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27
CHAPTER 3
STUDY AREA
3.1 GENERAL
This chapter highlights the study of Srisailam Left Bank Canal
(SLBC) location and also focuses on topography, soils, cropping
pattern, climatic characteristics and facilities of SLBC command area.
SLBC gravity scheme source of water is Srisailam Reservoir which in
turn is located in Krishna River Basin. The following description gives
an idea on the physical study of the Krishna River Basin with its
characteristic features and various reservoirs under Krishna River
Basin.
3.2 BASIN FEATURES AND RIVER SYSTEM
Geographical Location and Area
The Krishna River originates in the Mahadev range of the Western
Ghats near Mahabaleshawar at an altitude of about 1337 m above
mean sea level about 64 km from Arabian Sea. After traversing a
distance of about 1400 km , the river joins the Bay of Bengal in Andhra
Pradesh. The Krishna Basin is India‘s fourth largest river basin which
covers 258,948 2km of southern India, flowing through the states of
Maharashtra (69,425 2km ), Karnataka (113,271 2km ) and Andhra
Pradesh (76,252 2km ). The geographical location of Krishna basin lies
between the latitudes 13O 071 N and 19O 201 N and longitude 73O 221
E and 81O 101 E. The shape of the basin is triangular with its base
along the Western Ghats and vertex at Vijayawada. The principal
28
tributaries of the river are the Ghataprabha, the Malaprabha, the
Bhima, the Tungabhadra, the Musi, the Paleru and the Munneru.
Index map of Krishna basin and flow chart of Krishna River are shown
in Fig. 3.1 and 3.2.
Topographical features
The Krishna basin is relatively flat, except for the Western
Ghats. There are some highly vegetated hills in its center and at
northeast part. The basic mineral resources are granites and basalts
which have limited groundwater potential and a visible area of deep
alluvium in the delta area which has high groundwater potential.
Population statistics
The Krishna basin habitats are about 74.2 millions. The
density of the population is about 287 people per 2km having more
concentration in the irrigated areas and metropolitan urban centers.
The lowest densities of population are recorded in the southwest
portion and at the centre of the basin which lies in Karnataka state
(Deccan plateau). About 68% of the population resides in rural areas
that are dependent mostly on agriculture for their livelihoods.
Climatic conditions
The climate of the Krishna basin is largely semi-arid, visible
humid and dry-sub humid areas are found along Western Ghats of
Krishna delta. The eastern parts of Western Ghats are arid in the rain
shadow.
29
Fig. 3.1 Index Map of Krishna Basin
30
UPPER KRISHNA (K-1) MIDDLE KRISHNA (K-2) LOWER KRISHNA (K-7)
UPPER KRISHNA (K-1)
L=306 KM, CA=17972Km2
(MR=17128 Km2, KAR=844 Km2)
Available yield…. 647 TMC Allocation …..232 TMC
(MAH=227.05 TMC, KAR=4.51TMC)
Balance Yield = 415 TMC
GHATAPRABHA (K3) L=283 KM, CA=8829 Km2
(MR=2010 Km2, KAR=6819 Km2)
Available yield…. 128 TMC
Allocation …..100 TMC
(MAH=4.13 TMC, KAR=95.83TMC)
Balance Yield = 28 TMC
MALAPRABHA (K4)
L=306 KM, CA=11549 Km2 (KAR=11549 Km2)
Available yield…. 56 TMC Allocation …..57 TMC
(KAR=56.83TMC) Balance Yield = 1 TMC
TUNGABHADRA (K8)
L=531 KM, CA=47827 Km2
(AP=9036Km2, KAR=38790 Km2)
Available yield…. 430 TMC
Allocation …..416 TMC
(KAR=289.87TMC, AP=126.26TMC)
Balance Yield = 14 TMC
VEDAVATHI (K9)
L=391 KM, CA=23590 Km2
(KAR=18218 Km2 AP=5372Km2)
Available yield…. 51 TMC
Allocation …..54 TMC
(KAR=41.32TMC, AP=12.47TMC)
Balance Yield = -3 TMC
LOWER BHIMA (K-6)
L=346 KM, CA=24548 Km2 (MR=2833 Km
2, KAR=19198 Km
2, AP=2517 Km
2)
Available yield…. 85 TMC
Allocation …..49 TMC (MAH=1.51 TMC, KAR=41.74TMC, AP=5.51 TMC)
Balance Yield = 36 TMC
LOWER KRISHNA (K-7) L=611 KM, CA=36125 Km2
(KAR=1683 Km2, AP=34442 Km2)
Available yield…. 126 TMC
Allocation …..576 TMC
(KAR=1.69 TMC, AP=574.46 TMC)
Balance Yield = 450 TMC
UPPER BHIMA (K-5) L=515 KM, CA=46066 Km2
(MR=46066 Km2)
Available yield…. 364 TMC
Allocation …..328 TMC
(MAH=327.08 TMC, KAR=0.58 TMC)
Balance Yield = 31.09 TMC
MUSI (K-10)
L=267 KM, CA=11212 Km2
(AP=11212 Km2)
Available yield…. 46 TMC
Allocation …..34 TMC
(AP=34.14 TMC)
Balance Yield = 12 TMC
PALERU (K-11) L=153 KM, CA=3263 Km2
(AP=3263 Km2) Available yield…. 16 TMC
Allocation …..11 TMC
(AP=11.15 TMC)
Balance Yield = 5 TMC
MUNNERU (K-12) L=196 KM, CA=10409 Km2
(AP=10409 Km2) Available yield…. 78 TMC
Allocation …..36 TMC
(AP=36.31 TMC)
Balance Yield = 42 TMC
KURUNDWAD
L=290 Km
(CA= 15190 Km2)
GALGALI
L=389 Km
(CA= 22560 Km2) YADAGIR
(CA= 69863 Km2)
HUVANHEDGI
L=684 KM
(CA= 55150 Km2)
HUVANUR
(CA= 11400 Km2) KAGRAHARAM
L=869 KM
(CA= 132920 Km2)
BAWAPURAM
(CA= 67180 Km2)
LAKSHMIPURAM
(CA= 2400 Km2)
PONDUGALA L=1157 KM
(CA= 221220 Km2)
WADENAPALLY L=1191 KM
(CA= 235544 Km2)
DAMERACHERLA
(CA= 11501 Km2)
PALERU BRIDGE
(CA= 2928 Km2)
KEESARA
(CA= 9854 Km2)
M
A
H
B
A
L
E
S
W
A
R
B
A
Y
O
F
B
E
N
G
A
L
HIPPARAGIWEIR
ALMATTI
DAM JURALA
PROJECT
SRISAILAM NAGARJUNASAGAR
DAM
PRAKASAM
BARRAGE K
O
Y
N
A
R
I
V
E
R
G
H
A
T
A
P
R
A
B
H
A
M
A
L
A
P
R
A
B
H
A
T
U
N
G
A
B
H
A
D
R
A
R
I
V
E
