CHAPTER 3 STUDY AREA AND DATA USED - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/15649/8/08_chapter 3.pdf · Maharashtra, Karnataka and Andhra Pradesh.The break-up of the

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CHAPTER 3

STUDY AREA AND DATA USED

3.1 STUDY RESERVOIRS

To demonstrate the potential of sub-pixel classification approach

three study reservoirs namely Nagarjunasagar and Singoor Reservoir located

in Andhra Pradesh state and Vagai reservoir located in Tamilnadu state of

India have been chosen. Figure 3.1 shows the location and the corresponding

satellite images of three reservoirs.

(Not to scale)

Figure 3.1 Location of study reservoirs (R1-R3) and their satellite

images -IRS/LISS-III (FCC – R=3, G=2, B=1)

R1-Singoor

eservoir

R3-Nagarjunasagar

Reservoir

R2-Vaigai

Reservoir

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The following sections and Table 3.1 describe the characteristics of

each of these study reservoirs.

Table 3.1 Characteristics of the three reservoirs selected for this study

(Source: Respective Dam Authorities)

Reservoir

NameLocation

Riversystem

Duringimpoundment

Catchmentarea (km2)

Annualrainfall in

thecatchment

(mm)

Waterspreadarea

atFRL

(Mm2)

Storage

Capacityat FRL

(Mm3)

NagarjunasagarAndhraPradesh

Krishna 295.19 11,553 2,15,185377 to1500

SingoorAndhraPradesh

Godavari 165.4 847.03 12,096400 to1350

Vaigai Tamilnadu Vaigai 24.19 194.78 2253 500 to 750

Though many large reservoirs are present in India, these three have

been selected because of the following reasons:

i) Relatively large reservoirs

ii) Different physiographic, climatic and soil set-up of the

catchment

iii) Accessible for ground truth and sample collection

iv) They are of different shape, size and geometry

v) Availability of cloud free data

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3.2 NAGARJUNASAGAR

Nagarjunasagar is the world's largest masonry dam built across

Krishna River in Nagarjuna Sagar, Nalgonda District of Andhra Pradesh,

India, between 1955 and 1967. The dam contains the Nagarjuna Sagar

reservoir with a capacity of up to 11,472 million cubic metres. The dam is 490

ft (150 m) tall and 1.6 km long with 26 gates which are 42 ft (13 m) wide and

45 ft (14 m) tall. Nagarjuna Sagar was the earliest in the series of large

infrastructure projects initiated for the Green Revolution in India; it is also

one of the earliest multi-purpose projects in India. Nagarjunasagar was the

earliest in the series of "modern temples" taken up to usher in the Green

Revolution in India. The dam provides irrigation water to the Nalgonda

District, Prakasam District, Khammam District and Guntur District and

electric power to the national grid. The right canal is 203 km long and

irrigates 1.113 million acres (4,500 km²) of land. The left canal is 295 km

long and irrigates 0.32 million acres (800 km²) of land. The project

transformed the economy of above districts. 52 villages were submersed in

water. The hydroelectric plant has a power generation capacity of 815.6 MW.

3.2.1 Physiography

The district is in the Southern part of the Telangana Region

between 16-25' and 17-50' of the Northern Latitude and 78-40' and 80-05' of

Eastern longitude covering an area of 14,240 Sq. Kms. The District is

bounded by Medak and Warangal districts in the North, Guntur and

Mahaboobnagar districts in the South, Khammam and Krishna districts in the

East and Mahabubnagar and Rangareddy district in the West.

3.2.2 Climate and Temperature

The region experiences hot and dry summer throughout the year

except during the South West monsoon season. A year may broadly be

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divided into four seasons. It experiences cold season from December to mid-

February, summer season from mid-February to first week of June. South

West monsoon season from June to September and retreating monsoon or the

past monsoon season during October to November.

Cold season extending from December to February is followed by

summer when both day and night temperatures increase sharply. The month

May being the hottest month, the mean daily maximum temperature is about

40o C and the mean daily minimum is about 28o C sometimes the day

temperature crosses 44o C during this period. December is the coldest month

with the mean daily maximum and minimum temperature is 35o C and 20o C

respectively.

