W . R . D . A .
MEDIUM SCALE DAM &
IRRIGATION
PROJECT
PRELIMINARY DESIGN REPORT
BALE GADULA IRRIGATION PROJECT
(Command Area)
VOLUME 1
TECHNICAL REPORT
Irrigation Technical Assistance
Group
Democratic People's Republic of
Korea
Addis Ababa
June 1990Table of Contents
Page
I.       Introduction and General......................................................................................... •.................... 1
1.1.      Introduction ........................................................................................................................ 1
1.2.     General  ....................................................................... .. .......................... .......................... 2
1.2.1.       Name of Project ;>nd Location .................... ........................................... • ••• 2
1.2.2.       Designed Area, Type -f Irrigation and Crop Pattern.. 2
1.2.3.       Undertaking Organization and Work Paeriod ..............................................  2
1.2.4* Data and Survey ................................................................................................ ..  2
1.3* Geological Part............................................................. .. ..................................................  5
1.3.1* Geological Caharacteristics of the Project Area.....................................................6
1.3.2.     Chute Drop Site........................................... .. ............................ .. ..................... 6
1.3*3. Diversion Weir........................................... ....................... .. ..................... ..  8
1.3.4* Irrigation Canals Nos. 1 and 2 .............................................................................. 9
1.3.5* Infiltration Measurement ......................................... .. ...........................................10
1.3*6. Construction Materials ............................................................... ................ ....28
1.3.7. Stone Quarry ....................................................................................................... 32
2. Basic Calculation Data For the Project Design ............................................................................37
2.1.     Meteo-Hydrological Data .............................................................................................. 37
2.2.     Calculation            of Unit Irrigation        Water Requirement ......... 
45
2.3.     Formulation          of Maximum Drainage        in Minor                      Catchments ...... 59
2.4.     Formulation          of Flood Flow ............................................................  ••••••••.••••• 66
2.5.     Water Gate and Lifting Devices ............................................. ,.................................... 72
2.6.     Plain and Reinforced Concrete Pipes ..................................... .. ...................................  73
3.           Design of Irrigation Canals and Drains ...................................... ..................................... 74
3.1.     Irrigation Canals .................................................... ................................ ... ..............<e 74
3.2.     Escape Channels .................................... .......................e.......................................1024* Design of Irrigation & Drain Structures
Page
• 105
4 *1 • Irrigation Structures ................................. .. ........................ *................................................
4*1*1* Intake Gate of Main Canal No. 1 ..................................... .. ................................ 195
4*1*2. Diversion Weir in Main Canal No. 2 ......................... .......................••*..... 108
4*1*3* Drop Structures ......................................... ••••••*••••••••........................ ..  114
4*1*4* Chute Drop Structure 1 *...••••....................................... •................................... 117
4*1 *5* Open Channel 1 ....................................... .. ....................................................... ....
4*1.6. Irrigation Culvert .................................................... ............. •............ e................. 124
4*1*7* Off-take and Off-take with pipe or Turnout ....................................................... 128
4*2. Drain Structures ••••............................ *........... .. .................................. ..............................122
4*2.1. Outlet Gate *.............................................................. .. .......................  132
4*2.2O Inlet Structure ................................................. •••••••.................... .......................134
4*2.3. Road Toe Drain Structure .................................... .. .............................................. 135
5* Land Development and Design of Infrastructure ............................................••••••••••••• 139
5*1. General Scheme for Land Development ••••••••••••••*••*................................................... 139
5*1.1* Elements of Design ••••...................................••••••••........................ ..•••••• 139
5*1*2. Selection cf Design criteria in General Layout Plan** 139
5*1*3* Elements of Land Development ..............................................••••.......................139
5*2. Layout Plan of Field Blocks and Land Levelling................................................................. 144
5*2.1. Layout Plan of Blocks and Sub-blocks ••••*•••••••••••• 144
5*2.2. Land Levelling................................................................... .. ...................................
5*3* Design of Road System ....................................................................................................... 147
5*3.1. Arrangement of Roads ................................. ....................................... .. ................ 147
5*3.2. Design of Roads................................... .. ......................................... .. ................ ..  ^47
5*4* Design of Irrigation Distribution System ••••••••••........................................................  15^ 5*4*1* Destribution of Canal Structures(Tertiary, Quaternary,
Field Canals) ........................................................ ........... .. ................................ 1^
5*4«2* Size of Furrow ............... .................................*•••••••........................... •*••••• 150
5*4.3. Water Application I'* lur-'”*!’. .................................................. *.............. ..  1^1Pago
5.4.4.       Tertiary and Quaternary Canals .......................................... .. .................................... 158
5.4.5.       Determination of Irrigation Interval and Irrigation
IXiration .............................• •••..................••••••••••«......................... ..  159
5.5.     Design of Drain ....................................... ........................ ........................ .. .............. • •............. 164
5* 5*1. Dranage Structures ....................................................... •.................... .. .............. ....164
5 >5 *2. Unit Required Drainage ................... ................... ......................................... .. ............164
5.5-3. Arrangement of Drains ...................... .............................................. •............... •............. I64
5.5.4. Cross-section of Drain ............................................................ .. ..................................• • I65
5.5.5* Design of Drainage Structures .......................................... ........................ ..................... 166
5.5.6.       Design of Escape Channels ............................................................... .. ......................166
5.6.     Some Problems to be Considered in Construct ion of Irrigation
and Drain Network ............... ...................................... ............• •<)•••••...................... ..............  167
6. COST ESTIMATE FOR PROJECT CONSTRUCTION ....................................................................... 171LiBt of Figures
Figure 1.3.1. Infiltration Test Point & Sample Place ..............................................................................          4
Figure 1.3.2. Infiltration Measurement ..©•••••o*o* o
o
oe *eeoo***,****0*,*e 15
Figure 1.3 ©3. Figure 1.3 ©4 • Figure 1.3.5® Figure 1.3.6. Figure 1.3 .7 © Figure 1.3.8. 
" ” ” ’’
’’
"
*.........................................................................
••••••..................................................................... 18
• ©19
.............................................................  20
Figure 1.3.9* Percentage Passing .................................................................................................................  25
Figure 1.3.10. 
Figure 1.3.11. 
”
”
............................................ 26
 27
Figure 1.3.12. Construction Materials(Location) .......................................................................... 36
Figure
2.2.1.   Curves of
Crop Coefficient(Maize)
.........................................................54
Figure
2.2.2.   Curves of
Crop Coefficient(Barley)
••••••.......................................55
Figure          2.3.1©   General Expression for Drainage .................................................... ............................ 65
Figure            2.4.1.   Discharge     Graph per km2
Agarfa Catchment Area............................................................................................... 69
Figure 2.4.2. Discharge Graph per Unit Rainfall
Agarfa, Tenbel, Kubsa  ©.............................................................................................7° Figure 4.1.2.1. Probability Curve of Daily Maximum Rainfall(Goba) •••••••• 113
Figure 4.2.1. Graph for Calculation of Hourly Probability Rainfall(Goba) 138Table 2.5.1. Water Gate(Size) ..oo......................................................................................................................• •••• 72
Table 2.5.2. Lift Capacity .................................................................................................. ........................................... 72
Table 2.6.1c Dimensions of Plain and Reinforced Concrete Pipes ..................................................................... • ••• 73
Table 3.1.1.                Elements of Main Canals ............................................................................................................77
Table 3.1.2.                Elements of Secondary Canal 1. M.C. No 1 ............................... .............................................   78
Table 3.1.3.                Cross-section of Secondary Canall. M.C. No 2 ..........................................................................79
Table 3.1.4 •              Structures Summary ..................................................................................................................   80
Table 3.1.5<>           Organization of Structures (Main Canal No l) ................................................................... ...81-99
Table "
"
"
"
(S.C. 1. M.Co No l) ................................................. 100
(S.Co 1. M.C. No 2) ................................................ 101
Table 3.2.1.              Organization.of Structures(Escape Channel 1-21,000 m) .......................................................  104
Table 4.1.2.1. Calculation of Probability Sate ............................................................ .. ............................... ............Ill
Table 4.1.2.2. Calculation of Probability ................................................... »•............................................ .. ........... 112
Table 4.1.3.1. Hydro-engineering Calculation for 8 Types of Drop
Structures .......... ........................................... .. ................................... ..  116
Table 4.1.6.1. Table of Drop-cum-Culvert Calculation ................................................................................... ..  125
Table 4 .1.7 .1 • Calculation of Off-take with Pipe or Turnout ............................................. ................................. 129
Table 4 .1.7 .2. 
"
.................................. 129
Table 4 .1.7 *3 •          Application         of Water Gate ........................................................................................  131
Table 4 «2 .1.1.           Calculation          of Outlet Gates ....................................................................................    133
Table 4.2.2.1.              Calculation          of Inlet Structures ................................................................................... 135
Table 4.2.1.               Calculation of           Hourly Probability Rainfall (Gob a) ................................................   136
Table 4.2.2.               Calculation >f           Hourly Probability Rainfall(Qoba) .................................................... 137
Table 5.1.1.              Sub-block Area         Ac cording to Different Slopes ........................................................... 140
Table 5.1.2.              Area According        to Furrow Slopes ................................................................................ 141
Table 5.1.3.              Area According        to Different Angles Between Furrow and
Sub^-block Side ........ ..................... .. ............................................................................... 142
’Table 5.1.4. Soil Movement for Land Levelling
143List of Tables
Table 1.3«1« Infiltration Rate . ??
Table 1.3.2* Laboratory Summary Sheet • •••• ••......................................................................................................  23
Table 1 .3 .3 • Laboratory Summary Sheet ..••«.«.••••••••• 24 
Table 1.3*4. Soil Mechanic® ................................................................................ .................................................. ?9
Table 1.3*5* Soil Mechanic©  ...............................................................................................................................  30
Table 1.3*6. Soil Mechanic® ................................................................................................................................ 31
Table          1.3*7*          Physical          and          Chemical          Analysis          of          Water
35 
Table 2.1.1. Me tee re logical Pata l) Precipitation .............................................................................................. 38
Table 2.1.2. 
Table 2.1.3. Table 2.1.4. 
”
”
”
2) Evaporation  38
3) Others  38
4 Air Temperature ................................................................ 39
Table 2.1.5* Monthly Precipitstion ir Gere Worlds ......................................................................................... 40
Table 2.1.6. Air Temperature ir. G~rc Sored* ••••••••......................................................................................41
Table 2.1.7. Meteorological beta ir. Agarfa 42
Table 2.1.6. Monthly Evaporation Vet ir fcobe ............................. ................................ • •............................ 43
* 
• 
Table           2.2.1. Data for Calculation of Annua. 
44
ETc ............................................................... 50
Tatle            2.2.2. Calculation of Evapot ranaj : rat ior. ................................................................................ 51
Tatxe z • z • / • 
* 
••••..•••••••••••••••••••••52
Table           2.2.3. Average Evapot ranapi ratior ............................................................................................ 5?
Table            2.2.4. Ma> ;aun Unit teeter haqu; rwaer.t
................................................................   58
Tatia 2.3.1.             hourly Mean Inf i J t ratio/ haU ........................................................................................  59
Tabla 2.3.2.             Calouiatior. of Area fox Difft rant iarta of Table 2.3.3.             hainfall Acooraing to G;v«i Period of Time
C><ctMn< .................... 6
wuei it ie *>• aa . . tl
Tab la . • .4 . 
he inf a J J Accord i >♦/. to Give/. hr ri uflt i f *! let HLet it l «>
20, jGj 4C AMI .................................................................................................................. ei
Tabla z•3• c,a i ou lotion of Ea <je ae hai nf a J1 
•••••••••••••••••••••••
Table ..4.1. Data for Graph of Flood Flow .............................................................................................
Tatie • .4 .2 • Data for Graph of Flood Flow ..................................................................................LIST OF DRAWINGS (BALE-GADULA)
j'           ywW           i-i J ft jDRAWING ■ M'
,,fl ' ■„■' TITLE OF DRAWINGS
PAGE TOPAGE
SHEET
General Irrigation scheme (scale 1' IO OOOJ
f
t
1-3
3
, Layout plan of Irrigation (scale 1 5000)
4-8
5
H SS±3£
Longitudinal section of main canal (fPI)
9-10
- - *-—
2
H.o! <
► r «'
Longitudinal section of main canal (N 2)
f
II - 18
8
*• p ..
iTypical section of main canal
19
1
i >. 6
Secondary canal 1 of main canal N 1
4
20
1
.
Secondary ' canal r of main . canal ’ H* 2 !
21
1
Tertiary canal longitudinal section
22-34
13
ia
9
Cros9 section of escape IU* 1
35
1
£ A ■ ••>’■-•'• '  •- 10 -
Cross section of escape TI* 2
36
1
AA'Vn
37-39
3
.-
'2
Intake gate *
-»■- Chute drop fall M r
-S - 40'” ’
1
V- 13
'V ';. 3 .
Diversion weir
41- 43
r
3
J         ■' x p’ ■ '4
:
Drop structure (Main canal) , ( Escape)
44-51
‘8
*• Ik’ •> <” 15 •'
Drop structure ( 3rd ,4rh carat
—
52-55
—
4
•                i6
A.  .
;
Culvert (Main canal)
r
-----------------------
56- 66
II
’■ 'k4>' ’’I7-
Culvert (Secondary carat)
67- 70
4
f.' '■      1
k  18 '••
Culvert (3  , 4 ^cQjtat ’
rd      M
71 - 79
9
,1 ■. *i . i 19   •
Culvert (escape)
90
1
Dr o I rage culver t
Open channel of mem canal N®
Off   > iu*e
i>f f    tune
pipe i secondm y canal) Jh
4 canal 1 n            i ti »g ^uiuTable 5*4 .1. Distribution of Canal Structures(Tertiary, Quaternary and
Field Canale) .............................................. ................ .................... ............................. • 1^0
Table 5          .2 • Furrow Slopes after Land Levelling ....................................................................................  151
Table 5*4.3. Results of Infiltration Test ..................................... ....................................................................  152
Table 5 *4 *4 • Evaluation of Furrow Discharge Capacity ............................................................................  153
Table 5 *4 «5 • Discharge Capacity of Syphons and their Number Required •••• 155
Table 5 .4 .6. Distribution of Sub-block's Slopes in Percentage ...................................................................  156
Table 5              • Red Slopes of Field Canale ................................... .. .................................... .. ..................157
Table 5.4.6. Organisation of Fir',c Structures ..............................................................................................  162
Table 5 *4        • W.ajcr Works Sutmrar? ............................................... ,.............................. .................... 163
Table 5/                 Drainage Structu** .....................................................................................................   164
Table 5*5*2-        Typical Croae-aect,or
of Drain ........................................................................  165
Table 5*6.1.          Organisation of Drair.             Wcrke ...........................................................................  166
Table 5*6»2.         Canale 6 Stnjct^res Suaaary ......................................................................................     169I. INTRODUCTION AND GENERAL
1 J . INTRODUCTION
This report Is a sequel of the Technical Report on the Pre liminary Design Report of Bale Gadula Project (November 1987), which dealt with the design of Dam & Weir. This report will
deal with the command area of the above mentioned storage dam. Design of this project aims at developing and introducing irrigation system into the plain land in Bale-Gadula valley. 
It is certain that irrigation system in this area is the key 
to bring about high production of agriculture, which is verified 
by the data and informations collected.
Design of the head work for this project was carried out in 1988. This head work is expected to be a reservoir with available storage volume of 15 million cubic m blocading the river Weivb that has abundant water quantity.
for the project the agricultural soils investigation and the quality 
of water for the purpose of irrigation has been carried out as appen ded in here; (Appendix 2). Likewise, the agronomic aspect has been compiled. (Appendix 3). Ail those data and informations provided reference for the design of the project. Finally the engineering 
cost estimate has been carried out in an elaborate manner as presen ted in Appendix 1.•
>• DRAWING N?
TITLE OF DRAWING
•
F’AGE TO TAGE
.'
27 ‘ ' |
Chute drop ( 3^ 4^ tonal)
101
r.<\ r “
^28 ’’’
•1
InleT structure
102-104
t> Intel structure (Escape F2)
105 . ’
* • J .     •. V   • .
'«•’*  3  0  ’  •  *  |
Out let gate '            V
’*     ■'*' i•<;
r-
1
A
106- 109 J
4 *’
r‘
31
Rood side drain work
no
SHEET
1
3
1
4
1
1 ■ 32 1  Irish bridge
■ f  Kubso bridge
!“      t
IK;
. 1
1 1 *•
■ 5 ’34                     300 x 300,400 x 4?0( Portable lifting gate)
112- 113 114
2
1
~ 35
L ■; J6j -
300 x 400, 400 x 500(portable tiffing ga'e) Iftstglotlon of go** 400, 600
Instoiotion o* go** 800, 1000 Insrglotlor of go’* ’250 x’500. 500
115
1
’•■R”.
'!■'
M 38
..I.
'
116
117 *
118
Aet* \
29                   Gate o*ail 4Q0» 400 slulc* ao*e
40
W 4.
rk.;
1
-vl
1 1 1 1
•
42
1
?i‘-             45
• 1 *» G •’.             u [• I i - • 45
» ’V L *• t .>//., <6
7          "f
4——---------- -
-4 -     -*
“4 *-w-------
500x 500
600 x 600
800x800
IOOC x 1000
119
120
121
122
123
124 125 126 127-128
i?9 j 30
I-<33
1 34
135 13© i3r
i3b 139
r
;
r
;v 
I • 47
*'|v’.k-'4e ■*
,[*>■•■ 49 ;.l+rr--r -
»»
1250 k 1500
0 1 tor
0 2 tor.
05 ton
1 0 ton Geological te< tun of chute diuj
i •
d
2
3
-4
V.
* *'■
51
n
t _ -- ---- .
f       ■?
..
«» 4« TS ■ 9------ — -
------------J              M .
»
Geological be* IM of division
Solti of bale Gadulo
Orgoniionon of •iturruiet < 3r d . 4 th canal I
r. <
1- 2 -
1.2. GENERAL
1.2.1. Name of project and location
Name of project- Bale-Oadula Irrigation Project,
Command area.
Location-administrative- The project area lies around Gadula Kevale, Goto Wo re da, Bale administrative Pegion,
520 km f-fho Goda Kiflr Hagar 9 km from Goro Woreda.
-Geological- between east longitudes 40 21  and 40 37 
r
o 
0
north latitudes 7°O5’ *-~d 7°O7’•
1.2.2. Designed area,type of irrigation and crop pattern
area 1 4,500 ha.net.
type of irrigation 1 gravity irrigation by reservoir
method of irrigation t surface irrigation
main crop pattern 1 barley. wneat and saize...
1.2 .J. Undertaking organisation and work period
organisation 1 Irrigation ?eonmoal Assistants Group of the
DMooratic Copiah Republic of Korea for the deal, A Mediae Baals Daae A Irrigation Project Jesign Jff loe ,WRDA,Addie Ababa.
w>ru period 1 fra Jeceaber I486 to September 1490. a
1.2.4.
<ad eurwey
* Uu ebuXe data ootained ano. surveys lone pr*>*e to be useful
aud taw juruQ Lw tor iiiu iewala ae.it of igr.euiture.
v
1 L>4")<J to 1,410 a.* 3 •
of the
n
lone toward pnutb-ewt direction
and ite avpnurp width if 1 km to A km and i* a plain in a valley, 
tticlinet jon i N«»an f]ot* if C.Ol^ <• and from tim* to time 0.0) '£• border i On th* rl<bt aid* of th* area flow th* river Waijrh
that baa a catchemert of X«1M kw with abundant water
e
reeoume and or th* TKbt lie* a hi<b and eteep mountain
* •< •< • « . Cliuate
Netee-hvdr lopiea data Vaw b>er collected frrw atatlona in adjacent ot border nr tr»M euot ae Ooro. Robe, Ooba« Slnnana anc Oimnr, wMd ar* a« fcll<we<
a*<r re.nfal, per annuw i 7?C ar
OOA» Veperatufw per annua < 17 J* C mar air tounidll) i 6s,} <
a»^ w;or. apex i • 4‘ a .sz
J •* «4 • ' • *z<• * J y Or< ».* r»£ a<» Va * a/*r                 i i. ’. * i
Q
Lav* f*vovi^ <* oone *for cr<>> proving. Th* soil alaoat
C<44  -ata of tjMO#
o«a
wlxci
f •enure crops, xu
fl I »*Wfld
water
jraea
a don frm
lis a-.
Ham and t iw rw la
little
ea1IRlt) .
♦ • * •/ .4 .
IL tLia *rt<. ia i 4.
4
H w* -
fa
/ * aiaae JVi. k ; j 4
(Iwia la a petL i*y
r*a£ f J ufi UuH h    OlMlil 4
l he H* jeet «iWa .
iw4«a j4 aa a a 11-14     < U» area I Li
t»La1 la ** I         IL»    UBUl 1* ut K La
lu* UfWuJ'fi       I Ur     LaL a 4. 1 a ll- a l
w * i. „ * i *
hiPAh* . 1
> 4 - P1 a4W a aU4
la a-.—a edit -a
onl> n.
*. x.<.
« • • « Z <   » t • C *. { 4 1 & . ( #«  * j fi.
hi t . 61 I 4 < ». . 1 _■ Xh> m c alif »■ J *•
u*a-»«i. - » •• I - •■<     *    >•»- 4 -
in the project area but in Goro Woreda 9 1«?«4«6« Sooio-eoonomical data
***7 from the area.
This area has long been inhabitated 07 people who are in Oromo race. There are now 5 collective villagee originated in early l'?8oe wftk 
>
about 940 families and 
population.
Moot of the inhabitants are engaged, in eemi-a<Ticulture, semi- stock breeding.
The total cultivated area is eoee 1,800 ha. and in most oases wheat
barley, maize,
their need
for     f ood
Crop yield         per    aa production
No means of production lixe IturaL activities
1 ton      in average and when in drought little tractare are
ar
nettle te l ay
jxes or z&nuaXXy rander-
ing baaM-b re ax. lng
d.eie peasant Jan arrange
labour Ij                n« j* xsan * a .
louo.e cropping ua.ng mill ciisats and
rainy doiims llat joour ’<i* m a /a tr and tasy breed great nuaoer of jell Lea euan wi xea or jqm (5 aaada per faa_ ly in 
*<*« *g« • gvaio (2U aa ada
jn4ilijne4 peat^fwi . uul. fa-a *a« 
faBiiy , jooai, ala. an :ae aeii-
of :a».r lnouaa .
In L-giU lu iidl Kay jrg<wi.ae4 Jo-operat 1tee sila jC io peasants ia eaua fur etery tillage ae a 4Ail  aowaver, lid not
t
ruu 
r Ly • FU«.ei -*-'e >      .4e ou—apsr<B 1 tea «j?t
to JO i
a. lue eu4 Jl July 1 *<3m Uid In April 1 we «e re maxaMd Bo be
ttUuki a'jwuua^ .
riKja «0. Im
I I I fge*i «-e
1A-U- JA J»» A <**•
Uttxe a-e-Aj Ul <AL«U
pUAika egKl t^p^ly 4ae oSteBl-
.auel     in     Ku     *lk     teges     a^4     me     nuu,     i     eouaaia,     a     la     .     tare     eansa- suuie4-
OEOLOOICKL vaft
Project i Pala-Gadv]a lrri£«Mon Project R»ri t' t Qorr Awraja, Pal*
n
Project l.ncatlor t Bale-Oadv**. 0-rr, Bal* Region
}nvw*ti<atkor t Geological Peetcre* -f earth tor l%vere and pit* drl 1 ‘ In?