R
507 Km 542 Km
526 Km 573 Km 778 Km
1076 Km 1168 Km 1226 Km 1270 Km
1125 Km 1311 Km 917 Km 1026 Km
MIDDLE BHIMA (K-2)
L=483 KM, CA=17558 Km2 (MH=1389 Km
2, KAR=16169 Km
2)
Available yield…. 33 TMC Allocation …..168 TMC
(MH=0.13 TMC, KAR=167.63 TMC)
Balance Yield = -135 TMC
Bhadra River
Vedavathi River
D
IN
DI
R
IV
E
R Narayanpur Dam
SADALGA
(CA=2322 Km2)
BAGALKOT
(CA=8610 Km2)
1
4
0
0
K
M
SDIA River
U
p
p
e
r
B
h
i
m
a
L
o
w
e
r
B
h
i
m
a
Bhadra Dam
Tung
a
Fig. 3.2 Flow Chart of Krishna River
31
Soil profiles
Majority of the land in this basin lies on crystalline and basaltic
rocks and the soil in this area generally is shallow clayey with some
areas and some parts with gravelly clay and loamy. The western part
of this basin is having Entisols and Vertisols (black soil) and Alfisols
(red soils) in southern and eastern parts. The enormous flow of river
Krishna causes a high degree of surface soil erosion in monsoon
season. It takes fertile soil from upstream areas of Maharastra and
Karnataka, and deposits it in delta regions. Soils are deeper
considerably in valley bottoms and also in flat areas of Andhra
Pradesh.
Rainfall and evapotranspiration Information
Even though the average Annual rainfall is about 800 mm in the
Krishna basin, the extremities ranges from below 300 mm in the
northwest to a maximum of 1000 mm in the delta area. But the high
rainfall of 2000 mm occurs in Western Ghats. About 90% of the
rainfall is during the monsoon months of May to October.
Evapotranspiration potentiality varies spatially over the basin in
which the southern and eastern parts record a highest and a lowest in
northwest. Except in the months of July, August and September, the
evapotranspiration exceeds precipitation which causes the irrigation
necessary during the other months of the year. The characteristics of
the 12 Krishna sub basins with available runoff data is tabulated in
Table 3.1.
32
Table 3.1 Characteristics of Krishna sub basins (Adopted from Closing of the Krishna Basin – Research report)
Code Sub-basin Length
( km )
Area
(2km )
Annual rain fall
(mm)
Annual runoff
(3km )
Runoff coefficient
(observed)
Available yield
(TMCft)
Allocation (TMCft)
K1 Upeer Krishna 306 17972 1099 18.3 0.68 647.00 232.00
K2 Middle Krishna
483 17558 462 0.93 0.09 33.00 168.00
K3 Ghataprabha 283 8829 718 3.6 0.45 128.00 100.00
K4 Malaprabha 306 11549 528 1.6 0.20 56.00 57.00
K5 Upeer Bhima 515 46066 570 10.3 0.33 364.00 328.00
K6 Lower Bhima 346 24548 678 2.4 0.15 85.00 49.00
K7 Lower Krishna 611 36125 641 3.6 0.14 126.00 576.00
K8 Tungabhadra 531 47827 668 12.2 0.29 430.00 416.00
K9 Vedavathi 391 23580 411 1.4 0.11 51.00 54.00
K10 Musi 267 11212 669 1.3 0.16 46.00 34.00
K11 Paleru 153 3263 781 0.45 0.17 16.00 11.00
K12 Munneru 196 10409 901 22 0.22 78.00 36.00
Agricultural Potential
Diversified cropping patterns are persistent in Krishna basin.
The principal crops being cultivated here are rice, sorghum, corn,
sugarcane, millet, cotton, groundnut and variety of horticultural
crops. The total area under cultivation in the basin is about
203,000 2km , which is about to 77% of the total geographical area of
the basin. About 47,200 2km have considerable potential for irrigation.
Adding to this the Krishna basin produces a total hydropower of
2,997 MW at 60% load factor.
Existing and Expected concern of basins
The total storage capacity of major reservoirs, with live storage
more than 200 3Mm , is 42,910 3Mm as indicated in table 3.2. It is
found that the storage capacities of major and medium reservoirs in
33
the basin had almost reached the total water yield. The gage at
Vijayawada station has drastically reduced since 1960. The average
yield from the beginning of 19th century to 1960 at this station was
recorded to be 6500Cumecs during the months of August. It has come
down to about 100Cumecs in 2000-04. This caused the basin a closure
at the sea mouth with a discharge causing a substantial decrease at
sub basin level. For example the discharge from Upper Bhima River
has reduced from an average of 8,816 3Mm in 1970-80 to 3,615 3Mm
during 1994-2004, caused by the upstream development in the sub-
basin. It is a notable fact that the basin is experiencing an additional
evaporation of water of about 36,000 3Mm every year, thus causing the
change of atmosphere, and also increased humidity and decreased
temperature in areas of extensive irrigation development (Trent et al.,
(2007)).
The demand for domestic and industrial needs has also
increased with increasing population in the basin area resulting in a
competition among different demanding sectors. The rapid
development of projects proposed by each state provoked a conflict
between the states for water rights. To solve this situation among
three states an assessment committee named the Krishna tribunal
was formed in 1969. This tribunal made an assessment of water in
each sub-basin and allocated water based on ―equitable
apportionment‖ in 1976. Importantly, KWDT (Krishna Water Dispute
34
Tribunal) allocated 11,740 3Mm of surplus water from Upper Krishna
to Lower Krishna that has 12,740 3Mm water deficits.
