hL, 2, ano to ata.     3. 000
Length; 800 m
5Iop«:l. 60 m/km
’oiuma:
h*
316 x
349       CU. Tfl/ha ■
110,100
eu. m
ha
48 x
325       eu_ m/h* ■■
1 5, I 00
cu- m
ha
X
cu. m/ha =
CU m
ha
X
cu. m/ha =
cu m
Unit
Ut Trial
2nd Trial
3rd Trial
4th Trial
1
2
T
V
U
(
^P* Qf -
-
.r.*
.
^“rne
,
I.
‘'"■un,.
**
l/«ec    x    ha
L/aec   x   ha
L/«ee x ha
l/a«c
aq. m
cu. m
cu, m/iq. m cu m/aq, rn cu. m/aq. m
0. 03430
0, 001 00
5, 61
1,040
40/120
2, 64
i  112
r
0. 03430
0. 00058
5. 72
2,080
40/120
0. 03530
0. 03488dmaH1:S
Fr«n.t». 2.400 to .«•-
J. 000                    Length: 600  m
S,aptX>’ ‘0 m/ktn
Stored volume:       ha   364     X      349       eu. m/ha -      127. 300         cu. m ha     46     X    325       cu. m/ha -         31.200         cu. m
ha
X
ha X
ha    460
cu. m/ha =
cu. m/ha s
cu. m
cu. m
158.500 cu. m =0 0345
Item
Unit
let Trial
2nd Trial
3rd Trial
4th Trig*
U|
*2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/tec x ba
l/tec x ha
l/tec x ha
l/.ec
eq. m
cu. m
cu m/eq. m
cu. m/eq. m
cu. m/eq. m
5.53
5. 70
0. 03450
0. 00100
2.550
40/160
448
2.688
0. 03450
0. 00059
2,650
40/160
0. 03550
0. 03509
From eta.
to eta.
Length:
m
Stored volume:
ha
X
cu. m/ha «
cu. m
ha
X
cu. m/ha =
cu. m
ha
X
cu. m/ha -
cu. m
ha
X
cu. m/ha -
cu. m
ha
cu. m
hem
Umt
let Trial
2nd Trill
u2
u
Q
Type of eection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/tec x ha
l/tec x ha
l/tec x ha
l/Mc
•q. m
cu. m
cu, m/»q. m
cu. m/eq. m
cu. m/eq mA i -! s
b
fl
to st*’
000
Length: 000
m
Slope; g, m/km
rr^ *“
h*
160      x
325 cu. m/ha =
*2. OQO
eu. m
h*
X
cu. m/ha =
Cll. m
ha
X
cu, m/ha »
eu. m
ha
M
X                         cu, m/ha =
160
cu. m
52, 000 cu. m = 0,03250 cu. m/aq. m
Item
Unit
lit Trial
1----------------------- 2nd Trial
3rd Trial
4th Trial
-—
al
“2
q
Type of lection
wflttad area
Volume
Unit volume
Unit volume
Unit volume
l/sec x ha
l/icc x ha
l/iflc x ha
t/aee
sq. m
Cll rn
cu. m/aq. m
cu. tn/aq. m
cu. ni/iq. m
6.22
6, 20
0. 03250
0. oomo
1, 000
40/110
2. 26
1.00ft
0. 03250
0. OO H J
W
40/110
0. 03350
0, 03)63
rr&m    lta
-   aao      to aU.      1.200
Length: 400 m
&ore< *eluma;
ha 160 X 336 eu_ m/ha = 53,800 cu, m
ha 48 x 325 cu, m/ha - 15.600 cu. m
ha 24 X 306 cil m/ba * 7, 100 cu, ra
ha X
ha     2 32
cu. m/ha •
cu. m
76,500 cu. m
0, 03300 cu. m/aq. m
Unit
lit Trial
2nd Trill
3rd Trial
4th Trial
6. 21
RJ ^1 v4l
Vrvl
1/aec x ha
l/»«c x ha
1/soc x ha
1/sec
• q. m
cu, m
cil m/«q, m
cu. m/iq. m
cu. m/aq. m
6. 21
0. 03300
0. 00050
1.440
40/130
3. 06
1.224
0. O33DO
3. 0005 3
1, 440
40/1JO
0. 0335 0
0. 03 35 3
-I
From eta. 0 Stored volume
to Ha. 800 ha     96 ha
ha
ha
ha     96
Length: R00  m 525 cu. m/ha =
cu m/ha = cu.   m/ha   - cu. m/ha »
s, op«:l. So
"'/km
X
X
X
X
31.200             cu.  m
cu. m
cu. m
cu. m
31.200
cu. m             =0.0325 cu.m /•q m
Item
Unit
lat Trial
2nd Trial
3rd Trial
4<h Tmi
«1
u2
u
Q
Type of lection
Welted area
V olume
Unit volume
Unit volume
Unit volume
l/tec x ha
l/iec X ha
l/aec x ha
l/>ec
■q. m
cu. m
cu. m/eq. m
cu. m/aq. m
cu. m/iq. m
6. 42
6. 30
0. 03250
0. 00050
620
40/70
1. 02
816
0. 03250
0. 00085
605
40/70
0. 03300
0. 0333
From ata,
to eta.
Length:           m
Slope               m/km
Stored volume:
ha
x
cu. m/ha x
cu. m
ha
X
cu. m/ha «
cu. m
ha
X
cu. m/ha »
cu. m
ha
X
cu. m/ha =
cu. m
ha
cu. m
Item
Unit
lit Trial
2nd Trial
“1
u2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
Vmc x ha
l/iec x ha
l/aec
•q. m
cu. m
cu. m/iq. m
cu. m/iq. m
cu, m/rq mA1-Z0
co           goo
Length: ROD  m
Slope co. 90 m/km
ha
44         X
3Z5         cu, m /ha ■
14. 700         cu. m
h*     40
h»
K        306          £U m/ha =         14,700            eu. m
X
h* X
ha     92
cu m/ha =
cu. m/ha 2
cu_ m
CU, rn
29. 400 CH. m ’0,0320 cu, m/iq.m
Ucm
Unit
1st Trial
1--- -------------------- 2nd Trial
3rd Trill
4th Trill
6. 40
ill
Q
Type of tec Hon
Welted area
Tolume
Vnit volume
Oalt volume
U< volume
|/aec x  hi j/iec x  ha t/eee x ha
l/iec
iq. m
cu. m
cu, m/aq, m cti. m/aq. rn cu_ m/aq. m
6 40
r
0, 03200
0. 00100
590
40/110
1.28
1.024
0. 0320
0. 0011
590
40/80
0. 01300
0. 0331
f «mitteOD loit* Z Z00 
t4
LenflhUJOC- m
5l<yp«-0. <?0 m/km
Jt *r*d Tolqrat-
hd 92 X 331 cu. m/ha. a 30. 400 cu. m
ha 90 M 306 CTL m/ha W 27. 540 cu- m
ha X
ha X
h* 182 
cu. m/ba -
cu, m/bi »
cil m
cu. m
57,940 CU-m1 0. 031B cu. m/iq. m
Unit
1st Trial
2ad Trial
3rd Trial
4th Trial
*2
*
Q
^7Pt of _
•J nil,
r ^lt
l/««c x ha
l/a«c x ha
l/iee x ha
1/..C
aq. tn
cu. m
cil m/eq. m
CtL m/aq  m
r
CU. TTs/aq,. Tn,
t>, 50
6. 30
o. one
o. ooio
1, 3BO
40/105
2. 07
2, 900
0. D31R
0. 0016
1. 140
40/105
0. Q320
0. 03341
PJLM2! C
From *• 200 to ata. 3. 000
Length 800 m
Slope: °-80  ***/kni
Stored Tolum*!           ha     182     X          334        cu. m/ha •           60. 800            cu. m
Sa       48     X          306        cu. m/ha «           14. 700            cu. m
ha      *>6    X          325        cu m/ha «           31.200            cu. m
ha
ha 326
X
cu. m/ha •
cu. m
106. 700 cu. m = 0.0327 cu- "’/•q m
Item
Unit
let Trial
2nd Trial
Srd Trial
<th Trm
ul
“I
u
Q
Type of aection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/aec
eq. tn
cu. m
cu. m/aq. m
cu. m/eq m
cu. m/aq. m
6. 20
6. 23
0. 0327
0. 0010
2. 020
40/1 35
3. 28
2.624
0. 0327
0. 0008
2. 040
40/115
0. 0337
0. 0335
From eta. 3, 000       to ita.    4. 370
Length:l,370  m
Stored volume:              ha         326 x       335       cu. m/ha =         109. 300           cu. m
ha
x         306       cu. m/ha ■          29, 400           cu. m
ha       40     *       325       cu. m/ha -           13, 000          cu. m
ha
X
CU. m/ha s
cu. m
ha 462
4tb T*1
Item
Unit
lat Trial
2nd Trial
6. 15
3rd Trial
6. 00
“2
u
Q
Type of • ection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/«ec x ha
l/»«c
■ q. m
cu. m
cu. m/eq, m
cu. m/eq. m cu. m/aq.
2,850
40/155
4. 21
5, 760
0. 03290
0. 00125
2.780
40/1^5
0. 0329
0. 0010
0. 0339
0. 03415Al*22
LdtfijfthJJ&OO m
„ I, ITO
to |».
97 0
JhpMjQ m/Vm
f       1                                    M      462       x        341         tu. m/ha             157, 400          cu. m
M
M
$6
94
X 325
X 306
cu. m/ha a
cu. tn/hi *
31, ZOO
28. 800
cu. m
CH m
ha
X
cil m/M *
tu. m
I,* 
$52 
217,400 cu m
’ 0.0 3 J J cu. m />q ro
Item
Unit
1 at Trial
2nd Trial
3rd Trial
4th Trial
5.95
5. 7B
al
“1
u
a
Typ* of faction
Wetted * tea
Volume
Unit woluine
Unit volume
Unit volume
l/ioc x hi
l/aec x ha
l/i«c x ha
l/»«e
aq, m
CU. TTI
cu, m/aq, m
cu. m/aq. m
cu. in/aq. m
s. n
3.880
+0/J9J
6. 46
t 0. 35 0
0. 0333
0. 0016
3.750
40/110
6. 10
9 <H0
J, 740
40/140
+
0. 0333
o. ooto
0. 0313
0. QOJ 5
0. 034 3
0, 0349
0, 0348
ham iu. 5, 9?o
Co ate      6,570
Length: 600 m
:t ‘ *1 *BliiTn
r
e:
ha 652 k. 34B cu. m/ha ■ 227, 300 eu. m
ha 232 X 335 cu, m/ha - 77. 700 cu. tn
ha 48 X 304 cu- m/ha ■ 14. 700 cu. m
ha
X
cu- m/ha *
cu. m
Unit
lit Trill
Ind Trill
3rd Trial
4th Trial
5. 40
H «hMi
**■*
”1^.
l/avc x ha
l/i«c xha
l/a*e ■ ha
1/ioc
■ q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
5. 75
0. 0343
0. 0010
5.200
200/190
9. Z2
5.532
0. 034 3
0. 0006
5. 350
100/1,0
D. 0353
D, 0349
■DRAIN: C
From ita. 6. 570
to ita.
0, 170
Length:1.600 m
s ‘^:0.40 m/krn
Stored volume:
ha
932 x
349
cu. m/ha ■
325, 200
cu. m
ha
96 x
333
cu. m/ha =
32, 000
cu. m
ha
96 x
325
cu. m/ha ■
31,200
cu. m
ha
96 x
306
cu. m/ha -
29.400
cu. m
ha 1.220
417,800 cu.m *0.0343 cu. m/,, m
Item
Unit
lit Trial
2nd Trial
3rd Trial
tt l
u2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/eec x ha
l/iec x ha
l/eec x ha
l/lic
•q. m
cu. m
cu. m/eq. m
cu. m/aq. m
cu. m/iq. m
5. 61
5. 50
4th Tnn 5. 50
0. 0343
0. 0010
6. 850
200/210
10. 82
17, 300
0. 0343
0. 0014
6. 700
200/20S
10. 40
16. 600
0. 0343
0. 0014
6, 7C3
200/205
0. 0352
0. 0357
0. 0357
From ata.
to ata.
Stored volume: ha X ha x ha X ha X
Ha
Length: m
cu. m/ha ■
cu. m/ha — cu. m/ha = cu. m/ha *
Slope:
Item
let Trial
cu. m
cu. m
cu. m
cu. m
cu m =
2nd Trial
cu. m/eq. m
U1
u2
u
Q
Type    of    lection Wetted area
Volume
Unit volume Unit volume Unit volume
Unit
l/itc   x   ha
1/iec  a  ha
l/iec x ha
l/eec
■ q. m
cu. m
cu.  m/aq.  m
cu. m/>q. m
cu - m/iq mAl-24
to itaBOO
LengthzgOO
m
Slope:0, to m/k«i
ha H4
X
325 cu- m/ha =
27,300
cu, m
ha
K
cu. m/ha »
cu. rn
hi
X
cu. m/h.i =
cu. m
hi
X
cu. m/ha -
cu. m
ha B4
27. JOO
cu. m
- 0, 032 5 CU. m/oq m
(tom
Unit
1ft Trial
2nd Trial
3rd Trill
4lh Tri*!
U]
B2
V
a
Type nt lection
Wetted are*
Volume
Unit volume
Unit vdkluine
Unit volume
t/eec x ha
l/ifc x ha
!/■«€ x ha
l/iec
iq m
cu. ffl
cm   m/eq, m
;
cu. m/iq. m cu. m/tq. m
6.21
5. 7|
5. ao
52 J
40/(20
2. 64
2. 112
0, 0)250
0. 00250
«0
40/115
2. 44
L9S2
0. 0325
0. 0023
487
40/J |5
o. DJiS
0. 001 0
0. 03)5
0. 035 00
0. 0343
'■am i1at
to ft*
Ltnglhz            m
Slop*;               m/km
»o!un,e:          ha                  X                     cu. m/hl -
ha X
ha X.
ha
x
cm. rn /ha. -
cu. m/hi ■
cu. m/hi -
cu, m
cu. m
cu. m
cu. m
■DRAIN: E
From ala. C               to ata. 800
Length* 800   m
Slop«:0. 60
'"/km
Stored volume:               ha 54          X         325        cu. m/ha =         17. 500              cu. m
hi 96          X         325        cu m/ha «          31,200              cu. m
ha 48          X         306        cu m/ha «          14.700              cu. m
ha
ha 198
X
cu. m/ha «
cu. m
63. 400              cu. m      =0.0320 cu.m        /»q m
Item
Unit
1st Trial
2nd Trial
3rd Trial
Trial
«l
«2
u
Q
Type of erction
