Vaigai Basin

Introduction

There are 34 river basins in Tamil Nadu. For hydrological studies, they are grouped into 17

river basins. The Vaigai River basin is one of them. Vaigai river basin covers an area of about

7009.13 sq.km and hilly area extends to 2,101.68 sq.km and located in the Theni, Dindugal, Madurai,

Sivaganga, and Ramanathapuram Districts of Tamil Nadu. Vaigai, the main river originating from

Varushanadu valley with its tributaries forms a well-defined, compact drainage basin. It has a varied

climatic condition resulting often in unreliable rainfall, drought prone, sudden floods, etc. This gives

rise to unpredictable water resources condition but for the Periyar reservoir water flowing through this

basin due to the construction of the Periyar trans-basin scheme which made it possible to divert water

from the Periyar basin in the State of Kerala to Tamil Nadu.The index map of Vaigai River Basin is

shown in figure 1.

Figure 1 Index Map of Vaigai River Basin

Location and Extent

Vaigai river basin lies between the geographic co-ordinates Lat. 9o 15’ – 10o 20’ N and Long.

77o 10’ - 79o 15’ and falls within the Survey of India toposheets, 58F, 58G, 58J and 58k. The total

extent of the area is covered within the administrative boundaries of 20 taluks and 37 blocks. Figure 2

shows the Administrative boundaries.

Figure 2 Administrative Map of Vaigai River Basin

The Vagai basin is surrounded by Cauvery and Pambar Kottakaraiyar basins, on the north,

Gundar basin, on the south, west by Periyar basin and east by Bay of Bengal. The length of the basin

is about 289.59 km and the width varies from 15 to 55 km. The important urban settlements like

Madurai, Cumbum, Uthamapalayam, Bodinayakkanur, Theni, Periyakulam, Nilakottai, Melur,

Manamadurai, Paramakudi and Ramanathapuram are located in the study area.

The basin is an arcuate in shape, stretching from the Western Ghats mountain of Kerala in the

west to the Bay of Bengal on the east, with a general gradient towards North east, up to Theni and

then south eastern 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, and Bay of Bengal on the east. The relief Map of the Vaigai Basin is shown in Figure 3.

Figure 3 Relief Map of Vaigai River Basin

Physiographical study of vaigai basin reveals that the basin area can be broadly classified into

three units namely 1. Western mountainous terrain with valley complexes, 2.Central elevated terrain

and 3. Eastern coastal plain.

Drainage

The river Vaigai originates in the eastern slope of the Western ghat mountainous offshoot in

the Varushanad area and flows northwards through Gandamanayakkanur. The Suriliyar and Theniar

join Vaigai near Kottapatti. There after Vaigai flows east and south east directions till it confluences

with Bay of Bengal. Varattar, Nagalar, Varahanadhi, Manjalar, Marudhanadhi, Sirumaliar, Sathaiyar

originate in Palani hills and Sirumalai hills which are the main tributaries, joining Vaigai along its

course. Uppar river originates in the Alagar hills and joins Vaigai near Manamadurai. Then Vaigai

enters into the Ramnad big tank and the surplus only reaches the sea. The length of the Vaigai river

upto Ramnad big tank is 266.71 km and Ramnad big tank to sea is 28.40 Km. Vaigai river and its

tributaries are semi perennial to ephemeral in nature, and the flow in the Suriliyar and Vaigai is

mainly due to the Periyar lake water diverted through Viravanar and then to Suriliyar during the

monsoonal periods. Figure 4 Shows the drainage details of Vaigai Basin.

Figure 4 Drainage Map of Vaigai River Basin

Based on the natural drainage pattern, the vaigai basin is divided into ten sub basins they are

Upper Vaigai, Suriliyar, Theniar, Varattar - Nagalar, Varahanadhi, Manjalar - Marudhanadhi,

Sirumalaiar, Sathaiyar, Uppar and Lower Vaigai basin. The areal extent of each sub basin, hills,

plains etc. are given in the Table 1.

Geology

Vaigai river basin is covered by hard crystalline rock masses of Archaean age on the western

portion; nearly 74% are sedimentary rocks of Upper Gondwana, Tertiary and quaternary age are on

Table 1 Area and Percentage of Sub Basins in Vaigai Basin

Sl.