Barvay Period t February 1°^ to yvly 19*9-
'rtr^<uctiot
F* ret r** -or•<*           R-w’ yet or *«f
p»rf<H*ed f< r th* deeiyn of
lr thi H*< -oy.oa, evrwj or tte
C rwcUf t< tl*< etu4y of typ*
r o • <y« rr .
area Mjor attention wa»
f aMl* and tltir profiles and
• , < W< <1
the rt we n t.
dMf aa>«w«A .t
» nri. ♦ i
. <etnU aval • at la,        F*            . fioal   pile
• aril . G* . y : o<*
♦ tn-/ u-r*t auc)
oafia I* h > and
t. .!>¥•>        ■ 4^>tV t 1*4 t ••Will              aeaaaa   at r        •<oa of   the t> •■ FVr /♦  WM / J .ef <*><                <*<      the r   . te«            f t ig   • i . a d
*-b-. Lt       j <La t A; we ra
.a «a»d          f <       • » * i r
1 'l*t r * «f> . - «>« * 4 . f     1 i.t c                .sUriel*^, eniW i-e> u..fc I I *»i IU«
ll-vee I
1 - • 1 «*Vgj • l*€ i »*hm. u*«U u * i » 
‘ ■» M» * A w                * *- 6 -
1                 Geological Charateristics of the Project Area
The project area is a hi^h land lyin^ about east part of east
Africa and h-ie distribution of basalts errupted on many occasions
and ot-er substances and eluvium about the mountain sides.
The basalts that are dominant in the area save m ^ny weathered 
cracks, Urgs in size.
The rocks n xve been affected by weitnerm^ processes and tsus se— 
riouly dimpled %nd the bisil^iyer as the dominant rocks xs
supposed to have tens of metres in iepth .
Basalts h %ve been weathered at different levels, la tae lower
part of the valley boulder tapped *nd < revel snaped weathered 
zones can be seen but freen rooks ere not found.
Bed rook xs Qami.: whxoh xs overixed by aluvxun and *u*'.os
with tens of oe t tee t res or tens of xetree of lepta.
Line ihxe xa the project a-wa sluvxue nd  weathered  soils h*we been  developed  <enera~.y.  “he juee^nd  irea x*a iBdoa .  ver of ox ay <nd o1 <yey e**s L *a fuu.'ta reason atratue.
Jfcule llruy hxie
ou x** e j rwrx^d          *ea . i) .y . x . UquuIx ju
uu ipr. Idd9
the 4ku Mi V
been proposed bo be built 4 o x**/
a the luu 4Xta between 
4   • 
*Ad xnalAuee
*• U lUe »4ku 4ullex t< x xa XOe HOXAXty of U. MM* hk- 7 -
Th. elevation at the beginning point is 1,905- 54,. above „ea„ eea level and the last elevation of i* 1,830.79 n, a.m.s.l. 
with drop height of 77-94 • and inclination within 5-8°.
1.3.2.2.        Rock Form and Geological Features at the Chute Drop 
I
Basalt the bed rock with serious crakdown at its starting point is outcropped and down along the slope erruptive basalt and its extricated substances and Eluvium are found and further down sandy loam and clayey souls with more than 6 metres in thick ness can be seen.
1.3.2.3.       Geological Investigation at the Chute Drop Site
Over the 800 m of the water
way investigation has been
conducted at every 5^ to 100 m space according to different slopes. Borholes were drilled manually 2 — 6.3 m down upto where basalts were found. (See Chute Drop's Geological Map)
Conclusion and Recommendation
Having investigated geological conditions of the chute drop site it is assumed that no proble. will arise. In particular it has been proposed to provide a pipe dr„t that .ill .rousd „o significant problems. However, with drop height of 77.,„ , and „aUr qua
„ ity 
)
t
of 5.58 . /s stilling basin night be problematic because no bed rocks were found upto 6 . down fro. th. eurfaM, „blob meanB
3
stilling basin should be lain on calvev «ni i j have to be taken for safety.
soil and thus measure0- 8 -
1.3.3.       Diversion Weir Site
■
Survey period. : from Feb • 24 to Mar • 30 19®9
1.3         .3.1. The bed rocks at the site are heavily cracked basalts
with sand and gravels, $ver which clay layer lies.
These alluvial gravels were carried by the stream of
Asendabo river, their grain size being 5 - 10 cm,
dominantly basaltic gravels with easy abrasion.
The     diversion     weir     will     be     provided     on     the     Ase'aabo     river about 2.5 km downstream of the confluence with the main
canal No 1.
1.3.3.2. Investigation on the Diversion Weir
The diversion weir that is propsed to be given on the Asendabo river has a length of 19 m but over 70 m
long area survey has been performed for geological purpose. 5 pits were dug manually at space of 10 to
15 m according to geological conditions. 60 m thick layer of clay was found and further down sandy gravels> fine pebbles and boulder seen.
Recommendation 1
The   propsoed diversion weir will be built on the gravel bed and thus measure should be taken to prvent leaching phenominon. And there is possibility of piling up of sand, silt and fine gravels during operation, for the Asendabo river has a steep slope, which nesessitetes protection from it.- 9 -
1*3 .4. Irrigation Canals Nos 1 and 2
Survey period : Feb. 19 1989 - Mar. 31 1989
1.3    .4.1. The objective of this survey was to observe the depth 
of ifiltrated soil.
1.3  .4-2. Geological Survey
Assuming that cut will be about 1 m in depth, 40 pits
were dug by man power within 32 km of stretch to obserye the earth layers.
Within the reach of the main canal No 1 more than 4 m deep clay stratum lies posing no problems. But from the diversion weir upto chainage 1 + 300 below the clay layer gravels were found and thus preventive measures against seepage are
prerequisite. In other reaches
no sandy gravels            were seen •
Recommendation :
In the reaches of the main canal No 2 of which cutting depth will
be more than 2 metres detailed investigation is necessary prior
to construction and consideration should be taken into about
the indiltrated soil.
When constructing canals by embanking no problems will sure arise
because of clayey soil on the surface.
What should be taken into account in construction of the main canals
Noe 1 and 2 is that moisture has to be 2$ -                                          % in the soil for compacted embankment. Because the clay in the area is highly porous
with eerious swelling capacity, in every case compaction is in evitable7
10 -
If not, the canal'bank will be swollen and cracked causing waste of water, further more collapsing of the bank.
All this shows that great care should be taken of the construction of canal banks.
1.3.5* Infiltration Measurement
1.3     .5.1. Objectives
The objectives of the filtration test were to clarify
the infiltration loss and permeability in the canals and fields.
Two methods were chosen on
the site and tests
performed
on the main, secondary and tertiary canals and fields
according to the colour of soils.
First method was taken by laboratory of the WRDA. (See
Soils and Land Suitability of Bale-Gadula Area Report)
Second method was taken to determine the infiltration 
rate in the irrigation canals assuming of constant flow
in the main, secondary and tertiary canals during the
whole irrigation period.
1.3*5 *2. Test Equipments
2        concentric        doublering        infiltrometers        with        different        dia. have been usedj dia of inner cylinder, 30 cm
dia. of outer cylinder 70 cm
height
50 cm.Installation of flinders
For the purpose of measuring infiltration rate digging of
I
• 
earth -was done with diameter of 1 m and 40 cm in depth and bed horizontal, and at the cetre the two sylinders were driven 
A
c
into to a dpth of 20 - 25 cm. Around the inner Cylinder fine
earth was rammed slightly to keep water from channeling out
and 2 -3 cm diu. pebbles were spread in thickness of 3 -4
cm to preserve the surface of the soil. After that on the
inside of the inner sylinder a ruler or a hook gauge was
installed.
1.3 .5 *4 • Procedure
Having placed the sylinders we waited for 3 days until full saturation took place in both inner and outer sylinders and 
began measuring. Some places were impossible to take accurate measurement due to swell or crack of soil and thus suitable
sites were chosen for the test.
Intake rate was collected per day not per hour, of which period was 30 d£as, daily once at 8:30 am.(2:30 am. by Ethiopian time)
As the initial intake rate was high, water filled the sylin- ' 
ders to a depth of 15^mm and as it went lower, to a depth of
100 mm fixed. During measurement inner water went down slownly and outer water permeated both vertically and horizontally 
at a faster speed, which necessitated adding water into the outer sylinder so a6 to preserve the same water level as the inner one. In the initial stage water intake increased and decreased soon after a certain period of time narrowingdifference markedly bewteen intakes in inner and outer sylinders. After meaurements from all the places in which tests were carried out paraffin-wax coated samples were collected at the depth of 20 cm and 50 cm and brought to the laboratory of WRDA for physical analysis.
Following are the places where infiltration tests were performed^
-   Main canal No 1
-   Secondary canal of main canal No 1
-   Secondary canal of main canal No 1 
\ -
-   Main canal No 2
-   Secondary canal of main canal No2
- Secondary canal of
main canal No 2
-   Main canal No 2
-   Main oanal No 2
Chainage 0 + 000 Kubsa village
Down Kubsa
Sole Metena
Sole Metana
Alemkerem Dorene
Chainage 24 + 150
Brown colour Black
Black Black
Brown
Brown
Black
Brown- 13 -
Results
Initial infiltration rate Has very high in every place •
This was because, as mentioned, above, the earth is highly porous with serious swelling capacity due to the soil characteristics during dry 
and wet seasons, and wide cracks made us take long time for the test, which made impossible to collect correctly measured values within a short period of time, i.e, 30 days were needed in every spot. 
Fixed intake rate is 4 - 8mm per day but it has been proposed to apply 
to the design the values recorded within 10 - 15 days after beginning 
of measurement because 10 - 15 dajs after beginning of measurement the infiltration curve becomes gentle as seen in the figure. On top of that there is no whole day flow in the canals but day light irrigation only drying canals.
From this point of view infiltration rate of 20 - 25 mm/day has been proposed as suitable •4
•b'
■z
BALE GADULA PROJECT
Poi™
Figure 1.3.1
Fbiri z.
\ ° Po inf 5
I
OPoinf 6
GADULA
Point 12
NS
SYMBOL
DESCRIPTION
O
•
INFILTRATION TEST
POINT
WATER SAMPLE
PLACE
*
■
4
/
i
»
PROJECT TITLE
DATE SCALE TEAM
BALE GADULA IRRIGATION
4/1990 |: 125,000
KOREANu
U
n
d
L«< M li I' 'I 11^_LNFILTR ATfON         MEASUREMENT I I I
ILLAGE
T
I!
HGURE_l.-3JZ_ I I I
-o^n
l
■
M
B
II
k
l
l
I
I
l
I
IINFILTRATION RATE
Tabl s' 1.3.1
r
Nc. Place Preference
Point
Infiltration Rate
in cm/h
Infiltration Rate
in m/dav
Remark
IB
I
B
I         Kubsa                    Nr BM-10            i
0.9
0.4
0.216
0.096
•
2 Selena j Nr BM-22 3.25
1.5
0.78
0.36
* mita
•
i
1
3 Alem Nr BM-37
Ke rem
2.4
1.0                                  0.576
0.24
i
4        Doreni                   Nr BM-47                            5.5
3.1
1.32
0.^4
i
1
i
N)
r
j Selena Nr G-15
Mita
2-‘ ■
0.9
0.504
0.22
1
11
6         Eale                     | No. 21 + 700          1         1.74
Gadulla
11
1
0.6
1
i
0.42  j 0.14  :
1
1
' 7           Bale
Gadulla
24 + 150
4.13
2.9
0.99                         !         0.69
1
!
11
i
1
1
i
1
j
I - Initial Intake
B ■ Basic Intake•— W
^DULA BAI.F
Date 21/8/89 
I i
po^Lab.No. |DEPTH
I Location J
I
- J.L
r.i
Partic 1 e size nalysis
- tOTIFW |-SOIL ...
SL
O
N.   ,   D
G.rioC
»
^TclABSP-
I FiGATWC
37
■53    '
i
•G
• s
J_____
% clay
I % silt
s-.n
10- OOX’ 0 0^5 D-O2L5
d POROSITY
-W5 1,1             .
i
' 1.04 I 1.08
42.61 •2.74
35.0 2.50
<        70
26
-4 i
74
24          ’ 2
1.04          42.0      2.45               73            25         ! 2
1.53          36.0      <2.51
15(4)
15/4/
36
8’
70
4.9
76
28
mJ-D.U_20_ -L o L=» Li ■ i P-L= Pl_«
1,27
1.41
1.02
0.68
1.04
1.26 
—  j
!
29.51     J2.58 32.51     2.46 21.87     2.32 ; 21.04     2.59 30.68     £.56 32.04     £.61
86            12          : 2
74            24          ! 2
85            13          1 2
78 i      16          i 6
1 15 1 2 i
0.62
0.57
0.58
0.62
0.51
0.64
0.56
0.59
0.52
L‘V.X2.
density
rioistv.re content
i-d=
:J> o Xj=
Prepared by
*Table 1-3-3
•./UBA
Laboratory SuLim-y Sheet
*
Date ? 1/8/89
Project _____ BALE GADULA
- —UNIFIED
Partic 1e. size, jmalysis._
SOIL
1
| Loca.tion ’
21
20 cm
221       50 cm ^23         20 cm
24
50 cm
i I
I I I I I I I I
21+700
21+700
24+150
24+150
1.59
1.57
1.04
0.90
O.M.C
F---------- 29.60 34.51 23.38 22.66
fin*
-1CI
0.61
0.61
0.56
0.64
Liuid Limit
1-l.stic uicit
. 1 :.stic ' Inde:; Lhrink.~c:e li-"*it
= I'JJ-Xli.llLU?. = Opticivjn
= □i'ecific
dry density iioistrr zravity44
H+ ni
UUll.. | 
UHilili
lli | lIlIU' IU)
lull! Ulit
i
■ ildUil
WUU1
.UUul u U
—.ujiI.LI^UuL-;
i-i Ux
ijiL.
76.2 100
Medium SAND
SIEVE N®/SiZE
sa**p:e n® depth, pi
COBBLE
CLASSIFICATION
M
GRADATION CURVES
Plotted
j
7
-—
^f^^orLtp^ch. Laboratory
i_l
-sz-percentage passing
-93pr.»roirw;F passing riG»,pr   , ,(
✓ ■ : •' ■
i
A A a* -
HlIlMeihiy
’• |..J.
...urA-*-
TUi
^4-tu
.......... **■*'• 1^,...
11,1 ■•■‘th-l -■■, i- )
- - - • .ML*
:~X»3
UIL pK-
- .       - 4 ...»«..4
■ lj»M
M ediu<n
Coarse
GRAVE
iCCBBLE
pqrtrcT
sa.-wplaLOate \ SafcmifAad by ReportMK
Oate of
rz^t f'
.RADATION CURVES*:i
: h?
Table 1-3-6 w<r O.z 00028/90
r
co»^5Ot i l),< r iO1*! jz.n
' Since the samples have the same characterstic thedirect shear test is done on the representat ive sample
Representative TEGONA 5
' *W-
i-----------i_
' • 7 / 7
I
OJM•
1*3.6. Construction Material*
1.3         .6.1. Sand
3 sand quaries were located and obaarrad and aaarlaa at
different depths taken for gralr\ alia analyaia*
Sand in Katate and Chelchelo covering the surface of the
earth is 1 metre deep in thickness.
At Degona the quarry has 1 - 1.5 m layer of sand ? -1 m below
the surface which will require excavating equipment.
The analytic results of the aand  samples are as followei On  the basis of the curves of the grain  size we oan  have a rough idea, curves being gentle.
This means that the gran size is non-uniform (See analytical data)•
That is why in exploiting and using sand it is important
to assort it according to grain size ie . smaller than 0.2-
0.5 mm, bigger than 0.5 mm etc, and to use it for appropriate purposes, ie• sand of smaller than 0.2 mm for cement mortor and bigger than 0.5 mm for gravel.
The laboratory did not carry out the analysis of So^ and mica included in sand and it is advised that if they exceed 1 % in So^ and 0.5 in mica, they have to be removed from sand to be usedIP
fl fl fl fl fl fl p
fl
fl
fl
fl
fl
fl
fl
fl
fl- 32 -
inovod from oand to bo uood.
1.3    .6.2. Looation of Sand Quarry and Transport Condition and Distance
i
Sand quarries h .,ve been located in Chelchelo, Katate and Degona© Distance has been measured from the centre of the project area, 
i*e, Alekerem to the sand quarries including transport condition.
Degona sand quarry is located 74 km west of Alelkeram village, upstream of the Weiyb river. Transport condition is very 
favourable because it is along the existing national road all
the way to the destination.
Chelchelo 6and quarry is located 98 km east of the area along the national road to Sof Omar and in the same direction there
is Katate sand quarry site that has good raod condition inspite
of some 4 km of distance to be repaired and improved.
We may also reach the Katate
the raod to Ginnir which has
and Chelchelo sand quarries through little difference in distance.
1.3    .7 • Stone Quarry
A stone quarry is recommended as the main one about 800 □ west of the bridge across the Weiyb river, that is on the way from Alemkerem to Goro, and has abundant outcropped basalt. This place could be turned into a quarry to produce shaped stones crushed stones and gravel for concrete work.- 33 -
For this purpose a road should be constructed in the first place and the road is supposed to have a great deal of work to be done.
The distance from Kubsa comes to about 20 km, rather long and therefore, it is proposed to use small amount of stones around 
Kubsa, dam site and the Asendabo river that lies about the cross way over the existing path.
Down the Gadula village outcropped on the riverside are basalts that can be used, 3 km away from the national road from the Gadula
village to Ginnir.
As described above, in many places basalts are found to be used as shaped stones, crushed stones which could be collected from places. Where to collect it depends on the decision of the contractors. 
What is suggested here is that basalt should be used as shaped and crushed stones or gravel.
For canal stone-lining purpose the same nuarries could be recommen ded.
All the existing roads favour the transport condition from the quarries proposed.
It     is also advisable
to use   the
the
low hill   between           Gadula   and
ern           mountain   between          Lonene   and the existing road near Alemkerem
existing quarries, i .e , one near Donenne and another near the north- Alekerem and the last one beside- 34 -
All this shows that gravels in amount •
for road surfacing are very rich
For road surfacing purpose around Kubsa and Sole Metena areas
»
gravels could be exploited from the hill that BM - 11 is stationed on.
It is suggested to use as little porous basalt as possible as shaped and crushed stone and gravel.
********I
I
t
I
I
I
I
I
IK-r « i
r*
r wie - 3- T
9
.at Se*»ai V WM&f*
WATER RESOURCES DE^ELOPME.V
Mr-, . «A A J***
prvj** X
99*
AUTHORITY
hd U*t
*J* L40
ipit
REPORT SHEET
Lji iya
I. of
••«   <4
-4
«*A
Udlt
dhC
" Mit U<
LUii«i<IW4
„ 
(h
Pn,>K4i jnd chetnwcai analysis
:ak
dlH
’ (Mit u<
UK
□r wdfiH
bait
of Hl.tf
iyteU
>u to H>
fcare* LaOoruf
ory Setfioi
r«i M-SS-U
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0
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7
Tablo 1-3- 7
!
•     ***• 
’
• j     “
Lab. Serial Nfl 00489/89
Date! 14-8-89
Sender:
Medium & Small scale Dam Irrigation project
Address:
(Korean team) WRDA
Nature of Sample -River water Purpose of Analysis  - irrigation Origin of Sample - Weiyb River
Date and time of collection  31-8-89
Date and time of arrival - 7-8-89
Date of Analysis 7-12/8/89
Remarks
WATER RESOURCES DEVELOPMENT AUTHORITY
REPORT SHEET
Physical and cMawcal an«rv«
* e «»>•Temperature, (at the time of col ection):
Ap pe a rare ----------------------------------------
Odour:____________________________
Taste:-------------------------------------------------
SetHeable solids:------------------------------------------------------ Floating solids:------------------------------------------- -------------- Suspended solids:----------------------------------------------------- Color (true): -------------------------------------------- Color units
"      (apparent!222Color units
Turbidity;-------------------------- 52______________ Fl U Total solids dried at: iQ5°cmg/f
Total dissolved solids dried at 105°c-'mg /I Electrical conductivity at 25 r: 79.8 jUTtios/cm
PH: ________________________ LU_________________
Carbonate    alkalinity    as    Ca    Co^:—tui    nig/i* Bicarbonate alkalinity asCaCo^; zk mo/j
Hydroxide alkalinity as Ca cpy niJ mg/I
I           a*
Total hardness as Ca Coj-’
CATIONS. ftQ/e
H*
nhJ
0-45
_______A \ i J KiS ns OH-__________
Cl’ ____ LJ_____
Nat
5.6
K*:
1.7
Lit
Ag* _
Ba** -
Ca** -------- Mg**Lid Fe**
Fe*** Mn**
F-
n».oG .sb*____ Co-3 _L--------------- Sa —  ___
*•
4t
Pu
-   -   tfr   rnu)   _ *
Hu * iru-ru. outyi
lu. ( I S.lu.u       i jj,
£
BivCx'Cutai jx ;«>«.>.j jUL C:«Ai wOl
Boron_
KA Rate
..X’l
U**-v*-<\*r itoxpfM r<uu SMI
•U «/* . .FIGURE 1-3-12
BALE GADULA PROJECT2 .BASIC CALCULATION DATA FOR THE PROJECT DESIGN
y /
2.1. METEO*HYDROLOGICAL DATA
These      data      have      been      used      for      calculation      of      irrigation      water      require ment, drain water quantity and flood flow in the project design.
The project area being  efnewly  developing  area,  there ane no  meteo- hydrological data available .  That is why  we have analysed  and  used data collected from the adjacent areas.
For the calculation of irrigation water requirement, data on such zones as Goro, Sinnana and Agarfa were taken and. Goba and Agarfa for drain water quantity and flood flow.
Following are the data on those   zones; mean annual precipitation       7 20 mm
mean annual evaporation mean air temperature mean air hunidity
mean wind speed
mean sunshine hour maximum daily rainfall maximum hourly rainfall
: 1,672 mm
: 17.8°C
: 62.3 %
: 2.45 m/day
:     7*9     hrs/day : 56.2 mm/day
: 39*8 mm/day
In the following table are given meteorological cfta on the zonesl) Precipitation
No.        Zone
- 38 - METEOROLOGICAL BATA
Annual   Precipitation
max.      min •
ave rage
numbe r of
years
ye arB
Table 2.1.1
remarks
unit          mm         mm              mm
1 Goba 1279,5 704,7 948,4 23
2 Goro 1383,04 351,02 720 11
3     Robe        887,2            660,3           768,85                    4
. -4
Ginnir 1094,9
707,9
853,1
4
5
Sinnanal120,2
702,5
896,35
8
6
Agarfa 826,7
439,8
648,3
4
2 ) Evaporation
Table 2.1.2
number
No.        Zone
Annual
Evaporation
of
years
remarks
max •
min c
ave rage
unit
mm
mm
mm
years
1
Robe
1516,8
1496,4
1506,6
CD
2
Sinn ana
1990,1
1352 ,9
1671,5
2
3)
Others
Table
2.1.3
x Descrip 
’ t ion
Numbe r
No
max •
min •
ave rage
of
remarks
years
1
monthly humidity %
66,6 
______
62,3
-j
Agarfa
wind 
s pe e d m / s sunshine hour hr/day 9
'/
2
2 ,15^
2,69
2,45
7
Sinnana
3
4 ,8
1x21
12
Ooro- 39 -
4) Air Temperature
Table 2.1.4
number
No.
Zone
Max •
min o
ave rage
of
years
remarks
unit
c°
c°
c°
years
1
Goro
26., 59
9,96
18,3
8
2
Ginnir
23,48
•12,92
18,2
9 months
3-
Sinnana
2 4,12
5,8
15
6■owtwit r»t»< iriT»ri<n in none N^nrnA
mi.