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/eec x ha
l/eec x ha
l/aec x ha
1/>CC
■ q m
cu. m
cu. m/eq. m
cu. m/aq. m
cu. m/aq. m
6. 41
6. 41
0. 03200
0. 00100
1. 270
40/120
2. 64
2. 112
0. 03200
0. 00105
1.270
40/120
0. 03300
0. 03305
From eta. 800
to ata. 1,600
Length:800
m
Stored volume:
h* 198 
x      330
cu. m/ha =
65. 500
cu.
ha 48 
x      325
cu m/ha =
15.600
cu.  m
ha 
x
cu. m/ha -
cu.
ha 
x
cu. m/ha «
cu. m
ha 246
81. 100
Item
Unit
let Trial
2nd Trial
l/eec x ha
l/aec x ha
l/aec x ha
l/eec
■q. m
cu. m
cu. m/eq. m
co. m/eq. m
cu. m/eq. m
6. 05
3rd Trial
6. IB
“2
u
Q
Type of eection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
0. 03300
0. 00100
1. 500
40/110
2. 26
1. 808
0. 03300
0. 00074
0. 03400
0. 03374A I-26
Length; SOD     m
Slop*: 1.50 m/krn
„ b*00
h*   246          *
33?         cu. m/ha =            82,900         cm m
d  .alurnc-
ha     Q6        *         325        CM, m/ha ’           31, 200         cu. m
ha
ha
ha   342
X cu. m/hJi ~
X cu. m/ha i
CU. m
Cu. Tn
114,100 cu. m — 0,0.334 cu, m/sq. m
Kern
Unit
1st Trial
2nd Trial
3rd. Trial
4th Trial
6. 10
“I
n
a
Type of section
Watted area
Voluraa
'Jflit volume!
"nil volumn
7nit volume
*—------------------------
l/iec   X   h>
l/sec    x    ha
l/sec x ha
l/.ec
■ Q. rn
eth m
cu. m/sq. m , cu. m/sq, m cu. m/aq. m
6. 10
0. 03340
0. 00050
2. 030
40/120
Z. 64
2. 112
0. O3J40
0. 0006Z
2, 030
+ 0/120
0. 03390
0. OJ402
it*, 400
to it*. 
3. ZOO
Length: 8 00
m
Slop*: 0. 40 m/k m
volume:
ha
342 
x
340
cu. rn/h* ■
116.200
CU. Hl
ha
96 
x
325
cu. m/ha =
31.200
CU . STI
ha
4ft
x
306
cu. m/ba ■
14.7DQ
eu. m
ha
X
cu. m/ha a
cu. m
ha
486
162. 1 00
cu. m  a 0.0333 cu.m/iq. m
—
Unit
lit Trial
2nd Trial
3rd Trial
4th Trial
4
"i
u
Q
5, 95
Val ^,
t 'W‘ Vol
rU
‘  VO|
l/icc x ha
l/iac x hi
l/sec x ha
1/—C
»q, m
cu. m
cu, m/eq. m
cu. m/sq, m
eu. m /«q. m
6. 00
0. 01330
0. 00100
2, SfiO
40/lfi0
5+ 57
4.456
0. 03330
0. 00092
2.916
40/1B0
0. 03430
0. 03422From ata. 0
to iU<
800
Length:800
m
S, °PO^. 60 m/km
Stored volume:
ha
150
X
325 cu m/ha s
48. 750
cu, m
ha
X
cu m/ha x
cu. m
ha
x
cu m/ha «
cu. m
ha
X
cu. m/ha ®
cu, m
ha
ISO
4ft.750
cu. m
= 0.0125 cu.m/.q,,,
Item
Unit
lat Trial
2nd Trial
ird Trial
Uh Tnu
6. 25
*2
u
Q
Type of aeclion
Welted area
Volume
Unit volume
Unit volume
Unit volume
l/aec   x   ha
l/aec   x   ha
l/aec x ha
1/..C
■q. m
cu. m
cu. m/aq. m
cu, m/aq. m
cu. m/aq. m
6. 20
0. 03250
0. 00100
935
40/105
2. 07
1.656
0. 03250
0. 00110
930
40/105
0. 03350
0. 03360
Ftom ata. fl00
to ata. L.600
Length: 800 m
Slope' 1. SO m/km
Stored volume:              ha 150         x       336       cu. m/ha •          50.400              cu. m ha 96          X       325       cu. m/ha »         31.200              cu. m
ha X
ha X
ha ’46
cu. tn/ha •
cu. m/ha =
cu. m
cu. m
81.600
Item
“I
“2
u
Q
Type of section
Welted area
Volume
Unit volume
Unit volume
Unit volume
Unit
l/aec x  ha
l/aec x  ha
l/t«C x ha
l/aec
•q. m
cu. m
cu_ m/aq m
cu. m/aq. m
cu. m/aq. m
let Trial
0. 03320
0. 00050
0. 03370
1.520
40/110
2. 26
i. bob
0. 03320
0. 00074
0. 03394
1.500 40/105
2. 07
1.656
0. 03320
0. 00067Al-ifl
Z. 400
LengthiBOo
cu. m/ha =
IT»
B3, 250          cu. m
Slope:{], 60 m/km
1  600
to at*
h
ha   Z46          *
339
h»
?fi
<
325
cu. m/ha -
31,200
cu. m
ha
X
eu_ m/ha a
cu. m
ij
ha
X
eu. m/ha ■
cu. m
J
ha
Ml
114,450
cm. m
3  O.OJJ5 co, m/sq m
Item
Unit
1st Trial
2nd Trial
Jrd Trial
4th Trial
—
H|
aZ
Q
Type of section
Welted area
V plume
Unit volume
Unit valume
ijali volume
.1
l/iee x ha
l/sac x ha
l/iac x ha
l/aac
eq. m
cu. m
co, tn/aq. m cu. m/sq, ttl
5. 89
5.91
0. 03350
0. 00100
2.010
40/145
3. 73
2.984
0. 03150
0. ODOB7
2. 020
40/145
cu, m/sq. m i
0, 03450
0. 0J4J7
1
Trim    ita.    2,    400    to    ata,    1*2    00
’tarcdl vnluBsai
ha   312         X               344         co, m/ha »          1I7.400          cu. m
ha
96
X
325
«l m/h* =
31, 200
cu- m
ha
X
CU. m/ha -
cu. m
he
X
cu. m/ha -
cu. m
ha
438
148.600
cu. m  3    0.03190 cu, m/sq. fn
Item
Unit
1st Trial
2nd Trial
3rd Trial
4th Trial
1
5. 73
4
J2
Q
Ti
Y
l/aec    x    ha 1/aae « ha
l/lec x ha
1/..C
•q. m
cu. m
cu, m/sq. m
cu, m/sq. m
cu. m/sq. m
5. 81
0. 03390
0. 00100
2,520
40/155
4. 21
J. 36B
0. OJ390
0. 00077
2. 55D
40/155
0, OHM
0. 0)467DRAIN G
From at>. 0              to ata. BOO
Stored volume: ha 144 x
ha                 X
Len|[lh:fi00   m
325 cu. m/ha - 46,200
cu, m/ha =
cu m/ha «
cu. m/ha s
Sl ope: 1. 5q    "’/km
ha
ha
ha 144
X
X
cu. m
cu. m
cu. m
cu. m
46.200              cu. m            = 0.0325 cu. m /■q. m
Item
Unit
let Trial
2nd Trial
3rd Trial
4th Tru
U1
u
Q
Type of lection
Wetted area
V olume
Unit volume
Unit volume
Unit volume
l/tec x ha
l/aec x ha
l/aec x ha
l/aec
aq. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
6. 42
6. 50
0. 03250
0. 00050
925
40/85
1. 42
1. 136
0. 03250
0. 00079
910
40/85
0. 03 300
0. 03329
J
From ala. 800            to ata.        1.600
Length: BOO m
Slope: 0.70 m/km
Stored volume:              ha  144        x       333      cu. m/ha ■        47. 300              cu. m ha   96        x       325      cu. m/ha «         31.200             CU. m
ha
ha
ha 240
x                   cu. m/ha «
X
cu. m/ha «
78. SOO
cu. m
cu. m
co. m =       0. 03270 cu. m
Item
Unit
lit Trial
2nd Trial
«l
u2
u
Q
Type of a octi on
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/aec
aq. m
cu. m
cu. m/aq m
cu. m/aq. m
cu. m/aq m
6. 35
3rd Trial
6. 20
1.480
40/US
0. 03270
0. 00050
1. 520
40/125
2. 84
2.272
0. 03270
0. 00094
0. 03320
0. 03364AI-30
Le ng! It  BOO   m
Slope: Q, 75 m/km
ha 240 
*
336       cu. m/ha =
so, ano
cu. m
M     4B
325       cu. m/ha =
15. 600
ci. m
ha
cu nt/ha =
cu. m
cu. m/hn ■
CUa m
ha ZR8
96. 40D            cu m     - 0,Q JJ5 cu m/aq m
Item
Unit
l*t Tri*i
2nd Trial
3rd Trial
4th Trial
l/aec x ha
l/»«c x ha
l/aec x ha
l/aec
aq. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
6. 05
5. 95
“1
UZ
ii
a
Type of lection
Wetted ar«*
Valuma
Unit volume
ITnll volume
Unit volume
0. 0335 c
0. 00050
1. 740
40/130
3.'36
2.448
0. 01 J5D
0. 00065
1.710
40/130
0. 0J4C0
0. O34J5
1
/r *n ita_
S’-Srtd volume:
♦o ata.
h*
ha
ha
hj
Length:               m
Slope:
m/kni
X                          cu. m/ha =■
X
X
X
cu. m/ha =■
cu. m/ha -
cu. m/ba =
cu. m
cu, m
co. m
cu. m
Unit
lat Trial
2nd Trial
3rd Trial
4th Trial
■«Un
**turn
l/aec x  ha l/a«c x  ha l/a«c x ha
>/■•€
■ q. m
cu. m
cu. m/aq. m
cu, m/aq. m
cu. m/aq. mPFflJN: J!
From «ta. 0
co »ta. 60&
Length: 6 00
m
3lopa;D- 30
Stored volume!
ha gfc
X
525 cu. 
=
31, son
cu. m
hl
X
cu, m/ha 3
cu. m
ha
X
cu. m/ha =
cu_ m
ha
X
cm m/ha =
CU. m
ha 94
JI,ZDO
cu. m
= □.0125(1 cu tn/.q,
Kero
Unit
l*t Trial
2nd Trial
3rd Trial
l
< Mru|
U|
UZ
u
Q
Type or act it on
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/fl ee x ha
l/aec x ha
l/iec Jc ha
l/fiec
«q. m
cu m
co. m/tq. m
ex. in/iq. rr ctL. m/<q m
6. ZZ
6. 2 0
591
40/ IOQ
1, 90
L HO
0, 03250
0. 001 IE
595
40/100
0. 0J25O
D. 00100
0. 03550
O, 03348
.
From eta. 690
io it*. 1,400
Length:
m SOQ
00
Slop*: l»   m/km
Stored volume:
ha 96
x       337
cu- ra/h*
X
32. 400
cu. m
hail 4
X      325
cu.. m/ha
*
37. ODD
cu. m
ha
X
cu_ m/ha
cu. m
ha
X
eu_ ro/ha
■
cu. m
ha 210
4% 400
Tiem
Unit
l Bt Trial
2nd Trial
Ul
“2
U
Q
Type of aectlon
Wetted area
Volume
Unit volume
Urdt volume
Unit volume
)/wc x ha
l/aec k U
l/aec x ha
L/aec
■q. m
co. nr.
cu m/iq, m
cu m/iq. m
ux m/*q. m
6. OO
Jrd Tri*1
6. 1°
o onio
0 0R|00
0, 034ID
1.269
40/105
2 .03
1.450
0, 033)0'
0. .000 79
0 03359
I. J6&
40/105lb - MAIN DRAINSVater Table Control
'    Minimumi Ground /
Level /
Ling th (m)
Bed Slope
(m/km)
Bed
Width
(m)
Bed Elevation
(m)
Drained
Area
(ha)
LMocharfw (l/vec)
Water
Depth
(tn)
Waler Elevation
(m)
Stored Volume (cu.    m/
•9 m)
(l/eec a
hr)
Rainstorm
<>i (l/ttc)
Waler
Depth
(tn)
Water
Elevation
(m)
Drain I
0
940
Z, 140 2, 940
4.  140
5.  340
6.  540
12,  250
13.  950 20, 150 25. B40
25.610 30, 190
34.610
7)7. 10
737. 60
7)9. 35
738. 79
1,200 800
1,200 1. ZOO 1. 200 5,710
I, ?00
6,400
3.490
1.790
4. 760 4. 210
0.60
0. 50
0.20
0. 25
0. 35
0. 42
0. 40
0.27
0. 37
0. 50
0. 50
0.45 0.4b
2. 0
2.0
5.0
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
5. 0
736. 54
737. 04
735. 94
7)5. 14
7)5. 14
734. 98
736. 59
715. 99
7)5. 79
735. 61
738. 74
738. 14
738. 09
737. 93
734. 8)
7 3 5. 4 8
737. 83
737. 68
714.41
735. 06
737. 26
713.91
734. 56
714. 46
732. 1 8
716. 76
733. 71
7)1.43
730. 0)
729. 87
736. 71
734. 43
7 ) 1. 68
730. 72
734. 23
7J3. 27
729. 37
727. 00
726. 85
724. 60
730. 22
727. 85
727. 70
725. 45
7)2. 52
7)0. 1 5
7)0, 10
727. 85
724.35
723. 45
723. 30
720. 40
I, 808
2. 670
3.252
3.576
4. 116
4. 710
5, 725
6. Ill
6. 697
8. 394
9. 690
10. 388
11.100
541
800
975
1. 140
I. 270
1.415
1. 717
I. 833
2. 009
2. 518
2. 907
1. 116
3. 130
0. 50
0. 65
0. 65
0. 65
0. 65
0. 65
0. 75
0. 85
0 65
0. 85
0. 90
0. 95
I. 00
72 5. 2 5
728. 15
724. 25
721.35
721.40
719. 50
0. 0356
0. 0362
0. 0364
0. 0)70
0. 0372
0. 0)74
0. 0195
0. 0400
0. 0422
0. 0422
0. 0421
0. 0412
0. 0442
5.46
5. 35
5. 30
5 10
5. 05
5. 01
4. 47
4. 30
1.93
3.9 3
3. 94
3. 70
3.55
9.900 14. 300
17,200 18.200
20. BOO 2 3. 600 2 5. 600
26.300
26. 300
32. 900
18. 200
18.500
19. 500
2.25
2. 80
2. 95
2. 85
2. 85
2. 85
3. 00
J.40
3.15
3.25
3.50
3. 60
3. 60
718. 50
726. 90
72 6. 90
724. 00
722.10
6. 36 6. 25 6 20 6. 00 5.95 5. 91 5. 37 5. 20
4. 0 3
4. 03
4. 84
4. 60 4. 45
11.500 16.700
20, I 00
21.500
24. 500
27. 900
JO, 740
3 1.7 B0
32. 350
40, 540