Table 3.2 Reservoirs with more than 200 3Mm live storage in the
Krishna Basin. (Adopted from Closing of the Krishna Basin – Research report)
Name State
Gross storage
( 3Mm )
Live storage
( 3Mm )
Year of
completion
Srisailam AP 8,716 8,288 1984
Nagarjuna Sagar AP 11,550 6,920 1972
Tungabhadra KT 3,736 3,307 1953
Koyna MH 2,797 2,640 1967
Bhadra KT 2,023 1,785 1953
Ujjani MH 3,320 1,440 1980
Nira Deodhar dam MH 156 1,508 2001
Hidkal dam KT 1,444 1,317 1977
Narayanpur KT 1,071 869 1961
Alamatti KT 1,194 841 2002
Malaprabha KT 1,068 867 1973
Vanivilas Sagar KT 850 797 1908
Warna MH 974 779 1991
Dudhganga MH 875 680 1992
Bhatghar MH 673 666 1927
Dimbe MH 382 354 1998
Dhom dam KT 382 331 1977
Osman Sagar project AP 329 318 1920
Manikdho dam MH 308 283 1984
Vir Baji Pasalkar MH 374 275 1993
Kanher dam MH 286 272 2002
Veer MH 278 266 1965
Panchshet dam MH 303 256 1973
Radhanagari MH 237 220 1955
Chaskaman MH 242 211 2000
Himayat Sagar project AP 217 204 1926
Total 42,910 35,694
Note: AP = Andhra Pradesh, KT = Karnataka, MH = Maharashtra
35
As Andhra Pradesh geographically lies on the down stream part
of the basin it has experienced a shift in land use while the Karnataka
and Maharashtra states lying further upstream, have large dry regions
and want to continue developing their water resources to maintain
their agricultural growth and reduce poverty. The state wise water
allocation by Krishna Water Dispute Tribunal (KWDT) is tabulated in
Table No. 3.3 showing the details of water allocation to the three
states sharing the Krishna Basin, and current water demand from
existing irrigation systems.
Table 3.3 Krishna basin Water Allocation (Adopted from Closing of the Krishna Basin – Research report)
State Percentage
of basin area (%)
Water allocation
(3Mm )
Regenerated Flow
Allocation
(3Mm )
Water demand
2010
(3Mm )
Ratio Demand: Allocation
Maharashtra 25 15857 708 27144 1.71
Karnataka 42 19822 963 46980 2.37
Andhra Pradesh 33 22654 311 66004 2.91
Total 100 58333 1982 140128 2.40
3.3 Srisailam Project
The Srisailam project is falling in K7 namely, lower Krishna
sub-basin. Lower Krishna sub-basin lies between north latitudes of
"'0 04215 and "'0 221617 and east longitudes of "10 0077 and "'0 8981 . It
has a catchment area of 36125 2km and forms 13.95% of the Krishna
basin. The catchment area of the sub-basin lies in the States
Karnataka and Andhra Pradesh.
The Neelam Sanjeeva Reddy Sagar Srisailam project of Andhra
Pradesh is the first major hydroelectric project constructed across the
river Krishna. The dam is constructed in gorge portion of Nalamala
36
Hill range of Eastern Ghats, about 1.6 km downstream of Patalganga
bathing ghat near Srisailam town. The Neelam Sanjeeva Reddy Sagar
(NSRS) project was originally (in 1960‘s) formulated for generation of
hydropower. The project forms part of the scheme for integrated
development and utilization of the water resources of the River
Krishna. The construction of the project was completed and the first
power unit was commissioned in the year 1982. The catchment area
of Krishna basin up to Srisailam dam site is 206030 2km , subsequently
it has taken shape of a multipurpose reservoir by including drinking
water supply to Chennai city (Telugu Ganga Project) and irrigation
facility to within and adjacent basins of Krishna in Andhra Pradesh
(AP). Schematic diagram of Srisailam project is shown in Fig. 3.3.
It has too many balancing reservoirs to achieve the intended
targets and categorized as inter basin water transfer project. It was a
very crucial project of AP in respect of hydropower. Its components
were revised many times in the past. Presently, it has the following
components 1) Hydropower, 2) Telugu Ganga drinking water scheme
and 3) Irrigation facility to drought prone areas of Nalgonda, Kurnool
and Cuddapah districts through left and right bank canals. The
Telugu Ganga project is also providing irrigation facility.
37
Salient Features of Srisailam Project
Location
State : Andhra Pradesh
District : Border between Kurnool & Mahaboobnagar Districts
Latitude : '0 516 N
Longitude : "0 5478 E
Reservoir
Maximum water level : 271.88 m (El.892.ft)
Full Reservoir level : El.269.75 m (El. 885 ft)
Gross Storage Capacity : 8716 3Mm (307.80TMCft )
Active Storage : 7077 3Mm (250TMCft )
Water Spread area at F.R.L : 541.80 2m .