N
*
«AIK TI-.'MIWIIATIIilh; IN (lOIKI WOKHIDA
Table
----------- F^rly
>• . tear
J a'<
Feb
Mar
Apr
Muy
Jun
Jul
Auk
:i« p
Oat
Nov
6eo
AVo raxe
<4M
a,,]
,6
H./
/ ./.'
H,GJ
2-1J
J.dJ.
'1 *9 J
G .1 1
IJ
/.♦□
j . I f' tif         " »•     • >y         .n.nj           .'MJ          • j j' '>       ''ItZ/.          fI»G         J6 .J         .’ll ..’4       •7.1
f.lj
i     J1 .J ‘
t  Jt > J t 9 * JO____
l/.IO      ia.;<        111.67         16 .0/
\O.J   .’II .6 I     .71 .66
/l            in.J 2        I 1 •')'>
> -a
10,1 I       2d .
n,j          v.s            11.411     1 1             14.16       13 .4
/.
"> •■ • •'! > .     iJ              zzitj__ nun
■'1 ijj      X4t2.
_
•’J ,n        cl-LL        •'6 ,411
i Hi''           ±ZlLL                L2j!^    U.44           I/,I.'       |G ,h<j     HI ,0.1        1M              11X •      10.44       JO .94
"** / 1 .<
n i"            11 iM       11             I • ,/4       1 ‘ r?         1 '.14        1 1 ,69        1 ..III       H .96            1.4
I ' / / .         j'ulX-       Xi >11        ZM'         XM/      XI ,4         .■4 x        r'lZi *         J6 ,66         •’> .06     .'II .11/     .7 ,j
•*!> LI
r -;.'i       JJ^l           JIC'I         lLul L/XJ l'».<
pl l"l         L'.IZ       !•>,.7’      HI .91      1/.J5
M« f,4l j Jf
.VLIUfi,
" > '•> 11           i ■>>       1 >'."J    JlLiU
nxi .    f-j"!         |JI,.’G     p.h           1 ill         10.44        1- ,01
f        1,1                         ■ Ld/    >221!       ' 2d2      iliU           l"j ii J       j7’ Jd       J6 ,yj
"•> .'// /             12d±        P’.'J lllCil J/j/V
LI ia'/        i /               m.44       • /jJ.4.
•7 .4 ’ XLdlL
Pl»>' lb.7 3
‘J .904
J6,68f
lb..7 7= huridity in
S = wind speed km/day
nsaine hr
in   hour
l
bJ
I
wwwYears
1965 early
MONTHLY EVAPRATION NET IN ROBE
Table 2.1.8 Jan          Feb          Mar          Apr          May          Jun          Jul          Aug          Sep          Oct          Nov          Bsc
mid
late
month
1986
early
22.4
34.8
23.1
22.2
31.5
30.6
26 .4
40.3
40
mid
29.1
31.8
35
28.3
34.6
21.6
28.7
46.2
55.7
late
25.3
29.1
27.5
29.4
47.7
26
39
38.3
78.3
month
76.8         95.7         85.6          79.9          113.8      78.2           94.1          118.8      174
1987
early
55
7 '- .4
51.3
21.9
45.7
28.7
29.5
38.9
30.8
43.1
50.8
46 .6
mid
64 .2
56.9
22.5
30.8
13.7
29.6
32.4
33.6
27 .4
47.6
69.1
36.9
1 ate
64 .2
53.2
47.6
40.1
17 .7
38.6
37.4
38.7
28.6
46 .3
73.9
43.1
11 am th
I83.4
180.5
111.4
92.8
77.1
96.5
99.4
111.2
86.8
137
193.8
126.6
1496.4
1988
early
60.7
42-7
49.6
58.2
47
37 .8
20.1
23.1
22.3
35-9
42.5
mid
98.2
4^.3
85.9
25.9
43.3
53
22.4
22.7
28.7
16 .9
45.5
46 .6
late
63.8
60.6
26.6
- 64.3
15
-31.7
-24.4
19.6
28.3
58.1
66.8MONTHLY EVAPORATION NET IN ROBE
Table 3.1.8
Year
Jan Feb 
Mar Apr
May Jun Jul Aug Sep Oct Nov Dec
Total
early 48.3 
35.7 
66 3
1989
mid 61.5             67.9        58.7 late 67 .4            60.1         18.3 month 177.2       163.7       143.3- 45 -
2.2 CALCULATION OF UNIT IRRIGATION WATER REQUIREMENT
Calculation of unit irrigation water requirement is necessary 
to determine the capacity of canals and structures, and the arrangement and operation of irrigation activities.
For those purposes meteorological data on the adjacent areas
have been collected and used;
air temperature and sunshine duration from Goro Awraja wind speed from Sinnana
humidity from Agarfa .
Crop Evapotranspiration (ETcrop) has been calculated by Penman method and on its basis unit irrigation water requirement computed. Daily irrig tion duration of 12 hours was deduced and field efficiency turned out to be 85
Water loss in the canal is equivalent to infiltration loss plus evaporation loss according to the size of canal and water quantity© Net unit irrigation water requirement in the field is 1.Ol/s and gross unit irrigation water requirement including water loss
in the canal is 1.411, l/s, of which basis is as follows.
2.2.1.      Calculation of Evapotranspiration (ETo)
Penman Method
ETo = c(w,Rn + ( 1 + W ) . (ea - ed)j- 46 -
Whe re j
ETo
= reference crop evapotranspiration in ma/day
W      = temperature-related weighting factor.
Hn
= net radiation in equivalent evaioration in r^ra/day
f(u)= wind-related function
(ea-ed)= difference between the saturation vajour pressure at mean air temper ture ;<nd the nean actual vapcur pressure of the air
C = adjustment factor to compensate for the effect of day and night wether conditions.
a) (ea - edj
ea = 20.6 in mbar
When mean temperature is 17 .94°C it is 20.6 mbar
Mean- 47 -
Lucidity 64.7 sunshine durition(n, 12.1 hrs/day.
Ra (table 10) i 15.3 (ts/day) Ea « (u.25 ♦ 0.5 n/l)Ra - (0.25 ♦ 
N - 12.1 (in table ll)
0,5 ’llfl *3 -7«8o(n/d*X)
RnS    i    (1    -    )Rs    -    (1    -    0.25)7    .9    -    5.95    (in    n/day) (table 12)
Rnl i f(T).f(ed).f(n/H) - 14.2 x 0.18 x 0.25 - 1.385(ci/dtiy) in table 13 f(T) « (mean temp.17.94 C) 14.2 (m/day) in table 14 f(sd) - 0.184 (Cd - 13.32)
in table 15 f(n/!l) - 0.52
Rn : Rns - Rnl - 5«95 - 1.36 = 4.47 (mm/day)
f) Adjustment Factor (c)
Rs - 7.8
REmax = 64.7
Uday/Uweight =1.0
resulting in C = o.99
EvapotranspiTation (ETo)
ETo = C W.Rn + (l - W).f(u).(ea - ed) = 0.88(0.70 x 4«49 + 0.3 + O.85 
7.28) = 4.4O in mmX ’X'*
XX X X
, .xx*
- 48 -
2.2.2.         Calculation of Crop Evapotranspiration (ETcrop) Selection of Crop Coefficient
Crop coefficient(kc) should be obtained in the first place, with which evapotranspiraion (ETo) is related, and based on it^vapotranspiration (ETcrop) could be calculated, 
crop
Crop growth consists of 4
should be obtained within
stages and crop coefficient(kc)
these stages
1)initial
stage
15
days
2)growing
stage
25
days
3)    middle
stage
50
days
4)    late stage
1) Crop Coeff icier. (kc)
30   days
at Initial Stage
According to the
table 6 the evapotranspiration (ETo)
at initial stage coefficient (kc)
is 529 mm (August), wherein crop 
is C<,44 when irrigation interval is
7days according to the figure 6.
2)    Crop Coefficient (kc) at Middle and Late Stages
When  wind  speed  is 38  m/s and  humidity  66  % (in  average), according  to  the table 21  crop  coefficient (kc) at middle stage is 1.15 and at late stage ( .2, humidity being oonsi
de red low.
Vegetative period is 120 dyae G5/25/50/30).
On its basis curve of cro; coefficient is drawn,
Figure 2.2.1.As       September       is       at       growing       and       middle       stages       crop       coefficient       (kc) is 1.0 (figure 3.1.2.).
i
On the basis of all the data above shown crop evapotranspiration (ETcrop) is calculated;
/
ETcrop = EToKc = 4 .4^ x 1.0 = 4.4 mm
By this method the computation of annual evapotranspiration could be tabulated as follows;F
for i
of AH. gfo
rabl« 2-2-1
7
Hr
1—J______________
•
r»0f > (fsT r • i r ti l * r i <**
>
.
r.
»■■
—
**v
Tun*
Oct.
Nr)V .
D«c.
L___ ,
Mb r« t         Air ” r*»f
>-— - . ., Au< .
II.**
3*0.
17. ’*
T------ T
l* I
*1    1*." k- -
L1*.  a * >      1*. 01
17.”7
17. ™
II?2
18.73
Mr 0 ♦           41’
tt          T
^5           5 $            <1 '
70.
1
___ L
l ”-2’
61 .
62.’
4------- 1
i
4____ 4-
4------- 2
53
r
Mb pt            r<»trel r»> ttf c
•' 7' »» t t- 0 ’ ■             C. 4 < ft t- V, 4 hb
' r» •
.
iia               •♦ U—..
5. 1 L
5 .  1
R.6
u
66.
8. 7
10.8
Vf
Oft
f W'-
1 >.
3
■ >.* k
u.*
11.5
Pr-
t
T
0. 70
0.9-
i------ _U ■                                                                                4
4
1 2
0   ** VB 0.42' 1 1 .
c         * •             p T j 1p*
4 'n ' <«r h ? p,
0.  41
/" 4
41<'*Y ** f
*
K/
>'/
K.
13.1
7.* 7
12.
k
1 0.62 7
14.
8. 1
L
12? 0.64
<6?
13?
66.7
6. 3
12.'
0.52
15.’
h
62.
6.5
II.”
0.55
15.
5).3
8.9
ll?
0.77
14.2
u?
t
4------U-
M»rt»           V nr (;pH»d kw.
i*s
s
210
242
1*8
7
1*0
293. 7
)M.”
328. 1
0.25
216
146.”
111.’
138?
•> • VW 4 It «•»’’
x,        Wln<*
0. 25
0.25
0.21       0
■;
0.2
0.25
0.25
0.25        0.25
0.25
0.5
______
Wi *
I. *01 2.50
_______
I 2.2(
| 3.40
4.50
3.80
i/
______
2.50      1 1.70 hr
, 1.6
0
/
i,Calculation of Evapotranspiration
Table 2-2-
h«                  1                     Lxpitbblon
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct. 1
Nov.
Dec.
i----------- -- --------------------------------------------------------------------------------------------------------
•a  latie 5;
z
22.8
22.5
21.6
20.8
20 J
20
20.2
21.3
20.3 J
9.o         ;
*1.3        2
1.7
1 .........
/
12.7
12.53
13.24
14.62
13.4b
12.2
12.58
14.06
13.4o3
2.15 1
1.62 1
1.50
■
3-------- --------------------------------------------------- 1 ca - fcd
10. 1
9.97
8. 3b
6. 18
0 . JU
7.8
7.b2
7.24
7.34
7.45 1
0.18 1
0.2
I*
•*
t
'
* U . 2 7 (1 <                  ) t ab. 7
0.09
0.85
0.92
0.91
0. 78
1.0b
1 . 32
1. 15
0.85
0.o7
0.57
-
0. o4
1i
-
►            1 at. b
I---------- ----- - ■ ,
,
0.26
0. 28
0. 31
0. 32
a 32b
0. 3 1
0. 32c
0.30c
0.32
0.34
0.295
■■
0.305
L
H— i
‘.ra         «-l j !<uj (j                   a)
b---------- -----------------———■.. ■ .
__
i . 95
2.3/
Jul. 1 .
Aj • * 1 A J <o. X b t U. b
0. >1
0.4/
U. 35
0. 34
0.44
0.42
0.4 3
o. -o
0.38
0.39
------------ 0. m8
-»— ■ X-
0 . >4
*.                             Jab. JI
9 4 5
9.2/
7 id
6.98
«. 8->
8.2 1
8.55
9.15
7.75
7.80
9.09
<87
*
—i
'.t.         10
■' ■ 1
i 5.9 
—' ■■ ■"
14.6
15.4
15.4
15.1
14. /
14.9
15.2
15. J
15
U.2
13.7
JU
■"■'■■■5
Mia •                      A
1
/.09
0.9b
5. 39
5. 2 3o
0 J)4
0.1/
n.41
0.8m
>.8l
5.85
J1
~ '5
o.S2
7 40
.
m. u
14.0
14.5
14. 3
JV
a    . j a.
H»dj - U. >. - U.
14.2
)
13.
14. 1
14.2
I*. 1
J *
1^ 2
14   10
/77
0. Ibl
V. l« J
o.i7a
0.1/
0.1 /
0.18
‘ 0.18
0.17
.
0.1 7
.
0. 18
' 0. 18
1 4 • *4 t 0.18
la A
r
_____ L r1 * 2 - 2 - / i < r t
V
I I V
I
I
I
V
I
I
I
I
I
I
t
k
I I
i- 53 -
Average F//apot ran^p1 ration
Table 2.2.3
No.
Crop
Feb.
M
a r.
Apr.
May
June
Jul7
1
Maize
2.3
2.82
3.86
5.22
5.55
4.61
2
Barley 
t/h eat
2.32
4.40
4.32         3.39
Total
4.62
7.22
3.16         3.61
Average
2.31
3.61       4.08 1    4.305
1- 56 -
2.2.3.        Calculation of Unit Water Requirement
Calculation of unit water requirement has been made on the basis of maximum mean evapotranspiration(4 *30), for simultaneous irrigation for both maize and barley and sorghum will be undergoing.
a)       Net    Unit Water Requirement on the field
q FNR " 2’78 = 2.78
ETcrop T
= 1.00 l/s
ETo        Evapotranspiration               4.30 mm
: Irrigation period 12 hrs
q^P : Maximum Unit Water Requirement
on the Field in l/s
FKF • Net Unit             Water Requirement on the Field
. Field
t Un;t Water Requirement with Field Efficiency considered
n«»U J ha . naticM
Qu JM: C
if.wr^ance Loss in the 1 . J1. ! .          : r r. t   . .U 1 ji hr C ana 1
t
; f
,j r •                   1
I<
<*‘
C 4    *
j us '« 
' a/wa*
t 1«.»
I       * U L       Il • i■Ui
------------------------------------
t Water Requirement
21
-------------
Table 2-2-4
«••»<                          D i >, Kar            &®e* *
••                                               1 
B» -• • j®
- rerweatilitv
I
Evapera-
E
Length oi Canal
kn
Loss by infil tration•loss by evaporat
ion
Sum-
of
Losses
Rate
of
Loss
Unit
Water Reqmnt.
Final
Unit Water reqmt.
. T                                        « S
*to l *
<> >c
5.0
0.028
(■)
0.008
10
0.043
0.0083
0.05125
1.008
(1)
1.411
J.411
1 i to
5. « 
:*
0.028
0.008
13
0.039
0.0007
0.046
1.016
1.404
—
1.40
'f
***
* w >      t «:
to. ?$
2.20
0.028
0.008
7
0.017
0.0031
0.0206
1.01
1.382
1.4
1.38
1 o.?o
J.90
1 .B0
0.028
0.008
7
0.0125
0.0025
0.015
1.015
1.369
'1.37
f • « • la* •
♦*-* 
IS*
0. )5
1 . 30
0.60
0.22
0.008
2
0.0124
0.0002
0.0126
1.063
1.349
1.35
fj
a
r■
*I®V
F
ej
0.25
0.80
0.30
0.36
0.008
0.8
0.0057
0.00002
0.00576
1.0576
1.269
1.27
» ■ ................
•   » to 11 h r ito 14 r rn«
i •••< r
1.176
1.20
1.20
K«» u w X
In f h« f 1 • lv
4
1.00
1.00
_______
>
On the basis of the unit water requirement irdicated in the above table water requirement for a given area has been calculated and by so doing size of irrigation cnals and capacity of structures determined.- 57 -
rs
b t bottom 4idth of canal 1a)
a i wile slope of canal
v t 1.2
- Conveyance Loss oy Evaporation in the Canal
S • 
.011 Se 0
e i p&n-evapor ition in *n
B i width *>f water surf ice in m
3 i mount evaporated in canal per cm
in fo^/a/ka
Unit water requirement has been tabulated for different
canals in the following taole.f '■Kf*                    r> f
- 59 -
2.3. Formulation of Maximum Drain Discharge in Minor Catchment Areas
Formulating drain discharge In the minor catchment aims at determining the capacity of drains and their structures that fit
the local conditions of the project area.
The formula has been worked out by excess discharge, the difference between the hourly probability rainfall and the
hourly infiltration rate measured at 7 points.
Hourly probability rainfall; 50mm, 4Qmm, 30mm, 20mm Hourly mean infiltration rate : 22mm/h
Using expression of theoretical drain discharge for lOOha. of catchment area as a standard we could calculate the discharge for a given hourly probability rainfall. This calculated dis charge enables to work out the formula of drain discharge.
Formula:
Q = (10,336 R - 5) 0 F
in 1/s
R ■ hourly rainfall in mm
F - catchment area in ha.
0 - discharge factor
Chute area 0.3 - 1.0) moderate area: 0.5 - 0.7 flat area: 0.2 - 0.4
Following are the data for calculation:
table 2-3-1.2
2.3.1
Hourly Mean Inf Lit rat un dace
Table 2-3-1
Measurment Points
1
>
3
•4
5
0
7
Average
—
Max.Mia. Average as
Max.
9
32.5
24
5i
21
L’.-*
-a. 3
28.6
>2
Mln.
•4
Li
Id
H
9
a
29
U.9. 60 -
Average infiltrated ami unt for 6 minute* - 2.2mm.
2.3.2.        Calculatton of Aiea
for 01ff eient             I’m t a of Catchment
Table 2-3-2
*----------------
<
<
«♦
t-
<■
<•
e
*•*
*c
•
xT
m
r*>
<*
O
N
•
<»
*3
f*>
m
O
O
*-
:J
VV
o
e
er
<
CM
-
2.3.5. CalcuLtlo, of n^trlbutior of Hourly k.lnf.ll
Totalf
Time
i Rainfall
Intensity
Mean ralnfal 1 Intensity
Period
of
t lme
Rainfall In a period
of time
Cumulative Ra 1 n f a 11
0.00
0
0.00
0.0028
11
360
J*
o
1
0.0056
1
1
2          0.0112
0.0084
0.014
II
360
o
4
11
)60
3
5
*
0
3             0.0166
II
0.0196
IbO                            7
I e»
0.0O5o 0.01 1 3
0.0M4
J 0.024
0.0224
0.0252
H
100
*
2 5
5 0.026
6 0.0224
/ 0.0166
11
U.O25Z
loo                      9
i.
O.Ui *0
11
>oo
/                             41
11
0.014
5
40
o
0.028 o      0.0224
O.OI08
0.01 12
1
it
*
I■
• 
r
*
1
4*
-4
<r
I
6        0.0112
9        0.0056
10        0.00
0.0064
.00
O.OOSo
11
4
tsj I
I
50
0.00
Ung to given period* of time when It f* 50mm62 -
2.3.4. Calculation of Excess Rainfall
Table 2-3-5
50 mm
40mm
30mm
20mm
Rainfall
per 360S
In
filtration
per 360S
Excess
Rainfall
1
2
3
1
2
3
1
2
3
1
2.2
-
0.8
2.2
-
0.6
2.2
-
0.4
2.2
-
3
2.2
0.8
2.40
2.2
0.2
1.8
2.2
-
1.2
2.2
-
7
2.2
4.8
5.6
*> n
«. • Z
3.6
4.2
2.2
2.0
2.8
2.2
0.6
9
2.2
6.8
7.2
2.2
5.6
5.4
2.2
3.2
3.6
2.2
1.4
Q
2.2
6.8
2.2
5.0
5.4
2.2
3.2
3.6
2.2
1.4
7
2.2
4.8
5.6
0  o 
•- . a
3.6
4.2
2.2
2.0
2.8
2.2
0.6
5
2.2
2.8
4.0
2.2
1.8
3.0
2.2
0.8
2.0
2.2
-
*
2.2
0.8
2.4      2.2
0.2
1.8
2.2
-
1.2
2.2
-
1
2.2
-
0.8      2.2
-
0.6
2.2
-
0.6
2.2
-
J
2.2
2.8
4.0  2.2
—
1.8
3.0
2.2
0.8
2.0
2.2
-
2.3.5. Calculation of Discharge caused by Excess Rainfall
using expression cf peak flow.
Hourly Rainf
alls are suppeSec to
be 50. 40. 30. 20 nun.
Expression cf
peak
f low
Q 'FlF10
+ F 2F9
F 3R8   4 F?r
F 5R6 + F6R5 +
+F 7F4
* F8R83
9 z      * Wl
F 1 •••
FJ0
Cat< hn«eArea
In different size (ha)
RI ...
F 10
Rainfall for a- 63 -
- Calculation of drainage
1)     When the rainfall is 50mm,
Q 50 " F2R9 + F3R8 + F4R9 + F5R6 + F6R5 + F7R4 + F8R3 + F8R3 + F9R2
= [6.67 x 0.8 x 10 x 28 + 13.33 + 4.8 + 16.66 x 6.8] x 2= 210.6 x 2 = 421.216
Unit conversion: = -------------------------- 1000 
2)     When the rainfall is 40mm,
421.216 !22^-°'- x 
100 x 3600
- 0.0117 m3/s
% = F2R9 + (F3R8 + F4R7 + F5R6 + F6R5 + F7R4 + W
+F  R
94
=(6.67 + 0.2 + 10 x 1.8 + 13.33 x 3.6 + 16.66 x 5.0) x 2 z ---------------------------------------- -— = 3600
= 0.00836788 m3/s
3)     When it is 30mm,
Q 30 = F4R8 + F4R7 + F5R6 + F6R5 + F9R4 + F8R3
= (10 x 08 + 13.33 x 2.0 + 16.66 x 3.20) x 2 x ----------------------------------- - ----------- 3,600
=    0.00488733 m3/s
4)     When it is 20mm,
Q   = f R  + f r     f r  + f r
20         4    7         5   6 +    0   5         7   4
3
= (13.33 X 0.6 + 16.66 x 1.4) x 2 x —---------------------- ----- = 0.00174 a /s 3600
2.3.6.         General Expressionshave               been confirmed by the following equations X = A + BY
n
 nEYJl - Y.SX
22
n Y - (IY)
A -           5 x - B.S-Y- 64 -
n
V
X
(Sy )
a
yx
xy- £*
1
20
1.7A
A 00
3A.8
•>
a.
30
A. 88
<>00
1A6.A
3
A0
8.36
1600
33a. A
A
50
11.7
2500
585
S.Y 1A0
ZX
26.68
IY1
5A00
]<>600
XYX
1100.6
3735.2
F- ^J^0.6 - 3-35.2 wO 33H
A x 5400 - 19600
A • 26.66 - Q3336 x i*C • - 5.00
X -         A <                BY - BY •  A
% -       BF - A           - 0.3336   F - 5
The above
expression! <0.3 3 36F
result Ir as foll
ows:
i e <
1/s
F
•     hour.v 
rainfall     In
aa
f
•     catchaant
area     In
ha.
F • dlaruarpe lartor
atc»| area
J-at area
0.6       < Q area                 0.5 -- 0 T
0.2 ■   - 0.4Figure 2-3-1
-65 -
A
60
Il * *
£(J                 1
-
...