4 6. 900
4 7. 780 4 9. 400
2.40
3. 00 3. 20 3. 15
3. 10
3. 10
3.30
3.70
3.45 3.6q 3.  BS
4.  00 4. 00
739. 50 7 38. 94 7)0. 34
7 38. 1 a 738. 1 3 737    98 737 9) 7)7. 51 717. 01
734 73 734.  5  | 7JJ,    57
732.    82
7)0.  4  5
728, 20
72 7. 30
724. 40
722. 50
Al-HF rom
Sta.
to St*
Minimum Ground
Laval
Wittr Tabla Control
Raknatorm
Length
(m)
Bad
Slope (m/km)
Bad
Width
(m)
Drained Araa (ha)
(bacharge
(!/•.<)
Water
Depth
(m)
Water Elevation
(m)
Stored Volume (CM, m/
•9 "»>
“1
(l/eec m
hr)
Ql
(!/••*)
Water
Depth
(m)
Watar
Elevation
(m)
«1  ♦ u
2
Rainalorm 4 Irrigation Water
Q
Depth
(*n)
Waler
Elevation (m)
Drain I
0
731.45
731. 85
733. 25
733. 35
5, 520
0. 60
1. 502
450
740
880
0. 40
0. 0368
5. 15
7. 750
1.80
6. 05
9. I QU
5. 520
1. 90
728. 14
728.   54
W.      94
7 30. 04
J, 600
0. 60
5. 0
726.   80
2. 466
0. 40
727.   20
0. 0373
5. 00
12.400
1. 85
7. 120
728. 75
725.   >4
2.  05
728. 95
0. 30
5. 0
72 5. 08
726. Z4
727. 69
4. 100
2.935
727.   89
n. 300
0. SO
725.   58
0. 0395
4. 50
I 3, 100
2.35
72 7.43
5.90
5.40
14.550
15,800
723.   83
2.  55
727. 63
3, 2 JO
5. 0
723.   78
724. 33
726. 18
726. 38
14,500
3. 823
I. 145
0. 55
0. 04 06
2.  30
726. 08
5. 15
19. 700
722.   34
2. 60
3, 780
5. 0
I B, 280
72).   94
722. 89
724. 64
724. 94
5. 189
I. 550
0. 65
722. 59
0. 04 09
16.200
21.800
720.24
724. 69
5. 10
6. 210
0.45
0.45
0.20
5. 0
720. 89
719.   34
24. 490
0. 0429
4.25
4.20
3.80
24. 500
2.75
3.50
722. 99
6,430
1,930
0.90
TIB. 10
720. 24
722. 84
4. 70
26,400
30.200
3.00
72 3. 24
3,  90
719. 00
721, 60
722. 00
Drain 3
0 2,400
2.0
724.43
723. 76
722. 86
722.59
155
0. 30
6. 30
118
0. 55
724.73
724. 06
723.41
723. 14
0. 0360
5. 40
2.780
1.  50
2.0
0.0365
5. 22
5.560
2.  35
725. 93
725.26
725.21
724. 94
6. 12
3,260
6. 500
727.28
727. SB
125
0. 30
0. 0357
5.50
2. 270
6. 40—
Water Table Control
Rainstorm
Bed
Drained
Slope (roAm)
Width
(m)
Bed
Elevation
(m)
Area
•I
(h<)
Die  charge
Waler
Waler
Water
(1/eec)
Depth
(m)
Elevation
(m)
Stored Volume
(co. m/
(l/t€C X
■q m)
Depth
(m)
2,400
726.   OB
726. 38
727. 48
725. 63
725. 93
727. 13
1,400
0. 50
2. 00
700
210
0. 30
0. 0355
5. 52
3. 870
1.50
3. BOO
724. 93
725.23
726.43
4 0
1.600 4. 160
1. 600
2. 560
0. SO
0. 10
1. 00 2.00
721. 55
727.   75 727. 05 726.79
364
700
109
210
0. 30
0. SO
728.85
72B. 05
727. 55
727. 29
0. 0351
5. 70
0. 0376
4. 95
2. 080
3.460
1. 35
2. 10
6 60
5. 85
2, 400
4. 100
1. 40
2. 25
729. 95
729. 15
729- 30
729. CM
5«-lVt-
DRA1N: I
From eta. 0
to ata.      940
Length: 940 m
Slope:0, 60
"’/km
Stored volume:              ha       460    X         351         cu.m/ha =           161.200            cu. m
ha   1, 220     X         357        cu. m/ha *          434,400            cu. m
ha         46    X          325        cu. m/ha -            15. 600           cu. m
ha         80    X          306        cu. m/ha =           24. 400            cu. m
ha  1.808
635, 600            cu. m             =0.0352 cu, m
/•A- m
Item
Unit
1st Trial
2nd Trial
3rd Trial
4th T
r
ul
u2
u
Q
Type o( section
Wetted area
Volume
Unit volume
Umt volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/iee
•q. m
cu. m
cu. m/aq. m
cu. m/eq. m
cu. m/eq. m
5. 50
5. 46
0. 03520
0. 00050
9.980
200/225
12. 09
11. 300
0. 03520
0. 00063
9.900
200/225
0. 03570
0. 03583
From ata. 940 Io ate. 2, 140
Length:! ,200 m
Slope:0. 50 m/km
Stored volume:              ha    1.808    X          358        cu. m/ha «         646. 900             cu. m
ha      766    X          351        cu. m/ha »         268,700            cu. m
ha         96    X          306        cu. m/ha =           29, 400           cu. m
ha
X
cu. m/ha =
ha 2.670       -
Item
Unit
lot Trial
U1
u2
u
Q
Type of • ection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/eec x  ha l/aec x  ha l/aec x ha
I/..C
■q. m
cu. m
cu. m/eq. m
cu, m/eq. m
cu m/eq. m
cu. m
945, 000 cu. m =
2nd Trial
5. 42
0. 0354 cu. m/aq-
0. 0354
0. 0005
14.  500
200/280
17. 35
20. 800
0. 03540
0. 00078
0. 03618
14. 300
200/280669(0 *0
I OHO *0
9910 *0
*^toA
sez/oos
00Z '81
60000 *0
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SB7/005
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From iU. 4, 140        to ata       5, 340 Stored volume:              ha      J, 576 «
LengthJ^OO m
370 cu. m/ha = 1, 32 0, 200 cu, m
S,Ope: o. 35 m/km
ha
444 x
437 cu. m/ha -
152,000 cu.m
ha
96 x
306 cu. m/ha » 
29, 400 cu. m
ha
X
cu. m/ha =
cu. m
ha  4. 116
1,501, 600 cu. m
’0.03640 cu. m/aq. m
Item
Unit
1st Trial
2nd Tria)
3rd Trial
TrMl
U1
u2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/aec
•q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
5. 11
5. 05
0. 03640
0. 00050
21.200
500/285
26. 43
31.600
0. 03640
0. 00077
20. 800
500/285
0. 03690
0. 03717
From ata.5. 340
to ata.
6.540
Lengths 00 m
Slope: 0. 42 m/km
Stored volume:
ha 4.
116
X
372
cu. m/ha =
1.533,200
cu. m
ha
336
X
343
cu. m/ha « 
115. 000
cu.  m
ha
120
X
330
cu. m/ha -
39. 600
cu. m
ha
138
X
306
cu. m/ha « 
42, 200
cu. m
ha 4, 710 
1.710,000 cu. m= 0. 03670 cu. m/aq. H*
Item
Unit
lit Trial
2nd Trial
3rd Trial
4thT'<. 5. 01
“1
u2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/aec
aq. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
5. 05
5. 00
23, 500/”’
0. 03670
0. 00050
23,900
500/290
27. 11
32. 500
0. 03670
0. 00069
23. 550
500/285
26. 43
31,600
0. 03670
0. 00067
0. 03720
0. 03739
0. 0373?Al-39
1
>2-
250
Length:5,7] 0 m
Slope: 0. 40 m/km
6,5*°
fr* ”4
h*
7,0
X
374
cu. m/ha =
1.761,600
cu, m
„d*olu,nc                    h» 
I**
X
339
cu. m/ha ■
54.900
cu. m
h« 
681
X
325
cu. m/ha =
221.000
cu. m
h. 
1 72
X
306
cu. m/ha «
52. 600
cu. m
h>
 S.725
2. 090. 100
cu.ro >0.0366 cu. m/eq. m
Item
“1
“2
u
0
Type of lection
Vetted area
Volume
tfait volume
Unit volume
Unit volume
Unit
let Trial
2nd Trial
3rd Trial
4th Trial
l/eec x ha
l/eec x ha
l/eec x ha
l/aec
aq. m
cu. m
cu. m/eq. m
cu. m/eq. m
cu. m/eq. m
5. 10
4.45
4. 47
0. 0 3660
0. 00050
29,200
500/320
31. 36
178,500
0. 03660
0. 00308
25,500
500/300
28. 50
163,000
0. 03660
0. 00286
25,600
500/300
0. 03710
0. 03968
0. 03946
r, ^«U.]2l250
•^«d »oluTne.
lo
•ta. 13, 950
Length. 1.700 m
SI ope : 0. 27 m/km
ha 5, 725       X        395         cu. m/ha »           2. 253. 100      CU. m
ha 218           X        335         cu. m/ha x
73, 000    cu. m
h * 168            X        335         cu. m/ha =                 56. 200  CU_ m
ha
ha
X                        cu. m/ba «
cu. m
2. 382. 300 cu, m = 0. 0391 cu. m/aq. m
Unit
let Trial
2nd Trial
3rd Trial
4th Trial
*1
’*2
u
Q
4. 35
i
-ni»
I’ .
l/eec x ha
l/eec x ha
l/eec x ha
l/eec
■ q. m
cu. m
cu.   m/eq,   m
cu- m/eq. m
cu. m/eq. m
4. 30
_ 0. 03910
0. 00100
26.600
500/330
34, 34
58,300
0. 03910
0. 00095
26. 300
500/340
0. 04010
0. 04 005[RAIN:
From ata, 1 3,950     to eta. 20, 350
Stored volume:              ha 6,111       X
ha       296    X
ha 112          X
Length: 6,400m
400 cu. m/ha ■ 2,440, 600 cu. m
Slope: 0.
37 ">/km
ha
ha 6, 697
X
335 cu. m/ha »
325 cu. m/ha x
cu. m/ha =
99, 000     cu. m
36. 500     cu. m
58,800     cu. m
2,634,900 cu.m = Q03930 cu. m/.q.
Item
Unit
lit Trial
2nd Trial
3rd Trial
«l
u2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/eac x ha
l/aec x ha
l/aec x ha
l/aec
•q. m
cu, m
cu. m/aq. m
cu. m/aq. m
cu. m/aq, m
4. 22
3. 95
4th Trui
3.91
0. 039 10
0. 001 00
28, 300
500/325
32. 09
206. 000
0. 03930
0. 00306
26, 400
500/315
30. 63
196. 000
0. 03930
0. 00293
26, lot
500/Jh
0. 04030
0. 042.3 6
0. 04223
From ata. 20, 350 to ata. 23,840
Length:3k490 m
Slope: 0.50 m/km
Stared volume:              ha   6, 697    X          422        cu. m/ha =            2,830. 900     cu. m
ha 1.615 X 361 cu. m/ha =
ha 82 X 325 cu. m/ha «
ha
X
cu. m/ha =
582. 000     cu. m
26. 600     cu, m
cu. m
3,439,5 00 cu. m «               0.0409 cu. m/»9-m
Item
Unit
let Trial
2nd Trial
4. 00
3rd Trial
3. 9 3
4th *** J-
u2
u
Q
Type of aection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/aec
■ q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
33. 576
500/330
32. 84
1 14. 400
0. 04090
0. 00136
0. 04226
32.  900
500/ 325
321 09
1 14. 000
o.  04090
o. 001 33
0. 0422 3
32.^
500/^
0. 0409
0. 0010
0. 0419Al-41
630                      Length:l.79O m
X 422 cu. m/ha > 3, 55 3. 500 cu. m
Slope: 0. 50 m/km
ha B> 594
rt 4.o>uB,e:                  ha        !♦<     X        335         cu. m/ha « ha 1. 152        X        365         cu. m/ha *
M
ha 9.690
X                       cu. m/ha ■
48. 000   cu. m
420,000   cu. m
cu. m
4,021. 500    cu. m         ■ 0. 0414 cu. m/aq. m
Item
Unit
lat Trial
2nd Trial
3rd Trial
4th Trial
3.90
3. 95
■I
4
u
a
Type o( aection
Ya tied area
Volume
Umt volume
Unit volume
’Jail volume
l/aec x ha
l/aec x ha
l/tac x ha
l/aec
aq. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
3. 94
0. 04140
0. 00100
3 7, 000
500/345
35. ro
62.800
0. 04140
0. 00065
38,300
500/35 0
35. 88
69, 500
0. 04140
0. 00072
38.200
500/350
0. 04240
0. 04205
0. 04212
^iUZS.630        to ala.    30,390
Uw «d volume. ha 9 , 690 x 421
ha      546     X        350
ha        152    X        325
Len(th^760 m
cu. m/ha k 4.091.0C0 cu. m
SI ope -0.45 m/km
ha
X
cu. m/ha ■
cu. m/ha «
cu. m/ha =
191. 000    cu. ra
50. 000    cu. m
cu. m
1, 332.000 cu.m* 0.0417 cu. m/aq. m
Unit
let Trial
2nd Trial
3rd Trial
4th Trial
4
*2
a
Q
** °f '•cU
w On
3. 84
3. 70
% >01
n lQ^e
%
r.
l/aec x ha
l/aec x ha
1/oec x ha
l/aec
•q. m
cu. m
cu. m/aq. m
CU. m/aq. m
cu. m/aq. m
3. 70
0. 0417.