No. Name of the sub basin

Total area

in Ha.

Hilly area

in Ha. Percentage

Plain area

in Ha. Percentage

1 Upper vaigai 822.02 558.97 67.99 263.05 32.01

2 Suriliyar 640.10 217.95 34.05 422.15 65.95

3 Theniyar 651.65 310.84 47.69 340.81 52.31

4 VarattarNagalar 631.82 231.31 36.62 400.51 63.38

5 Varahanadhi 380.28 200.65 52.75 179.65 47.25

6 Manjalar 612.74 309.68 50.54 303.06 49.46

7 Surumalaiyar 541.59 131.66 24.30 409.91 75.70

8 Sathiyar 782.76 119.29 15.24 663.45 84.76

9 Uppar 882.29 21.35 2.42 860.94 97.58

10 Lower Vaigai 1063.88 - - 1063.88 100.00

TOTAL 7009.13 2101.68 - 4907.43 -

the eastern portion (26%). Aerial photographs and satellite data were also utilized in the demarcation

of the boundary conditions of various lithological units and to delineate structural features. Figure 5

shows the geologic formations in the Vaigai Basin.

Figure 5 Geology Map of Vaigai River Basin

From Manamadurai to the Bay of Bengal, rocks of upper Gondwana, teritiary alluvium and

coastal alluvium are spread over the Archaean formations unconformably. Aeolian sands are also

found to occur in isolated pockets in the Cumbum valley and coastal areas.

Land Use

Vaigai basin reappraisal study uses LISS IV Mx of IRS P6 satellite imagery of March 2009

for analysis of land use changes over a decade in Vaigai river basin. In the present study high

resolution satellite imagery was used to classify the land use at micro level. Finally the interpreted

land use themes were digitized using Geo media professional GIS software V5.2 and all the spatial

data have been converted into vector format for GIS analysis. Figure 6 Shows the Land use

Classification of the Vaigai Basin.

Figure 6 Land use Map of Vaigai River Basin

The Land use category of Vaigai basin is shown in Table 2

Table 2 Vaigai Basin-Land Use Category

Sl.

No

Land use category Area in Sq.Km

Percentage

% I Level II Level

1 Built up land Settlement 124.00 1.77

2

Crop land

Wet crop land- Paddy, Sugar cane

and banana.

Dry crop land- Groundnut, ragi,

cholam, cumbu, maize, cereals,

cotton, chilies, black gram,

vegetables, floriculture etc.

Grooves

1574.20

670.10

115.00

22.45

9.56

1.63

3 Forest land Medium Dense forest

Dense forest and plantation

Hills covered by shrubs/ scrubs

Reserved Forest

217.00

1324.50

532.80

11.00

3.09

18.89

7.60

0.16

4 Waste land Barren land, Rocky out crop, stony

waste

Area affected by alkalinity/salinity

Land covered by shrub/ scrub

1636.00

242.30

356.10

23.33

3.50

5.07

5 Water bodies Back swamp

Tanks

Reservoir

25.10

148.40

32.43

0.36

2.12

0.47

Total area 7009.13 100

Land use change detection

The land use change detection study is analysed for the period of 2001 to 2009. The land use

study reflects that the following category have increased in its extent i.e built-up land 82.76 Sq.km i.e.

1.18%, dry crop land 202.50 Sq.km i.e. 2.86%, waste land 188.36 Sq.Km i.e. 2.60% and decreasing

trend have also been observed especially in the category of crop land area 270 Sq.Km i.e. 3.86%

which is mainly due to the depletion of water level found to occur in many parts of the basin area. A

comparative statement is shown in the table 3.

Table 3 Comparison of Change in Land Use

Sl.

No.

Land use category Area in

Sq.Km

As on 2001

Percenta

ge

%

Area in

Sq.Km

As on

2009

Percenta

ge % I Level II Level

1 Built up

land

Settlement 41.24 0.59 124.00 1.77

2 Crop land Wet crop land-

Paddy, Sugar cane and banana.

Dry crop land-

Groundnut, ragi, cholam,

cumbu, maize, cereals, cotton,

chilies, black gram, red gram,

vegetables, floriculture etc.