I_
-1
—
Z.£>
General Expression tor Drainage
Q = 0 3336R 5 *
F
R:
Rainfall
per hour in
F    Catchment area
in
e
Discharge factor Steep area t 0-8 —
1-0)
Moderate  area  10-5  ~  07) Flat area ( Q.2 —04)
i- 66 -
2.4. FORMULATION OF FLOOD FLOW
Formulating flood flow aims at determining capacity of the diversion weir on the river that fit the specific conditions of the project
area, thue ensuring euceesful design work.
The formula ie barec on the discharge data collected from Agarfa, Tenbel and Rubra that belong to catchment, and daily maximum precipitation obtained from Agarfa. We could work out the formula using the graph of unit rainfall (mainly of rainy season) and
discarge per unit catchment area. Re commendec fcnnula:
4 . 5.7-iC"6 r
F* '6 t
m^/e
F • daily rainfall
F • catchment area
• diachargt factor
in
ir.
t-teej area 
•oOtrata toret. 
fiat area 
i 0,6 
i
- 1.0
- 0,7
i 0,2 
-     0,4
tai- 67-
/
Da fa for Graph of Fl o od
Table 2-4-1
Agar fa
No. >
Year
6
Month
Daily
Max.
Painfall
D i scharge
Q m /s
3
O/ F=71‘3!
■
Remarks
X
1
1987
Jan
-
Is
0.237
0.00033
Agarfa catch.F*719km:
2
Feb
20.2
0.505
0.9007
3
Mar.
12.8
3.91
0.0054
. ;r.ed figures used in graph
4
Apr.
23.1             |
38.86
|0.054
5
May
14.9
164.2
0.223
1
6
Jun.
36.5
>. *5
| 0.014
1
7
Jul.
14.9
0.00087
8
Aug.
9.7
6.53
0.00915
L
9
Sep.
19.8
L
9.46
| 0.013
10
Oct.
30.4
>
|| 0.0155
ll
Nov .
-
92
0.3068
12
Dec .
28.4
0.829
0.00115
13
ma
Jan.
-
0. 2 r
0.00032S
14
Feb.
15.3
0.i23
0.0008’
15
Mar .
13.’
0.823
1 0.00114
16
Apr
- ----------- —--------------------- .—,
30
I )            L 
| 0.014• 6B
a a a a
■
■
■
■ i
i
i
i
l
I
I
I
I
I I
I-tfi-
Discharge Graph per Urn Agar fa Catchment Area
FIGURE 2-4-1»
DISCHARGE AGARFA
GRAPH PER UNIT RAINFALL^" figure 2.4.2 TENBEL ■ KUBSA
Bl
k
k
k- 71 -
Formulation of discharge per km  in the Agarfa Catchment of 719 km . Index and constant numbers for precipitation in graph 2-4-1 are;
2
2
Index X” lg 100 
- lg 1 = 1.544 lg 82 - lg 416
constant a =               1
“6716
= 0 2/
-*
f (R)       0 (aR)Z = <0.2 x R)1'54 m 1/s f (R) = 0.000111  ’
1  54
in m3/s
Formulation of discharge per unit rainfall in catchment areas; Agarfa, Tenbel and Kubsa.
index and constant numbers for precipitation in graph 2-4-2 are;
index X =
lg 500 - lg I = lg62 - lg39
1.67
constant a = 1___________________  - 0.0C29
390
f(F) »          (0.00             ?)1'53                 =    0.00005133?' =3
unit conversion fl?1 functions generalized; f (RF ) » 5.’ kQ 6
. 0O5133F1'69 , 1.34  l.M.
in u’ a
p
which result in Q * 5.7.10 ° R* ''  p‘
-4
J in m’/s- 72 -
2. 5 Water Gate & Lifting Devices
The equipment used in the irrigation projects now under construction by the WRDA are modified to be introduced into our design for the water gates and lifting devices.
♦
Water gates vill be installed at intake, off-take and escape structures These are the water gates and lifting devices:
Water Gate
Table 2-5-1
Gate size
350x400
450x500
550x530
650x900
850x900
1050x1030
1300x1500
Channel
Size
e « 300 300x400
f ' 400 
400x500
t = 500
0 = 600
0 =800
1000x1000
1250x1500
Lift Capac-ty
Table 2-5-2
Lefting
capacity (T)
0.1
0.2
0.5
1.0
D:a,of Spindle
23
25
30
34
Aft shown above, the wafer gater equipment 6 have been proposed to suit
capacity Other equipments out of
e'cord with the need. Any wafer gate t designed to be operated manually.2. 6 Plain and reinforced concrete pipes
plain and reinforced concrete pipes have been chosen to use in the design 
of cross-structures, off-take and escape structures in the irrigation canal. 
They are equivalent with the ones now being used in the projects undertaken by the WRDA.
Considering the load acting on the pipe, a load acting simultaneously both from interior and exterior, a , load acting differently according to conditions etc, plain or reinforced concrete conditionshave been chosen to suit the specific situation of the site.
Pipes either with additional reinforcement or without are used in the design for different loads acting on the pipes.
Following are the dimensions of plain or reinforced concrete pipes; (table 2-6-1
Plain Concrete Pipe
Table 2-6-1
Reinforced Concrete Pipe
Dia.
Length
n 
Thickness ii Dia.
ii
ii
Length
Thickness
20
100
il
;i
3i
-
-
-
ii
n
30
100
3.5                        30
II
i
:i
i
ii
100
4.45
40
100
4                         40
1
■I
100
4.76
50
100
ll
4.5 -
u
-
-
60
100
5                            60
II
1
II
II
II
100
6.35
80
100
7                            80
1
100
7.3
1 100
100
8                          100
1
100
8.89- 74 -
3. Design of Irrigation Canals & Drain.
3.1.        Irrigation Canals
Irrigation canals consist of main canal, secondary canal, tertiary canal, quarternary canal and field canal.
3.1.1.        Main Canal
Main canal is again devided into main canal No.l and main canal No.2 according to the topographic situation. What was taken account of particularly in scheduling 
irrigation canals^to facilitate smoth supply of water and construction of structures with less expense.
Main canal Nc.l starts flowing from the Gadula reservoir through the outlet pipe into the Weyib River, topography 
being considered, 
upto 50m downstream from which
water is taker up,This canal has a capacity of discharging 
f .35 r- s into the irrigable area and commands 538 ha. in 
kubsa Quarter and on the other hand supplies water into the
•nair canal . 2 . 
* ,K end of * •»< main < anal No.l the river Asendab takes water f 'x ? snme .. \  Rm downstream^at which there
x
r
live;
t diver? or wt . r , and continues into the main
■ «-nal .« ? us »< shorten the length of canals
number of structures and to add the
tl«a( of t lie canal.
:.cad of w«ttr is proposed in the main
* 
*• e *1 ♦ 
. I . . : < y produ< e 3 700 km max . of
«= l i 14 ; < 4
! Ju ! ut uj <71* nr.r. ctstl Bo. < :e
car com and 4,000bs of imftL* ♦ *we. 
the uain car.als it »u cur priBclfle te
of drop structure rather ttar ami ctMl, the
e ir iMftfc flewiM
4 * t. m* * **♦
1 <wl a.r 1 w is **» > 1* <u • vf
irt< <v*4lhnii * tSs anu'MR
of tSaie
**tv« ’
than drop etc, with efficient utllltetl'* cf ^h'<rt|K| f*  '*• 
r
*f
economy.
For the de6ign of individual structures it has beer rre|c»e< < rrvvits
generalized and useful cnee such as drops ard off-tales, drvje and 
drops and outlet gates eto.
In the main oanale 204 poo of drops, ^6 pcs of culverts, pee of orf-laeoo
etc. are propeed and so thore aro 3^0 pcs of structure* altogether.
3.1.2.       Secondary Canal
The secondary canals oonsist of secondary canal 1 of main oanal
No.   1   (C   -   1   -   l)   and   secondary   oanal   1   of   main   canal   No.   2(C   -   2   -   l) 'and will be lined or unlined aocording to topography.
Secondary canal 1 of main oanal No. 1 (C-l-l) oommundo 538 ha
of    irrigable    land    and    secondary    canal    1    of    main    oanal    No.    2    doos /
403 ha of irrigable land.
There are proposed 22 pcs of off-takes, 13 pcs of culverts comprising 35 pcs altogether in the secondary canals.
3.1.3.       Determination of canal capacity
Canal capacity has been calculated with several reaches divided aocording to water quantity and slopeAX * XX
)
- 76 -           .
Main canal No.l 0 + 00 to 3 + 600 design water quantity qd = 6.35 m /s
3
i Donation
Water quantity Q = WC/ Ri Wetted area W = (b + mh) h Wetted perimeter x = b + 2h / 1+
i    =    1:3000 
n
 = 0.025
m =    1-5
3
=  q.22   x'3q.2O    f 0.922^0.00033 =  6.35   m /s
= (5.5 +  (5 x    1.25) x     1.25 = 922 m2
= 5.5 + 2 x 1.25 /“T + 1.52 =    10 m2
hydraulic radius R = W = 9.22 
X             10
velocity co-officient C = 5 R  =
= 0.922
y
1 x q ^^Q.223 0.025
= 39.3
y = 2.5 /n - 0.13 - 0.75/r ( /n - 01?
= 2.5/0.025 - 0.13 - 0.95/0.921 (/0.025 - 0.1) = 0.223
This how cYial capacity has been determined . In the following tables is given the arrangement, ozfelemente of canals and. structures.
1J
Name
of Canal
Kain canal
Elements of main cnals
Designed Water Qty.
m3 /s
1:3000
3600
5.900 TWO--------
9200 13245 
(4500ha)
6.35
(3960ha)
5.588 (396OJ
5,588 own— 
4700 T2616)
5.809
5.632 4.825
3.76
1:3000
1:2000
1:2000
1:2000
13245r- 20710
22921 22721-------
26+660
0.68 0.77 0.73 0.706
1.657 5"5)
1.065 0/521
1.90                  1:2000
1.20                  1:2000 0.529                1:1500
0.578
0.492 0.45
0.85           2.20          ti               1 1.0               1     0.50
0.81        1 1.60l         11            1 1.0 0.65      I 1
\      0.40F.FMFNTS OF SECONDARY CANAL.I M.C. NO.I
Table 3.1.2
•
Kb^ of
Cun* 1
— -................. 4
, „ — . MM— I tt 1r*61 e
Area
■ . 
De«<
water
q r v.
.
DI arharge
R
H
a
m
m.
b
1
Remarks
Serf. f.*** 1 1
v . C . 'ir. 1
o*ooo-
o-» ] oo
0 4 1 00-
0* >00
0* >00-
0*R>0
MW-
1*0 SO
1*0*0-
1*6*0
507.6
ri
•i
5 RO
0.827
it
tt
0.834
0.6
0.50
0.4
1.0
1.0
0.8
0.038
lined
ii
it
ii
ii
H
ii
ii
0.0288
n
i_-------------------------------------------------4
ti
ii
it
ii
If
ii
ii
0.017
ii
0.773
0.773
1.00
0.50
0.4
1.0
1.0
0.8
0.0021
earth
• •
»»
ii
0.834
0.6
0.50
0.4
1.0
1.0
0.8
0.025
lined
1*650-
1*800
n
ii
ii
ti
it
ii
11
11
ii
0.033
ii
•«
1*800-
2*250
u
it
ii
ii
ti
ii
11
11
ii
0.0284
ii
•«
2*250-
2*400
529
0.757
ti
ii
it
ii
II
If
ii
0.0196
ii
2*400-
2*600
it
ii
ii
ii
ii
it
11
11
ii
0.0165
ii
fl
2*600-
2*850
n
H
ii
ti
ii
ii
11
11
ii
0.0288
ii
ft
2*850-
3+200
311
0.482
0.528
0.4
0.45
0.4
1.0
1.0
0.6
0.0143
ii
11
3*200-
3*450
’sff
ii
ii
ii
II
ii
it
11
It
it
0.0226
ii
ft
3+450-
3*800
188
0.275
ii
II
ii
ii
11
If
it
0.0246
it
3*800
-4*050
ii
ii
ii
11
ii
ii
11
11
it
0.0217
it
-CROSS*SECTION OF SECONDARY CANAL-1 MC .No 2
T bl  3.1.3• J
|: aflit of
w ay. al
Reach
Irrigable
Area
Design
W. Qty
Discharge
B
H
a
m
ml
b
acm e .
i
Remarks
|SC - 1
Uc.No 2
Q*000-
0<220
403
0.563
0.60
0.6
0.45
0.4
1.0
1.0
0.6
0.0172
Lined
Canal
1 
tl
0*220-
04300
373
0.551
II
II
II
II
II
II
II
0.0375
11
II
0*300-
0*740
II
II
II
II
II
II
It
II
II
0.012
11
II
0*740-
0*900
330.5
0.482
0.541
0.40
0.40
0.40
1.0
1.0
0.6
0.0207
11
II
0*900-
1*400
II
II
II
II
It
It
II
II
It
0.0288
11
II
1*400-
1*550
260
0.413
II
II
II
II
II
II
II
0.0203
11
II
1+550
2+320
II
II
0.454
0.60
0.50
0.40
1.0
1.0
0.6
0.005
Earth
Canal
II
2+320-2+600 2+600-3+400
II
(61.7)
II
0.137
0.541
0.40
0.4
0.40
1.0
1.0
0.6
0.01955
Lined
II
(36.1)
II
0.274
0.40
0.40
0.30
0.75
0.75
0.60
0.01
Earth
II
3+800-
4 MIO
(10.5)
O.O69
If
II
II
II
II
II
II
II
11
II
*
.9                   |
•
L*. *
£      s 0 1STRUCTURES SUMMARY
bl
TA ad W XeC 3.1.4   J . A .
Type of Nan^\^tn,ct'
of              \»re
Canal
i------------ ---------
Intake
GAte
Cu1 vert
Drop
off
take
off
take wi   th pipe
Head
Regulator
Chute
Drop
Open 
Channel
Outlet
Gate
Inlet
Structure
Road 
Toe
Drain
Works
Total
Main Canal No.1
1
3
1
1
23
Main CAnal No.2
1
23
1
30
1
1
3
15
15
277 1
Sub-total
2
26
1 7
187
206
2
30
1
1
I
3
15
15               300 1
Scd. Canal 1 Main Cana 1 No. 1
6
12
1       18 I
Scd. Canal 1 
Main Canal 2
7
10
1 17 1
Sub-total
1 3
22
•
'        35        \
Total
2
39
204
2
52
1
1
1
3
15
15      1      335 1Main canal No.1
ORGANIZATION OF STRUCTURES
Table 3.1.5
Location
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Inlet
Outlet
Structure
Types
Adooted
Remarks
1
Intake Gate 1
0 4 000
4500
6.35
0.15
1.25x3
i
1940.30
1940.30
water,sur
race            dirr
separated arenes.
- 7-------------------------- 7 2              Drop -                     1
2 4- 240
ii
ii
1.60
2.50
1939.56
1937.96
Tvne 1
3
Drop-cum-culvert
2 4- 380
n
ii
1.60
0.8x3
10.00
1934.91
1936.31
••
4
Drop                     2
2 4- 480
ii
ii
1.60
2.50
1936.28
1934.68
It
1
Drop                      3
24-600
4500
6.35
1.60
2.50
1934.64
1933.04
II
 !
6
"4
24800
ii
ii
1.60
2.50
1932.97
1931.37
II
7
"5
24960
ii
ii
1.60
2.50
1931.32
1929.72
II
8
” 6
3 4 040
ii
ii
1.60
2.50
1929.70
1928.10
II
9
"7
3 4 160
ii
ii
1.60
2.50
1928.06
1926.46
II
10
” 8
3 4 320
ii
ii
1.60
2.50
1926.41
1924.81
II
11
“9
3 4 400
it
ii
I .60
2.50
1924.77
1923.17
II
1
12
“ 10
3 4 440
ii
ii
1.60
2.50
1923.16
1921.56
II
13
1
Drop cun-culvert 7
3 4 470
ii
4.58
0.8x3
66.00
1921.55
1916.97
separated
~T chute dr£
14
Offtake                  1
34546
538. 1
0.774
0.6x1
7.00
1916.95
1916.95
ii
15
Drop                   11
34690
4 500
6.350
1.60
2.50
1916.95
1915.35
type If*t
j
•4 III    '«<
*
1
____4
—-d
-4
•k
•
-—-4
'
k
(
•’
ij
-
1 
ft
•
9*
£
—
1 p«
I
•»
k      1
« De
»
*■
1
•
P
t-
J
•
t
£
u
f
I
i
»*■>5
*•
C
I
w*4         £
r
9
C
<
«
•*
f"       o
•
<
ir *•*
»r
ft
-
••
Rn
w
ft.
c
r
r
?*
•
-i
••>  t 1
- • ■ --* c
L—4 ______1----- 41 --—    d
—J  A
d
*5
1
H
*
—*
«*
—%
«-
♦--
r *•
C
»—  r-                R w
e
ip
4
r
•
«
•
•H
<
-
«
r*w*V
<
— i —14 —
r        r»
! i rs ~u —1
**
-4          I *% i—- 4—- i A 4 4 
4
W
V
4P
____ 4                 4
C
L 4 4 4 4 4
c      F                 e-           . 5□bought: on of snvcr^ts
.AH*t ; UI
Irt1 getie
ini
r"
-------- ’
Q
I                  1              D            L        . »±SAe-i32
Inlet                  Jut let
Structure
UlOlT
teaerfte
e e    kJ 12                 —
S* M III
S* «•(>(
- ” '
x
 l tv
5<3
1A /” L m
* 5
—
M
1•
• fl           F
>M4
. t ) *
K
5M F*
><♦
—
•C
r-------------- -
Uu .,4           Oft
..*♦-* *■                    1
•
—
*>uv
* ‘ .11
- <»1>I
• t M 1 *<MAI 1 *i‘*k
1 * m<
1 • . .»i
1 *•
1 « • 4
0 It 1           IQ    JU               ’U         a’m                   tNpe
“t""
%pe
1 ~
T
r
T
*• * t]
I**
*
.1
F                   *•
M
♦F
4T* r
————
Ml
>   ’0
0 <0 1
4    JU     I >4         41
F                                     ■ F
1 ll          4       i ’aa   BJ
-------- f
■y  f ►
........
rpr
*'         4
•      ffW
tu
JM
%pu
I IQ a> ’<3 J'k F^pu
■5
-T
f                             *■
tw                IQ
r
r-----------
I Q 1 JI 1 Q 1 4 I
>1
<• • ♦
• 4 1 -|
*1
~1
5
V
n
t
t
*
T
tM
M                               •      i •>
t                   F—             F
-
k J
U IM          1     JU       I Q »        U|    I Ql     ’0
F                     ~F       —
Fvpu
f—             r
i
jif
v  ■ T-----------
tvpu
1 u               •al* »       ►        ‘ PHI ) -Y   H      •               • I
1!
4 • >              i J
♦    • I
FrF
r
■ r
u 4            ♦    JU        l ’Ql        < 1
M|
~T
F—             I                r
—
tvpe    >
r t\pu
i • » l
*»t
| L 1‘I
T'T -
rTr
Y"
• Mi
•  .'i
•<. F»
w    1 tu                                        4Q
brr
77 IQ I ’W ’0
r
M                               «    • v >
k J                                                   —
ISpu
V
•
r
tw
b
t
r
L ___
F
ai
F------
1.2* JI >1
*WCANTZATTON OF STRUCTURE.'
w*ff CF
t tt- rrr<
------------- ■
1 -^r a  11 on 4L------------------
Ttt  igiM*
Are*
Q
H
B
D
L
Location
Structure
Inlet
Outlet
Types
Adopted
Remarks
/ r
—4
Tw                       71 ---- —- - ---------------- —4
7*/.nn --------- ---------
3.331
.  .
A. 700
1 .60
2.20
1757.95
1756.35
Type 2
M ------------ 4
’ n ■’ 6 •            in
7*500
40
0.193
1 .60
Type 3
-lid
brr’p                    7 9
7*520
3.331
4.700
1 .60
2.20
1756.29
1754.69
Type 2
V
—Li
■>n --------------- —---------- -4
7*660
ri
II
1 .60
2.20
1754.62
1753.02
ii
Z
------ J
>1
— ■ ---- --------------- --
7*760
II
If
1 .60
2.20
1752.97
1751.37
ii
It.
-------------j
3?
-----------------------------
?*8ao
II
II
1 .60
2.20
1751.33
1749.73
it
---------- U
T*-^t •        rnlvr?! t—              ■■ ■
<L
_
“■ 7.0/.0  •
7*020
It
II
1 .60
08x3
8.00
1749.69
1748.09
Type 2
M
<  • nVr vi ! 6 n pr
- - ■ ..........