0. 0010
39.900
500/365
38.23
182 . 500
0. 04170
0. 00176
38.500
500/360
37. 44
178,000
0. C4170
0. 00172
38.500
500/360
—
0. 0427
0. 04346
0. 04342DRAIN: 1
From «U. W. J’O to *t»-             3‘*’ 610
Length4^^0 m
0.45 m/km
Stored volume:              ha 10*          *       434        cu. m/ha «            4, 510. 000     cu. m
h. 712x
ha 
ha 
ha 11,100
350       cu. m/ha =               2 50. 000    cu. m
x
x
cu m/ha =
cu. m/ha ■
cu. m
cu. m
4. 760. 000    cu. m
<0. 04 30 cu.m/,,. m
Item
Unit
1st Trial
2nd Trial
3rd Trial
*‘bTrJ
ul
“2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
U nit volume
l/aec x ha
l/aec x ha
l/sec x ha
l/aec
aq. m
cu. m
cu. m/aq. m
cu. m/iq. m
cu. m/aq. m
3. 53
3. 55
0. 04JQ0
0. 00150
39, 000
500/360
37. 44
158. 000
0. 04 300
0. 00142
39. 500
500/3 60
0. 04450
0. 04442
From ata.
to ata.
Length:
m
Slope:
m/km
Stored volume:
ha
X
cu. m/ha  K
cu. m
ha
X
cu. m/ha  Z
cu. m
ha
X
cu. m/ha  S
cu. m
ha
X
cu. m/ha  ■
cu. m
ha
Item
Unit
lat Trial
2nd Trial
U |
u2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/aec x ha
l/sec
■ q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
s.Al-41
lU . 5.520 
Length5^20m
Slope: 0. 60 m/km
h>
600    x         350         cu. m/ha =         210, 000         cu. m
jw**
ha 455 x 325 cu, m/ha ■ 148.000 cu. m
ha 447 X 306 cu. m/ha = 137, 000 cu. m
ha X
ha 1 1. 502
cu. m/ha «
cu. m
495. 000 cu. m =0. 0330 cu. m/«q. m
Item
•1
•l
a
Q
Type of eectlon
Vetted area
Volume
Unit volume
Unit volume
Unit volume
Unit
l/aec x ha
l/aec x ha
l/aec x ha
l/eec
■ q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
lat Trial
2nd Trial
3rd Trial
4th Trial
5. 70
5. 10
5. 15
8.550
300/190
11. 10
61. 000
0. 0330
0. 00400
7, 600
300/180
10. 26
56. 500
0. 0330
0. 00376
7, 750
300/180
0. 0330
0. 0020
0. 0350
0. 03708
0. 03676
® «U. 5, 520 to eta. 7,120 
Length: 1.600n>
Slope: 0. 60 m/km
volume:           ha 1   .502    X        368         cu. m/ha =         551, 500         cu. m ha        700    X        370         cu. m/ha »          259,000          cu. m
ha
168    X        337         cu. m/ha ■            56,500          cu. m
ha          96    X        325         cu. m/ha »            31,200          cu. m
to 2.466
898,200 cu. m =                0. 0364 cu. m/eq. m
lat Trial
2nd Trial
3rd Trial
4th Trial
u2 
l/aac x ha
1/aec x  ha
1/«ec x ha
l/aec
•q. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
4.75
5. 00
5. 00
0. 0364
0. 0020
11,700
500/180
13. 86
22. 100
0. 0364
0. 0009
12,400
500/185
14. 38
23.000
0. 03640
0. 00093
12. 400
500/165
0. 0384
0. 0373
0. 03733>RA1N: 2
From eta. ", 120 to eta 11, 300 Length:4l 80 m
S lop«:0.30 m/km
Stored volume:
ha 2, 466    X          373      cu. m/ha a ha       100    X          330      cu. m/ha - ha       144    X         325      cu. m/ha « ha       225    X          340      cu. m/ha « 
h* 2.935
921,000         cu. m
33, 000       cu. m
46, 800        cu. m
76, 500        cu. m
1,077,300     cu. m
- 0. 0367 CU. m/.q, m
Hem
Unit
let Trial
2nd Trial
3rd Trial
Ttm
“1
u2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/eec x ha
l/eec x ha
l/,«c
■q. m
cu. m
cu. m/eq. m
cu. m/eq. m
cu. m/eq. m
4. 68
4. 50
13, 700
500/235
20. 03
83, 600
0. 03670
0. 00284
13, 100
500/235
0. 0 367
0. 0020
0. 0387
0. 03954
From eta. 1I, 300 to au. 14, 600
L«ngth3.300 m
Slope :0. 45 m/km
Stored volume:
ha 2,  935    X         395         cu. m/ha  s          1. 160, 900      cu. m
ha         700     x         380         cu. m/ha  a              266,000      cu. m
ha             96    X         325         cu. m/ha  ■                31,200      cu. m
ha            92    X         306         cu. m/ha  =
28,100      cu. m
1, 486,200 cu. m= 0. 0389
Item
Unit
let Trial
2nd Trial
U1
u2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/eec x ha
l/eec x ha
l/eec x ha
l/eec
•q. m
cu. m
cu. m/eq m
cu. m/eq. m
cu. m/eq. m
4. 20
4.25
16, 200
500/23°
0, 03890
0. 00200v
16. 000
500/230
19. 44
64, 000
0. 03890
0. 00168
0. 04090
0. 04058Al-45
Length:3780 m
U.*00
W .U. 18’38°
Slop*.* 0.45 m/km
p*'**
ha 3.823         X        406         cu. m/ha »           1. 550,000    cu. m
ha I-004                X        358         cu. m/ha «
360. 000   cu. m
h. I30
X        332         cu. m/ha =               43a 100    cu. m
ha  232 X 325 cu. m/ha 3
ha 5, 189
75.400    cu. m
2, 028, 500 cu. m 30. 0391 co. m/iq. m
Item
-—"
tt 2
8
Q
Type of taction
Wetted area
Volume
Vadt volume
Unit volume
Unit volume
Unit
lit Trial
2nd Trial
3rd Trial
4th Trial
l/eec x ha
l/eec x ha
l/aec x ha
l/lec
eq. m
cu. m
cu. m/eq. m
cu. m/aq. m
cu. m/aq. m
4. 25
4. 20
0. 0391
0. 0015
22.000
500/275
25. 09
95. 000
0. 03910
0. 0OIB3
21.800
500/275
0. 0406
0. 04093
fOm    ,la-IB.   380   to   eta.   24,590
SI ope : 0. 20 m/km
klT”ivoLUme.
5.  189    X       409         cu. m/ha -           2,123. 500  CU. m
412     X
348
cu. m/ha  S
143. 000
cu. m
373     X
325
cu. m/ha  S
121,000
cu. m
456     X
306
cu. m/ha 9
140. 000
cu. m
Unit
let Trial
2nd Trial
3rd Trial
4th Trial
l/eac x ha
l/eec x ha
l/eec x ha
l/aec
eq. m
cu. m
cu- m/eq. m
cu. m/aq, m
cu. rn/eq. m
4. 10
3.75
3. 80
26.400
500/365
38.23
238. 000
0. 03940
0. 00370
24,200
500/350
35. 88
223. 000
0. 03940
0. 00347
24. 500
500/350
V91 '«h.
0. 03940
0. 00200
0. 04140
0. 04310
0. 04287X
from «ta. 0
Stored volume:
to gta. Z, 400
ha 280         X      341
Lengthy,400m
cu. m/ha = 95, 500 cu. m
Sl °P’:0.28 m/ktn
ha 108  x 325 cu. m/ha ■ 35,100 cu. m
hi 128  x 306 cu. m/ha * 39, 200 cu. m
ha  x
ha 516
cu. m/ha =
cu. m
169. 800 cu. m
’0. 0330 cu.m/
l(J n,
Hem
Unit
1st Trial
2nd Trial
3rd Trial
6. 20
5. 33
u2
u
Q
Type of a ection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec x ha
l/eec x ha
l/aec
eq. m
cu m
cu. m/aq. m
cu. m/sq. m
cu, m/aq. m
*» T,i,;
5. 40
0. 0330
0. 0010
3. 140
200/160
7. 04
16, 900
0. 03300
0. 00328
2, 750
200/150
6. 37
15, 300
0. 03300
0. 00296
2,7«0
200/150
0. 0340
0. 03628
0. 03596
From eta.2,400        to eta.    4. 200
Lengthy 300 m
SI ope: 0.15 m/km
Stored volume:             ha      516    X         360      cu.m/ha= 185,100
cu. m
ha     344    X        337      cu, m/ha «        116, 000            cu. m
ha        56    X        325       cu. m/ha =          18. 200            cu. m
ha      144    X        306      cu. m/ba a          44, 000            cu. m
ha 1 , 060
363, 300 cu. m ■ 0. 0343 cu. m/®4- m
Item
Unit
let Trial
2nd Trial
3rd Trial
4ih
“1
u2
u
Q
Type of lection
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/«ec x ha
l/aec x ha
l/aec x ha
l/aec
•q. m
cu, m
cu. m/aq. m
cu. m/eq. m
cu. m/aq. m
5. 30
0. 0343
0. 0020
5,620
200/235
12.98
23. 400
0. 034 30
0. 00221
5,560
200/2*5
o. 0363
0. 03651Al.47
A              to.U. 2«400
f^,u-         '
ha 223            ’
LengthrZ 400m
340 cu, m/ha = 76.000 cu. m
Slope: 0. 50 m/km
j rol»»me:
S'jr*®
ha 192  *
ha  *
ha  x
ha *15
325 cu. m/ha «
cu. m/ha «
cu. m/ha =
62, 000         cu, m
cu. m
cu. m
138, 000         cu.m = 0. 0332 cu. m/aq m
learn
Unit
lit Trial
2nd Trial
3rd Trial
4lh Trial
“1
“2
it
Q
Type of faction
Vetted area
Volume
Unit volume
Unit volume
Unit volume
l/aac x ha
l/aac x ha
i/aac x ha
5. 65
5.50
l/fl«C
aq. m
cu. m
cu. m/aq. m
cu. m/eq. m
cu. m/aq. m
0. 03320
0. 00200
2. 350
100/140
4. 34
10. 800
0. 03320
0. 00250
2.270
100/140
0. 03520
0. 03570
' r7TT1 iu. 2 40q    ‘O »t». J. 800
Length:!,400m
Slope
**•< volum,.
415        X        357         cu. m/ha =         148,800          cu m
h« 192
ha 9 J
X 325
X 306
cu. m/ha »
cu. m/ha t
62,000
28, 400
cu. m
cu. m
ha
X
cu. m/ha ■
cu. m
ha 700
239,200
cu. m = 0. 0342
cu. m/eq. m
Unit
lai Trial
2nd Trial
3rd Trial
4th Trial
5. 50
5.52
w
 * tion
c
UMt
1/tec x  ha 1/eec x  ha l/aac x ha
l/aac
eq. m
cu. m
cu. m/aq. m
cu. m/aq. m
cu. m/aq. m
0. 0342
0. 0015
3,840
200/150
6. 38
8.900
0. 03420
0. 00128
3.870
200/150
0. 0357
0. 03548DRAIN' 5
From |U. 0
to eta.. 1
.600                     Lengthd ,600 m
Sl  OP-0.50 w/kw
Stored volume:             ha  300        X          342        cu. m/ha s          102, 500           cu. m ha    64        X          325        cu m/ha =            20, 800           cu. m
hi
hi
ha 364
X
X
cu. m/ha «
cu. m/ha «
cu. m
cu. m
123. 300           cu. m
’ 0.0338 cu. m/,, m
item
Unit
let Trial
2nd Trial
3rd Trial
<'* Thu
U1
u2
u
Q
Type ol section
Wetted area
Volume
Unit volume
Unit volcme
Unit volume
l/aec x ha
l/l.C B h*
l/aec x ha
1/mc
•q. m
cu m
cu m/eq m cu. m/eq. ra
cu ro/eq m
5. 60
5. 70
0. 0338
CL 0015
2,050
100/135
4. 08
6.500
0. 0333
0. 0018
2. 080
J 00/135
0. 0353
0. 035!
Fromita. l,6C0tosta. 4,160
Len<tlu2560tn
Slope. 0. I 0 mAm
Stored volume:
ha 364
X         351
cu m/ha ■
129.100
cu. m
ha 144
X         325
cu- m/ha ■
46.700
cu m
ba 192
X         306
CU- m/ha •
51. 7 CO
cu m
ha
X
cu m /ha ■
cu. m
ha 760
215.200
Item
Unit
1st Trial
«1
°2
u
Q
Type of section
Wetted area
Volume
Unit volume
Unit volume
Unit volume
l/aec x ha
l/aec * ha
l/eec x ha
l/eec
•q m
ci m
cu. m/eq. en cu m/eq. m co. m/»q m
0. 0336
G. 0020
0. 0)56
5.040
200/220
II. 66
29. too
0. 0)560
0. 00425
0. 0)?>5
5.43° 200/210
10.
27,600 0, 0JJ60
20^'*APPENDIX 2
FLOOD PROTECTION WORKS CALCULATIONSAZ-1
Tables from A2/l to A2/32 Diagrams from I to 32
AWASH RIVER
DISCHARGE-WATER ELEVATION
Mahning's formula has been used for the calculations, adopting a rough ness coefficient of 20 for the low water bed and 5 for the high water bed; the hydraulic gradient adopted is 20 cm/km.