Hydrology
Catchment Area : 2, 06,030 2km (79,530 Sq.Miles)
Mean Annual Rainfall
Maximum : 1016 mm (40 inches)
Minimum : 635 mm (25 inches)
Design Flood : 53,770 Cumecs
19 lakh sCu sec at Srisailam moderated
to 38365 Cumecs 13, 55,680 sCu sec )
Deep Bed Level of River : El. 152.4 m (El. 500 ft)
38
KRISHNA RIVER
JURALA
PROJECT
TUNGABHADHRA RIVER
ALMATTI
PROJECT
DINDI RIVER
LEFT BANK CANAL
850 Mm3-121410 ha
RIGHT BANK CANAL
621 Mm3- ID CROP - AREA
76890 ha and length – 125 KM
SURPLUS ESCAPE INTO
PENNAR RIVER
SRISAILAM
RESERVOIR
YA=7075MM3. FRL+269.75M
POWER HOUSE
770MW
Telugu Ganga project – 425 Mm3 to
Chennai and 1656 Mm3 flood water for
irrigation and length – 434 Km
NAGARJUNA
SAGAR
RESERVOIR
POWER HOUSE
810 MW
LEFT BANK CANAL RIGHT BANK CANAL 90 MW 60 MW
PRAKASAM
BARRAGE
KRISHNA RIVER
BAY OF BENGAL
Fig. 3.3 Schematic Diagram of Srisailam Project
39
Minimum Tail
Water Level : El. 163.00 m (El. 535.00 ft)
Maximum Flood Level
observed at Dam Site : El. 187.25 m (El. 614.35 ft)
(Prior to construction of dam)
Diversion Arrangements
Diversion Channel
Bed Width : 15.24 m (50 ft)
Length : 594.36 (1950 ft)
Discharge with upstream : 283.2 Cumecs
Water Level at El.174.80 m : 10,000 sCu sec (El 573.50 ft)
Bed Level : El 167.64 m (El. 550 ft)
Diversion Tunnel
9.14 m (30 ft) Dia Circular (lined)
Length : 686 m (2250 ft)
Invert Level at Entrance : El. 161.54 m (530 ft)
Discharge with Upstream : 566.4 Cumecs
Water Level at El.176.11 m : 20,000 sCu sec (El.577.80 ft)
DAM
Type : Gravity Dam
Top elevation : El. 275.54 m (El.904.0 ft)
Height above the deepest
foundation level : 143.26 m (470 ft)
Total Length at Top : 512 m (1680 ft)
40
Spill Way
Crest Level of Spill way : El 252.98 m (El. 830.00 ft)
Maximum discharge observed : 30,021Cumecs (10, 60,830 sCu sec )
Minimum Observed : 16.98 Cumecs (600 sCu sec )
Gross Length of spillway (between)
faces of training walls : 266.39 m (874 ft )
Spillway gates Number & Size : 12 Nos & 18.3 m x 16.7 m (Clear)
(60‘x55‘)
River Sluices Number & Size : 2 Nos & 3.65 m x 9.14 m (12 ft x30 ft )
Power House
Left Power House Number of Units : 7
Capacity of each unit : 110 MW
Right Power House Number of Units : 6
Capacity of each unit : 150 MW
Maximum tail water level : El 193.55 m
Minimum tail water level : 163.06 m
3.3.1 Sedimentation Studies and Life of Srisailam Reservoir
Silt formation in reservoirs on Krishna river has been
extensively studied by Govt. of A.P at the time of preparation of
Pulichintala project report (on the river Krishna) and later at the time
of Krishna-Pennar project and lastly for the project Nagarjunsagar. All
these studies have shown extended life for the reservoir. Colonel Ellis
calculated the useful life of the reservoir as 370 years for a dead
storage capacity of 4643 3Mm (164TMCft ). At Srisailam reservoir, the
storage capacity up to MDDL is 3686 3Mm (130TMCft ) and therefore
41
the useful life of the reservoir based on the study is predicted to be
more than 300 years by Andhra Pradesh irrigation authorities. The life
may perhaps be even longer due to the fact that a large number of
reservoirs have been constructed or under construction in the upper
reaches which will trap most of the silt. Capacity table of Srisailam
Reservoir is shown in Table 3.4.
Table 3.4. Reservoir Capacity table of Srisailam Reservoir
Sl.No Reservoir Level (m )
Area in
( 2m )
Capacity
( 3610 m )
1 222.50 29.22 481.06
2 225.55 32.36 574.71
3 228.60 35.96 678.91
4 231.65 39.38 793.87
5 234.70 43.51 920.07
6 237.75 47.65 1059.30
7 240.80 55.75 1216.71
8 243.85 66.07 1400.99
9 244.75 69.78 1462.14
10 246.90 80.12 1622.48
11 249.95 101.21 1896.87
12 252.975 136.97 2257.14
13 256.025 179.16 2735.56
14 259.075 241.50 3370.70
15 260.30(MDDL) 272.18 3685.72
16 262.125 317.57 4223.63
17 265.18 399.45 5306.86
18 268.225 496.19 6675.01
19 269.75 (FRL) 541.80 7465.30
3.3.2 Annual Evaporation Losses from Reservoir
The submergence area of the reservoir lies in Kurnool and
Mahaboobnagar districts of Andhra Pradesh state. Month-wise rates
of evaporation in mm/day observed at Kurnool IMD station is given in
Table 3.5.
42
Table 3.5. Monthly evaporation losses observed at Kurnool IMD station
Month Evaporation losses ( daymm / )
Month Evaporation losses ( daymm / )
Jan 3.6 Jul 4.5
Feb 5.2 Aug 4.0
Mar 7.0 Sep 3.9
Apr 8.0 Oct 3.3
May 8.5 Nov 3.4
Jun 6.9 Dec 2.9
3.3.3 Water Balance at Srisailam Project
Outflow
Outflow of water from existing, ongoing and proposed projects
on Krishna River up to Srisailam project details are given below:
Existing Projects
a) 1911 3Mm and 1274 3Mm of water by way of westward diversions
through Koyna and Tata hydel works respectively.
b) 387 3Mm from Tungabhadra Right Bank High Level Canal Stage-I for
irrigation of areas in Upper Pennar sub-basin.
c) 992 3Mm from Tungbhadra sub-basin through Kurnool-Cuddapah
Canal for irrigation of areas in Middle Pennar sub-basin.
Hence the total outflow from the existing projects works out to be
4564 3Mm .
Ongoing Projects
a) 538 3Mm of water through Srisailam Right Bank Canal for irrigation
in Middle Pennar sub-basin.
43
b) 850 3Mm through Srisailam Left Bank Canal for irrigation in Lower
Krishna sub-basin downstream of Srisailam project and Musi sub-
basin.
c) 1246 3Mm of water through Telugu Ganga project for irrigation in
Middle Pennar sub-basin and water supply to Chennai city.
d) 256 3Mm of water through Tungabhadra Right Bank High Level
Canal Stage-II for irrigation in Upper Pennar sub-basin.
Hence the total outflow from the ongoing projects works out to be
2890 3Mm .
Proposed Projects
a) 394 3Mm of water from the proposed Upper Bhadra project of
Tungabhadra sub-basin for irrigation in Upper Pennar sub-basin.
Hence, the total outflow of water from the existing, ongoing, and
proposed projects works out to 7848 3Mm .
3.3.4 Srisailam Reservoir Distribution System
A proposal was made to divert water from Srisailam reservoir to
Gorakallu and Owk balancing reservoirs of SRBC and also to
Velugodu and Sri Pothuluri Veera Brahmendra Swamy balancing
reservoirs of Telugu Ganga Canal to a possible extent and the actual
field requirements are to be met from balancing reservoirs.