288.3
0.366
0.40
4.00
1748.09
Type 1
t-
In nt                         J] ---- -
8*100 • —
20
0.097
0.70
Type 1
——      -4
Prnj                          3 3
 ,
8*860
3.331
6.700
1.60
2.20
1747.78
1746.18
Type 2
CO
■4
*’                           3*
8*620
II
it
1.60
2.20
1746.14
1744.54
II
—,. -4
2 Ill
8*700
II
it
1.60
2.20
1744.50
1742.90
II
*'
*’                           36
84820
II
it
1.60
2.20
1742.84
1741.24
II
37
84900
II
ii
1.60
2.20
1741.20
1739.60
II
6^
inlet                         12
84990
30
0.165
1.10
Type 2
6*
Hr op                      38
94-000
3.331
4.700
1.60
2.20
1739.55
1737.95
Type 2ORGANIZATION OF STRUCTURES
NAME OF STRUCTURES
Outlet
2
Location
9+143
Irrigable Area
1.89
11.00
Inlet
1737.88
Outlet
1736.28
Types Adopted Type 2 
Separated
Off-take with pipe I 9+ 160
256.5
0.327
4.00
1736.27
Type 6
Drop
9+240
2616
3691
1.60
2.20
1736.23
1734.63
Type 3
9+340
1.60
2.20
1734.58
1732.98
9+400
1.60
2.20
1732.95
1731.35
9+460
1.60
2.20
1731.32
1729.72
Inlet
9+500
0.145
1.10
Type 2
Drop
Drop
9+520
2.616
3.691
1.60
2.00
1729.69
1728.09
Type 3
9+580
1.60
2.00
1728.06
9+720
1.60
2.00
Off-take with pipe J
9+756
101.4
Drop
0.137
■L72A.77
Type 1
9+800
2616
3.691
1.60
2.00
1722.1-
Type 3
9+860
Inlet
1.60
2.00
10+000
Drop
0.145
1.10
Type 2
10+020
2616
3691
1.60
2.00
10+080
10+160
1721.44
Type 3
1.60
1.60
2.00
7 nnORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
•
B
D
L
Locatio
Inlet
n                  Structure
Outlet
Types
Adopted
R
82
Drop                   si
10+260
2616
3.691
1.60
2.00
L716.52 L
714.92
rype 3
83
Inlet                    ]5
I Of390
2.5
0. 145
1.10
Type 2
84
Drop                   52
10+400
2616
3.691
1.60
2.00
1714.85 1
713.25
Type 3
85
”                      53
10+560
»t
ii
1 .60
2.00
1713.18
711.58
ti
86
"                       56
10+760
II
n
1.60
2.00
1711.47
L709.87
ii
87
Drop cum culvert 6
10+950
•1
II
1.60
0.8x2
8.00
1709.78
L708.18
Type 3
88              Off-take with pip
' o)10+960
135.3
0.2065
0.30
9.0
1708.17
Type 3
—
80
Prop               55
11+0.20
2616
3.691
1.60
2.00
1708.14
1706.54
Type 3
°0
”                56
11+100
it
1.60
2.00
1706.50
1704.90
k L
01
”                57
11+160
«i
ii
1.60
2.00
1704.87
1703.27
rL
02
”                58
11+260
u
ii
1.60
2.00
1703.22
1701.62
pL
03 1          "                  59
11+680
it
ii
1.60
2.00
1701.51
1699.91
94
” 60
11+-740
it
ii
1.60
2.00
1699.78
1698.18
95            ” . 61
11+800
it
ii
1.60
2.00
1698.IS
1696.55
96
” 62
11+-900
it
ii
1.60
2.00
1696.50
1694.90
97 | ()ff-take with pipe)              io)11+984               64
0.1377
0.30
9.0
1894.85
Type 35
3
ORGANIZATION OF STRUCTURES
NAME OF STRUCTURES
Drop
Off        take        with        pip'? Drop cum culvert 7
102         Drop                    65
103
Location
Irrigable Area
124-140                        2616 124-340
llj 124-400                       88 12+436                    2616 124-580
124-640
1.60          2.00
1.60          2.00
0.1377
3.691           1.60
1.60          2.00
1.60          2.00
Location
Inlet           Outlet
1694.78 1693.18 1693.08 1691.48
0.30         3.00       1691.45
0.8x2          8.00       1691.43     1689.83 1689.76     1688.16
1688.13     1686.53
Structure Types
Adopted
Type 3
*
104
124-720
1.60
2.00
1686.49
1684.89
it
105
12+800
1.60
2.00
1684.85
1683.25
it
106
Off take with plp<
2 124-860
310.7
0.482
1083.22J
Type 2
Drop
124-880
2616
3.691
1.60
2.00
1683.21
1681.61
Type 3
107
108   I ••
109    / "
110 1 “ 72 1
111]
70
71
|  124-940
j         134-000
134-080
13+140
13+200
1.60
1.60
1.60
1.60
2.27
2.00
2.00
2.00
2.00
73                      ±
1681.58 1679.98
1679.95 1678.35
1678.31 1676.71
1676.6S 1675.08
1675.0- 1672.78Separated
112 i      Drop cum culvert8 j
»
i
iORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B’
D
L
Location
Inlet
Outlet
Structure
Types
Adopted
Remarks
IB
Off take                      1
13+245
403.0
0.563
1.00X2
1672.78
Separated
114
Drop                        74
13+320
1 1 74
1 .657
1.60
1.50
1672.74
1671.14
Type 4
115
II
75
13+420
it
ii
1.60
1.50
1671.09
1669.49
»i
116
If
76
13+560
ii
ii
1 .60
1 .50
1669.42
1669.82
ii
117
If
77
134668
ii
ii
1 .60
1.50
1667.77
1666.17
it
Drain - l
118
• 1
78
13.020
ii
ii
1.60
1.50
1666.04
1664.44
a
110
II
70
134080
n
♦i
1.60
1.50
1664.41
1662.81
ii
120
n                            80
144036
ii
ii
1 .60
1.50
1662.78
1661.18
it
Drain-2
121
n
81
14+0.80
it
ii
1.60
1.50
1661.16
1659.56
• ii
122
fl
82
14+140
ii
ii
1.60
1.50
1659.53
1657.93
ii
123
8 3
14+180
ii
ii
1.60
1.50
1657.91
1656.31
ii
Drop cum culvert 9
14+280
ii
ii
1.60
0.8
8.00
1656.26
1654.66
Type 4
Drain 3
125     Off take with            pipe
13)     14+295
22
0.0688
0.3
4.00
1654.65
(1654.6:
Type 6
126     Drop                             84
14+380
1174
1.657
1.60
1.50
1654.61
1653.01
Type 4
127     Drop                             85
14+420
II
ii
1.60
1.50
1652.99
1651.39
Type 4
128
" 86
14+460
II
it
1.60
1.50
1651.37
1649.77
129          rt
87               14+500            II
M i
ii
1.60         1.50
1649.75       1648.15     ■                    Drain"^
<0
O
IORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
II
B
D
L
Locat ion
Inlet
Outlet
Structure
Types Adopted
Remarks
130
Drop                    88
141540
1.174
I .657
1 .60
1.50
1948.13
1646.53
Type 4
131
Off take        with pipe
1414 1 545
95.6
0.1377
0.4
28.00
1646.53
1646.23
"5
132
Drop                    89
141580
1.174
1.657
1.60
1.50
1646.51
1644.91
"4
133
ii                        90
141620
ii
ii
1.60
1.50
1644.89
1643.29
ft
134
ii                        91
141700
ii
ii
1.60
1.50
1643.25
1641.65
h
135
ii
92
141780
ii
it
1 .60
1.50
1641.61
1640.01
ft
136
it                        93
141880
ii
ii
1.60
1.50
1639.96
1638.36
it
137
ii
94
151100
ii
ii
1.60
1.50
1638.25
1636.65
if
138
it                        95
151180
ii
ii
1.60
1.50
1636.61
1635.01
a
FT
139
96
151275
ii
ii
1.60
1.50
1634.96
1633.36
140
ii
97
151360
ii
ii
1.60
1.50
1933.32
1631.72
it
141
ii
98
151440
ii
ii
1.60
1.50
1631.68
1630.08
rr
142
ii
99
151540
ii
ii
1.60
1.50
1630.03
1628.43
ri
143
Off take        with pipe
15     151630
89.5
0.40
28.00
1628.38
628.08
Type 5
144
Drop                     100
151640
1.174
1.657
1.60
1.50
L628.38
1626>2£..
Type 4
145
ii
101
151800
ii
ii
1.60
1.50
626.70
625.10 |
1ORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Location
Inlet
Outlet
Structure
Types
Adopted
Remarks
146
Drop cum culvert 1(
15+940
1.174
1 .657
1.60
0.8
8.00
1625.03
1623.43
Type 4
147
Off fake with pipet
>16+040
114
0.206
0.4
3.00
1623.40
1623.40
Type 7
148
Drop                    102
16+-060
1.174
1.657
1.60
1.50
1623.37
1621.77
Type 4
149
Culvert
16+540
•1
it
0.15
2.22
0.8x2
600
1621.53
1621.38
Type 6
ISO
Drop                    103
17+000
II
ii
1.45
1621.15
1619.70
Type 7
1S1
Culvert                  12
17+140
»»
ii
0.15
0.8x2
600
1619.63
1619.48
Type 6
152
"                   13
17+750
'll
ii
0.15
0.8x2
600
1619.18
1619.03
Type 6
-
153
Off take with pipe
1 7 + 760
56
0.1377
0.3
300
1619.03
Type 9
154
Drop                   104
17+800
1.174
1.657
1.45
1619.00
1617.55
Type 7
155
”                       105
17+880
H
ii
1.45
1617.51
1616.06
Type 7
156
” 106
17+960
m
ii
1.60
1.50
1616.02
1614.42
Type 4
157       ”                       107
18+060
it
ii
1.60
1.50
1614.38
1612.78
it
Drain 2
158       ” 108
18+120
ii
H
1.60
1.50
1612.74
1611.14
ii
150       ”                       10Q
18+200
it
ii
1.60
1.50
1611.10
1609.50
it
1 160 " 110
18+260
it
ii
1.60
1.50
1609.47
1607.87
•i
1 161 1 ” 111
18+300
ii
it
1.60
1.50
1607.85
1606.25
irORGANIZATION OF STRUCTURES
No. |
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Locatic
Inlet
m
Outlet
Structure
Types
Adooted
Remarks
162 1
Drop cum culvertlA
18+ 345
1.174
1.657
1.60
0.8
i.00
1606.23
L604.63
Type 8
Drain 9
—
163
Off take with pipe
18)18+ 355
91.6
0.137
0.3
3.00
L604.63
Tvpe 8
164
Drop                    112
184- 380
1.174
1.657
1.60
1.50
1604.61
603.01
Tvpe 4
165
"                        113
184- 440
ii .
it
1.60
1.50
1602.98
1601.38
n
166
"                        114
184- 500
ii
ii
1.60
1.50
1601.35
1599.75
99
167
"                        115
184- 560
ii
ii
1.60
1.50
1599.72
1598.12
99
168
" 116
184- 640
ii
ii
1.60
.1.50
1598.08
1596.48
It
-
169
“                        117
184- 720
ii
ii
1.60
1.50
1596.44
1594.84
*
170
Drain 10
" 118
184- 800
ii
ii
1.60
1.50
1594.80
1593.20
*
171
”                        119
18+ 880
ii
ii
1.60
1.50
172
1593.16
Drop cuid culvertl5
1591.56
h
18 + 940
ii
ii
1.60
173
Drop                    120
0.8
8.00
1591.53
19 + 000
1539.93
Type 4
ii
ii
1.60
1.50
1589.90
1588.30
it
174
121
19 + 060
ii
ii
1.60
o
1588.27
1586.67
—
1 / j
176
177
ii
122
123
”____________ 124
19 + 140
19 + 220
19 + 28q
ii
ii
ii
it
ii
ii
1.60
1.60
1.60
//
//
1586.63
1584.99
[1583.36
1585.03
[1583.39
1581.96
ii
ii
—I-------------- Drain -1\
1 Type 7
\U. xl'iJViiK.ORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Location
Inlet
Outlet
Structure
Types Adopted
Remarks
178
Drop                        125
19+340
1.174
1.657
1.60
1.50
1581.93
1580.33
Type 4
179
2 126
19+420
ii
ii
1 . 60
i sn
1580.29
1578.69
ii
Drain 12
180
127
19+520
ii
ii
145
1578.64
1577.19
Type 7
181
Out let                         3
19+550
1.014
1.60
0.80
3.00
1577.18
Separated
182
Off take with          pipel
9 19+560
32.3
0.0688
0.3
3.00
1577.17
Type 8
183
Drop                          128
19+580
1.174
1,657
145
1577.16
1575.71
”7
184
it                           129
19+640
'n
ii
1.60
.1.50
1575.68
1574.08
"4
-
185
ii                           130
19+700
ii
ii
1.60
1.50
1574.05
1572.45
ii
186
ii                           131
19+800
it
ii
1.60
1.50
1572.40
1570.80
•  it
Drain 13
187
ii
132
19+920
it
ii
1.60
1.50
1570.74
1569.14
ii
188
ii
133
20+000
it
ii
1.60
1.50
1569.10
1567.50
ii
189
ti                           134
20+060
it
ii
1.60
1.50
1567.47
1565.87
ii
190
it                           135
20+140
ii
ti
1.60
1.50
1565.83
1564.23
it
191
Off take with          pipe;
0)20+155
273
0.413
0.60
2500
1564.22
1563.92
Separated
192
Drop                          136
20+260
1.174
1.657
1.60
1.50
1564.17
1562.57
Type 4
Drain 14
1ORGANIZATION OF
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Location
Inlet
Outlet
Structure
Types
Adopted
Remarks
193
Drop                   137
20+400
1.174
1.657
1.60
1.50
1562.50
L560.90
Type 4
194
fl                       138
20+700
1.174
1.657
1.45
1560.75
L559.30
Type 7           J
)rain 15
195
Culvert                    16
20+760
755
1.065
0.15
0.8x2
600
1559.27
L559.12
Type 6
196
Off take       with pipe
21) 20+J 70
42
0,0688
0.3
3.00
1559.12
L559.12
Type "
197
Drop                      139
20+800
755
1.065
1.60
1.30
1559.10
1557.50
Type 5
198
Drop                      140
20+880
it
ii
1.60
1.30
1557.46
1555.86
*/
199
n                         141
20+960
• ii
ii
1.60
1.30
1555.82
1554.22
n
-
200
it
142
21+060
it
it
1.60
1.30
1554.17
1552.57
//
201
it                         143.
21+140
ii
ti
1.60
1.30
1552.53
1550.93
//
202
ii
144
21+200
ii
it
1.60
1.30
1550.90
1549.30
//
Drain 16
203
ii
145
21+340
ii
ti
1.60
1.30
1549.23
1547.63
//
204
ii
146
21+460
ii
ii
1.60
1.30
1547.57
1545.97
H
205
it                         147
21+580
ii
ii
1.60
1.30
1545.91
1544.31
h
206
ii
148
21+680
ii
it
1.60
1.30
1544.26
1542.66
n
207
it                          149
21+800
ii
ii
1.60
1.30
1542.60
1541.00
n
-
'9organization of structures
No.
NAMF OF
STRUCTURES
I.or At ion
Irrigable
Area
0
H
B
D
L
Locat ion
Tn Let
Outlet
Structure
Types Adopted
Remarks
20R
Prop cum culvert 17
214060
7SS
1 .065
1 .60
0.6
8.00
1540.92
1539.32
Type 4
Drain 17
200 1
Off take with pipe.
2 21*070
3R.S
0,0688
it
0.3
3.00
1539.32
1538.32
210
Prop                  1 SO
224ORO
7SS
1 .065
1 .60
1.30
1539.26
1537.66
"5
211
”                     1 si
224R2O
•f
1 .60
1.30
1537.59
1535.99
if
212
”                     152
22* 140
f*
it
1 .60
1 . 30
1535.93
1534.33
it
211
Prop rum culvert1R
224S60
•9
ii
1 .60
0.6
8.00
1534.22
1532.62
"4
214
jOff take vith pipe;
1 224S70
3R.0
(\06RR
0.3
3.00
1532.62
1532.62
if
-
215
Prop           1S7
224660
1 .065
1 .60
1 . 30
1532.57
1530.92
"5
216
”            ISA
224760
-
V 1
it
1 .60
1 . 30
1530.92
1529.32
■ it
21"
Prep rum culvert 1^
22*010
• •
it
1 .60
0.6
8.00
1529.24
1527.64
"4
J 2 1 R j Of f taVr with pi pr
2*) 22*021
52. 1
0.1377
0.3
3.00
1527.62
1527.62
"9
, 210     p o                       j«,«,
rr
21*0.20
360
0.521
1 .60
1 .00
1527.56
1525.96
"6
.
220
x 2
2341R0
••
I .60
I .00
1525.8^1524.26
if
721
1U
234260
..
ii
1 .60
1 .00
I 524.2cil 522.60
T
if
158
234340
II
ii
1.60
I .00
■
1522.5dlI 520.95
if
1ORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
0
II
n
0
L
Location
Structure
Tn 1 or
Out let
Types
Adopted
Remarks
238
Drop                         170
254000
169
0.521
1 .60
1 .00
I 502.24
1500.64
Type 6
239
”                            171
25♦080
h
ii
1 .60
1 . 00
1300.39
1498.99
ft
240
"                             172
254180
ii
ii
1 . 60
1 .00
1698.92
1697.32
it
241
"                             173
.’51260
ii
H
1.60
1 .00
1492.27
1695.6/
ii
242
"                             174
254360
H
H
1.60
1 .00
1695.61
1494.01
ri
24 3
Drop cun culvert 21
25+450
ii
ii
1 .60
8.00
1693.95
1492. 15
T'/p- 5
244
Off take with pipe
28 ) 25+450
41
0.068*
0.3
6.00
1692.34
Type 6
245
”                   29
254-460
29.8
0.0681
3.00
1692.36
Typ«> 6
240
Drop                         175
254-480
369
0.521
1.60
1 .00
1492.32
1690.72
Type 6
247
”                          176
254560
ii
ii
1.60
1 .00
1690.67
1489.07
it
24S
”                          177
254620
»l
ii
1 .60
1 .00
4889.0 1
1487.43!
,,
249
”                          178
254680
II
ii
1 .60
1 .00
1       . 19
1485. 79^
it
250
”                          179
254740
II
ii
1.60
1 .00
1683.83
1484.23,
•I
251
”                          ISO
25+840
II
H
1.60
1 .00
1484.08
1482 48
ii
 1
252
" 181
24+920
II
H
1.60
1 .00
1682.41;
1480.83,
•f
253
"                          1S2
25+980
II
ii
1 .45
1480.79
1479.34,
Type *
1
D
^0ORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Locat ion
Inlet
Outlet
Structure
Types Adopted
H emar xs
223
Drop                          159
23+500
369
0.521
1.60
1.00
1520.84
1519.24
Tvpe o
224
" 160
23+640
ii
ii
1.45
1519.15
1517.70
'■ 8
225
Culvert                         20
23+950
ii
ii
0.15
0.8
600
1517.50
1517.35
••1
—
226
Off take with pipe
25     23+960
42.9
0.0688
0.3
300
r■
1517.35
1517.35
” 11
227
Drop                        161
24+020
369
0.521
1.60
1.00
1517.30
1515.70
"1
"0
228
Off take with pipe
26     24+090
48.2
0.0688
0.3
600
1515.04
1515.5-4
r.                                               —
229
Drop         162
24+140
369
0.521
1.60
1.00
1515.62            15U.02
'• 0
230
”              163
24+300
ii
ii
1.60
1.00
1513.91
11
1512.31
231
”             164
24+420
ii
■■
1.60
1.00
1512.23
1510.o 3
II
232
"             165
24+540
II
ii
1.60
1.00
1510.55
1508.95
II
233
Off take with pipe?
1        24+570
35.4
0D688
0.3
3,00
1508.92
1508.92
” 11
234
Drop                   166
24+640
369
0.521
1.60
1.00
1508.88
1507.28
•' 0
235
"                      167
24+720
ii
0.521
1.60
1.00
1508.88
1505.63
II
236
” 168
24+800
ii
ii
1.60
1.00
1507.23
1503.98
II
237
"                      169
24+900
ii
ii
1.60
1.00
1503.91
1502.31
IIORGANIZATION OF STRUCTURES
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Location
Inlet
Outlet
Structure
Types
Adooted
Remarks
i 254        Culvert                22
26+050
369
0.521
0.15
0.8
600
1479.29
1479.14
Type 7
Off take with pipi
30) 26+060
0.0688
42.5
255
0.3
3.00
1479.13
ii
256        Drop                 183
26+080
369
0.521
1.60
1.00
1479.10
1477.50
Type 6
257           “                     184
26+200
H
ii
1.60
1.00
1477.44
1475.84
Type 6
258           "                     185
26+320
If
ii
1.60
1.00
1475.77
1474.17
ii
259
" 186
26+460
II
ii
1.60
1.00
1474.OS
1472.47
ii
260
“                     187
26+580
II
ii
1.45
1478.39
1470.94
it
261
Culvert                  2 3
261650
II
ii
0.15
0.8
600
1470.S9
1470.74
Type 7
262
Regulator
26+660
(TJ 25.6------------ (K ) 41.5
n.0fiR8
0.0688
1470.74
•
1< Secondary canal l.main canal 1
ORGANIZATION OF STRUCTURES
z
»
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Location
Inlet
Outlet
Structure
Types
Adopted
Remarks
Off take 1
Culvert 1
04-100
597.6
0.827
0.50
0.80
5.0
1913.15
1912.65
Off take 1
0.30
3.0
1912.65
i
Culvert 2
04-900
580
0.773
0.44
0.80
5.0
1897.76
1897.32
Off take with pip
■ 2) "
0.30
3.0
1897.32
"3
14-0.50
0.30
3.0
1997.00
"4
n
0.30
3.0
1997.00
-
Culvert                       3
24-250
529
0.757
0.45
0.80
5.0
1864.0C
1863.55
Off take with pip
» S) "
0.30
3.0
1863.5'
•
”6
II
0.30
3.0
1863.5'
Culvert                        h
24850
311
0.482
0.40
0.60
5.0
1850.1C
1849.7C
Off take with pip k————.
>      i«
0.30
3.0
1849.7(
8
ii
0.30
5/0
1849.7(
Culvert                    5
34-450
188
0.275
0.40
0.60
5.0
1838.8(
1838.4C
Off take with pip
e <?) " . '
1838.40
ro)"
•
1838.Art
Culvert 6
44-0.40      77            •     0.134       0.40
pipe tl
12
it
ii
0.40       5.0       1824.60 1824.20 1824.00
•f
•
1824.00ORGANIZATION OF STRUCTURES
Secondary Canal 1 Main Canal 2
Table 3.1.5
No.
NAME OF
STRUCTURES
Location
Irrigable
Area
Q
H
B
D
L
Locat
Inlet
ion
Outlet
Structure Types
AdoDted
Remarks
Off-take 1
0 + 000
403
0.563
1672.78
1
Culvert 1
0 + 200
373
0.563
0.40
0.60
5.0
1669.34
1668.94
p-------------
Off-take with pi^e
1 0+200
0.30
5.0
Culvert 2
0 + 800
330.5
0.482
0.40
0.60
5.0
1659.08
1658.68
Off-take with pipe
------------ ----- ----------- CO.
2 0+800
0.30
3.0
1658.68
\
Off-take with p|j>^
3 0+800
0.30
3.0
1658.68
J
Culvert 3
1 + 400
260
0.413
0.40
0.60
5.0
1642.20
1641.80
Off-cake with pipe
(1J
1
1 + 400
0.30
3.0
1641.80
J
Off-take with pipe
j          1+850
0.30
3.0
1637.26
•
Culvert 4
2 + 600
87.3
0.413
0.40
0.60
5.0
1629.64
1629.24
Off-take with pipe
ft)
,
2 + 600
0.30
3.0
1629.24
>
)
Culvert 5
3 + 200
61.7
0.137
0.40
0.40
5.0
1617.51
1617.11
Off-take with pipe7
}
3 + 200
0.30
3.0
1617.11
Julvert 6
3 + 800
36.1
0.137
0.40
0.40
5.0
1609.20
1608.80
(
Iff-take with pipe8
3 + 800
0.30
3.0
1608.80
________ r
7 1____ L
Culvert 7 
/ll-Liiku With lllpi:.. 1
? ♦ »8l
1 u. 5
0.06"9"
0.40+
n TH r<r
3.2. ESCAFE CHANNEL.
Escape     channel     has     been     designed     for     evacuating     Inflow     into     main     canals from surroundings and excess flow in canals,and maintaining Aials.
The    existing    natural    drain    will    be    used    as    the    escape    channel    1    Horn    the out let gate 1.
Escape channel 1 from the outlet gate 1.
Escape channel 2 from the outlet gate 2 is provided
at chainge 9 + 163 of the main canal No.2
Its     capacity     has     been     calculated     sc     as     to     discharge     the     water     rejected from the main cnals and from the field irrigation network.
3.2.1.         Calculation cf Ta1 Water (escape channel 2)
tail        water tail water
in    main    cnal    01    :    1.89    ir’/s. in field irrigation network:
Q2 « (0.336 x R - S) C F
« 0.336   > 33 - 8             x C.2 x 181.5 « 2/8 1/s - 0.21.8 m3/s
drair. catchment area F
IE:.5 ha
hourly rainfall for .OX probability F • 33mr.
discharge facto? f : C . 2
drainage water ti*a* ought tc Lx re acted through escape;
0*0.            -»   (.    *     1.89* C.218 -2.11 m.s/s
3.2.2. check • up of ae>< «p« capacity
c « wc /ST
» 2.95 x 3t. 3 /C St > t. 0009 - . . n 5 / s /
Whe i t
Sect ion 'ferea b ( 2 9X hydraulic radio* i - C. velocity coefficient ( - jrDeigned water quantity Q hence ok.
There    are    recommended    9    pcs    of    drops,    3    pcs    of    drain    culverts    and    3    pcs    of inlets. (Ref:Table 3.2.1.)
Drop     structure     Type     4     in     the     sain     canal     has     been     adopted     here,     and     drain culvert and inlet have been given separately.Escpe channel ( 1-2,1000m)
NAME OF STRUCTURES
' ~ 7\ ;
Out let 2 .   n--------------- Main canal No.2
ORGANIZATION OF STRUCTURES
Table 3.2.1
No.