The symbols are as follows:
h =       water elevation (m a. s. 1. ) A =      wetted area (aq. m)
C =      wetted perimeter (m) R =      hydraulic radius (m) V =       water velocity (m/sec)
Q =      discharge (cu. m/sec)SKQTlQF.r No. J
1.
Low Waler Bed
High Waler Bed
A
(•«. “)
C
(-)
A
(»)
V
(m/eec)
Q|
(cu. m/eec)
A
(•4- «•)
C
(m)
V
(m/aec)
Qz
(cm, m/eee)
Q»
Ql ♦Qi
(cm. m/nc|
—
744. 62
744. 00
741. 00
750. 00
752. 00
754. 00
M
114
221
337
493
34
44
42
42
62
1. 00
2. 42
3. 96
5.44
7. JO
0. 20
0.5J
0. 46
0. 19
1. co
10
59
144
294
490
-
1.442
4. 396
7. 310
1. 0
3. 0
9. 0
0. 07
0. IS
0.21
•
101
697
1.535
0
10
59
247
953
2. 025
•
« 1
?“?vh
(m)
Low Water Dad
Higa H*t«r oea
A
(■4 m)
c
(m)
R
(m>
V
(m/aec)
Qi
(cu. m/aec)
A
(•4 m)
c
(m)
R
(m)
V (m/aec)
(cu. Qmz/aec)
□-
Ql ♦ Q2
(cu. m/aac)
741. 48
744. 00
746. 00
748. 00
750. 00
752. 00
754. 00
1
104
176
252
328
404
29
J8
43
43
4)
43
1. 45
2. 74
4. 10
5.85
7. 64
9.40
0. 36
0.56
0. 72
0. 92
I. ii
1. 30
15
58
127
2 32
364
525
1.462
4. 386
7. 310
1. 00
3. 00
5. 00
0. 07
0, 15
0.21
102 657
1.535
0
15
50
127 334
1. 021 2.  060SECTION: No. J
Low Water Bed
High Water Bed
h
(m)
A
(•4- >
ro
C
(-)
R
(m)
V
(m/aec)
Qi
(cm. m aar)
A
(•q
C
(m)
R
(m)
V
(m/nc)
Q?
(cu. m/aec)
Q•
Qi ♦ Qz
(cu. m/i«c)
739. 4B
744. 00
746. 00
7 41. 00
750. 00
752.00
102
114
274
364
454
43
50
52
52
52
2. 37
J, 68
5. 27
7. 00
0. 73
0.51
0. 61
0, 87
1. 03
1. 20
52
125
231
376
545
-
-
727
1. 615
6,545
0. 5
2.5
4. 5
0. 02
o. 13
0. 19
14
474
0
52
125
252
850
1.240
1, 705SECTION: No 4
Low Water Bad
h
(m)
A
(aq,
c
(m)
(m)
V
(m/aac)
Q| (cu, m/aac)
A
(aq m)
1 MJ. 10
141. OQ
744. 00
746. 00
748. 00
750. 00
80
176
291
411
531
42
56
62
62
62
1. 90
3. 14
4. 70
6. 63
8. 55
0. 44
0. 61
0. 80
I. 00
1.20
35
107
233
4H
638
720
3,600
6.480
L
L
L
____________SECTtON: No 5
Low Water Bed
High Water Bed
/
h
(m)
A
(•q. m)
C
(m)
*
(m)
V
(m/eec)
Qi
(cu. m/e«c)
A
(•4 m)
c
(tn)
R
(tn)
V
(m/eec)
Qz
(cu. tn/eec)
Q«
Ql ♦ Qz
(cu. m/tec)
7 59. 05
742. 00
744. 00
746. 00
746. 00
750. 00
69
160
246
140
452
59
45
51
51
51
1. 77
3. 96
4.06
6. 67
0. 50
0. 42
0. 67
0. 4 3
I. 01
1. 20
29
107
206
744
520
•
2. 200
5, 120
6. 048
1. 50
3. 50
5. 50
0. 09
0. 16
0. 22
•
198
817
1. 770
29
107
404
1. 161
2. 290SECTION No $
Low Water Bed
b
(m)
A
(■!• m)
C
(»)
R
(m)
V
(m/awc)
Q|
(cu. m/a«c)
A
(aq m)
c
(m)
High Water Bed R
(m)
V
Qi
(cv m/aac)
Q| ♦ Qfc
(cu. m/nc)
7 JI. 41
742. 00
744. 00
746. 00
748. 00
136
223
319
415
44
52
54
54
3. 09
4. 29
5. 92
7. 68
0. 60
0. 75
0. 93
1. 12
Bl
167
297
465
Bl
726
3.630
6.534
0. 50
2. 50
4. 50
0. 02
0. 13
0. 19
L
L
____________
»
t‘7VSECTION: No. 7
Low Vater Bad
High Water Bed
h
(m)
A
(•q. rn)
c
(«)
R
(m)
V
(m/aec)
Qi
(cu. m/aec)
A
<«q rn>
C
(m)
R
(m)
V
(m/oec)
Qz
(cu. m/aec)
Q«
Ql ♦ Qz
(cu. m/aec)
734. 72
7)8. 00
740. 00
74Z. 00
744. 00
746.  00
747.  00
60
149
zss
175
501
564
41
M
63
70
70
70
1. 19
2. 62
4. 05
5. 16
7. 16
8. 05
0. 16
0. 56
0. 72
0. 67
1. 06
1. is
21
83
184
126
510 647
•
714 1.591 5. 0)2
0. SO
Z. 50
>. 60
0. 02
O. 13
0. 16
•
14
467
605
21
83
184
140
997
1.452
*?£F.AV! -• 
' •      " 1
- r'~r^-
2. ?V a|H»lSECTION N’© 8StQUQU; No. 9
r~
Low Water Bad
High Water Bed
1 (■»)
A
(•4. «n)
C
(m)
JI
(m)
V
(m/aac)
Qi
(cv m/aec)
A
(•9 m)
C
(m)
R
(m)
V
(m/aac)
Qz
(cu. m/aac)
Q»
Ql fQZ
(cu. m/aac)
7M. 59
731. 00
740. 00
742. 00
744. 00
746. 00
45
176
271
375
479
39
47
55
55
55
2.44
J. 74
4. 93
6.42
i. 70
0. 44
0. 64
0. 52
1. 02
1.20
46
120
222
342
575
-
724
J. 620
6.516
0. 5q
2. 50
4. 50
0. 02
0. 1J
0. 19
-
14
470
1.240
0
46
120
2J6
052
1.415
H
rrSECTION: No | 0
Low Waler Bed
h
(m)
A
f»q. m)
c
(m)
A
(n»)
V
(m/eec)
Ql
(cu. m/o«c)
A
(•q m)
7 J 5. 54
739. 00
740. 00
742. 00
744. 00
162
262
370
492
50
57
61
61
1. 24
4. 60
6. 06
7. 99
0. 62
0. 76
0. 95
I. 12
100
204
351
540
4.289
8,576
>
L
LSECTION Na. 11
Tl/?Y'i
(»»•/« -na)
*O ♦ <O
•O
(saa/UJ »v>)
ZO                       A
(ui)
nan > ai • m If fl 1USECTION: No. 1 J
Low Water Bed
h
(m)
High Water Bed
A
(■4 m)
C
(ns)
R
(m)
V
(m/aec)
Q|
(eu. m/«ec)
R
(m)
V
(m/aac)
Qz
(cu. m/aec)
Q•
Q(
(cu. m/i«c)
728. 05
734. 00
736. 00
7 38. 00
740. 00
74*. 00
744. OO
15b
Z63
3B6
520
654
788
52
61
70
70
70
70
). 04
4. H
5. 5Z
7. 42
4. 34
11. 30
0. 6o
o. 75
o. aa
i. oa
l. 26
1. 44
95
197
340
561
823
1. 135
-
1. 50
X 50
5.50
0. 09
0. 16
0. 22
-
125
520
1. 140...... ----- .—
Qi
|cu, m/«cc)
A
(•, m)
R
(m)
V
(m/a«c)
□z
(cm m/aac)
Q-
□ i *Qz
(cu. m/aac)
flo 162
280
450
660
890
-
-
-
1,492
2.984
4,476
2. 0
4. 0
6. 0
0. 11
0. IB
0.23
164
530
1,010
0
80
162
280
614
1. 198
I, 920SKIM No a
Low Water Bod
h
(m)
A
m)
c
(m)
R
(m)
V
(m/nc)
□l
(cu. m/aac)
A
(•9 m)
High Wat«r Bad
R
(m)
V
(m/eac)
Qz
(cu. m/aac)
Ql *Qi
(cu. m/«ac)
At
(•q. m)
729. 50
714. 00
736. 00
7 36. 00
740. 00
742. 00
744. 00
746. 00
122
218
530
442
554
666
778
46
56
61
61
61
61
61
2.65
J. 90
5. 42
7. 24
9. 08
10. 95
0. 55
0. 70
0.88
1. 06
1. 25
1.40
67
153
290
468
694
935
600
1.400
2. ZOO
1. 50
1. 50
5. 50
7. 50
0. 09
0. 16
o. 22
54 224 484
o
67
155 290 522 918
122 218 JJO 990
1. 612 2. 554
L
si/tv ®tqiiSECTION No 16
Low Water Dad
h
(m)
A
(■<• m)
c 
(m)
R
(m)
V
(m/nc)
Ql
(eti. m/aac)
A
(aq m)
c
(m)
High Water Rad R
(m)
V
(m/aac) (cu. m/aac)
Q-
Ql ♦ Qa
(cu. m/ioc)
728. 66
732. 00
734. 00
736. 00
734. 00
740. 00
741. 00
76
162
264
378
496
414
80
90
97
102
102
102
0. 95
1. 80
2. 72
3.71
4.87
6. 02
0. 27
0. 42
0.55
0. 68
0.82
0.95
20
68
145
257
407
583
380
760
2. 0
4. 0
L
’I
i
iSSECTION: No. 17
b
(tn)
A
(■q m)
C
(m)
Low Water Bed
R
(m)
V (m/eec)
Qi (co. m/aec)
A
(■q m)
C
(tn)
High Water Bed
R
(m)
V
(m/eec)
Qz
(cu. m/eec)
Q•
Ql *02
(co. m/eec)
726. 76
7 34. 00
158
44
7U. 00                    244                     5)
7)6. U0
740. 00
742. 00
>6)                     58
471
574
58
58
J. *9 4. 70
h. 26 8. I)
10. 00
0. 67 0. 60 0.97
I. 16 1. 32
106
198 352 546
165
346 I. 0)8 1.7)0
1. 00
J. 00
5. 00
0. 07
o. 15
0. 21
24
156
36 3
0
106 198 176 702
I. 128SECTION; No. ]b
Low Waler B®d
High Watar Bad
h
(m)
A
(•9- in)
c
(m)
R
(m)
V
(m/nc)
Ol
(cu. m/eec)
A
(•q m)
R
(m>
V
(m/aec)
Oz
(cu, m/eee)
Q=
Q| ♦ Qz
(cu. m/iac)
721. 59
732. 00
TH 00
736. 00
7 SB. 00
740. 00
TO. 00
104
190
219
401
513
625
43
50
57
60
60
60
2. 42
3. BO
5. 07
6. 70
•.55
10. 35
0. 91
0. 70
0. B5
1. 02
1.20
I. 35
53
133
246
409
615
B44
-
-
-
122
610
1, 09B
0. 5 0
2.50
4.50
0. 02
0. 13
0. 19
2
79
209
10
53
133
246
411
694
1. 053
1______
L
1
t
_________________
TnSECTION: Nc 19
Low Water Bed
A
(iq. m)
C
M
V
(tn/aec)
Q|
(cu. m/fec)
A
(■q ni)
C
(m)
High Water Bed
R
(m)
V
(m/aec)
Qz
(cu. m/aac)
Q« Ql 6Ql
(cu. m/aec)
721. 52
132. 00
734.00
7 36. 00
731. 00
740. 00
105
31
iei                     44
270
320
424
50
53
S3
2. 76
4. 11
5. 40 6. 04 6. 00
0. 56
0. 73
0. B7
0. 45
1. 14
54
132
235
304
4BJ
641 I. 944 3, 240
I. 00
3. 00
5. 00
0. 07
0. 15
0. 21
45 241 6M0
0
59
1 32 4du 595
I. 16JSECTION, No ZU
Low Water B»d
High Water Bad
h
(n»)
A
(•q. n»)
c
(tn)
A
(m|
V
(m/aac)
□l
(cu, m/aac)
A
(aq m)
C
(m)
R
(tn)
V
(m/aac)
%
(cu, m/aee)
Q•
Q| ♦ Qz
(cu. m/aee)
727. 52
732. 00
7)4. 00
736. 00
7)3. 00
7)9. 00
207
201
373
465
511
30
46
54
54
54
5. 45
6. 10
6. 90
0. 60
9. 47
0. 00
0. 95
1. 0)
1. 21
1.28
102
267
JO 4
562
655
-
-
-
2, 108
). 462
2. 0
J. 0
0. II
0. 15
254
520
0
162
267
304
816
1. 175
___________
L
____________
__
_________________SSG71ON; No. 21
High Wjior Bed
Q•
C
(m)
R
(m)
V
Qa
Ql *Q2
(cu. tn/tac)
(cu. m/aec)
0. 5
0. U£
2. 5
0. I 1
9
HO
542
0
74
148
256
702
1» 5
U. 16
I. 007SECTtffl; No zt
Low Waler Bed
h
A
(■9- m)
C
(m)
R
(m)
V
(m/eec)
Qi
(cu. m/eec)
c
Im)
High Waler Bed
(m)
726. 64
ni. oo
733. 00
735. 00
737. 00
740. 00
96
169
258
351
458
34
45
55
55
55
2. az
J. 76
4. 70
6. 52
5. 32
0. 56
0. 69
0. 8 0
I. 00
1. 17
5.
117
206
358
535
L. 0
4. 0
L
L
A ^’23SECTIOS: So 2J
Low Water Bed
(«)
A
(M-m
C
(»>
V
(m/eec)
Qi
(eu. m/aec)
A
(M "»)
C
(m)
High Water Bed R
(n»)
V
(m/eec)
Qz
(cu.ro/oec)
Q•
Ql +QZ
(cu. m/aec)
726. 50
7 32. 00
7 34. 00
7 56. 00
I 736. 00
1   7 39. 00
no                      57
186
276
m
420
46
53
65
53
2. 97 4. 04 5. II
7. 02 7. 95
0. 58 0. 72 0. 16
I. 04 I. 12
64
134
258
187 470
226 I. I >0 1.582
0. 5
2. 5
J. 5
0. 02
0. 11
o. 16
4 147 255
0
64
134 242
5 14 72 3
►?-?vA
(•q- rn)
C
(m)
R
(m)
V
(m/eec)
□l
(cm. m/aec)
A
(•q m)
C
(m)
High Water Bed
R
Im)
V
(m/iac)
Qz
(cm. m/eec)
Q•
Qi ♦ Qz
(cm. m/aec)
730. 00
7 32. 00
7 54. 00
736. 00
84
208
330
468
606
44
61
71
74
74
1. 91
3.41
4.65
6. 32
8. 20
0. 45
0. 64
0. 80
0. 97
I. 16
38
133
264
455
704
365
1,725
6.5
Z. 5
0. 02
0. 13
0
38
133 264 462 928
L
ASECTION: Na. 25
/
Low Waler Bed
R
High Water Bed
h
(m)
AC
v                        Qi
(tq. m)                   (m)                    (m)                    (m/aoc)            (cu. m/eac)
A
{•4. m)
c
(m)
R
(m)
V
(m/iec)
Qz
(cu. m/iec)
Q-
Ql ♦ Qz
(cu. m/iec)
726. 63
730. 00
732. 00
7 34. 00
735. 00
117
ZI6
330
390
47
56
62
62
I. 49
3. 66
5. 32
6. 30
0. 52
0. 71
0. 17
0. 47
61
15)
267
>78
-
2,910
4, B50
1. 50
2. SO
0. 09
0. 13
•
262
630
0
61
15)
549
1. 008
VSECTION: No. Zb
Low Water Bad
h
(m)
A
(eq.»)
c
(n>)
R
(m)
V
(m/aec)
Ql
(eii, m/aec)
A
(aq. m)
725. 46
730. 00
7 32. 00
734. 00
736. 00
123
207
306
412
42
51
60
60
2.93
4. 06
5. 10
6.88
0.58
0. 72
0.85
I. 02
71
149
260
420
1.347
4. 141
I
LstQTLQF; ir•>SECTION: No. 29
Low Water Bed
High Water Bed
h
(m)
A
(•<1. m)
C
(m)
R
(m)
V
(m/eec)
Qi
(eu m/eec)
A
(•9
C
(ml
R
(m|
V
(m/aec)
Qi
(eu. m/'eecl
Q«
Qi ♦ a2
(cu. m/aee)
723. 62
726. 00
726.00
730.00
732. 00
734. 00
42
120
213
320
4 34
35
45
56
65
65
1. 20
2. 67
3. 88