3.3.4.1 Srisailam Right Branch Canal (SRBC)
Srisailam Right bank canal envisages utilization of 538 3Mm of
Krishna water for bringing 76890 ha of land under irrigation which is
at present under rain fed cultivation on the right bank of the Kunderu
44
Valley. Out of the 76890 ha of total ayacut, 67744 ha is in Kurnool
district and 9146 ha is in Cuddapah district.
SRBC is proposed to utilize Krishna water drawn from Srisailam
reservoir during the flood season through the head regulator at
Pothireddipadu. The water thus drawn will be conveyed in an open
channel of 125km length cutting a cross Krishna-Pennar ridge and
stored in Gorekallu and Owk resources formed by damming up minor
streams, to utilize the same during rabi season.
3.3.4.2 Telugu Ganga Canal (TGC)
Telugu Ganga Canal (TGC) connects Srisailam reservoir in
Andhra Pradesh with Poondi reservoir in Tamil Nadu. The length of
the canal from Srisailam reservoir to Poondi reservoir is 434 km . TGC
envisages utilization of 425 3Mm of Krishna flood water to irrigate 1,
11,290 ha in Kurnool and Cuddapah districts and 890 3Mm of pennar
flood water to irrigate 123434 ha in Nellore and chittor districts.
Balancing reservoirs to store flood water of Krishna and Pennar are
Velugodu reservoir, Sri Potuluri Veerabrahmendra Swamy reservoir,
Somasila reservoir, Kandaleru reservoir.
3.3.4.3 Link canal Operation policy
The release of water from Pothireddipadu head regulator is
possible only when the water level in Srisailam reservoir is above
266.70 m . It is notable that the yield available through the natural
streams does contribute to the yield that is required to meet the
demands which are contemplated by A.P state Government. The link
discharge is to be let into the same natural streams in addition to
45
their natural flow. However, in the case of floods in these streams, it
is proposed to regulate the release of Krishna waters from Srisailam
into these streams in such a way that the combined flow would not
inundate the surrounding areas. Schematic diagram of Srisailam
Right Bank Canal and Telugu Ganga Canal is shown in Fig. 3.4.
3.3.5 Details of Command Area of Srisailam Reservoir
The details of the command Area under different canals of
Srisailam reservoir are shown in table 3.6.
Table 3.6 Command area of Srisailam Reservoir distribution system
Srisailam left bank canal
(SLBC)
Srisailam Right Bank Canal
(SRBC)
Telugu Ganga
Irrigation (TGI) Total
1,21,410 ha 76,893 ha 2,34,726 ha 4,33,029 ha
Crops that are proposed to be grown in the command area are show in
table 3.7.
Table 3.7 Crops of Srisailam Reservoir distribution system
Period SLBC % Area SRBC %
Area TGI
% Area
Kharif Cotton 10 Cotton 35 Paddy 4.3
Chili 30 Chili 25
Ground nut 15
Rabi Ground nut 30 Jawar 25 Ground nut 95.7
Pulses 15 Wheat 15
46
PENNA RIVER
KRISHNA RIVER
SRISAILAM RESERVOIR
315.73 cumecs
Pothureddypadu Head Regulator TUNGABHADHRA
RIVER
315.73 cumecs 315.73 cumecs
Banakacherla Cross Regulator @ Basin Boundry
RIGHT BANK
CANAL
76890 ha ID Crop
141.58 Cumecs
SURPLUS ESCAPE
INTO PENNA RIVER
196 Cumecs
Telugu ganga project drinking water to
Madras. Capacity of canal 315.73 Cumecs
Gorakally Balancing
Reservoir
Irrigation Canal
Irrigation Canal OWK Reservoir
Velugodu Balancing Reservoir
Irrigation Canal
430707 ha 141.58 Cumecs
Sri Pothuluri Veerabrahmendra
Swamy Reservoir
42.47 Cumecs
Chinnamukkapalli Reservoir
42.47 Cumecs
Somasila Reservoir
PENNA RIVER PENNA RIVER
325 Cumecs
Kandala eru Reservoir
113.27 Cumecs Irrigation Canal
123432 ha
Poondi Reservoir
28.32 Cumecs
CHENNAI
Fig. 3.4 Schematic diagram of Srisailam right bank canal and Telugu Ganga canal
47
3.4 SRISAILAM LEFT BANK CANAL PROJECT (SLBC)
Aliminitte Madhava Reddy project (AMRP) popularly known as
Srisailam Left Bank Canal (SLBC) was contemplated in 1983 to
facilitate irrigation in drought prone areas of Nalgonda District for
about 3 Lakh Acres Irrigated Dry(ID) crops. The project also supplies
drinking water to the fluoride affected villages enroute. This scheme
has two alternatives 1) the gravity scheme of AMRP from foreshore of
Srisailam Reservoir through two Tunnels. 2) the lift scheme of AMRP
from foreshore of Nagarjuna Sagar Reservoir (for early benefits). The
canals of both alternatives in the head reaches converge at a common
point at 25 km from the end of the second tunnel of gravity scheme.
When SLBC gravity scheme come into existence, SLBC lift scheme can
be utilized for other purpose. Schematic diagram of Srisailam Left
Bank Canal is shown in Fig. 3.5
3.4.1 Location of the SLBC Command Area
SLBC project in the present study is located on the river
Krishna in the state of AP, India and shown in Fig. 3.6. The length of
the main canal is 185 km . High Level Canal (main canal) has bed fall
from elevation +233 m and low level canal at +177 m . High level canal
feeds Low Level canal by proposed distributory channel near Dindi
Balancing Reservoir. High level canal provides irrigation to 2.2 lakh
acres command area while low level canal covers 80,000 acres for
SLBC gravity scheme.