Location
IrriRable
Area
Q
H
B'
D
L
Locat
Inlet
ion
Outlet
Structure Types
Adopted
3
Remarks
0+000
210
1.89
1733.28
Drop structure 1
0+050
2.11
1.60
1735.25
n              h                              2
1733.65
0+150
2.1 1
1.60
1733.58
1731.98
»•             ”               3
0+250
2.11
1 .60
1731.91
1730.31
Inlet structure 1
0+290
65.5
0.058
Drain culvert 1
0+300
2.11
0.25
1.00x2
5.00
1730.27
1730.02
Drop structure 4
0+350
2.11
1.60
1729.99
1728.39
”                    5
0 + 500
2.11
1.60
1728.28
1726.68
Inlet structure 2
0+890
113.5
0.1445
Drain culvert 2
0+900
2.11
1.00x2
5.00
1726.40
1726.15
Drop structure 6
0+950
2.11
1.60
1726.12
1724.52
”                       ”                 7
1+050
2.11
1.60
1724.44
1722.84
— -              — ■ - —■ Inlet structure 1
— --------
Drain culvert 3
1+490
181.5
0.218
1 + 500
2.11
1.00x2
5.00
1722.52
1722.27
Drop structure 8
1+600
2.11
1.60
1722.20
1720.60
---------
”-----------”              Q
1+650
2.11
1.60
1720.57
1718.97- 105 -
4.DESIGN OF IRRIGATION AND DRAIN STRUCTURE
4.1. IRRIGATION STRUCTURES
4.1.1.      Intake Gate 1. of Main Canal No.l
It has been designed that the water coming out through the outlet pipe under the Gaula dam is discharged into the river Weiyb ? • a downstream where topography is well conditioned and the bed rock is stable, and is taken up by diversion weir into the the main canal Jo .I. This intake is supposed to have one outlet gate and overflow crest (8 m in height) so that it may release into the river 13*29 m^ of emergency flow that is dis charged Through the outlet conduit of the dam.
The outlet gate is to supply the dischar ge from the outlet conduit of the dam and reject sediments during operation,
4*1.1.1. Determination of Intake Gate Capacity
In calculation of flow the spillway is planned to be submerged.
in : flow coefficient 0.33?
t submergence coefficient 1.0 b : gate size 3x 1.2? = 3.75 m H : water depth 1.35 mSince     the     design     water     quantity     for     irrigation     in     the     main canal No. 1 is 6.35 m^/s this is beyond necessity..
Calculation of overflow crest legth
Qef = emergency flow 13.29 m^/s m = flow coefficient 0.37
H = overflow depth 1.05 m
1
Crest length B = ----------------- ^sf m/2g H 2
2
_ ______ 13.29 
3
= 5*69 m
0.37/2 x 9.8 x 1.052
design length B = 8 m, hence ok.1
- 107 -
4.1.1.2.  Calculation of Lifting'Capacity of the Gate
Lifting capacity Se = K fPopen + (G +
= 1.2 0.4 x 2.786 + (0.107 + O.O54 = 1.4 T
Whe re:
K : coefficient of operation characteristic
r
f : friction coefficient 0.4 G : weight of gate
Q : weight of spirile Hydraulic pressure against gate
1.2
107 kg 54 kg
P = | r (H  - H )b 
22
open 2 
' 2 
1'
= | 1.0(2.15  - O.8 ) x 1.4 - 2.786 T
22- 108 -
4*1»2. Diversion Weir in Main Canal No2
The irrigation  water streams al •'•ng  the main  canal No  1  into  the river Asend^bo  2.5  km downstream where it continues through  the diversion weir to the main canal No2.
The UBage of 2.5 km of the river course is to decrease the length 
of canal and number6f structures, which make it possible to add 
the water of the river that ha3 400 km of catchment area during operation•
4.1 •2.1. Determination of the Diversion Weir Capacity
Calculation of storm run-off
The storm run-off has been calculated using the formula
f
_6    1   54   1   67 in m3/s
of flood flow worked out ©n the basis of analysis of
the data collected from the adjacent zones.
Formula : Q = 5.7•10  R *  F *
F : catchment area 400 km
R : daily rainfall when 1 % probability
<$> t discharge factor 0.5
= 5.7 X IO-6 X 621’54 X 4OO1,67 X 0.5 =
•= 36.35 m3/s
On this basis overflow crest length is calculated .
Length B = ------------------- ----------— + b’ m ^2 g H—
2
62 mmx*\         \A\ X v XI
\'.V\
x V ’ -X. •'k •
- 109 -
Wherej Q : Flood 
36.35 mVs
H : Spill water depth 0.8 ro
m : O.49
Entrance-related contracted width
b* = O.i/h = 0.1 x 0.9 x 0.8 = 0.072
=------------ -------------- J— + 0.072
O.49 2x9.8 x 1.0 2
= 16.82 m
in design 17 m.
4.1.2.2.          Calculation of stability against erosion on the bed of the diversion weir.
Calculation of length to be sealed off:
C : sand and fine gravel 4*5 0
H : 1.50 m
L = C  H = 4.5 x 1.5 = 6.75 m
q
Calculation of length of converted seepage line
L
o ■ LZ ‘ JL1
Where; : length of seepage line horizontal
or graded less than 45°, 4.65 m 1>2 : length of seepage line vertical or
graded more than 45°, 8 m
L o
 * 8 + J x 4.65 = 9.55 m 1
Since L  = 9 »55 
q
6.75 there will be no erosion in the
weir bed.
4.1.2.3.       Determination of capacity of diversion weir calculation of flow
in case of the overflow submerged;
flow Q = m
hJ inm3/eM : discharge factor 0.385
(T: submergence coefficient 1.0
b : gate size 2 x 1.25 = 2.50 m
H : water depth 1.20 m
Design water quantity in the main canal Q = 5•588, hence ok.
4.1.2.4.         Calculation of lifting capacity of the water gate Lifting capacity:
S L = K f + (G + Q)
P open
= 1.2 0.4 i 3.16 + (0.107 + O.O54)
K    : coefficient of      operational
f     : friction coefficient             0.4
G    : weight of gate                    107 kg
= 1.71 T
characteristic l 2
0
Q : weight of spindjile (d = 50mm, 1 = 3.50m
presumably)
Water pressure acting on the gate
■ I 1 <H2 -
. | x 1.0 (2.J5  - l.o ) x 1.4 . 3.16 T Hence,2 T is proposed of lifting capacity.
54 kg
22Ill -
4«1»2.5. Drawingup of probability curve of maximum daily rainfall
Station 
: Goba
Number of years : 23 (19&2 - 19^4)
CALCULATION OF PROBABILITY RATS
““
m    Year     Ri           v__ Ri
K ’Rav       K - 1         (K -l)2
p = m
n + 0.4
Table 4.1.2.1
x 100
Remarks
1     1?63     56.2
1.49
1.45
0.49
0.45
0.24
0.20
2.99
2
1?77     54.7
7 .26
3
1981     53.2
1.41
0.41
0.17
11.53
4
1978     51.3
1.36
0.36
0.13
15.81
5
1982    41.5
1.10
0.10
0.01
20.08
6
1968    40.8
1.08
0.08
0.006
24.36
7
1972    40.4
1.07
0.07
0.005
28.63
8
1976    39.4
1 .?6
0.06
0.004
32.9
9
1983   39.9
.1.05
0.05
c .003
37 .12
10
1980     38.5
1.02
0.02
0.004
41.45
11
1962     37.9
1.00
0.00
0.000
45.72
12
1973     37.2
0.99
—0 .< 1
0.000
50.00
13
1964     35.8
0.95
-0.05
U.003
-4.27
11
1967     35.7
0.95
-0.05
0.003
58.55
15\
1966    34.1
0.91
-0.09
0.008
62.82
16
1969     34.0
0.90
-0.10
0.01
67.09
1L
1974     32.8
0.87
-0.13
0.017
71.36
18
.1.970    31.0
0.82
-0.18
0.032
75.64
12
-1979  ?9-7.
0.79
-0.21
O.O44
79.91
20
27.40
0.73
-0.27
0.073
84.2
21
1975     25.8
0.69
-0.31
O.u9
88.46
22
19.75  25.8
0.69
-0.31
0.096
92.73
23
1984     23.2
0.62
-0.38
0.144
97
Sum              865.4
1.311
Rav=37 .6- 112 -
AAdj djus usttmmeent nt f faaccttor or : : C Cvv
0.244
i
n -1 Cs/Cv « 2
/      1.311 '23-1
I
■
■
. CALCULATION OF PROBABILITY             Table
*
p %
0.01
o.i 0.5 l 5
10
20
30
KP
2.18
1.93 
1.744 1.6
6 1.43 1.32
1.20
1.10
KP.Rav
82
72.6 
65.6 
62.4 53.76 49.6
45.1
41.4 
-
p %           40         50         60         70         80         90         99           99.9
KP
1.04
O.98 ,0.92 0.86 0.79 0.7
0 O.52 
O.42
1
KP .Rav
39.1
37.0 34.6 32.3 
29.7 
26.3 
19.
.6 15.8
■
i
B
i
i
I
■
I
IJ
■         IN tf. ». A.
I ' /
■ W        A             UI*l*IUNfc
KCUFFtL * (HIM CO.
figure 4J-2.1-
PROBABILITY CURVE' OF DAILY MAXIMUM RAINFALL (G0BA)
1/34 •!.3 • Drop Structures
Drop    structures    are    propsed    17    pcs    within    5,938    m    reach    of    the    maih canal No 1 and 187 pcs within 32,598 m roach of the main canal No 2
The natural ground inclination on which structures are designed 
is I.42 $ in average being very slopy. That is why it is proposed 
to provide lined channel of drop structures so as to ensure safe
flow of water in the canal.
But for the sake of eoonomy  drop  structures are proposed.  They  are divided  into  8  types according  to  design  irrigation  water require ment and drop height.
4*1.3.1. Hydro-engineering Calculation of Drop Structures Calculation of overflow crest width
2.74 m 6-35
£: adjustment factor O.85
Q: design water quantity 6.35 m /s
H : head water at inlet with approaching velocity
J
o
accounted in m
V: velocity in the waterway in m/s
m: flow coefficient 0.43
cX : coefficient of uneven velocity 1.0.Water quantity             per unit width;
6*35
2.74 ’
2.315
Calculation of
stilling basin;
X
A
Zo
^lmt
1.62
0.844
= 1.919
A
To 
^lmt
2.87 '
0.844
3.40
t- yater depth in canal
P - drop height 1.6 m
downstream of drop
1.25
= 1.45
should be provided.
Z^Zo =       cZ q  -
2
1.1 x ,2.319
2g
 02 2 “ 2 x 9-8 XO.95* x 1.25*
t
=0.21 m
Zo’-AZo -4^
1.62 - 0.21 
0344
.
I
When 0 = O.95 we can get = 3.85 from the table.
Calculation of depth of stilling basin (d)
do =                ■ /o)hlmt“ (3‘85 “
3  4) x
-     °’844 = °-88 m
d    =(fd0      +    (</"-    l)t    -    1.05    x    0.38    +    (    I.05    -    l)    x    1.25 «= O.46I m
Hence depth of stilling basin d -
<T : coefficient of submergence = (l.?5 - 1.1).
0.5m i  recommended.
8r. cvl.tirr. ”f ’•Mb of
b "pin
T wu,jr d w t
.
. „ deitb of thr MiHW bM-in
___________ 1 x -
? j o.F y O.o^t
Pietanor ef w«t*r dropped I]
Jv»rjtiF djrtano* 1- * '^lrt“  j
-
. c .O’- (/ .77
1 .6   * 1.25))       2.26
(? x
k
•> l
M(.fc44 - OeM
7.S6
tr
^nrtl e  rt ;inp bMir
r
lanrtl * uprir>nr pr w^tjnr
• 3
E
J x    1 .25 - 3.75 m
ianftl o#
pr Wet j or. *•*
6 E
6  xl .2^ - 7 .5>O m
or th#M *i rwee . otm i.yer 9 4* f 't f typae O* ct j <<rurUr*t.
F i canal depth 1.2^ m
calcu 1 xt^lone h ve bean
F.»aa» mm it* o« . 
» tat .•
-e 4.1 , < . dtj th of "St
fa»»art b- 117 -
4 .) .4 .    CWitr:   pr,p ■T?nrT’rPR i Chu*.« 4rop ) i>
in 41**     *•* r*a*,» tlJ* *• in wan*i
No I. I
ita «trj4tural n 4 l^jn* ter •
;.>ee •J/. of 4i*cb*r«* 
77.74 « of drop o#i«ht tnd
iw ot«-l cipo »*4b *rz*^ “
"*•
Thin    shuts    drop    w    ^••n    chosen    to    decrease    i    $reat    cumber    of    irop 
• truatjrwf' construction ’•**•* 
Isb^r and -soney, %ad to creat*
for     the     future     i     pose-     rweooroe     ty     intilizin<     water     if.         •     scnprsben- s ive »v
HowttVw r, m (Alt lee.jn 11 
dt nioture
*een proposed onXj SxmfMijnof Chute Drop 1
4 .1.4.1. 
 118 -
CalCUl 'tiOn
Discharge Q ■ 5-588 .7
Drop height H i 77 *94
m
150 cm
Velooity Vj »3.16 
/
mQ
V 2 :7.11 m 8
/
Diameter of piPe
Diameter of piPe
Cross section Wl
Pl «
D2 *
: 1.766 m
2
1 0.785 m
100 cm 2 
W2
Discharge capacity Q
~                    = °-259 /14.89
= /4C.&3
At " 0.05
0 3,6 (; ;«7<, ,r) '■          3  o.of6      -+ 8 +2.4j
o./5
Q, = s.see          7%*“56; *
* £ 1 e r trance « ex1e t f z»4-
’ exxex.t, ct1 contraction,
<
'’’tai, ^‘'discharge.
-
0.313
tr:trash rack
Islentht, 
1
e
>...cflife:Ve7.^ = ^8 = 7a2m/s
Bead at exit Cf j.:pe:h c
7 ,122
“ 19.^ = 2.586 m- 119 -
V2
Hoad at inlet of chute droP:0i xet
n        = D + 2 2g
= 1.50 + 2 x 
■ = 2.52 m
Hence 2.55 ™ has been used in the design’
Operation head, at exit of pipe
= 1.0 + 2.536
<0
6
(7
= 3.586
/ ki
•x
r-
in
W)
/
-1 -
*
«• ?
1.
Discharge per unit width at exit of pipe : q = —= (circular converted into re ctangular :b = O.9)
Calculation of Stilling Basin
9  5.588 
r
0 9 ” 0                        m /b
_3 /„
o
limited water depth : h pressurized water depth
3
= 1.577 n
= 1.53 2
1
 3 let
:h P
h
2fconjugate water depth2
Az = — % 0 =
2 2    ■ 2x9.8xo.952xl.25" 2g0 t
Unit water quantity at exit:
Depth of stilling baBin: d 0 e 1.05 h" -
2.242 - 0.18
>o _2O
- AZ
= i.05 X 2.54 - 1.25 - °«20 E 1,22
 I.50 m taken.
c
1
Calculation of Length of Stilling Basin
1.58 x O.58           0.92 1 x 6.202
5.04
9.8 x 0.923
4.1 x 0.92 x 5.4'j0,533
8.93 m
15 “
*1       added to this value, eo the length of stilling basin
w&6
became 10.55         •121 -
4•!*4.2. Hydrodynamical Calculation of of tho Chute Drop
As a retaining wall
Stilling Basin Flank Wall
 tg0 + / (l + ' tg 0)(l -
2
= - tg 14° + = - o.249 +
Earth pressure: Acting point: Z
(1 + tg 14°)(l -
2
th4~. 371 ' th 14 
’
1.062 x 0.676              = 0.593
0.593        +0.08 tg(30.86°+14
= 10.04 x 0.684 = 6 .87 Tm
3
1.12 m
Acting mementt M = EZ             = 6.87 x 1.12             = 7.69 Tm
Calculation of sectional
A
M o     bh2  R
o o
area of steel bar : 769000
100 x 462x 30
0.0454
cJ. = 0.042
F. = C< D
Rc
%1
46 = 7 .36 cm^
Sectional area of
b  h     = 0.042 x
o
16  mm = 2. 0 cm
30
2,100 x 100 x 2
Thus we need 4 pieces of bars per m in arrangement4.1.4.3. Calculation of Steel Pipe's Thickness (Chute Drop)
Condition for calculation
H : water depth max. 77 *94 m
D : pipe diameter 1U0 cm - 120 cm
r : volumetric weight of water 1 t/m^
K : nonuniform coefficient of pipe material 0.8 - O.85
climate coefficient of pipe material 0.8
m^:     climate     coefficient     of     pipe     0.9     (when     there     is     water)
d 1 pipe thickness mm
r
I
2
R t strength of pipe material 2,400 kg/cm
r      .        B      .        D 2     R      K      m^
________ 1 x 77.94 x 100 " 2 i 2,400 i O.o5 x 0.8 z 0.9 =
_
““
= 2.65 x 1.5 = 3.975 mm, if however, operational condition
and erosion are taken into account and
Y^q D is taken,
1,00c
^100 “
130
1,500
- 7 .7 mm = 8 mm
^50 ■
130
*= 11.53 - 12 mm
Hence,
when diameter
is 1,000 mm thickness
will
be
8 mm and
when diameter
is 1,500 mm thickness
will
be
12 mm.,-xs ;
.....
/'
- 123 -
4.1.5. OPEN CHANNEL I
Open ohannel has been designed, from chainage 0 4 OOO to 0 + 3000 of the main canal No 2. The reach contains sand and gravel in the
bed and that is why, in order to prevent loss of irrigation water ^cement lined bed and cment masonry in the wall are proposed.
%
design water quantity : 5.588 m^/s (q) design slope : i = O.GO95
I
bed width t b = 2.U0 m
roughness coefficient : n «= 0.025
4.1.5.1. Check-up of Discharge capacity of the open channel
r
f
Q = W c/r i
3 in in /s
= 2.442 x 35.19     O.576 x O.OO95 = 6.35 m3/s
Wetted area            W = (mh + b)h = (0.2 z 1.1 + 20) x 1.1
Wetted perimeter : X - b + 2h 1 + m2
- 2 + 2 x 1.1 /l + 0.22
W 2 442
= 2.442 n 3/s
Hydraulic radius t R « 
- —4^2 * " " 0*576
Y = 2.5 / 0.025 - 0.13 - 0.75 /O.576 (/ 0.025
- 0.232
4.42 m =
- 0.1)
1
o *c25 X
O.5760,232
= 35.19
[Calculated discharge Designed discharge I
Hence ok•
- 124 - i Q = 6.35 
c
5.588 n?/B
Designed Cross Section of Open Channel
4.1.6. Irrigation Culvert
Irrigation  culverts will be provided  in  the main  canals,  secondary canais.  cana^-crossing  sc in  reads,  secondary  roads and  operational reads.
The culverts that are jrejsec for the ntm canals are divided into
1      tyjies      according      tc      water      quantity      and      structural      characteristics fcjid ether types are ciawn separately.
Type*, fron. 1 tc 5 ire j .^nec to c  cro; t
t              >pfc in c
 ..tiderat ton
of economy.- 125 -
Calculation of discharge capacity of culverts
- Drop-cum*cu lve r ts have been calculated as pressure pipes*
Discharge capacity
l
Whe re; ft -
Design flew being 6*35 s' a, triplex pipe with diameter of 0.8 m is recommended*
Table of Drop—cum—culvert Calculation
Table 4.1.6 .1
Typ«
Discharge
(4’
Diameter ?f pipe
( D'
Pi re length
(L)
Hemarka
1
o . A 4
2.3 x )
y 3
Moe 112 MC  Nol
Mrs 2 1 3 MC  No2
c9
s .->88
0.8 x 3
8
Mce 4 1 5 MC  Mo2
3
} .09
0.8 x 2
8
Moa 6 Jk 7 MC  Ho2
4
L.0f5
o .3
9
Moe 9,10,14, 15, 17,18,19. MC  No2
5
0.53
0 .6
9
5o 21 MC No2
3 .09
0.8 i 2
40
Mo 8 MC Mo2- 126 -
- Drop-oum-oulvert 2 in the main canal No 1 has been designed a6 a ohute-drop type•
Design flow : Q
6.35 m^/s
d ! diameter of pips 0.8 m plus triplex
Hi i W
water depth at inlet 2.5 m
sectional area of pipe 0.502 x 3 = 1*5^9 m
2
Q =/UW /2g(H - (0.708 - 2i ' d)
- 0.67 x 1.51 ,/2 x o.8(2.5 -’(6.70(5 - 2 x O.O45) x 0.8) « 6.35 ni^/e
A6 the design flow ie
pipe with diameter of
6.35 0.8 m.
it is recommended to^rplex
- The irrigation culverts .types 6 &7 in the main canal No 2 and
the culvert 1 in the main canal No 2 have been designed as followsj Calculation cf culvert type 6
Design water Quanttity 1 Q « 1. 657 tr?/s Water depth at inlet 1 E  « 1.0 m
c
t
r  : 0.726 I 0.6
Diameter of pipe : d - 0.8 a Discharge Q «= /X W /2g  E  - d ;
f
c
c  0.6 j. O.5'j2 ft * .V \ Sj - 0,7 26 J 6 .H 7 « 0,86m^/6
Duplex pipe Las been designed with diametej of 0.8 n ,
Different types of culverts have been calcuj .tfc
d ahown  tuve and th* 
tt
results are given in the table LejunjTable 4 <>1.6 .2
type
di o chare ge
(Q)
dia. of pipe
(D)
pipe length
(L)
remarks
6
1.657
0.8 X 2
6.0
Nos 11,12,13,16
MC No 2
7
O.521
0.8 x 1
6.0
Nos 20,22,23 MC 2
-
5.588
1.00 X 3
7.0
No 1 MC No 2
4 .1.6.2. In the same provided in
way as given above the culverts that will be the secondary canals have been calculated
To practice          econony off-take
structures for the tertiary
canals have been drawn together with outlet
Embarcing all 6 culverts in secondary canal 1 of the main canal No 1 and 5 culverts in secondary canal 1 of the sain canal No 2 for the sake of convinience, they have been divided into 4 types to be drawn.
of culverts.- 128 -
4.1.7. Off-take, and Off-take with pipe or Turn-out
A structure that bifurcates main canal into secondary 
designated as an off-take and any other structures
with pipe or turnout•
At the end of the main canal No 2 is provided a regulato
4.1.       7 .1.’Calculation of Capacity of Off-take 1 in Main Canal No 1 
Design flow :                   = 0.774 m^/s Fipe diameter :D = 0.6 m
- Q -
/2g(H0
- 0.736 x 0.263 ,/2 x 9.8 (1.25 - 0.726 x 0»6) « 0.634 e"/s
Where: E  • E « 1.25 m
o
Eydraulic radius: R = ——- «= ■ Velocity coefficient : C = 52.06
e  0.15
-     0.738
2 y .8 y 7 52.06* x 0.15
Thai ia the
Lupucit) u!
!. Leei. calcuuledOff-take with pipe or turnout is classified into
12 types to be drawn.
Calculation off-take with pipe or turnout
Table 4 .1.7 .1
Type
Design discharge
(Q)
Pipe diameter
(D)
Pipe length
(L)
Remarks
I
0. 344
0.4
4.0
Nos 1)3>4>o,
MC No 2
2
0.482
0.6
4 .0
Noe 5 * 12
3
0.206
0.3
9
Nob 8,9 * 10
4
0.137
0.3
4.0
Nob 2 & 11
5
0.137
0.4
28
Nos 14 & 15
6
0.327
0.3 - 0.4
4
Nos 7, 13 & 28
7
0.206
u.4
4
No 16
8
0.137
0.3
3
Noe 18 & 19
9
0.137
0.3
3.0
Nos 17 & 24
10
0.0688
0.3
6.0
No 26
11
0.0688
0.3
3.0
Nob 21,22,23,25 27,29,30
12
0.413
0.6
25
No 2Q
Table 4.1.7 .2
No. of Structure
Design dis
charge (q)
Diame ter
of pive(D)
No 1
MC No 1 0.774
No 1
MC No 2 0.563
0.6 x 1
0.8 x 1
Length of Pipe (L)
7
4
Remarks
included     in     drop- cum-culvert 8
regulator is drawn together in culvert 23 of the main canal No 2 130 -
n citv of Water Gate
- Calculation of Lifting apa
Off-take gate
Water depth before gate Height of gate
Width of gate
Water pressure imposed on
, H = 1-25 ">
, h' = 0.7 m
j b x 0.65 m
the
gate
. P            H2- (H- b')2 ? x 1.252 -
= 0.41 T
(1.25
0.7)
Lifting capacity : S = K(fP + G + Q)
= l.l(0.4 x 0.41 + 0.0228 + 0.015) = 0.222 T It is applicable to lift with O.5 T.