3.2.3 Rainfall

The average rainfall in the district is 772 mm. 71% of the annual

rainfall is received during south west monsoon (i.e. June to September).

September is the rainiest month. The variation in the annual rainfall in the

district from year to year is large. On an average there are 46 rainy days. (i.e

days with rainfall of over 2.5mm or more).

3.2.4 Drainage

The district is drained by rivers Krishna, Musi, Aler, Dindi, Hallia,

Kongal, Peddavagu, Krishna, the prominent river in this district enters at

Yeleshwaram in Deverakonsa taluka. It enters Krishna district after traversing

a distance of about 85 kilometers. Musi river, a tributary of the Krishna is

next in importance in this region. It enters from the North West direction and

after travelling 64 kilometers in an easterly course falls into the Krishna near

Vadapalle. The rivers Peddavagu and Dindi are the other important rivers

which fall into the Krishna. The Hallia is a small river originating in the hills

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west of Narayanpur and flows for 72 kilometers in a South East direction,

finally falls into the Krishna river. The Aler river flows in Bhongir taluk

before joining the Musi river.

3.2.5 Soils

The soils in around the study reservoir are mainly comprising

loamy sands, sandy loams and sandy clay loams. In the areas of flat

topography and alongside the river Krishna and its tributaries comprises

mainly of black cotton soil.

3.2.6 Forest

The district contains dry mixed deciduous forest. The characteristic

species commonly found in this type of forests are Anogeissus Latifolia

(Chirumanu), Chloroxylon swieknia (Billudu) and Harduickia binata (Eppa).

Southern Tropical Thorn Forest also most common type found in Nalgonda

district. Density of the forest is very thin and thus it has an open appearance,

in the absence of a canopy. It usually occupies very poor and rocks soils

subject to over grazing and over exploitation. Accacia is the predominant

species of this forest.

3.2.7 Agricultural

In Nalgonda District, Agriculture is the main occupation for 70% of

the population. The land under cultivation forms 46.73% of the geographical

area. The major crops in the district are Paddy, Jowar, Bajra, Maize,

Redgram, Greengram, Groundnut, Sesamum, Castor and Cotton. Nagarjuna

Sagar, the major irrigation project provides irrigation facilities to the extent of

1.24 lakh hectares.

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3.3 SINGOOR RESERVOIR

The Singoor dam is constructed across the river Manjira at its 490th

km. The river Manjira takes its origin near Bhir (Maharastra State, India) in

Balaghat hills. The catchment area of Singoor reservoir lies in three states of

Maharashtra, Karnataka and Andhra Pradesh. The break-up of the area of the

catchment is as follows.

Table 3.2 Catchment area of Singoor reservoir in other states

Sl.No. State Area in Sq.Km1. Maharashtra 6,4742. Karnataka 4,0143. Andhra Pradesh 1,608

Total 12,096

The Singoor reservoir is located near Singoor village, Medak

District, Andhra Pradesh which is at a distance of 100 kms from Hyderabad.

The geographical location of the dam site is 17o 45’ N Latitude and 77o 56’ E

Longitude. The total length of dam is 7.52 kms which consists of 327 m long

over flow masonry dam, in the river gorge portion and 81 m non over flow

masonry dam, flanked on both sides by earthen embankments. The maximum

height of earth dam is 27.60 m and that of masonry dam is 33.5 m, radial

gates 17 nos. of each 15 x 13 m size are provided at crest level + 510.6m.

The spillway is designed to dispose a maximum flood of 7,80,000 cusses.

3.3.1 Climate

The climate of the sub-basin is characterized by hot summer and

mild winter. The monsoon sets early in June and continues upto October.

Winter is from November to mid February and summer is from mid February

to end of May.

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3.3.2 Geology and Soils

The soils differ in their capacity for crop production and stability

for irrigation. The behaviour of sub-soil, water plays an important role in the

conversion of soil nature. The principal types of soils in the catchment and

sub-basin area are medium black cotton mixed soils, red soils, red earth mixed

with disintegrated rock and loam. As the soil in the catchment area is mainly

black cotton which gets eroded very easily much silt is carried into the stream

that drain into river Manjeera which eventually has resulted in the silting up

of Nizamsagar reservoir, which is located upstream of Singoor reservoir.