Grooves

2629.5

38.03

2359.30

33.64

3 Forest

land

Medium Dense forest

Dense forest and plantation

Hills covered by shrubs/ scrubs

Reserved Forest

2075.55

29.68

2085.30

29.74

4 Waste

land

Barren land, Rocky out crop,

stony waste

Area affected by

alkalinity/salinity

Land covered by shrub/ scrub

2049.04

29.30

2234.40

30.9

5 Water

bodies

Back swamp

Tanks

Reservoir

198.47

2.83

205.90

2.95

Total area 7009.13 100

Geomorphology

The different land forms of Vaigai Basin are shown in the figure 7.

Figure 7 Geomorphology Map of Vaigai River Basin

Soils

The Soils of Vaigai Basin is classified as Deep Red Soil, Red Soil, Red Sandy Soil, Black Clayey

Soil, Laterite Soil and Alluvial Soil. Deep red soil is prevalent in cumbum valley near Chinnamanur,

Uttamapalayam and Cumbum areas. Between Vaigai dam and Peranai red soil is prevalent. The soil is

red to yellowish red and sometimes brownish in colour and has a thickness varying from 0.25m to 3m

in this area. The Red Sandy soil is the soil mixed with sand or quartz fragments. These are found in

the area in vicinity of quartzite outcrops. Black coloured, black to brownish soil is found in some part

of this area near Andipatti, Meenakshipuram in this basin area. Lateritic soil is distributed in

Kodaikanal hills and slopes and North West of Manamadurai. Alluvial Soil occurs predominantly in

lower Vaigai basin and along Vaigai river and its tributaries. The figure 8 shows the Soil

Classification of Vaigai Basin.

Figure 8 Soil Map of Vaigai River Basin

Groundwater Potential Zonation

The ground water potential is very good in Cumbum valley area including Chinnamanur,

Uthamapalayam and upto Theni. It is also observed near Alanganallur, Palamedu, Achampatti,

Melakkal, and Virattipathu. In coastal area, east of Ramnad and west of Mandapam the ground water

potential is very good, but the quality of ground water is poor due to semi marine deposits and very

near to coast. The ground water potential in south of Bodinaickanur, west of Melur, east of Viraganur

regulator and up to Ramnad is good. In general majority of areas in Vaigai basin the ground water

occurrence is moderate to poor.

Population Size: Urban and Rural

The sub basin wise urban population of Vaigai Basin is 2.009 million and rural population is 2.781

million and total population of Vaigai Basin is 4.790 million as per projected population in 2011. The

basin is divided into ten sub basins. Subbasin wise rural and urban population of male and female is

given in Table 4

Table 4 Sub Basin Wise Male and Female Population in Vaigai Basin

Sl.

No.

Name of the

Sub Basin

Male Population in

2011

Female Population

in 2011 Total

Rural Urban Rural Urban

1 Lower Vaigai 196890 126555 206839 127097 657381

2 Manjalar 36495 24388 35708 24158 120749

3 Sathaiyar 168478 766567 165062 749810 1849917

4 Sirumalaiyar 142501 24860 137357 24309 329027

5 Suriliyar 68733 150658 67121 148836 435348

6 Theniyar 52268 95639 51314 95064 294285

7 Uppar 117696 64861 114326 62193 359076

8 Upper Vaigai 91049 21601 88399 21175 222224

9 Varahanadhi 42814 63886 40665 62338 209703

10 Varattar Nagalar 94450 63920 91343 62677 312391

TOTAL 1011375 1402936 998135 1377658 4790103

Population Density

In Vagai basin, the population density is the highest in Sathaiyar sub basin (2364.71 persons

per sq.km) and the lowest is at Manjalar sub basin (197.47 Persons per sq.km). The sub basin wise

population density in the Vaigai River basin is given in the Table 5.

Table 5 Sub basin wise Population Density in Vaigai River Basin

Sl.

No.

Name of the Sub

basin

Area

(Sq.km)

Total population in

Million in 2011

Density in

Persons / Sq.Km

1 Lower Vaigai 1063.88 0.657 617.55

2 Manjalar 612.74 0.121 197.47

3 Sathaiyar 782.76 1.851 2364.71

4 Sirumalaiyar 541.59 0.329 607.47

5 Suriliyar 640.10 0.435 679.58

6 Theniyar 651.65 0.294 451.16

7 Uppar 882.29 0.359 406.90

8 Upper Vaigai 822.02 0.222 270.07

9 Varahanadhi 380.28 0.210 552.22

10 VarattarNagalar 631.82 0.312 493.81

Total 7009.13 4.790 683.39

Hydrometeorology

Raingauge Stations

Vaigai basin lies in Theni, Dindigul, Madurai, Sivaganga and Ramanathapuram districts.