48
NSP L.B. Canal
Command Area
K
R
I
S
H
N
A
R
I
V
E
R
NAGARJUNA
SAGAR RESERVOIR
SRISAILAM
RESERVOIR
K
R
I
S
H
N
A
R
I
V
E
R
TUNGABHADRA
RIVER
SRBC 1.9 LAKH
ACRES & TELUGU
GANGA DRINKING
WATER TO CHENNAI
TUNNEL - 43.5 KM
KRISHNA
RIVER
DINDI
RIVER
DINDI RESERVOIR
DINDI BALANCING
RESERVOIR
TUNNEL – 7.25 KM
DINDI RIVER
UDAYA
SAMUDRAM TANK
AKKAMPALLI
RESERVOIR
MUSI RESERVOIR
LIFT OF WATER FOR
EARLY BENEFITS
Fig. 3.5 Schematic diagram of Srisailam left bank canal
2 Lakh acres SLBC
command area
1 Lakh acres SLBC
command area
49
The mandals of the district benefited by SLBC gravity scheme are
shown in Table 3.8.
Table 3.8 Mandal wise command area and population particulars of
SLBC project
Sl No Name of the mandal Command Area in
acres
Population as per 2001
1 Devarakonda 3754 7870
2 Pedda Adsarlapally 27642 33340
3 Peddavoora 44057 40052
4 Anumula 16245 36683
5 Gurrampode 14919 25794
6 Nampally 199 1022
7 Nidamanoor 21913 29060
8 Kangal 32364 35650
9 Chandur 185 2057
10 Monugode 209 3546
11 Nalgonda 18698 23055
12 Thipparthy 40322 40073
13 Vemulapally 18774 38281
14 Miryalaguda 607 9331
15 Tripuraram 11327 15528
16 Nakrekal 18688 49635
17 Shali Gouraram 1678 7335
18 Kethepally 21893 33228
19 Suryapet 374 1983
20 Mothe 1985 1543
21 Kattangur 4342 13466
22 Achampet 2611 1438
Grand Total 3,02,786 4,50,000
50
Fig. 3.6 Location & Layout of Srisailam Left Bank Canal Project
51
3.4.2 Climate of the SLBC Command Area
Climate and Rain Fall
The climate in this area is characterized by general dryness
except during the South-West monsoon season. The year may be
divided into four seasons. The cold season from December to
February is followed by the summer season from March to May. The
monsoon season which is from the month of June to September
contributes about 71% of the annual rainfall. October and November
constitute the post-monsoon season or retreating monsoon season.
On an average there are about 46 rainy days i.e. days with rainfall of
2.5 mm or more in a year in the District.
Temperature
There is no meteorological observatory in the District. The
account which follows is based on the records of the observatories in
the neighbouring Districts, where similar meteorological conditions
prevail. The day and night temperatures increase rapidly from mid of
February. The Month of May is the hottest with a mean temperature
of C040 and a minimum of C020 . At times the day temperature goes
to C045 . During end of May and in early June prior to the onset of the
monsoon, the day temperatures drop appreciably. The day and night
temperatures decrease visibly from October. The month of December
is the coolest month with a mean maximum temperature of C030 and
a mean minimum temperature of C016 . Rarely in the mid cold season
may the night temperature drop down to C010 .
52
Humidity
The relative humidity is generally high during South-West
monsoon season. The decrease in humidity starts from the post
monsoon period and the driest part of the year is summer where the
relative humidity at the noon is recorded to be around 35%.
Cloudiness
During the South-West monsoon season, the skies are most
heavily clouded or overcast. The skies are generally clear or lightly
clouded in the rest of the year.
Winds
Winds are generally light with some strength during the later
part of summer and early part of the monsoon season. In May and
the South-west Monsoon season, winds are predominantly westerly or
North Westerly. In the period October to February, winds from
Easterly directions are common. In the next two months, the morning
winds are light and variable in direction, while in the afternoons they
are generally from the East or South-West.
Special weather Phenomena
During the post monsoon, the depressions which originate in
the Bay of Bengal and move in a North Westerly direction affect the
weather over the District causing occasionally wide spread heavy rains
and strong winds. Thunder storms occur in the later half of the
summer season, the South West Monsoon season and early part of the
post monsoon period.
53
3.4.3 Topography and soils of the SLBC command Area
The Nalgonda district was formerly known as Neelagiri (Blue
Hill). The district lies in the southern part of Telangana Region whose
Northern latitudes lies between '0 2516 and '0 5017 and Easter
Longitude lies between '0 4078 and '0 0580 covering an area of
14,240 2km . This district is surrounded by Medak and Warangal in
the North, Guntur and Mahaboobnagar in the South, Khammam and
Krishna in the East and Mahaboobnagar and Rangareddy in the West.
The Gross Command Area under Srisailam Left Bank Canal is
1.93 lakh ha . (4.87 lakh acres) and the cultivable command area at
61.8% is 1.214 lakh ha . (3 lakh acres). The command area is situated
in seven Taluks of Nalgonda District Viz. Devarakonda, Nampally,
Nidamanur, Miryalguda, Nalgonda, Nakrekal and Chandur. The
predominant soils in the area are Red soils. Under this group, loamy
sands, sandy loams, sandy clay, loamy and silt soils are covered.
These soils are well suited for irrigation.
3.4.4 Cropping Practices of SLBC
Based on the classification of soils and crops grown in this area,
the tentative cropping pattern proposed by Agricultural Department of
Andhra Pradesh under the project is as follows. Only irrigated dry
crops are proposed to extend irrigation facilities to 1.214 lakh ha (3.00
Lakh acres) as shown in Table 3.9. It is proposed to have a single
crop in the command area spreading over a period from July to
January according to crops so as to make the intensity of irrigation
100%.
54
Table 3.9 cropping pattern of SLBC
Sl Crop Crop Period Proposed area % of
irrigated
area Acres Hectares
1 Cotton Aug to Jan 30000 12141 10
2 Chilies Aug to Dec 90000 36422 30
3 Ground Nut July to Oct 45000 18211 15
4 Ground Nut Oct to Jan 90000 36422 30
5 Pulses Nov to Jan 45000 18211 15
3.4.5 Infrastructural facilities
Railways and Roadways
The Command Area under Srisailam Left Bank Canal is well
connected with roads developed by Public Works Department (PWD)
and Zilla Parishads (ZP).
The PWD road between Hyderabad and Nagarjuna Sagar is an
important road which links not only the capital of Andhra Pradesh but
also the flourishing coastal districts of Guntur, Krishna and Nellore.
The Mahaboobnagar - Nalgonda (via Devarakonda) PWD Road
approaches the Nalgonda town and runs along the periphery of the
town, which intersects three PWD roads connecting the District
headquarters. The National Highway No. 9 crosses the Command
area of SLBC. The Bibinagar – Nadikudi Broad Gauge Railway line
crosses the command area.