K: Coefficient of operational characteristics — 1 1
O
f: Friction coefficient -0,4 G: Weight of gate - 22.8 kg Q’ Weight of spindJle - 15 kg
Having calculated the lifting capacity 0.2, 0.5 T have been re commended. A lift with capacity of leES th._  ,
n
lifts with capacity of 0.1,
• > 1 win b© manually operated*- 131 -
Application       of       water       gate       is       as       follows       according       to       the       designed       sectional area of canals;
Table 4d.7.3
DRW No
Sectional area of
witer way
Size of gate
79
300 x 300
350 x 400
79
400 I 400
450 x 500
80
300 x 400
350 x 400
80
400 x 500
450 x 500
81
0 = 400
450 x 500
81
0 = 600
65O x 700
82
0 = 800
850 x 900
82
1,000 x 1,030
1050 x 1030
83
0 = 500
550 1 5304.2.DRAIN STRUCTURES’
4*2.1. Outlet Gate
^outlet gates have been proposed in the limited space of canal alignment of 5 to 10 km for the sake ,of operation/and maintenance of the irrigation canals, and disposal of drainage water flown
into the main canals.
Efluent released frdm the sluice gate will be discharged: ‘through natural gullies and drains©
4 *2.1.1. Calculation of inflow toward outlet gate 1
Catchment area : F = 210 ha
Hourly rainfall for 10 % probability : R = 33 mm Discharge factor : 0 = 0.8
Inflow :Q = (0.3336 R - 5)0 F
= (O©3336 x 33 - 5) * 0.8 x 210 = 1,009 l/s 4.2.1.2© Calculation of Discharge Capacity through the Gate
Drop height before pipe
: H  «= 1.10 m
o
flow coefficient :                              /Z = O.591
*1 = 0.726
Diameter of pipe :                              D = 0.8 x 2
Sectional area of pipe                         W =0.5 x 2
Discharge :              =/XV. / 2g<'Ho _^dj
0.591 X 1.0 /2 X 9.8(1.1 - 0.726 x 0.8)
Emergency drainage being considered, duplex pipe of di a. 0.8 m has been proposed.- 133 - Calculation for the outlet gates 2 & 3 followed suit.
Tbale 4«2.1.1
No of
Structure
Chainage
Inflow (Q)
Pipe Bia.
Remarks
1
MC No2
4 + 300
1.009 m3/s
0.8 X 2
2
9 + 143
I.89
1.0 x 1
3
19^+ 550
1.014
0.8 x 14.2.2.        INLET STRUCTURE
Inlet structure will he provided to conduct drainage water coming from minor catchment areas around the main canals to main canals and thus drain it through escape.
15 inlet structures are classified into 3 types according to drainage water quantity.
4.2.2.1          Calculation of inflow water into inlet Catchment area : F = 20 ha
Hourly rainfall for 10 £ probability : R = 33 mm Discharge factor : 0 = 0.8
Inflow : Q = (0.3336 R - 5) 0 F
structure Type 1
= (O«3336 x 33 - 5) x 0.8 x 20 = 96.14 l/s
= O.O96 m3/s
4.2.2.2.          Capacity of Inlet Structure
Q = £ mb /2g
* 0.9 x 0.36 x Q.7 [2 x 9.8 x 0.22 ^
■= 0.103 n /  ,
32
3
s
Inflow:^ «= c.096 n//e ^discharge capacity of inlet structure Q = 0.103 n?/e, hence ok.
Types 2 4c 3 followed suit in calculation- 135 -
Table of Calculation of Inlet Structures
Table 4.2.2.1
Type
Inflow (q)
Width of
Inflow (b)
/
Remarks
L
0.097.
0.7
Nos
1, 4, 5, 69 H
2
0.145
1.10
Nos
2,1, 8, 9,12, 13, 14, 15
3
0.193
1.40
Nos
3 & 10
4*2.3. Road. Toe      Drqin Structure
The main canal goes side by side with the existing main road 
and across the existing road drain. Therefore, in order to 
evacuate water in the £ully it is necessary to provide : drain aqjLeducts which have been added to the drop structures in the main canal•
4*2.3.1. Calculation of inflow into the road toe drain structure 15
Catchment area : F 1.24 ha
Hourly rainfall for 1 $ probability : 47 mm Discharge factor : 0 1.0
Flow: Q = (0.3336 x R - 5)0F
3  (0.3336 x 47 - 5) 1 x 1.24 « 13.24 l/s
= 0.01324 m^/s
4 .2.3 .2. Calculation of drain capacity
.   U.85   x   0*86   x   0.3 « O.OI46 m3/a>
x /2x 9.8 x 0.01
which is adequate to evacuate designed wtaer quantitybit from time to tim
Cross    sections    of    drain    structures    vary    a for the convenience's Sake the floowi S
for No 1 to No 15»
Q b
ction has been recommended
o
30
TABLE OF CALCULATION OF HOURLY PROBABILITY RAINFALL (Goba) Table 4.2.1
Ko.       Tear        Rainfall          kJ-     (K -1)       (K - l)2               P=
 100 Remarks
n + u .4n
(R)
R
1
I960
39.8
1.97
0.97
0.624
0.73
<
1979
32.2
I.45
0.45
0.202
16.35
•s
J
1975
23.5
1.06
C.06
0.0036
25.96
4
1973
*5
1.06
0.06
0.0036
35.58
1972
23 .4
1
0 .06
0.0036
45.19
6
1974
18.8
C £ c
1 c.
—  * y
0.0225
54.8
7
1971
17.3
<Qc
V4
-1 • 2 -
0.0441
64 .4
8
1981
17.3
0.78
< c
- • £
O.O484
74.0
c
197C
f c c
• J X
-0.45
0.202
83.65
1
1976
11 •€
'c✓
• J*
- .48
0.23
93.26
Total
221.8
. .384
Kfa&r rfa.mfa.il pel AG ju fettle nt ffactor
Lcur   1 • —n- . cv . / —~1
, 1 JEj
~ ' 10 - 1
- C\3?9
Lee J.         Cal Cu J a t fa C ext Ct
?cv.I
- 137 -
Table 4.2.2
I
p %
100
1
20
5
10
10
5
20
2YEAR3
50
70
80
90
95
99
I
KP
2.13
1.72
1.52
1.30
o.o95
0.766
0.669
0.541
0.461
0.323
I
I
I
I
I
I
I
I I I I I I I I
I
IIP       47 .24        38.14         33.7       28.83        21.07         16.22         14 .84        12
10.22         7 .1699 99- 139 -
CHAPTER 5 LAND DEVELOPMENT AND DESIGN OF INFRASTRUCTURE
5.1. GENERAL SCHEME FOR LAND DEVELOPMENT
5ol.l. Elements of Design
The Bale-Gadula irrigation project has been designed to arrange, 
in a most sophisticated manner, the villages, roads, irrigation 
and drainage canals, fields and land preparation within the pro
ject area. All these elements should be observed in detail relating 
one with another.
5.1.2o Selection of Design Criteria in General Layout Plan
Selection of design criteria in general layout plan for an
arable land is of great importance•
Taking topographical fe itures into account the layout has been 
planned with the principle that design criteria should be the
main road from Alemkerem village to Kubsa village, the existing 
national road from Alemkerem village to Gadula village and the
secondary canal 1 of the main canal No 2, and all other elements ... 
should obey this design criteria.
5.1.3. Elements of Land Development
- In the project design full cnsideration has been taken - into 
tor all the conditions ot irrigation end steep topographical
features and narrow width of the area, and road space has been 
proposed to be 6uu m x 600 m.
Therefore,     net     irrigated     area     of     one     block     is     34     ha.     and     net     irr igated area of one sub-block is 8.5 ha. with a size of 600 m
x L5< m.
In     most     cases     the     space     between     tertiary     c     male     is     1,200     m and between tertiary drains 6 U m .
It has been designed t use existing gullies as drains.Sub-block Area According to Different Slopes
Table 5-1-1
No.
of
Quar
ter
\ Slope
hrea\
(ha) \
\7'
0.033
0.025
0.02
0.017
1.0125
0.01 c
r
1.0066
0.005
0.005 '
1
•
1
538.1
66.2
144?
123.9
63.5
39.5
52.7
41.6
6.5
2
260.4
54.1
67.7
38.3
55.4
32.9
12.0
3
1063.9
15.9
49.6
171.0
239.1
195.9
208.7
113.9
35.5
34.2
4
634.5
22.5
112.3
178.9
192
56.9
36.5
20.0
15.4
5
88.0
14.4
29.8
33.3
10.5
6
371.6
58.6
44.4
76.9
60.3
36.0
52.7
9
33,7
7
95.6
4.0
11.4
46.5
33.7
8
89.5
15.7
30.6
9
23.4
4.0
6.8
9
505.9
37.4
53.2
117.9
117.9
75.3
65.2
30
9
10
68.7
4.3
44.2
8.6
11.6
11
273.0
1.0
11.2
27.3
105.2
110.4
17.9
12
112.8
12.8
19.2
48.7
27.1
5
13
398.0
11.1
185.5
34.7
11.3
Sub
Total
4500.0
286.9
574.1
1123.
(1077.
8616.6
466.0
221.3
51.0
83.3
0 7.
6.3
12.8
25.0
24.0
13.7
10.4
4.9
1.1
1.8
TotalZ
100
93.7
80.9
55.9
31.9
18.2
7.8
2.9
1.8- ui -
Area According to Furrov' Slopes
Table 5 • !
No. 
of
Quar
ter
\ Slope
\ * 
\rea\
(ha) \
0.01(7.'
0.0066
0.005
1.0033
0 007
1 002
0.0017
3.00125
1
538..
76.1
197.0
3o.O
9.-
8.
27.6
3.7
70.3
2
260.4
3i .0
59.3
6.
48.
8.
22.7
2U.6
33.6
3
1063.0
199.0
357.9
54.8
l-»5.8
99.6
60. ~
4 .0
98.9
4
634.
193.6
229.
'6.0
'01.4
.M
30.8
28.7
J7.0
5
88.0
1“./
29.6
Im . 4
r  . i
3.4
4.5
3.
6
□71.6
1
lo6.4
40.6
38.
31 8
-6.9
.5
21 0
7
JS. 6
5.0
28.7
2m
10.0
8. o
9.0
-.2
r.5
8
89.5
6/
5m. 4
6.4
3.4
2.4
?.A
14.2
9
505.9
118.8
160 3
82 2
47.7
.6
J .8
4.5
31 0
10
68.7
42.0
7.3
8.
7.8
.1
11
273.0
15.9
55.7
5.9
32.1
53.7
28.5
z3.0
58/
12
112.8
25.3
32.1
JO.4
23.9
4.5
4.5
12.J
13
398.0
48.7
77.6
11.7
64.8
46.5
61.0
24.8
62.9
Sub 
Total
4500.0
841.1
1425.4
327.9
600..
^66.7
52j.2
l°6.5
427.1
?.
18.7
7.1.7
7.3
3.3
8.
7.
.2
9.
-
TotalZ
100
81.x
49.6
.2.3
9.0
20. J
3.7
9.- H2-
Area According to Different Angles Between Furrow and Sub bl.
*
*
Table 5-1-3
No. of
Quarter
Angle
Area (ha)
0°
10°
15°
20°
30°
1
538.1
431.7      .
21.2
25.6
30.5
29.1
■
2
260.4
252.0
6.7
1.7
3
1063.9
900.1
17.0
90.3
36.1
20.4
4
634.5
505.2
51.0
12.5
19.8
46.0
5
88.0
88.0
6
371.6
329.8
4.3
14.9
19.2
3.4
7
95.6
86.1
•
8
89.5
65.3
12.4
11.8
9
505.9
426.5
25.5
38.9
15.0
10
68.7
29.1
19.0
12.0
8.6
11
273.0
273.0
12
112.8
89.6
18.7
4.5
13
398
398.0
Sub tota1
450C.0
3874.4
131.6
180.6
183.4
130.6
(2 )
86.0
3.0
4.0
4.1
2.9
Total
100
14
11.0
7.0
2.9
■
■o
Soil Movement for Land Levelling
TABLE 5-1-4
Area According to Class (in ha.)
No. Of
Quarter
Cis
Area
(ha.)
1
2
3
4
5
6
7
Soi 1
Quantity 
(M )
s
Quantity
ha.
1
2
3
4
5
6
7
8
9
10
11
12
13
TOTAL
538.1
260.4
1,063.9
634.5
88.0
371.6
95.6
89.5
505.9
68.7
273.0 112.8 398.0
43.3 25.5
332.4 77.9
5.8
46.5
6.3
18.1
6.4
238.5 103.0 489.7 267.0
27.5
138.0
24.3
38.7
233.5
21.9
74.9
38.9
190.9
148.0
97.5
199.3
107.5
43.5
139.0
55.0
38.8
99.9
31.9
65.1
5.6
142.1
67.9
31.9
42.5
102.9
17.0
78.7
7.5
7.8
52.5
8.6
87.7
41.1
48.0
23.4
30.4
4.9
8.8
4.2
56.5 27.2 12.3
17
8.5
2.5
17.0
5.2
8.5
31.8
17.0
8.5
444,120
200,480
623,910
562,900 76,050
321,830 86,280 73,800
425,710
54,000
255,000
115,070
325,530
825
770
586
887
864
866
902
825
842
787
934
1 ,020
818
4,500.0
562.2
1886.8
1173.2
594.1
184.7
58.7
40.3
3564,680
792
%
12.5
41.9
26.1
13.2
4.1
1.3
0.9
TOTAL
%
100
87.5
45.6
19.5
6.3
2.2
0.9
Soi1 Quantity per ha
II
II
in class 1 -300 m’
II
II
II
II
"
2.-600
II
II
II
"
3.-900
II
II
II
"
4.-1200
II
II
II
"
5.-1500
II
II
II
"
6.-2000
11               7.-2500- In the project design it has been planned to leavJUs they are, the villages such as Gadula, Donene, Alemkerem, Volte? Nagea(Solemitana) and Kubaa that are 4 - 7 km apart fr?m one another within the projeot
v
area. This is because they are located in suitable places to reach the field and from one to another. One village consists of 160 to 25'0 families and there re some 940 families altogether, 
and total area taken by villages is 20'9 included).
(36 ha. for schools
One country house has a floorage of 1,800 m , which is very wide. More space has been given for the future dwelling houses in the design, cultural facilities and production purpose buildings of which total space is 318 ha.
Uncultivated area is found for further expansion around the existing villages.
5.2. LAYOUT PLAN OF FIELD BLOCKS AND LAND LEVELLING
5•2.1© Layout Plan Of Blocks and Sub-blocks
Planning of blocks and their sizes should be observed in relation with comprehensive mechanization of agricultural activities, irrigation and drain system and land levelling • Topographical features and natural slo;es should also be taken into account.
In the design of the project every specific condition has been observed and analysed such as uneven topograjhy, steep elp^ee, long and narrow shape of the jreject area and furrow irrigation and we came to the conculueion that 600 m y. 6 JO in size of a
block is nost suitable and sub-block 6 JO m in length and 1^0 01 in widthattention has been paid to decide the direction of furrows of a sub block as paralel with the countour lines as possible# That is, in order to acquire optimum angle of the furrow direction with the contour, thorough ob6evation has been made within a quarter, while trying to arrange the sub-blocks to have inclinations of 0.007 to 0,002 %•
Deep gullies and national roads divide the area into 13 qarters
which are again sub-divided into blocks and sub-blocks.
Blocks amout to 1% with net irrigated area of 34 ha and sub-blocks 673 with net irrigated area of 8.5 ha.
5.2.2. Land Levelling
Land levelling is a soil movement to supply one-sided slope within a sub-block for a successful operation of furrow irrigation and drainage and agricultural activities.
Attempt has been m .de to minimize quantum of land levelling work and thus supply uniform slope within a sub-block. But
in a sub-block with grat difference in original slopes non-uniform slopes h ;ve been given. In this case a check dam had to be supplied as a boundary.
Furrows are laid vertically to the longer side of the sub-block keeping in view the conditions for irrigation and mechanization 
and when macrorelief levelling is required they have been given at external angle to the longer side of the sub-block.
Soil movement calcul ution has been done with sub—block as unit. In order to ensure accurate calcul -.tion of soil movement 40 standard aub-blocke with different sloj.es and reliefs have been chosen •Soil movement per ha has been follows;
Class
- 146 - classified
Description
into 7 classes which are
as
1  very undulated, compressed and protruded blocks
2          undulated, compressed and protruded blocks
3          very undulated blocks
2,000 h
1,500  "
4 
blocks
with a lot of reliefs
5 
blocks
with reliefs
6 
blocks
with a few reliefs
1,200 '•
900
600 
"
7 
blocks
with few reliefs
300 
"
Following are the hectres according to class.
Calculation       resulted       in       ftal       soil       movement 72$ in average.
r f 3,564,680 m3                    and per ha of5 <3. DESIGN OF ROAD SYSTEM
5*3 .I. Arrangement of Roads
Road is an important means to facilitate successful agricultural production and smooth management. Arrangement of road system sh ould be abserved in relation with size and Bhape of field and arrangement of irrigation and drainage canals •
In this design full consideration hvs been taken of about the location of villages, topographical features, size of field, comprehensive mechanization of farnr work and arrangement of irrigation and drainage canals, and road spacing has been re commended to be 6Ov x 600 m in most cases •
The project area being long and narrow in width, main road and field road are considered major road system and highly used ones are inter-connected by connecting roads.
The national roads that run through Alemkerem village, Donene village and Gadula village toward Ginnir is very useful.
Newly     designed     main     road     is     suggested     to     go     from     Alemkerem     upward, the dam site through Woltenagea and Kubsa. With the main raod as
axis, field roads have been designed with spacing of 600 ,m.
5.3.2. Design of Rooads148 -
Total length of roads and surfaced section
Name of road 
length (mJ
Surfaoed (mJ
Hain road
17 ,500
17,500
Connecting road
18,810
. 18,800
Field road
12b,030
35,930
Total
162,340
72,240
- Width and thickness f read
Kame of roud
T r v-idth (in)
Thickness
Main road
6
50
Connecting road
5
40
Field road
4
30
Horizontal
hag* o* r ,.c
Ha in ro*c
Connect; fag roac
Fln . Horj radius
50
15
- VertjetJ curvet
Vc rt 1 < a - curvet 11. u..
j o.e.1 t 1 
. c
lit t J LCtC
ul 1 lneliniticn
cUld It It aOVlfcaUfc 11
j i DVltU itbi
thal.
a uf
v* j C j dm j ourv*
11. the roOfi w-tX. t . 1 */.
t 1 oj*e and aft
cl which
UMJt.
than <0 u of
Vertical curve with .
. t e J 4 -) e t j j             nV .fltd .In this projeot al’ the roads will go along the flat and almost
flat areas which made unsensible to have drawn road longitudinal sections «
Road toe drain
It is prrequisite to protect erosion by water flow and to ensure
safety of the road and therefore, road toe drain should be provided without conditiono
Cross strucutre on the road
When the road comes across a small drain and irrigation canal, concre culvert is provided and when g~mg across wider drain, an Iri3g 
road given. At the junction of the small river down the Kubea village
a bridge ha6 been proposed.nr ’G* 'V ]RF]aAT]OF n]!
*-•<•}. Pi rt ribut j nr «f Cnnn) "trurtuT*i» TVrt • v;» , mM* rnar.v , F i a 1 d Canale
Tabla 5>4.1
Cana] Er trne j or
Ku"b»”f of FtTMCtVT>P
T ctai
3rd
dtt
F i a 1 d      Tola
Ou . v t
Pmj
**hu  t* 
droj
Tu     rn- ou t
Lined 
canal
■ J*
ktt
>w
--
i
Kr
r*» .
FC* 
/  -
jer
t
r. suc
t
T«"
TO"
Jfce
?7t .48
W .3
t <O"
--•-
__
Q*
Q7
c
J77
7
Lar        h>
L.  -
.(*4 
>—■■■■, J
0.0067
-
( .. i<    < . <-;
< .2?
. ??
c .uoi
. 184
0.002
- -                                ■ 1 . ■■—J
• X . *                Be            hirrvw
Mu.'ior crofH ,r-w< i» H>» fn>d .r>* oi* wb«at
•Rd a a l re |
that l» planted
lanted in furrow*,
• I | 1 led       U     ’hr inaant det
/•
AT
J
4K
4
oe
I
r
i
r
J
4
ce
Fw 4 i *i.ei«/ lj
I « . 4 t-^l 1 hf ».ii
4A
t Ju
la -
£ a«at I a
4i
.a«•- 151 -
I4 5 *4
ClI**j
f i n * 11 on
1 -0 .01
i **) • >67
i *'».• ^>
7i - ' .''''33
i «0
i eO /Xtf
ix.xn
1 •"/ • >0 1 J ,
4  *)<J<) h 
t
4 841
1425
328
6-X
367
325
l* >A7 
477
FHtlo i
18.7
31.7
7.3
212
8.1
7?
-,
22,
9-5
• In              tub-b I odeu furr-ww
of tn<    plot •
5*4.5. W«twr Appiicitirr • ■ **-- <«
- Unit fw-wn tV.*- |UiH‘, jtj -er j
nn
> —   ?•-*, 
in
*,o to* *. ;n^r ilia
.4^              9,
Hu .w
n^.-. .i .aL«.-vd 3 
1a/<
.                u Jur-^u *n x«v *4 ***•
’ .. 1
a.’
l 4 lean L
!•>
M k - *SJ     •-
U C 4.•
4
Hj
kU
*• 
a
-4
*
fUBMw
*A I, *
•*«    *4 4- 152 -
-Increment of unit required water due to irrigation operation
Daily irrigation unit has been recommended as sub-block (B = 59^ m, 1 - 144 m, about 8.5 ha).
There will be no nighttime irrigation in principle and so 2 shifts daily for only daylight irrigation i.e, in each shift 2 hours of preparatory work and 6 hourB of irrigation operation sug.ested. In this case 4»25 hectares of field would be irrigated in each shift period and assuming
constant     irrigation     period     as     2.8 
n 
hr     in     c'nsieration     of     the     soil-     ’s     intake
d
capability, water required by one furrow would be increased as follows^
q =
- Evaluation of irrigation duration
qi hr = u.302 l/s
Following is the water quantity required by one furrow during a given period of irrigation interval(6days);
6 x 100 x ETcrop
7
= 3035.3 1
Results of infiltration rate in the project be low;
Ko. of
area are given in the table Table 5-4.3.
measured 
point
Initial intake
cm/hr
Last intake
cm/hr
Ave rage
cm/hr
Remarks
1
c c
X • >
3.1
4.3
2
4.12
2.9
3.515
3
2.25
3 .5
2.375
4
2.4-
1
1.70
5
2.10
0.9
1.50
6
1.78
0.6
1.17
7
J .9
o.A
O.65
Average
?.8€
J .486
2.1/2As shown in differences
- 153 -
the aboi ve table, the values from one another. Therefore,
last intake          has been obtained, and again
taken from 7 places have big average value of initial and average value taken from 7 places
which is assumed a6             the design infiltration tempo, then infiltration
rate in the furrows
is as follows;
Mf = K x W 0.5 = 1,087 in 1
Where; K = Infiltration rate
W = Area of a furrow M^= Infiltration rate
per
hour 21.73 mm/hr
2
100   m
per hour in 1
Duration of seaseless irrigation ;
Where ;
t = Duration o
f ceaseless
irrigation
- Evaluation of furrow
discharge
capacity
Table 5.4.4
i=0.01
i=0.0067
i =0.005
1=0.0033
i=0.0025
i =0
h
B
m
V
Q
V
Q
V
Q
V
Q
V
Q
V
Q
m
m
m
m/s
m^/s
m/s
m^/s
m/s
m^/s
m/s
m^/s
m/s
m^/s
n/e
0.05
0.10
1
0.21
0.