There are 27 non-recording rain gauge stations in this basin.

Based on the distribution of rainguage stations and the availability of data (min 30 years), 25

rain gauge stations having long-term records in the basin are considered for detailed analysis. The

details of the rain gauge stations such as, their location, geographical coordinates and the study period

are shown in Table 6. For the purpose of rainfall analysis, month is taken as a time step.

Table 6 Geographical coordinates of rain gauge stations

S.No Name of Raingauge

Station Taluk District Source Latitutde Longitude

1 Andipatti Dindigul Dindigul PWD 10°03'45" 77°59'00"

2 Bodinayakkanur Uttamapalayam Theni PWD 10°01'11" 77°19'40"

3 Chittampatti Melur Madurai PWD 09°59'50" 78°16'36"

4 Cholavandhan Vadippatti Madurai PWD 10°01'20" 77°57'49"

5 Gudalur Uttamapalayam Theni PWD 09°40'48" 77°14'07"

6 Idayapatti Madurai North Madurai PWD 09°46'30" 78°16'15"

7 Kallandiri Madurai North Madurai PWD 10°02'10" 78°12'10"

8 Madurai Madurai North Madurai PWD 09°56'26" 78°07'58"

9 Manamadurai Sivagangai Sivagangai PWD 09°41'44" 78°27'30"

10 Manjalar Dam Theni Theni PWD 10°11'23" 77°37'56"

11 Melur Melur Madurai PWD 10°01'44" 78°20'04"

12 Mettupatti Vadippatti Madurai PWD 10°02'48" 78°06'56"

13 Nilakaottai Nilakottai Dindigul PWD 10°09'45" 77°51'15"

14 Paramakudi Ramanathapuram

Ramanathapu

ram PWD 09°32'51" 78°35'21"

15 Peranai Nilakottai Dindigul PWD 10°05'20" 77°51'30"

16 Periyakulam Periakulam Theni PWD 10°07'31" 77°32'03"

17 Periyar Kerala State PWD 09°34'50" 77°10'44"

18 Pulipatti Melur Madurai PWD 10°05'10" 78°17'30"

19 Ramanadhapuram Ramanathapuram

Ramanathapu

ram PWD 09°22'15" 78°49'50"

20 Sivagangai Sivagangai Sivagangai PWD 09°51'20" 78°29'14"

21 Thekkady Kerala State PWD 09°35'54" 77°10'23"

22 Uthamapalayam Uttamapalayam Theni PWD 09°48'05" 77°19'42"

23 Vaigai Dam Andipatti Theni PWD 10°03'05" 77°35'45"

24 Veerapandi Periakulam Theni PWD 09°57'45" 77°26'09"

25 Viralipatti Nilakottai Dindigul PWD 10°06'25" 77°43'35"

Monsoon and non-monsoon periods

Vaigai river basin lies within the tropical monsoon zone. Based on the hydro-meteorological

features of the basin, year is divided into two periods (i.e.) 1) Monsoon period spanning from June to

December and 2) Non-monsoon period spanning from January to May. The monsoon period is further

sub-divided into Southwest monsoon period spanning from June to September (4 months) and

Northeast monsoon period spanning from October to December (3 months). Similarly, the non-

monsoon period is further sub-divided into Winter period spanning from January & February (2

months) and Summer period spanning from March to May (3 months). The sum of all the seasonal

rainfall gives the annual rainfall. As the monsoon period brings heavy rainfall, it improves the

recharging of groundwater as well as storage of surface water. Hence, the monsoon period is

hydrologically significant for water resources analysis. But in the case of non-monsoon period, the

rainfall is insignificant.