Marketing Facilities
The command area is having considerable marketing
potentiality due to the existence of good communication network for
transport connecting three major towns. These places have adequate
55
facilities to market both eatable and non eatable agricultural
products. A good number of outlets were established for the supply of
agricultural necessities like seeds, fertilizers and pesticides to farmers.
Financial Institutions
The command area is provided with 151 financial institutions
including the Nationalized Banks, Commercial, Co-operative and
Rural Banks. These institutions provide the financial assistance to the
farmers for meeting their agricultural expenses, purchase of livestock,
acquisition of new lands, improvement of land and drainage and other
necessities.
Medical and Health Facilities
Medical and Health care services are adequately available to the
public from forty four noted public health centers and government
hospitals in and around the proposed command area.
Household Income
The cultivation of the major portion in the command area is
mainly dependent on rain fall and to some extent on ground water
through wells and deep wells due to non availability of canal irrigation
facility. As per 2001 census about 16% of population is cultivators.
Majority of population in this command area are dependent on
agriculture and other associated services. Majority of land owners
among the cultivators are holding less than 2 ha . Based on this fact it
is observed that the level of household income is very low for many
families. In the light of this fact, introduction of canal irrigation in the
56
proposed command area is absolutely necessary to increase crop
production and thereby household income can be increased.
Availability of Manpower for Agriculture
The availability of agriculture labour is abundant as 40% of
workforces are agriculture based. Hence adequate labour would be
available even after the introduction of canal irrigation.
3.5 AMRP (SLBC) LIFT SCHEME
This AMRP lift scheme contemplates lifting of water from
foreshore of Nagarjuna Sagar Reservoir at two locations and expects
to provide irrigation facility to an extent of 1, 09,250 ha (2.70 lakh
acres of I.D.) land in 21 Mandals of Nalgonda District for early
benefits. This project also provides drinking water to 516 fluoride
affected villages. The High Level Canal runs from an elevation of
+233 m MSL and the Low Level Canal from +177 m MSL. The High
Level Canal provides irrigation for 2.20 lakh acres, while the Low
Level Canal covers 50,000 acres.
High Level Canal
Head works:
The approach canal work of the system, the link canal and the
Akkampally Balancing Reservoir (AKBR) works have been completed
among the head works of high level lift scheme. The commission of
four pumps each of 25,000 HP, having a discharging capacity of
600 sCu sec has also been completed.
57
Main Canal:
The part of main canal from 25 km from tunnel 2 of gravity
scheme to Musi reservoir has been completed. The majority of work
on Udayasamudram Tank has been completed except minor works
like erection of gates for surplus weir and others are in progress.
Distributories/ Irrigation Potential:
The distributory system works were taken up for a total
command area of 2, 20,000 acres in which work‘s for 1,10,000 acres
had been completed and remaining work is in progress.
Salient Features of High Level Canal:
Approach Channel
Length 3.325 km
Bed Width 15 m
FSD 4 m
Surface fall 1 in 4000
Discharge 85 Cumecs
CBL at Starting 151.45 m (496.91‘)
FSL at Starting 155.45 m (510‘)
Intake Structure
Height of the pier 40.00 m
Width of the pier 1.50 m
No. of Gates 2 Nos Stop log gates
Size of gates(vent size) 12 ft x 24 ft
No. of pieces 5 Nos
Bottom piece Wt 2.592 MT
Top piece Wt 3.042 MT
Intake Tunnel
Length 1.470 km
58
Diameter of Tunnel 6m diameter – circular
Lining 30 cms thick concrete
Slope 1 in 288
Bottom(Invert) level at in take 145.00 m (476 ft)
Invert level of Tunnel at end 140.00 (459 ft)
Surge Pool
Length 50 m
Width 20 m
Depth 62 m
Bottom level of surge pool 138.00 m (Excavated)
Draft Tubes
Size of Gates 2.60m x 5.00 m
Weight of Gate 8.07 MT
Capacity of Gantry crane 15.00 MT
Pump House
Service bay length 18 m
Machine Hall length 60 m
Shafts
No. of shafts 5 Nos
Length 92 m
Diameter 3.50 m
Delivery pipe lines
Length 655 m
Diameter 2.5 m
Pump Motors
Pump Type Vertical shaft single stage
Francis Turbine
Normal speed 428.6 RPM
Dynamic Head 100m 81m 74m
Input (KW) 15020 15240 15100
59
Discharge(Cumecs ) 13.68 16.85 17.90
Efficiency 89.3% 87.8% 86.9%
Guide vane opening 60% 80% 90%
Guide vane Center line 142.00 m
Submergence of GC C/L
below minimum water
level
11.00 mm
Allowable frequency
range
50.5 Hz to 47.5 Hz
Motors
Type Vertical shaft AC motor
Speed 428.6 RPM
Power 18 MQ – 11 KV
Frequency 50Hz Pf(leading) 0.95
Cistern
Length of Dam 2.290 km
Left Flank 908 m
Right Flank 1.325 km
N.O.F 57 m
Off take regulator 3 vents of size 5.0 m x 2.85 m
FRL / MWL 247.00 m
TBL 249.00 m
Capacity 282 Mcft (0.282 TMCft )
Capacity at sill level 244.150 180.77 Mcft
Sill level at O.T Regulator 244.150 m
Emergency gate sill level 237.00 m
Link Canal
Length 9.26 km
Discharge (R/D) 67.96 Cumecs (2400 C/s)
69.67 Cumecs (2460 C/s)
Bed Width 20 m
60
F.S.D 3.00 m
Free Board 0.90 m
Bed fall 1 in 7000
CBL at Staring 244.00 m
Akkampally Balancing Reservoir
Location Near Akkampally (V)
Length of Dam 4.991 km
Location of Head
Regulator
1.403 km
F.R.L 245.0 m
T.B.L 249.0 m
M.W.L 246.0 m
Sill level of Head
Regulator
231.0 m
Head regulator – 4 vents 6 m x 2.5 m , vertical gates
Flood Discharge 216 Cumecs
Canal discharge 78.76 Cumecs
Capacity at FRL 245 m 1.5 TMCft
243 m 1.0 TMCft
231 m 5 Mcft
Catchment Area 30.50 2km
Main Canal
Length of Canal 111 km ( km 23.18 to
km136.150)
CBL at starting 230.606
Top width of Bank L/R 6 m / 8 m
FSL at starting 233.706
CBL at km 93.530 (in fall of US
Tank)
218.305
CBL at km 100.93 (outfall of 215.284 / 215.134
61
US Tank)
Udayasamudram Tank
Length of bund 4.61 km
Capacity 1.528 TMCft
FTL 220.0 m
TBL 223.70 m
MWL 220.605 m
Catchment area 29.50 2km
Sill level of outfall
Regulator
215.134 m
Low Level Canal
The low level canal running from +177 m contour is planned
with the main aim of drawing water by gravity during flood and to lift
water by means of three numbers of 4 MW pumps during non flood
season from the foreshore of Nagarjuna Sagar Reservoir. This canal
will irrigate a command area of 50,000 acres in Nalgonda District with
total length of 85 km for SLBC lift scheme.