4. 93
6. 68
0. 32
C. 55
0. 70
0. 82
1. 01
13
66
149
262
448
943
2.429
I. 00
3. 00
0. 07
0. 15
66
424
0
13
66
149
328
472
3c
(m)
R
(m)
V
(m/aac)
Qi
(cu. m/aac)
A
(•9 m)
C
(m)
R
(m)
V
(rn/aec)
Qz
(cu. m/aac)
Q| ♦ Qj
(cu. m/aac)
30
48
58
58
50
I. io 3. 30 4. 40 6.23 7. 13
0. 47
0. 63
0. 76
0.97
1. 06
38
100
194
350
4 38
284
2. 180
3. 120
0. 30
2. 30
3. 30
0. 01
0. 12
0. 15
3
262
467
0
38
100
197
612
905
*
L
Lvj        pt
/Z
frcnpffr no. ji
IMV^WU K*tvDIAGRAM 1
SECTION 1
1 T A I r O S' 5IJ I 1lb
i.
■ii
iv
.v
! -.
'<
*-1.>.000 cu
DIAGRAM 2
SECTION 2
| ITAI CONSUL!'rDIAGRAM 4
SECTION 4
. I I'Al cOHSUt I !SECTION 5
tnirosH i r1I
ZiOUGffAM 5
section 6OtAGMH 7
SECTION 7
11t rIDIAGRAM 8
SECTION 8I1.S0O
1A00
DIAGRAM 9
SECTION 9
WATER LEVEt10OO
i loo
I.qm w.m/wt
DIAGRAM 10
SECTION 10
WATER LEVEL
_________ _
I ITALCOVlt t.T 1IDIAGRAM 11IDISCHARGEIDIAGRAM 13
SECTION 13
< ■' £•DIAGRAM 14
SECTION U
WATER level
I r UCO«I! | TI
n.
I(DIAGRAM 10
SECTION 18
WATER LEVEL
' i r a|_co%'SUL r 1It a4 & UH A M O t
500
750
1.0.00  CM
DIAGRAM 19
SECTION 19
no
WATER lEVEl7>tjQ
. m / fc* C-DIAGRAM 21
SECTION 21Ts
zJiK*
OOP_______________  0
IA 00cu.m/i«e.
DIAGRAM 22
SECTION 221 OOO<
• sDi a f H A R D ErDIAGRAM 25
SECTION 25
WATEN Lt¥«
______
*
1I
|1DIAGRAM 26
SECTION 26
WATER LEVEL■I
I
I
zcharge.
QQ!J
7*0__________________________________________ r ------------------------------ L
II
ciagrah 21
SECTION 27T5OA/
X<
ISECTION 32Tables from AZ/33 to A2/45
BACKWATER CURVES AND STORED VOLUMES UPSTREAM OF THE MELKA WARAR DIVERSION WEIR
The symbols are as follows:
h
Q 0.  2  =
water level (m a. s. 1. )
discharge for hydraulic gradient 0. 20 m/km
i _
Al
Actual hydraulic gradient distance between the sections (m)
Ah
=
i x Al
^8 
=
A
Am
L
V
average ground elevation of high high water bed width (m)
water bed (m a. 9.1.)
s
wetted area of the high water bed (sq.m) average wetted area of the high v.a.er b
length of the stretch (km) stored volume (10^ cu.m)backwater curve and stored volume upstream of mrlka warar O *       100 ru, m/i*c
/
BjcJcwjttr Curve
*
(m/km)
Sloped Volume
,
| Seedon
h
(m)
Ja
1i•02
(cm. m/fecj
AL
(km)
Ah
(m)
N
[m)
h - ht
(m)
L(
(mJ
A
(•q. m)
Am
m)
1
LV
1
(km) 1 (10 GU. m)
—
16
|5
14
U
12
11
10
9
a
7
t.
5
4
1
z
1
76
439
700
J90
1
7Jft,S6
738.87
718. 89
730. 91
738. 93
739. 00
739. 85
739. 94
740, JB
740. 67
741. 54
743.ZO
744, IB
744.72
745.76
747.54
330
370
420
450
185
135
190
1IO
120
1 10
60
70
130
70
50
35
o. oi a
Q. 015
0. OU
0. 010
0.059
0. 105
□ . 055
0.165          1 0+139
o. its
0. 555
0. 404
0. 119
0.555
o. too
b. bJO
0 62
I. Ofl
2. o&
2.53
b. 14
5. 95
5. 20
2, (ifa
2. 11
5. 24
2 + 99
2.90
z. at
2,55
2.21
o. □]
0, 02
0. 02
0. 02
0. 07
Q. 65
0. 29
Cl. 44
0.2 9
0. &7
1. 56
1. 10
0 34
1. 04
1.79
739. 00
738, 50
738.00
731 50
739. 30
73 9. 50
740,00
741.50
742. 30
742.50
74 3. 50
744. 50
745,50
746. 50
0 86
0.37
0. 99
0. 41
250
450
800
1.000
I, 000
1, 500
2, 200
I .500
1. 500
l. sou
I. 500
1.500
1, 500
I, 500
215
167
710
410
0
191
439
556
205
0. 40
1, 00
1.40
I. 9o
1.20
1. 90
2.20
2. 10
1. 70
I. JO
1. to
1
. .      1, 10
J. 10
1
*
J
I. 605
V »N»Section
l________
h
(«)
Q
1 = 0.2
(cu. m/eec)
Backwater Curve
i (m/km)
oiorea volume
AL
(km)
16               739. 35             375
0. 62
1.08
2.08
2.53
1.14
5.95
5.20 2. 66
2.11
5.28
2. 99
2. 90 2.86
Ah (m) 0.04
0. 05
0.06
0. 06
0. 17
1.65
0.20 0. 48 0. 33 1. 10 0. 94 0.71 0.74
1.68
h•I
(rr<
V
1
(10 cu. m)
739. 39
739. 44
739. 50
739. 56
739. 73
430
510
560
230
170
741.38              450
741.58
742.06
210
225
hi (m)
738.00 738. 50 738.00 738.50 739. 30 739. 50
740. 00
741.50
742.50
742.50
743.50
744.50
745.50
746. 50
A
(•q. m)
Am
(eq. m)
L
(km)
1. 35 0. 89
1. 44 1. 00 0. 26 0. 23
38 08
250
450
800
1,000 *
1.000
1.500
2,200
1.500
1.500
1.500
1.500
1.500
1, 500
1.500
>
■
338
400
1,150
1.000
260
345
3,040
120
0
369
775
1.075
630
302
1,692
1,580
60
148
775
1,500
1,200 >
362
3,040
3.480
126
c
Kz
J
0. 40
1.00
1.40
1.90
1.20
1.80
2.20
2.10
1.70
1.30
1.60
1. 10
1. 10
1
J.
—,otJ< 1backWATM CVAVE awp STORED VOLUME UPSTREAM or MULKA WAKAK
{j •        250 Cia_ m/fec
1                     Bjckwatar Curve
5lor«4 Volume
.
1 Section
—1
M              (cu. m/j«c)
(m/km)
(k   A na L)
Ah
(m)
hr
(mJ
h - hj
(m)
it
A
(■q. m)
Am
{•q. m)
L
(km)
V
(10 J cu, m) |
16
15
14
13
U
11
10
9
8
»
6
5
4
3
Z
1
739.58
739.63
739. 69
739.78
739, 86
740.09
742.15
742.23
742,68
743.04
744. 1 9
744.96
743.7k
746. 44
748. 06
749. 41
400
470
550
630
250
190
92 0
270
Z7D
240
220
220
220
140
140
180
0. OH
0. 06
0.04
0.03
0. 20
0. 35
0.02
0. 17
o.n
0.22
0.26
0.26
0.26
0. 64
0. 64
0.39
0. 62
1.08
2. 08
2.53
1. 14
5.95
5. 20
2.66
2. II
5,28
2. 99
2. 90
2.86
2. 55
2.23
0.05
0.06
0.09
0. 08
0.23
2. 06
0. OB
0. 45
0. 36
1. 15
0. 77
0. 75
0, 73
1.62
L 42
738. 00
738.50
7JB.00
731,50
739. 30
739. 50
740. 00
741.30
742.50
742,50
743.50
744.50
743. 50
746. 50
1.58
1,13
1.69
1.28
0.56
0.59
2* 15
0,73
0. 18
0.54
0.69
0.46
0.21
■
250
450
800
1. 000
1.000
L 500
2. 200
1.300
1.500
I.50Q
I. 500
1.500
1. 500
1.500
390
5 10
1.350
1.280
560
880
4. 700
i* too
240
810
1,040
690
315
450                  0.40 930                  LOO
1.315 1. 40 920 L 90 720 1.20
2, 790
2. 900
1. 80
2.40
670                  2. 10
525
9Z5
1. 70
1.30
865                  1. 60 502                   1. 10
I. 10
180
930
1.830
1.750
865
5. QUO
6. 380
1.410             1
8 90
1*400
L 380
152
1
J1
23, *6> F
—1 FBACKWATER CURVE AND STORED VOLUME UPSTREAM OF MELKA WARAR
Q= 300 cu. m/sec
Stored Volume
Section
739.80
739. 86
739.94
740.04
740. 13
740. 39
742.60
742.61
743.07
743.42
744.67
745.33
746. 07
7 46. 50
14B.67
747 m
Backwater Curve
(m/km)
0.102
0.072
0.005
0.037
0.230
0.372
0. 001
0. 176
0.165
0.238
0.221
0.255
0.255
0.705
0.546
0. "S4O
>-ht
(m)
4
(mJ
A
(•q. m)
Am
<«q. rn)
L
(km)
0. 06
0. 08
2.08                    0. 10
2.53 0.09
1.14
0.26
5. 95                   2.21
5.20                    0.01
0.46
0. 35
1.25
0. 66
0. 74
0.73
1.79
1.24
738.00
738. 50
738.00
738. 50
739. 30
739. 50
740. 00
741.50
742. 50
742.50
743.50
744. 50
745.50
746.50
1.80
1.36
1.94
1.54
0.83
0.89
2.60
1. 11
0.57
0. 92
1.17
0. 83
0.57
0. 30
250
450
800
1.000
I. 000
1.500
2,200
1.500
1.500
1,500
1.500
1,500
1.500
1.500
450
610
1.550
1,540
830
1.335
5.720
1.665
855
1. 380
1.755
1,245
855
450
530
1,080
1.545
1.185
1.082
3,527
3, 692
1.760
1. 117
1.567
1.500
1. 050
65 7
0.40
I. 00
1.40
1.90
1.20
1.80
2.20
2.10
1.70
1.30
1.60
1.10
1.10
1,080
2. 160
2.250
1. 300
6. 350
8. 100
3.700
1. 900
2.040 2. 400 I. 155OACKWATiR GUJl V" JET AND JTOJtED VOLlfMZ UPSTR
B*ckwir*r Curv«
,'
0
{cu. m/ftc)         1 fm/kmj
' i * o. £
" dL
(km)
dh
(m)
(«)
h - h|
(m)
A
A
(•q. m)
Am
(r. m)
L
(km)
1       740. IS
740. 24
740. 35
740. 4 9
740. 61
740. 93
742.68
742,79
741, 45          1 743. 5 7
744.SL
745. 93
1     146, 65
747. 36
749, 40
750. 54
465
560           1 690
41 0
340
330
1, 250
360
400
320
260
J4O
360
200
Z»fi
360
0.15
0. 10
C. 07
0. 05
0-2*
0. 29
0-02
0. 25
0. 20
0. Ji
n. 47
0 . 25
0.25
0-80
0.51
0.25
0. 62
i. os
2- os
2.53
1.14
5. 95
5.20
2. 66
2. 11
S.2S
4. 99
Z. 90
1, «*
2. 55
1-23
0. 09
0. 1 1
0. 14
0. 12
0. 32
1.75
0. 1 1
g. 66
0. 42
I. t4
1= 42
|       EL 72
o. Ti
2. 04
1. 14
7J3. 00
731.50
73S, 00
75», 50
719, 30
739. 50
7 4 0. 00
741.50
742.50
742.50
743. SO
744.50
745. 5 0
746.50
2. 15
1. 74
2 k 35
1. 99
1.31
1.43
2. 68
1.29
0, 95
1. 37
i. 01
I. 43
1. 15
0.A6
250
450
BOO
1. O DO
1. Q0O
1, 500
2.200
1. 5 00
1 . 5OQ
1.5ao
1. 500
4. 500
1.500
1. 500
537
703
1. BSD
1. 990
lr 110
2. 140
5. 900
1.930
1.4ZO
2. 050
I. 510
2. 1 40
1.720
1. 290
66Q
1. 331
L 935
1. 650
1 1. 725
4. 020
3. 913
1. 625
1. TJ5
1. 7B0
1.H25
I. 930
4-503
0. 40
1. 00
1.40
I. 90
1.20
1. 40
2.20
2+40
U 70
1- 30
1.60
I. 10
1. 10
I. Ml 2, 710 J, 140 2. 0 70 7. 250 S. 4 DO
3f 410
2. 950 2. 410 2. 92c 2. 1JQ I. *55
______________
J
].
IHrBACKWATER CURVE AND STORED VOLUME UPSTREAM OF MELKA WARAR Q x 500 cu. m/aec
Tabl.Vtl *n?
OT6 T
or-l T
090 ’£
o»r *5
0 9? V
OHR >
096 '•
074 *B
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1
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(Ul,,
(U1 b.)                   (uj -bi)                        IU4)
A
uiv
•ttiTHCA p*Joig
j«a/<u*n>            009      - D hvhvm vy-!3rt JO H w tflihin ~Ftn-IESA <T3 moj n-Hrv ta u71O WUWDpw
V             L ’
(M
N-q
(“1
(»)
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(unf/cu;
7V
pw/iB nj
?0•J
• AJA') J IMlJp VQBACKWATER CURVE AND STORED VOLUME UPSTREAM OF MELKA WARAR Q 3      700 cu. m/iec
Backwater Curve
Stored Volume
rrr
i • 0.Q 21
lm) r
u. m/aec)
1
(m/km)
AL
(km)
Ah
(m)
ht
(m)
h-ht
(m)
A
(•q. rn)
741.10 590
741.27 770
741.45
741.65
1,000
1.200
741.82 670 742.07 800
742. 98                 1.450
743. 22                      470
744.40                      750
744.77                      470
747. 10         1 1.280
747.28                      770
747. 76                     770
1 748.23                         280
I
| 751.40 1 730 1 751.81 1 850
0.28
0.17
0. 10
0.07
0.22
0.15
0. 05
0.44
0.17
0.44
0.06
0.17
0.17
1   1.24
| 0. 18
I 0. 14
0.62
1.08
2.08
2.53
1. 14
5.95
5.20
2.66
2. 11
5.28
2.99
2. 90
2. 8b
2.55
2.23
0. 17
0. IB
0.20
0. 17
0.25
0. 91
0.24
I. 18
0.37
2.33
0. 18
0.46
0.47
3. 17
0.41
738. 00
738.50
738.00
738. 50
739. 30
739. 50
740.00
741.50
742.50
742.50
743.50
744.50
745.50
746.50
3. 10
2.77
3.45
3.15
2.52
2.57
2.98
1.72
1.90
2.27
3. 60
2.78
2.26
1.73
250
450
800
1.000
1,000
1.500
2.200
1,500
1.500
1.500
1.500