The details of Annual dependable rainfall of each sub basin are given in the table 7. The

average annual rainfall is worked out to be 775.19 mm

Table 7 Annual dependable rainfall (in mm)

Sl.No Name of the

Sub-basin 25% 50% 75% 90%

1 Lower Vaigai 229.38 180.47 137.19 106.87

2 Manjalar 111.29 77.59 48.45 15.28

3 Sathaiyar 139.13 106.92 76.18 43.69

4 Sirumaliyar 105.95 86.70 65.25 41.37

5 Suriliyar 112.34 85.36 64.87 47.07

6 Theniyar 96.02 77.34 50.22 32.32

7 Uppar 160.61 119.38 93.01 70.38

8 Upper Vaigai 137.99 102.61 70.12 42.32

9 Varahanadhi 83.88 70.59 45.25 29.57

10 Varattar

Nagalar

107.25 87.24 56.59 40.75

Meteorological details of the Vaigai Basin is given in the Table 8 & 9

Table 8 Climatological Parameters

Table 9 Maximum and Minimum of Mean temperature

Name of the

Climatological Station

Minimum in

Mean Temperature

Maximum in Mean

Temperature

Viralipatti (1973-2017) 24.280 Celsius

(January 1974)

36.460 Celsius

(Apr 2016)

Parthibanur (1976-2017) 24.570 Celsius

(December 2013)

34.750 Celsius

(May 2017)

The monthly average maximum temperature of the Viralipatti station varies from 27.690

Celsius (December 1978) to 40.100 Celsius (April 2017). The monthly average maximum temperature

of the Parthibanur station varies from 25.730 Celsius (November 2006) to 40.630 Celsius (April 2017).

The monthly average minimum temperature of the Viralipatti stations varies from 17.410

Celsius (February 1976) to 7.310 Celsius (April 1975). The monthly average minimum temperature of

the Parthibanur station varies from 18.150 Celsius (December 2013) to 30.340 Celsius (April 1998).

S.

No

Climatological Parameter

Viralipatti Parthibanur

1 Average monthly temperature

Maximum. in. 0 Celsius

33.47 34.44

2 Average monthly temperature

Minimum. in. 0 Celsius

24.99 25.09

3 Average mean temperature in 0 Celsius 29.23 29.77

4 Average relative humidity in % 60.89 67.78

5 Average wind velocity in km/hour 7.45 4.16

6 Average Sunshine hours / day 6.58 5.87

7 Pan Evaporation in mm/month 218.78 153.25

Eto values (mm/month) of FCS for Vaigai basin

Name of

the basin

& FCS J

AN

FE

B

MA

R

AP

R

MA

Y

JU

N

JU

L

AU

G

SE

P

OC

T

NO

V

DE

C

Av

era

ge

Vaigai

basin -

Parthiba

nur FCS

100

.8

108

.6

134

.5

132

.0

134

.2

117

.6

115

.3

120

.3

122

.1

107

.9

93.

9

90.

2

114

.8

Vaigai

basin -

Viralipa

tti FCS

104

.2

110

.6

137

.6

139

.5

139

.5

116

.7

113

.2

120

.3

120

.9

112

.5

97.

5

96.

7

117

.4

Surface Water Potential

The Vaigai river has its origin in the eastern slopes of western ghats in Gandhamanayakkanur

Zamin at an altitude of 1524 m. The river course follows the Cumbum valley and joins with Suruliyar

before it reaches Vaigai dam. Periyar, Palar and Koraliar are its tributaries. Beyond Vaigai dam, it is

more or less a plain deltaic region until it falls into the sea. The length of the Vaigai river from origin

to Ramnad big tank is 266.71 km. and below Ramnad big tank upto sea is 28.40 km. Thus, the total

length of the Vaigai river from its origin to sea is 295.11 Km. Figure shows the flow diagram of

Periya Vaigai river system.

Figure 9 Flow diagram of Periyar Vaigai system

There are eight Reservoirs in this basin. They are (1) Periyar Dam (2) Vaigai Dam (3)

Manjalar Dam (4) Marudhanadhi Dam (5) Sathaiyar Dam (6) Sothupparai Dam (7) Shanmughanadhi

Dam and (8) Sirumalaiyar Odai.