After construction of Singoor reservoir the rate of siltation at Nizamsagar

reservoir has reduced comparatively.

3.4 VAGAI RESERVOIR

The study reservoir Vaigai lies in the middle of the Vaigai River

basin, which is one of the Seventeen river basins of Tamilnadu. Cauvery

being the first this basin is considered as the second granary of Tamilnadu.

Vaigai basin is about 7031 Sq. Km. and it’s catchment area covers the Theni,

Madurai and Ramanathapuram Districts of Tamilnadu. A small portion of the

basin is also located in the Idukki District of Kerala. It lies between the

geographic coordinates of 9o 15’ N to 10o 20’ N latitude and 770 10’ E to 790

15’ E longitude and falls within the survey of India toposheets 58G, 58F and

58K. It has varied climatic condition resulting often in unreliable rainfall,

drought prone, sudden floods, etc. This gives rise to unpredictable water

resources condition.

3.4.1 Physiography

The Vaigai river basin occupies an arc shaped area, which stretches

from the Westernghat mountain of Kerala in the West to the Bay of Bengal in

the East, with a general gradient towards Northeast, initially upto Theni and

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then towards South East direction up to the sea. The river basin is flanked by

Western ghats on the south and West, southern slope of Palani hills

(Kodaikanal hills) Sirumalai hills, Alagar Hills, etc on the North, Nagamalai

ridges on the South and Megamalai Hills and Bay of Bengal on the east. The

western Mountainous terrain are of relict type, representing the oldest part of

the peninsula that has escaped the denudation and are composed of ancient

crystalline rocks. The average elevation varies from 1000m to 1400m above

m.s.l., but many peaks rise over 2000m.

3.4.2 Drainage

The river Vaigai originates in the eastern slope of the Westernghat

mountainous offshoot in the Varushanad area and flows northwards through

Gandamanayakkanur. It is joined by several tributaries over a length of 43

Km, and reaches the plain area. Varattar, Nagalar, Varahanadhi, Manjalar,

Marudhanadhi, Sirumaliar, Sathiar, originate in Palani hills and Sirumalai

hills which are the main tributaries, join Vaigai along its course. Vaigai

enters into the Ramnad big tank and the surplus only reaches the sea. The

total length of the Vaigai River upto Ramnad big tank is 230 Km. Vaigai

River and its tributaries are semiperrennial to ephemeral in nature.

3.4.3 Rainfall

The total number of hydromet stations that are in operation in the

Vaigai river basin is 81. Revenue Department, Public Works Department,

Forest Department, Railways, IMD and Electricity Board maintain these

stations. The parameters such as rainfall, air temperature, air humidity, wind

velocity, sunshine hours, evaporation etc. are observed in these stations.

Annually 800-900 mm is being recorded generally in the region between the

seacoast and the Vaigai reservoir and 700-800 mm in the Suruliar Valley

surrounded by mountain ridges.

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3.4.4 Temperature

The Vaigai basin has a typical tropical climate. Except in the hilly

regions on the west and the north the mean maximum temperature in the basin

area reaches 37-380C in the month of May and the mean minimum

temperature is about 19-200C in the months of January and February. The

maximum temperature exceeds 400C in summer and the hilly region

experiences a moderate maximum temperature of 280C, while the minimum

temperature falls below 100C. The mean maximum humidity of the basin is

about 70-80% and mean minimum value of the humidity lies between 40-

50%.

3.4.5 Geology

Vaigai River basin consists of hard crystalline rock masses of

Archaean age for the most part (74%) on the western portion and sedimentary

rocks of upper Gondwana, Terriary and quarternary age on the eastern portion

(26%). The Archaean formations are metamorphised rocks such as cordierite,

sillimanite bearing bneisses, quartzites, calc, gneisses and granulites. They

are associated with basic charnockites and pink granites. Pegmatite intrudes in

the charnockites, pink granites and gneisses are found at several locations.