1.500
1.500
1.500
770
1,250
2. 760
3.150
2. 520
3. 850
6.550
2.580
2,850
3. 400
5, 400
4, 160
3, 380
2.600
1,010 2, 005 2. 955 2. 835
3, 185
5,200
4.565
2. 715
3, 125
4,400
4, 780
3. 770 2. 990
2,005
4, 130
5.380
3.820
9, 350 2.20                  10.050
2.10
1.70
1. 30
1.60
5. 700
5. 320
5.710
7, 650
4. 150
3,290flACKR'xTErt CUR VC AND STCIRJCD VOLUW5 U
Stored Volumt
A
I tq- m)
250
450
eoo
1,000
1.000
1.500
050
1.  3 96
J, 030
3,  490
2.  870
4,  350
2.      200
I,      5CQ
7. 120
J. Q0Q
I.      SOO
2.   910
I,   500
3,     6J0
J,  5O0
•». U50backwater curve and stored
Q =      900 cu
“   UPSTREAM   OF   MELKA   WARAR i/«ec
Backwater Curve
Section
h
(ra)
Q
1 = 0. 2
cu. m/eec)
i
(m/km)
AL
(km)
Ah
(m)
ht
(m)
L
(km)
V
(103 cu. m)
<j
"1
16
15
14
13
12
11
10
9
8
7
6
5
4
1
•
*
Am
(•q. m)
741.70
741.91
742.13
742. 34
742.52
742. 75
743. 50
743.76
744. 56
745. 06
747.59
747.81
748.23
748.68
752.04
\       752.
J
680
900
1.250
1,520
910
1. 130
1,760
730
820
580
1,480
1,050
1.010
350
1        1. OSO 1. wo
-1
0.35
0.20
0. 10
0. 07
0.20
0. 13
0. 05
0.30
0. 24
0.48
0. 07
0. 15
0. 16
1. 32
0.15
0. 62
1.08
2. 08
2.53
1.14
5. 95
5.20
2.66
2.11
5.28
2. 99
2. 90
2.86
2.55
2.23
0.21
0. 22
0.21
0. 18
0.23
0.75
0.26
0. 80
0.50
2.53
0.22
0. 42
0.45
3. 36
0. 34
738.00
738.50
738. 00
738.50
739. 30
739.50
740. 00
741.50
742. 50
742.50
743. 50
744. 50
745.50
746.50
h - ht
(m)
3. 70
3.41
4. 13
3.64
3.22
3.25
3.50
2.26
2. 06
2.56
4.0$
3.31
2.73
2. 18
250
450
800
1.000
1,000
1,500
2.200
1,500
1.500
1.500
1.500
1.500
1.500
1.500
Stored Volume
A
(■q. m)
920
1.530
3. 300
3.840
3.220
4. 870
7. 700
3. 390
3,090
3. 840
6. 120
4. 960 J
4. 090
3.260 I
1,225
2. 415
3.570
3.530 4. 045 6. 285
5.5 95
3.240
3. 465
4. 980
5,540 4. 525
3. 675
0. 40
1.00
1.40
I. 90
1.20 1.80
2.20 2.10 1.70
1. JO 1.60 I. 10
I. 10
490 2.415
5. 000
6. 700
4. 850
11, 300
12,300
6. 800
5,  900
6. 4 70
8, 700
4. 970
1 0. 12
1
-Tn
----------------
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cjfTwoxf <wcv
wxxvjM^avffBACKWATER CURVE AND STORED VOLUME UPSTREAM OF MELKA WARAR Q =      1,050 cu. m/eec
Section
Backwater Curve
(m/km)
Stored Volume
Ah
(m)
ht
(m)
h • h(
(m)
L.
(m)
A
(■q. m)
Am
(»q. m)
L
(km)
V
(IOJ cu.
742.10
742.35
742.59
742.82
743. 00
743.21
743. 95
744.22
744.87
745.38
747.50
747. 80
748.38
1.000
1.420
1,740
1. 100
1. 330
2,050
5.95
5.20
I, 480
1,050
1. 170
748.84 1 380 1 I. 38
751.37 1 1.140 1 0. 17
752.75         '         1,370         I 0. 12
0.25
0. 24
0.23
0. 18
0.21
0.74
0.27
0. 65
0.51
2.12
0.30
0. 58
0.46
3.53
0. 38
738. 00
738.50
738.00
73B.50
739. 30
739. 50
740.00
741.50
742.50
742.50
743.50
744.50
745.50
746. 50
4. 10
3.85
4.59
4. 32
4.00
3.71
3. 95
2.72
2.37
2. 88
4. 00
3.30
2. 88
2. 34
250
450
800
1.000
1.000
1,500
2.200
1,500
1,500
1,500
1,500
1,500
1,500
1,500
1, 025
1,735
3, 680
4, 320
4,000
5. 560
8. 700
4. 080
3,560
4. 320
6.000
4. 950
4. 320
3, 510
1,330
2,707
4, 000
4. 160
4. 780
7, 130
6. 390
3.820
3. 940
5. 160
5. 475
4, 635
3. 915
0. 40
1.00
1.40
1.90
1.20
1.80
2.20
2. 10
1. 70
1. 30
1.60
1.10
1. 10
530
2,707
5. 600
7, 900
5. 740
12.800
14, 050
8. 020
6, 700
6. 700
8. 750
5. 100
4, 300
1
11
1
r
BH,BACK HA TJETH CUM VE AfJD 5TOHCD VOLUMi UPSTREAM OF MELKA WAR All
Q • hJ 00 £U. m/lBC
Stared Volume
j = 0. 2
J
' AL I1 Ah
(km)                     <raj
h|
|m)
h - ht
(m)
(mJ
A
(aq. m)
Am
{■El m)
T|
(km)                     (1 © i cu. ml |
712.20
742.47
742. 72
74Z. 95
745.14
743.35
144. 0B
744.35
744. 95
745.44
747.La
7<7. 41
741, 50
741. 04
0.41
0.23
1
1
I, 030
I. 470
E 790
I . 400
2. ISO
I . 03Q
J r 550
I. I6D
1. 130
751*>L                  b. 2 20
0. 62
i. oa
2, OH
2*53
1. 14
5. 94
5. 2C
2. 66
2. 1 1
• *2b
2. 99
2. 7M
2. 44
2.55
2.13
0.Z7
0.25
a. 2 J
a. 19
a*zi
o. 73
a. 27
o. 60
a. 53
2. 2Q
0. 30
0,52
0. 3 4
3. 32
<3. 54
751. 00
738.50
731.00
7)8.50
739. 30
739. 50
74 0. 00
741.50
742.50
742.SO
743* 50
744. 50
745*50
7<6. »O
1.20
3. 97
1. 72
4. 45
3. 84
3. 85
4. 08
z. as
2. 45
z. va
4. IB
3. 4 8
3. 00
£. 54
250
450
H00
i. ooo
l, 000
I, 500
2. 200
I. 400
I. SOU
I, 500
1. 300
I* 500
I, 800
1.500
I. 050
1.790
3. 780
4.450
3, B40
5. 770
a. 76o
4, 2BO
3. 670
4. 470
- 6. 260
5. 240
4, 400
J. »l U 1
I. 420
2. 785
4.615
4, 145
4. 805
7* 365
6. 620
I. 975
4. D7O
5, J6*
5. 740
4. 860
4, 155
0.40
1.00
1.40
1.90
1.20
I* BO
2.20
2. 10
1. 7U
1. JO
i. 60
I. 10 J
i, 30 f
|
568
2, 785
6. 460
7. &5 0
5. 770
1 3. 250
14.550
li, 340
6. 900
6. 97V
I
I
9. J TO f
3. 350               r
/
4 4TG
r
/
744.72
k. 150
L
__J 
Xi.ou 1 I
[-
1Table, from Al/« “ 42/51
CURVES »O^SIM:AMOFTHE
BACKLeU WA^P^RSfON WEIR
symbols are as folio*91 distance between
iVie 3ectior‘s
0
water elevation (m
— for
actual hydraulic g^  ’
e
a<ial to
die
L x i (m)* J Hi
DAGKVirATK<< CURVE DOWNSTFEAMQF
M   X(jl r f
y
,^
Q t 10G etir
L
(m)
f
o
(m}
0,
(ca. m/i*d
-fl fl*
4» * i *
2GQ
345
120
>no
150
190
130
240
210
125
170
160
340
220
220
160
1.05
0. 55
Lt?
J. 05
1.1)
LG*
Lit
r» 1
■ ‘S-^i
** ! fWta]
;
0.2CJ
1 wr 0.W a. aj o.)H
fl. 221 0. 24> 4. i J) ]. J12
AlU 0. 275.
0. J12 4 3al
i. tn
■
1, 440
4.250
2, HO
i. 21 n
2, 010
2, 520
2. Old
It 0?Q
L S4Q
I + 070
tip
i> 3jq
I, zgo
!> 220
l < 070
*40
728.JO 728, 99 729. 17 710.56
7JI.27 731,99 732. 55
7 3 3. 05 733. 4?
73J. 80 734.35 714.52
735.25 j
735.34
735. 54
735. 72
735.30
W
1
1
{
'■’’5
til
>
*■  T
2U
E.^
Ck
I      .■ % » vui > 1
■; >
I >
*
o. w 0.
I.W L!S 1.25 0. 51 2.4'+ C.9I
Ml
■»
!1
f iF
4
■
f
Ct?
i-Ti
I
■
t 23
4IH
i :♦»
.u
1
a. ;*
__ J
iA 2-5(J
BACKWATER CURVE DOWNSTREAM OF MELKA WARAR Q «      400 cu. m/aec
Section
L
(m)
ho
(m)
Qo
(cu. m/aec)
1
 ■
(m/km)
Lxi
M
--------- ------------ 1
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
3. 440 6. 250 2, 140 3. 210 2, 010 2. 520 2, 01 0 2. 990 1,84 0 1.070
610 2. 330 1.290 1.220 1,070
340
729. 80 730. 49 730. 99 732. 47
733. 12
733. 48
733. 98
734.50 734.66 735. 25 736.20
736. 37
737. 17
737. 31
737. 49
737. 75
737. 84
400 635 215 395 425 400 350 775 315 190 340
3 05 540 460 360 345
1. 00
0. 63
1. 86
1. 0! 0. 94
1 . 00
1. 14
0. 52
1.27
2. 10
1.18
1. 31
•
0. 74 0. 87 1. U 1. 18
0. 2 00
0. 079
0. 690
0. 202
0. 177
0. 200
0. 262
0. 053
0. 322
0. 885
0. 276
0. 34 3
0. 109
0. 151
0. 246
0. 276
0.69
0. 50
1. 48
0. 65
0. 36
0. 5C
0. 52
0. 16
0. 59
0. 95
0. 17
0. 80
0. 14
0. 18
0. 26
0. C9
1
1Table A2/48
BACKWATER CURVE DOWNSTREAM OF MELKA WARAR
Q=
600  u, m/»ec
c
Section
L
(m)
h©
(m)
Qo
(cu, m/fec)
-3_
Qo
*■°
A!
4= L x 1
(tn)
(m/km)
32
31
30
29
23
27
26
25
24
23
22
21
zo
19
IS
IT
3,44 0
6. ZSO
Z, 140
3.210            1
2, 010
2, 520
2. DIG
2, 990
1,040
1,070
610
2, no
l 29O
t
1,220
1, 07 0
340
730. 50
7J1. 19
731. 84
733. 10
733. 94
734.25
734. 71
735. 11
735.30
736.21
737. 35
757.45
73B. 01
738. IS
736. 37
730.72
|       736.82
600
830
350
525
605
630
600
1.0ft 0
-
jao
260
650
540
015
625
470
49<]
1. 00
0, 72
1. 71
1.14
0. AR
0. «
1. oo
0. 56
I. M
2. 30
0. *32
1. IO
0. 73
0.96
1. 27
1.22
0. ZOO
0. 104
0. 590
0.261
D. 15J
0. 1 HO
0. 200
0. 064
(i. 500
1. 060
0. 170
0. 242
0. 108
0, 164
0. 325
0. 300
0.69
0. 65
1. 26
0. B4
0. 31
0.46
0.40
C. 19
0. 91
I. 14
0. 10
0. 56
0. 14
D. 22
0. .35
O. 10
1 1642.5^
BACKWATER CURVE DOWNSTREAM OF MELKA WARAR Q « : 800 cu. m/i«c
Section
L
(m)
h
o
(m)
(cu. m/iec)
1
■
( m/km)
L*i
fm)
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
3,440
6. 250
2. 140
3. 210
2, 010
2, 520
2. 010
2, 990
1, 840
1. 070
610
2, 330
1,290
1,220
1,070
340
731. 20
731.89
732. 66
733.44
734.54
734.90
735.37
735. 74
735. 95
737. 02
738. 08
738. 19
738. 70
738. 84
739. 08
739. 51
800
1.020
590
610
850
830
830
1. 350
470
360
860
760
1. 100
810
565
650
1. 00
0. 78
1. 36
1. 31
0. 94
0. 96
0. 96
0. 59
1. 70
2. 22
0. 93
1. 05
0. 73
1. 01
1.41
1.23
0. 200
0. 123
0. 367
0. 344
0. 177
0. 186
0. 186
0. 070
0. 580
0. 980
0. 172
0. 220
0. 106
0. 200
0.400
0. 300
0. $9
0. 77
0. 78
1. 10
0. 36
0.47
0.37
0.21
1.07
1.06
0. 11
0.51
0. 14
0. 24
0.43
0. io
1
739. 61A2-51
Table A 2/50
BACKWATER CURVE DOWNSTREAM OF MELKA WARAR Q -       900 cu. m/iec
Section            >
L
(m)
(mJ
%
(cu. m/«ecj
°0
1         ’     °*<o/ ( m/kmj
A = L ii
(ml
32
31
30
29
za
27
Zb
25
24
23
22
21
20
19
ia
17
3,440
$, 15 D
2, 140
3,210
2. 010
1,520
2,010
2,990
1, B40
1.070
610
2, 330
1,290
1,220
1,07 0
340
731. 60
732.29
733. 07
73 3. 78
7J4. 59
7J5. 00
735.54
7 35. 95
75$. 18
738. 32
738. B0
738. RS
739. 28
759.40
7 19. 52
740. 04
740, 14
900
1.140
700
800
885
865
890
1.460
510
600
1. 090
975
1. 34Q
950
640
710.
1.00
0. 79
1.20-
1. 12
1.02
k 04
1. 01
0.6Z
1 76
k50
0. &3
0. 92
a. fi?
0.95
1,40
k. 26
0.200
0. 1Z5
0. 330
0. 252
0.206
0. 216
0. 204
0. 076
0. 620
0. 450
0. 136
0. 170
0. 090
0. 180
0. 395
0. 320
1
1
i
L
1
0. 69
0, 78
0. 71
0, 81
0.41
0. 54
(l. 41
0. 23
1.14
0, 43
0. 08
0.40
0. 12
0.22
0.42
o. io
1hackwati r CURVJ downstream of melka warar
Q - 1. 100 tu. m/sec
Backwater Curve
Section
ho
Qo
1
L
" —                -u Ah
L
--------------- mJ
32
31
30
29
28
27
26
25
24
23
22
21
20
19
1 8
1 7
16
731.20
731.89
733.24
734 16
735. 1 8
735. 61
736.15
736. 55
736 93
737. 90
738. 79
738. 91
739. 50
739. 66
739. 81
740. 39
740. 52
1. 100
1. 060
750
870
1 . 060
1.060
1.200
1 . 380
680
540
1.085
975
1.400
1. 390
670
790
0. 20
0. 21
0. 43
0. 32
0. 21
0. 21
0. 20
0. 1 J
0. 52
0. 83
0. 20
0. 25
0. 12
0. 1 2
0. 54
0 38
3 44
6 25
2. 1 4
3. 21
2. 01
2 52
2. 01
2 QO
I . 84
l. 07
0. 61
2. 33
I. 29
1.22
I 07
0. 34
0 A**
1 35
0. 92
1.02
0. 43
0 54
0 40
0 >8
0 97
0. 89
0 12
0. 59
0. 16
0. 15
0. 58
0. 13I
j
■I
L
*