0015
o.l7
0.
0012
0.15
0.
001
0.12
0.
0008
0.11
0.
0007
0.10
0.
0006
0.
075
0.10
1
0.26
0.004
0.22
0.
0030
0.19
0.
0028
0.16
0.
0022
0.13
0. 001Q
0.12
0.
0016
rO a- 154 -
As seen in the above table, when furrow depth is within 5 cra w^ter application will not problematic for whatever 6lope of furrow is. However, as furrow discharge capacity is by far higher than unit required water, providing a condition for water lingering will make possible for the furrow to intake water in a shorter period of time, which nesessitstes providing such condition to shorten irrigation
hour.
Furrow chech-dam
Furrow chech-dam is compulsory to ensure consistent irrigation in the furrow. Chech-darn could be taade of plastic bag or cloth filled up with earth or of steel or vinyl plate. But what has to be cared for is
that any chech-dam should be lower in height than the maximum depth of furrow to avoid flowing over a ridge to another.
Chech-dams should be spaced at different distances and with different sizes. That is, the critical water depth is 15 cm , when the spacing should be 1C c for furrow slope i = 0.01, and 50 m for slope i = 0.002 etc.
Usage cf syphon tubes
Syphon tubes ere usee for conveying water over the field canal bank into furrows.
Here is the formula tc de tern me the discharge capacity of a syphonj <*              e EoWhere; Q = Discharge of a syphon in m^/s W = Sectional area of a syphon at exit
in m
H=
o
Difference      in      head      between      inlet      and outlet of a syphon 0.2 m
/X = Discharge factor
Sum total of loss coefficient
* n - 0.009
Discharge   Capacity       of Syphons and their Number Required
Table 5.4.5
Dia.
Velocity Dis
charge
Commandable
Number of
syphons Number of
in mm
in m/s
in l/s
number of
syphons required
furrows
required per ha
for eaoh shift
r20
1.18
0.35
1
100
428
30
1.23
0.85
2.4
42
178
40
1.26
1.54
4.4
23
96
t  5°
1.28
2.44
7
15
60
The syphons in the table above with different diameters are for Q = 0.302         1/b and required for constant irrigation.
In order .tc^horten irrigation dur^tion'it is neoessary to ohoose a suitable one for discharge capacity of a furrow, i .e, a 50 nun dia syphon with discharge capacity of 0.604 l/s will be able to feed 4 furrows .
It has been proposed to plan 25 % of each size syphons required for every shift assuming constant flow into furrows as 2.8 hrs.- 1% -
Relationship between field, and syphon
Field, canal capacity is;
q’ x n
Q = ~--------------- = 63 l/s
Where; Q = Discharge capacity of a field canal l/s n = Number of furrows fed in each shift 848 
q^= Water required by one furrow 0,0706 l/s >1- Field canal efficiency   95 %
e
Distribution of sub-block's slopes in Percentage
Table 5-4.6
X^lope
Classi, ficatiorS
0.033
0.025
0.02
0.0167
0.0125
0.01
0.0067
0.005
4
287
574
11.23
1,078
617
466
221
134
Ratio %
6.3
12.8
25
24
13 .7
10.4
4-9
2.7
Sub-block slopes have close relationship with bed slopes of field canals. Since the clay is dominant in the rroject area the maximum permisible flow velocity in the field canal should not exceed 0.8 m/s0 Bed slopes of the field canals are given accordingly in the table below- 157 -
n = 0.03 
Table 5*4.7
Elements of Section
Q
n no
0.0133
U.01
0.0067
0.005         %
h
B
m
a
b
V
Q
0.06
0.2
0.25
0.75
0.2
0.3
V
0.80
Q
0.07
0.2
0.35
II
II
It
V
0.70
Q
0.07
0.25
0.25
II
II
II
V
0.66
Q
0.068
0.25
0.30
If
If
If
V
O.56
Q
0.067
0.25
0.35
II
II
II
V
0.50
AS can be Been in the above table, when bed slope of a field canal is more than 1.33 % a drop is required to be provided to make less slopy. In order to moderate slope of a sub-block with more than 1.33 % inclina
tion (i.e, 3.33 %, 2.5 
2 $ and 1.67 
24 pcs of check-dams are
required for 3.33 % slope fields, 14 pcs for 2.5 % fields, 8 pcs for
2 % fields and 4 pcs for 1.67 % fields'Vhen drop height of 5 ° is proposed. They are recommended as permanent or proviosional ones.
W hat is suggested here is th t plastic material or imperishable and du — rable cloth should be used as a check-dam which will be installed before irrigation and removed later on rather than costly permanent ones re quiring good quantity of material.
y11
r
t
♦
I
i
«
i
i
*
i
I
I
I
tJ
I
i
4     i*i*«•%- 158 -
Providing bed sope of less than 1.33 $ in the field canal means
more than 20 cm of water depth, which will pose no problems for
syphon usage. However, when abnormal flow (i.e, H^0.2 m) occurs
it is required to highten water level in field canals by using 
a steel plate or canvas as a check-dam.
It is always inevitable to m iko water level of the field canal
20 cm higher than that of the furrow (Z = 0.2 m).
5*4.4. Tertiary and Quaternary Canals
- Tertiary canals take water off from the secondary canals or
in many cases directly from the main canals and distribute
water to field canals. They are what is called connecting canals
as permanent irrigation water ways.
In the project design for the important tertiary canals longi
tudinal sections have been drawn and required structures given.
Eowever,  a layout plan  has been  substituted  for the logitudinal sections in  case that terti try  canals run  over moderate reliefs and have fewer cross-works and commands less than 10U hectares.
Discharge capacity is given below;
Where; = Discharge cajacity of tertiary canal in l/s
K = Area of stmd ird sub-bl'’Ck 8.5 ha
Q = Discharge caj -city of a field canal 63 l/e 1 = Comn. and able area in ha
- conveyance el!jciency of tertiary canal
92 /- 159 -
— Quaternary canals as small sized and permanent ones connect tertiary canals with the field canals.
Plowing of water to the field canals from the quaternary canals will take place through a certain turn-out.
Discharge is as follows in general}
When;l>-S- , 
> 2>
= Q
%  =   2Q
2,     Q4   =  3 Q
Where; Q^= Discharge of quaternary canal in l/s n = number of field canals commanded Q = Discharge of field canal 63 l/s
5Determination
of Irrigation interval and Irrigation Duration
- Determination of daily irrigation hour is affected by irrigation condition and its operational org mization •
That is, if a field were surrounded by banks and had a flat
Surface all over it, it would be possible to feed water constantly all through 24 hours. However, if longitudinal or vertical slope
of a block had a certain tg(/ value, surface irrigation without furrow would sure be impossible. Being the case some labour w?uld be required. What has relation with tgf{ is absolutd^ralue • It
means that furrow irrigation would be unconditional and night time irrigation is unsafe in any case.
Considrering all those factors we tried to avoid night time
irrigation and day light irrigation has been recommended most suitable.- 160 -
It has been propsed to plan 12 hours of irrigation per day and 4 hours of preparatory work, i .e, 16 hours of work period altogether, which will be done by 2 shifts, each 8 hours. Therefore, assuming irrigation unit as one sub-block (8.5 ha),irrigation unit per shift will be 4.25 ha (424 furrows).
Determination of irrig tion frequency has close relationship with agricultural activities and climatological situation and exert decisive influence upon the determination of irrigation structural capacity •
Constant irrigation without interval will maximize the utilization of irrigation works and input and minimize the size of works and construction unit rate which is related with topographical features o
however, in case of non-paddy field irrigation, constant irrigation is not permisible for the sake of management and irrigation interval is inevitable.
There is another factor that influences irrigation interval and that i^physical characteristic of soil.
lased on the analysis cf the physical features of soil in the project area anc climatical data irrigation interval h-s turned out to be
l£ days . lfc days cf inUrv.i. 
; t jfnes’% opacity of all the
structures as against wnen it it 6 days interval. And there is
also a certain diflerence 1 r. maxing best use of rain between when it is short and when it it 1 .ng. Jn nt/.or words when it is shorter
it w -aid be unnecessary to arrmge ;rj;/-.tion for the next interval 1! there were an eicett Ju.j.ialJ auiang given interval.161 -
That is why it has been proposed to shorten the irrigation interval
for the sake of economy if it wore possible to arrange supply of water required for crop vegetation, and to control agricultural management such as planting, weeding, fertilization, pest kiling.
What is necessary here in this case is to provide satisfactory soil moisture content by initial irrigation.- (62-
Orqanization^JieKl Structures
Table 5JL8
length of Canal
Nuinbei •Of sti
>
Total Km
3.16 11.60
9.45 7
7.75 19.40
8.97 22.48 22.15 26.95 22.82 27.83
8.51
Tertia. Canal
Quat. Canal
Field Canal
Total
Culvert
Drop
Lined
Canal
II
II
II Pcs
3.16
II
C-1-1
C-1-1-1
C-1-1-2
C-1-1-3
C-1-1-4
C-2-0-1
C-2-0-2
C-2-0-3
C-2-6-4
C-2-0-5
C-2-0-6
C-2-0-7
C-2-0-8
2           1.65      7.95     25            4
1.2        0.75      7.5       18             4
1.2        0.75      5.05
14              3
C-2-0-9 11.47
C-2-0-10 6.05
IC-2-0-11              5.01
C-2-0-12            16.01
C-2-0-12-1         13.6
C-2-1-0              40.29
C-2-0-13              2.74
C-2-0-U 7.43
C-2-0-15 7.90
0.6        2.85      4.3         8            2
1.41    3.05   14.94     26            4
0.72      2.80      5.45     15             5
2.          4.20    16.28     49              8
1.7        4.20    16.20     35            8
2.2        4.8      19.95     4?            10
2.27      3.6     16.95     36            9
3.58      3.9     20.35     47            10 0.86      1.05       6.6       15            3 0.95      1 7C          S.77      i /             3
0.45      0.90      4.70       e            1
I    0.70      0.90     4.41       4              2
3.26      1.95    10.85     2?            5
1.85      1.95      9.80     24              2 9.45    30.83     42              □ 0.77        '.C“T/        4
1.13       1.76       4.55     10             2 2.2'        <          v.
2.67       7.2       -                2 0.85      4.7         €
1 . 10      5 .£                      2
0.2?       < >         •
2.22    4.30      1090      30
1.20   i 0.9             /
II 5
5
5
3
16
5
12
4
17
7
3
■ucture* Chuta
Drop
II
2
2
1
4
4
7
0. 10 2. HO •
1.40 7.40 7
0.6'         3.17        1
0.45       2.10
0.60 2.9/ 7
0.60 3.00
6.60 2.40
4
Turn- Out
II
14
9
6
6
18
9
23
20
27
23
19
5
10
7
2
19
17
39
4
12
10
11
6
6
1
26
7
5
1
2
1
3
?
4
II
2
/
1
1
1'
4
11
11
C-2-0-16
C-2-0-16
9.82
5.05
C-2-0-19              €.50 C-2-0-20              2.03 C-2-0-21            17.48 C-2-G-22             2.1 C-2-0-23              3.63
1.03
i
C-2-G-24
C-2-0-25
C-2-0-26
3.01
3.60
3.77
C-2-0-27             2.60
C-2-0-26              3.52
C-2-0-29              3.60
c-2-0-30
TOTAL 376.48 30.3 70.97 27' . 1 Or i 9‘
1        377                7Major Works Summary
TAble 5.4.9
Earth Work
Concrete Work
Pcs.
Total
Cut.
Fill
Embank
ment
Total
Form-
Work
C-10
C-15
C-20
Dry
Stone
Masonry
Round
Steel
Steel
Plate
Wooden
Slab
Cui ver’
Drop
Chute Dro| I Off-lake
L j ned
CoHul
Eartli
Cafid J
95
97
7
m3
540
267
834
106
520
143.330
II
345
204
602
72
415 66.730
II
195
63
232
34
105
II
m3
134.65 34.06
223.7 125.4 194.6
II
18.20 1.20
1
1.44
II
106.3
32.8
221.1 10.30
194.6
II
10.15
0.06
1.60
0.80
m2
702
185
1,327
112
_m2
228
48
75
33
kg
215.8 699
kq
2,380
m2
0.28
1.23
766,660
TOTAL
Sum
581
145.537
68,368
629
76,600
599.50
21.80
565.10
12.6
2,326
384
915
2,380
1.50- 164 -
5-5- DESIGN OF DRAIN
5»5*I. Drainage Structure
Table 5.5*1
Classif • A re a\. 
ba
Drain Extensi
on
Structure
Total
km
Second • 
Drain 
km
Field 
Drain 
km
Sub-block Drain 
km
Escape
km
Total
pcs
Culv.
pcs
Drop
pcs
Irish Dridge
pcs
Inlet
pcs
4500
382.1
39.4
43.0
2Q6.2
2.6
130
104
17
6
3
per ha
O.O85
0.009
0.01
0.066
0.029
5.5*2* Unit Rquirec Drainage
Unit rquired drainage has been calculated classiying drinage in the mountainous areas and that in flat areas keeping in vie* the topographical features.
Formula of Drainages Q « (0.3336R - $)0F
( See page
)
Ir. tne design 1C £ probability for rainfall runoff per hour
(E              beer, taxer., when F «• 34 m/hr.
Discharge factcr in mountainous areas j 0.8
in fi t arep.e
wuf r crt;n£j’( ' ir. e.^-anta: nous areas) per ha: 5P? l/e ir fl -1 arene )
Arrangement       of Drain*
: 0.2 taken,
i 1 .21 l/e
Drain*  will ir.  genera.  g< a.ong  tiae b^ eiae with  blocks and 
•ub-tlockfc     anc     tnui     n..jt     /     r     .     /au     ii     f     j     t     standard     sub- tjoc> aJiC IbeJJ fajttCiL/ JS ® .j • n.
Field blodorfcinfc vary r ij .i jin/t ul c n in diflerent w t ana*; a l j                    »- 165 -
strucutres. Spacing of secondary drains have been designed to be 600 m (equal to the width of a block) or 1,200 m and the existing gullies are left intact to be used as drains#
5«5*4* Cross-section of Drain
Typical cross section
Table 5-5*2
Q(l/e)
'''Slope
S .ize x Xfi)
q
i < 0.02
0.02 - 0.1
0.31-0.003
0.003 - 0.0013
h
15
15
15
20
15
b
20
20
30
30
h
20
20
30
30
50
b
25
30
40
50
h
100
25
25
30
35
b
30
40
50
60
h
25
30
35
40
150
b
40
50
60
70
h
30
30
200
35
45
b
40
6c
70
so
h
30
30
250
35
45
b
60
30
90
b*
4HylhulK calcuiatior or
. nr nnr structural calculating dimensions
rr ^_»ct)or b«vr baen U th*
<h. method aF of the irrigation 
Mhet it th'farent n tha. mt rawiiimu" flow velocity baa been
propoeet tc b« ' • * .* v ▼ , 
it Vm^c* dreiw ***,
it th* irr-.f tine canale and V . 1.6 m/a
. » 'h» •QMnUrjr aaxiaua flow
r
. • • * 
the drain presumably
11
en< •< rtM  ** <■<»** ,#•-• t <• b*** <u trainee tc be n • o.oj^. Sh* . «»> »»•>• o-v < nr. v /x • tc'.ot v dtf have been suggested V< r**au<y< th<   o* v« ocit; .
4
• **>♦<' ■ tUC . CU 4M*< A/
• t * r.M beer. dram, because
ti<erw > Ui
w.ur w.tF wooth elope
Ui«>« 4r<>| >’».ruc'.Miw«
Ifr* .<n o* -4fc w
.
Kyftreu. ** c«.au
'♦        * • beer fl De lfi
1 IM *»•*<•« Mt '. I.ru u
TUDbi .
U41 . * i. 4 v i . t. j
he &/ X
I             -....... * .
•r),*
iha . *              t -.Uh..
&.£> . 4. ;«
1
..
•t
«.«■ .       . I . . ,I I I
I
I
I
I
I I M
k•
T
r
ri
»■
e
'■o
— i
<7
•n
k
•-
H
K»-
X
o
*30 —«<
*« -*
►* -»
.
1
fc- 1 IM
•
1
•*
?
3
H
•
*
r
•
*-
— .
£*
*—>
r&
£3
'JX>
-M
yf
3;
5>
M*
LJ
J
», J
hl        J
*
M U4 J p*»U*V VUv JCANALS & STRUCTURES SUMMARY
Ta.L/< 5 6-2.
No
Name of
Canal&Road
Extention
in m
Intake
Diversion Weir
Culvert
Drop
Off-T
Off-TP
Regulator
Chute
Drop
Open
Canal
Outlet
Gate
Inlet Works
Road Dr^ i n
I   MC - No 1
5,938
1
3
17
1
1
2  MC - No 2
26,660
1
1
23
187
1
30
1
1
3
15
15
3   C - 1 - 1
4,050
6
12
4  C - 2 - 1
4,410
7
10
■
5     Tertiary C
30,300
6  '.Quaternary C
7 ,970
95
97
377
5
7   Field. Canal
277,210
3     Sub-total
(419,538)
(2)
(1)
(134)
(301)
(2;
(42Q'
(1)
(0)
(p
( 3)
lsl
✓Q Escape 1
2,100
3
8
l'j  Escape 2
450
11  Subtotal
(2,550)
(3)
(8)
(3)
12  3ranch D
39,410
13  Block Drain
43,850
101
14  Sub-block D
296,220
15  □uD-total
(379,480)
(101)
16  Main Road
17,500
17  Connect Road
18,810
18     Field Road
126,030
19  Sub-total
(162,340)
20       Total
963,908
2
1
238
309
2
429
1
6
1
3
18
____
tobe continued171 -
Chapter 6
COST ESTIMATE FOR PROJECT CONSTRUCTION
Cost estimate for project construction has been mapped out on the basis of the unit rates currently going in the irrigation pro
jects under construction by the Water Resources Development Authority.
Cost has been summarized for every kind of work after detailed calculation of work procedure.
10 percent of cost for different kinds of work, has been estimated for transport fee with exception of soil movement calculation cost
and 15 percent of cost for different kinds of work has been expected for contingency.
Cost for provisional equipment has not been estimated and there fore, it should be discussed with the contractor just before construct ion.Ml nt ' H'Arn n ' t ’
’ ’MH' ’
U't-» V r
1 r ♦ t» ’>
r.?> It’ <*•»♦ t
V P — 9 • V e
1 V* •
. . . . r» <1re V *
r
*' *
i; 111 Utt
A
Ht» <’ < ftnr
*•» » orirlj* • • f
-4
1 OM V *»
-4 -
• *- f»fw             '
• - 111
< M H#' *      • * * \
4
• .*>•** '- ♦
4-
tl<           w
4
s
!»»#!<
4
<     Ko*<
4
k0<v -4 v< >4 *♦*$
■4
«>- <4
<4     '♦»3t
** ‘
%ff 1
*♦-* •* *9-*19 ■ • * t
+•
'mi«-"?’1 »
'"’•      —wr~ F                  1« ; -r r •» - ' -»-*W         9**
i----------------------
T r~»F1
L_______ U
•T*T
• »—•
•-»Tt
k
4
r~**i
T
-*
'<«• ’ 1
Tt r ’
f •«
r:
re
to
••♦* 1 •* •"* *•
47 H4 /f 1
’<^7
-« ’
k
! ire. k.   —
, k. :                   »:*
T«
k
1
4
«A.
4. •
' H *•• * I «h« 4 v
• ■ *
<4 7
V9
I
«*
■
f
9
I
I
I
I
I
’>»•!*«
-4
• 4«.<u
9
4mu Ue»<4 t luf
_J
>
♦
*           —4 kb—-4
B
>•
_ISUMMARY
Cost   Estimate
Soil Movement
concrete
Cement
Reinforcement .
Iron             •
No
Unit
Qty.
Per
Unit
price
per unit
total
per
unit
total
per
unit
total
per unit
total
per unit
total
Main Canal
32598
15873786
362920
9522
2857
198459
174144
Secondary Canal
m
8660
1058363
12997
1663
639
794
Escape
H
2550
5l7lQ3
1986 3
285
86
6655
Other Canals
»»
56 5 1 l 30
160909
2805
86 2
5896
2380
Drain
3'Q680
1670297
8886 5
656
L36
Road
«»    1 h? -60
5380687
608011
95
28
1922
183
LoPd Leve . 1i •>          ha
-.>00
-8238823
3566680
1
779 OO5-»
a
1 665"296
16624
6388
193726
i
1
l’6707
----------------------------------
mint- 167 -
The existing gully will be used as escape 1.
5.6.     SOME PROBLEMS TO BE CONSIDERED IN CONSTRUCTION OF      IRRIGATION AND.’DRAIN NETWORK
*   In the first place in land levelling smooth slope should be provided 
so that favot&ble condition for furrow irrigation can be created.
*  Prior to land levelling roads, canals and drains should De constructed.
*  As the roads will in most cases be constructed along banks of canals
and     drains,the     surface     level     of     the     roads     should     be     30     to     50     cm higher than water level.
*  Maximum water level in the drains should almost be the same as the designed ground level.
*  While constructing any structures or canals/drains all dimensi nns should be strictly observed according to the drawings and constructional and technical requirements thoroughly implemented, particularly compacted embankment properly done •
*  Every spacing of roads and canals is from the centre to another, i.e, for field blocks 600 m of cracing from the centre of the road
to the
opposite and for sub -blocks 150 a of spacing form
the centre of the canal to the other.- IP
Organization nf Praln c.
Tnblo *.*.1
I»»nn1h f‘ Pmin («
(ulvprt
_______ __ 1—
(p)
>
Mt
Me Of i—
Qv* t r-
r
—*
lote!
____ 4---------------- 4
prim ‘h 4
Fine*
w
Plnrl
pf«
30      zr     60 <
RO
Drop
H»1M
4-
H-
11
4P ,950        10.080          R«
-- OQC          1 “          0       6
*■
» r
*
M
<
71.930
600     I 4 SC        16. WK           £                3       1
pc 5 1
1
1
1
3J
<4
9<.440            1/.900      i* .7or
6     340                     10     17       5
$1 .900
c 150     • *S(
•
' .7*
5S.7OT 1*
664
1
6
6
<               B                                   ( 330
<
t
3; . 3*0           ; .osr
z cr
I • If                1         1 7T W'
e .760           • J»r           RO'
( 76t
;
< r*r
;
-» <»< * *
5
?
>• 9
(w
90'
39 760            ; 4</          < Rfr
10 1(
•* *1
?C/ ;,<.?■
*1
• /           c        6       1 11      1         1
• 4-
/ ♦t 14
It 1(
• < ✓
u
9 790
2( M' <- 40
?<• KX
Xr
<- 04' *     9 7f
4< 3
t44
■i TO! A.
.’/*• 4b(
.0' ZK Z      at?
44*
■
■
■
■
I I
■
■
I I I I I I I I I I
I
IMl \\ v, 
'\MMK

Summery