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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)


MALAPRABHA (K4)

L=306 KM, CA=11549 Km2 (KAR=11549 Km2)


(KAR=56.83TMC) Balance Yield = 1 TMC

TUNGABHADRA (K8)

L=531 KM, CA=47827 Km2

(AP=9036Km2, KAR=38790 Km2)



(KAR=289.87TMC, AP=126.26TMC)


VEDAVATHI (K9)

L=391 KM, CA=23590 Km2

(KAR=18218 Km2 AP=5372Km2)



(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)


Allocation …..49 TMC (MAH=1.51 TMC, KAR=41.74TMC, AP=5.51 TMC)


LOWER KRISHNA (K-7) L=611 KM, CA=36125 Km2

(KAR=1683 Km2, AP=34442 Km2)



(KAR=1.69 TMC, AP=574.46 TMC)


UPPER BHIMA (K-5) L=515 KM, CA=46066 Km2

(MR=46066 Km2)



(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)



(AP=34.14 TMC)


PALERU (K-11) L=153 KM, CA=3263 Km2

(AP=3263 Km2) Available yield…. 16 TMC


(AP=11.15 TMC)


MUNNERU (K-12) L=196 KM, CA=10409 Km2

(AP=10409 Km2) Available yield…. 78 TMC


(AP=36.31 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)


(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

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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.

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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

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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

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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.

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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

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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.

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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




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





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





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.

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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