Salient Features of Low Level Canal
Approach Channel (To Pump House)
Bed Width 7.0 m
FSD 3.10 m
Side Slopes ¼ : 1
Bed Fall 1 in 4000
Value of ‗n‘ 0.025
Q (Required) 22.50 Cumecs
Q (Designed) 22.56 Cumecs
Velocity 0.86 sec/m
Bed Level 152.350
62
FSL 155.450
Approach Channel (To Head Regulator)
Bed Width 11.00 m
FSD 3.0 m
Side Slopes 1 : 1
Bed Fall 1 in 4800
Value of ‗n‘ 0.025
Q (Required) 40.0 Cumecs
Q (Designed) 40.45 Cumecs
Velocity 0.963 sec/m
Bed Level 175.240
FSL 178.240
Link Canal
Bed Width 13.0 m
FSD 2.50 m
Side Slopes ¼ : 1
Bed Fall 1 in 4000
Value of ‗n‘ 0.025
Q (Required) 32.00 Cumecs
Q (Designed) 32.76 Cumecs
Velocity 0.962 sec/m
Bed Level 175.20
FSL 177.7
LLC at Starting Bed Width 13.0 m
FSD 2.5 m
Free Board 0.9 m
Side Slopes ¼ : 1
Bed Fall 1 in 4000
Value of ‗n‘ 0.025
Q (Required) 32.00 Cumecs
Q (Designed) 32.76 Cumecs
Velocity 0.962 sec/m
63
Bed Level 175.20
FSL 177.70
3.6 AMRP (SLBC) TUNNEL SCHEME
The existing Srisailam reservoir on Krishna River is at higher
elevation than the command area. Taking advantage of this location,
a canal has been proposed under gravity scheme. The Srisailam
reservoir and the command area of this project are separated by high
mountains which are called Nallamalai Hills. Therefore it is inevitable
to pierce the Amarabad Plateau of Nallamalai hill range through a long
tunnel of 43.50 km in the Mahabubnagar District, which forms part of
the Srisailam - Nagarjuna Sagar Wild Life Sanctuary and Srisailam
Tiger-Sanctuary. The flow diagram of SLBC gravity scheme is shown
in Fig. 3.7
The components of the Tunnel Scheme are as follows
The Head Regulator situated in the foreshore of Srisailam
Reservoir at about 4 km upstream of the dam.
Tunnel-1 for a length of 43.5 km crossing the Amarabad plateau,
which opens into Dindi valley.
A Balancing Reservoir is proposed to be constructed between
two Tunnels, across Dindi valley, about 30 km down stream of
existing Dindi Reservoir. Capacity table of Dindi Balancing
Reservoir is shown in Table 3.10.
A 7.25 km long tunnel-2 which is crossing the hill range between
Dindi and Peddavagu valleys.
64
Table 3.10 Capacity table of Dindi Balancing Reservoir
Elevation
H (difference
in elevation)
m
Area in
2Mm
Capacity in
21213
AAAAh
V
3Mm
Cumulative capacity in
3Mm
205 - 0.086 - -
220 15 2.202 13.62 13.62
230 10 6.578 41.95 55.57
235 5 9.252 39.39 94.96
240 5 11.570 51.95 146.9
245 5 14.015 63.86 210.77
250 5 16.525 76.26 287.03
Increasing the size of existing Udayasamudram tank. Capacity
table of Udayasamudram Tank is shown in Table 3.11
Table 3.11 Capacity table of Udayasamudram Tank
Elevation
h (difference
in elevation)
m
Area
in 2Mm
Capacity in
21213
AAAAh
V
3Mm
Cumulative
capacity in 3Mm
212 - 1.439 - -
213 1 2.381 1.89 1.89
214 1 3.191 2.78 4.67
215 1 4.012 3.59 8.26
216 1 4.968 4.48 12.74
217 1 6.309 5.63 18.37
218 1 7.519 6.91 25.28
219 1 8.897 8.20 33.48
220 1 10.246 9.56 43.04
Open Canal from exit part of Tunnel-2 for a length of 25 km to
join the common point of AMRP Main Canal (i.e., at km 25).
From there, an open contour canal is proposed which finally
drops into the existing Musi Reservoir. The length of the canal
including tunnels will be about 185 km from the head Regulator
to Musi Reservoir.
65
66
Main Canal (High Level Canal) lining from Common point to two
schemes of SLBC and Musi reservoir is proposed. Distibutary
channel is proposed to connect High Level Canal and Low Level
Canal near Dindi Balancing Reservoir.
3.7 PLANNING OF STUDY AREA
The operating procedures followed at present in the state and
elsewhere in the country are not based on any scientific method, but
only based on the norms developed as per previous experience as
discussed in chapter 2. It is necessary to apply the scientific methods
for evolving the optimal operation policy, for proper utilization of the
resources available and compare these results with the present policy
to see if there is any scope for improvement in its operation.
In the present work, the study area comprises of SLBC gravity
scheme, AP. The present study includes assessment of the feasibility
of SLBC gravity scheme and evaluation of optimal quantity of water for
its cropping pattern. The main components of SLBC gravity scheme
include canal head regulator, tunnels, Dindi Balancing Reservoir,
Udayasamudram Tank and lined and unlined portions of main canal.
The detailed design of these components is carried out keeping the
demands of SLBC gravity scheme in view.
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