< <

Summery

Summary: Melka Sadi-Amibara Irrigation Project Feasibility Study

Melka Sadi-Amibara Irrigation Project Feasibility Study - Summary

1. Project Overview

The document presents a feasibility study for the Melka Sadi-Amibara Irrigation Project in Ethiopia, conducted by Italconsult for the Imperial Ethiopian Government's Awash Valley Authority in 1969. The study focuses on irrigation engineering aspects (Volume 4 of the study).

        Key Project Details:
        Location: Awash Valley, Ethiopia
Total Geographic Area: 17,770 hectares
Gross Arable Area: 16,899 hectares (95.1% of total)
Net Arable Area: 13,809 hectares (after deductions)
Water Source: Awash River and tributaries
Study Date: July 1969

    

2. Irrigation Parameters

2.1 Irrigation Method

Gravity irrigation was selected over sprinkler irrigation due to:

Lower costs (60% less for network downstream of secondary canals)
Lower running costs (no pressurization needed)
Similar labor requirements
Only slight water savings (10-15%) with sprinkler

2.2 Water Requirements

Calculated using Blaney-Criddle formula with crop coefficients. Key crops and their requirements:

Crop	Water Requirement (mm/decade)	Peak Requirement (l/sec/ha)
Cotton	Variable	1.03 (3rd decade September)
Summer Tobacco	Variable	1.08 (2nd decade August)
Winter Maize	Variable	1.08 (3rd decade March)

2.3 Irrigation Network Design

The system is organized hierarchically:

Field Canals: Serve individual plots (800m long × 75m wide)
Unit Canals: Serve Irrigation Units (48 ha each)
District Canals: Serve multiple Units
Main Canals: Serve entire subareas

3. Key Infrastructure

3.1 Diversion Weirs

Two main diversion weirs were proposed:

Weir	Location	Length	Design Discharge	Function
Melka Sadi	Southern extremity	40m	1,500 cu.m/sec (100-year flood)	Supply Melka Sadi subarea
Melka Warar	Melka Warar Gorge	60m	1,100 cu.m/sec (100-year flood)	Supply Amibara subarea and provide storage

3.2 Drainage Network

Designed to:

Collect and convey rainwater and surplus irrigation water
Control water table levels
Prevent waterlogging

Field drains spaced 75m apart based on soil permeability calculations.

4. Flood Protection

Two main flood protection systems:

Western Dyke: Along Awash River to protect against river floods
Eastern Dyke: To intercept runoff from Aleideghi Plains

Designed for 100-year flood events with peak discharge of 1,600 cu.m/sec.

5. Electric Power Supply

Estimated requirements at full development (1980):

Peak demand: 770 kW
Annual consumption: 2,194,800 kWh

Supply options considered:

Diesel power units
Connection to 132 kV Koka-Dire Dawa power line
Hydroelectric plant (not detailed in this volume)

6. Key Tables and Figures

The document contains numerous tables and figures including:

Water requirement calculations for various crops
Soil moisture characteristics
Canal and drain design specifications
Flood routing calculations
Irrigation calendars for different crops

        Conclusion: The study provides comprehensive technical details for implementing a large-scale irrigation project in the Awash Valley, with careful consideration of water requirements, infrastructure design, flood protection, and power supply.
    