Pyroxenite intrusions are also found to occur at few places. These Archaean

formations are well exposed on the western and central area of the Vaigai

River basin. The high rising mountains composed of the above mentioned

rock type have yielded material due to weathering and erosion and they were

deposited in the valley and intermountain basins as valley filled sediments are

of quaternary age. On the eastern portion from Manamadurai to the Bay of

Bengal, rocks of Upper Gonawana, tertiary alluvium are spread over the

Archaean formations uncomformably. Aeolian sand is also found to occur in

isolated pockets in the Kambam valley and coastal areas.

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3.4.6 Soils

Generally six types of soil cover are found in the basin area. In the

hills and forest area, dark, black to brownish black coloured humus soil is

found to occur with enriched organic material. The upper Vaigai basin is

marked with deep red soil to thin red soil along with foam loamy soil and

Aeolian soil in pockets. The central basin area is marked with thin red sandy

soil and red soil. Occasionally black clayey soil occurs as pockets in some

locations. In the lower Vaigai basin area, alluvial soil is met with most part

boarded near by laterite soil cover. Coastal alluvial soil is found to occur

along the coastal tract.

3.4.7 Agriculture

The agricultural land is broadly grouped into five categories;

intensively irrigated crop land, sparsely irrigated crop land, dry crop land,

groves / orchards and coastal plantation. Intensively irrigated cropland

covers 31.17% of the area, where mostly wet crops like paddy and sugarcane

are raised and is hydrologically significant and directly influenced by surface

water resources. Sparsely irrigated cropland covers 14.75% of the area,

where mixed crop cultivation like groundnut, cotton and pulses are raised in

addition to paddy. Dry cropland covers 15.44% of the area, where less water

consuming crops such as oil seeds, Pulses, Ragi and Maize are grown and the

cultivation practice mainly depends on rainfall. The groves / orchards and the

coastal plantation covers 1.39% of the area. Groves / Orchards is seen

adjacent to the water courses in general and form a stretch of land in the flood

plain area, in these area cash crops such as coconuts, plantain, vegetables,

betal leaves and flowers are raised. Coastal plantation is nothing but natural

vegetation and thorny bushes. The casuarinas, other fire woods are raised by

human activities in addition to other small plantations being cultivated in the

local strip of low lying moisture zone.

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The forest land is broadly grouped into five categories; scrub forest,

dry deciduous forest, semi-deciduous forest, low ever green forest, and

plantation (coffee, tea, cardamom, pepper etc.).

3.5 DATA USED

Table 3.3 details the different satellite data, sensor and resolution

pertaining to three reservoirs used in the study.

Table 3.3 Details of Image data used (Date of Pass) w.r.t the three

reservoirs

Name ofReservoir

Satellite, Sensor and ResolutionIRS 1C-LISSIII

(24mresolution)

IRS 1D-LISSIII(24m resolution)

IRS P6-LISSIII

(24mresolution)

IRS 1C-PAN(5m resolution)

Nagarjunasagar 23.10.2001

12.12.200124.12.200125.02.200214.09.200211.05.200227.11.200222.12.2002

-------- --------

Singoor --------

12.11.200529.08.200501.04.200515.06.2005

15.01.200503.02.200623.03.200606.10.200515.05.2005

15.01.200503.02.200623.03.2006

Vaigai 26.02.1999

07.05.199926.06.199917.11.199921.04.200006.01.200225.02.200219.08.200230.06.2002

-------- --------

Note: IRS-1C, 1D & P6 data were used for per-pixel and sub-pixel

classification. IRS-1C (PAN) and P6 (LISS-III) used for validation.

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3.5.1 Field and ancillary data

Since this study is by and large a field cum laboratory based study

several data other than the satellite image data were collected, incorporated

and used. The field data includes reservoir water level data (bed level, MDDL

and FRL), soil types and ancillary information on vegetation types, climate &

temperature, field photographs of vegetation types, physiography,

landuse/landcover and crop types.

3.6 CONCLUSION

The above sections described in this chapter pertain to the study

sites chosen for the research work. The satellite image data set from various

sensors that has been used in this research work has also been explained in

detail.