There are about 1,411 tanks in Vaigai basin out of which 1049 are system tanks and 362 are

non-system tanks. The total storage capacity of tanks in Vaigai basin is 507.78 Mcm and the

registered ayacut is 75622.06 Ha. In addition to this there are 994 tanks located in Gundar and Pambar

& Kottakaraiyar basin benefited by Vaigai system. The total storage capacity of tanks outside the

Vaigai basin but receives supply thro’ Vaigai system is 224.30 Mcm and the ayacut benefited is

39817.07 Ha.

There are 10 gauging stations in Vaigai river basin and all the ten gauging stations are

maintained by PWD. They are given in Table 10 along with their sub-basins.

Table 10 Anicut / Dams and Sub basins

9 Anicuts

5 Anicuts

Palanichettipattipatti Anicut

Chattarapatti Anicut

Veerapandi Anicut

Varushanadu Valley

Upparpatti Anicut

Uppukottai Anicut

Kothur Anicut

Seelayampatti

Kuchanur Anicut

Markayan Kottai Anicut

Chinnamanur Anicut

Uthamuthu Anicut

Cumbum Anicut

Payathevan Anicut Vairavan Anicut

New Vairavan Anicut

Power House

Periyar Reservoir

Theniyar River

Shanmuganadhi Reservoir

Suriliyar River

Vaigai Reserv oir

Varahanadhi River

Sothuparai Reservoir

Direct Canal

Manjalar River

Manjalar Reservoir

5 Anicuts

Marudhanadhi

Reservoir

Marudhanadhi River

Sirumalaiyar Odai

Sathaiyar Reservoir

Sathaiyar River

Periyar Main Canal

Uppar Riv er

Amachiapuram Anicut

Pickup Anicut

Link Canal

Syphon

Peranai Regulator

Thirumangalam Main Canal (TMC)

Varattar Nagalar or

Virahanur Regulator

Parthibanur Regulator

Ramnad Big Tank Legend

Reservoir

Anicut

Regulator

Bay of Bengal

Vaigai River

Not to Scale

18th Channel

58 villages canal

Sl.N

o. Anicut / Dam Sub-basin

1. Suruliyar upper anicut Suruliyar

2.

Palanichettipattianicut

(the last anicut of Cumbum valley)

Suruliyar

3. Vaigai dam VarattarNagalar

4. Manjalar dam Manjalar

5. Marudhanadhi dam Manjalar

6. Peranai regulator Sirumalaiyar

7. Virahanur regulator Sathaiyar

8. Parthibanur regulator Lower Vaigai

9. Sathaiyar dam and Sathaiyar

10. Ramnad big tank Lower Vaigai

Reservoirs

There are eight reservoirs in this basin. Their names, storage capacity, ayacut and catchment

area is given in Table 11.

Table 11 Reservoirs in Vaigai Basin

Sl.N

o.

Name of the

reservoir

Year of

constru-

ction

Capacity

in Mcm

Registered

Ayacut in

Ha

Water

spread

area in

Sq.Km

Catchment

area in

Sq.Km

1 Periyar 1895 443.56 84268.82 26.44 602.95

2 Vaigai 1959 194.78 55104.85 25.90 2253

3 Manjalar 1967 13.48 2128.45 1.969 119.10

4 Marudhanadhi 1979 5.34 2668.00 0.725 53.35

5 Sathaiyar 1965 1.59 606.97 9.35 91.71

6 Sothuparai 2001 2.83 1159.91 0.144 87.04

7 Shanmughanadhi 2004 2.25 663.96 0.346 25.86

8 SirumalaiyarOdai 2009 0.44 127.83 0.122 17.80

Total 664.27 146728.79 64.996 3250.81

Tanks

There are about 1,411 tanks in Vaigai basin out of which 1049 are system tanks and 362 are

non-system tanks. The total storage capacity of tanks in Vaigai basin is 514.37Mcum and the

registered ayacut is 75622.64 Ha. In addition to this there are 994 tanks located in Gundar and Pambar

& Kottakaraiyar basin benefited by Vaigai system. The total storage capacity of tanks outside the

Vaigai basin but receives supply thro’ Vaigai system is 224.30Mcm and the ayacut benefited is

39817.07 Ha. Sub basin wise System and Non-system tanks, their total storage capacity and ayacut

benefited are given in Table 12.

Outflow to Sea

The Vaigai basin receives maximum rainfall during Northeast Monsoon and therefore there is

appreciable surplus to sea during Northeast Monsoon season. The surplus flow from Ramnad big tank

is measured as the surplus outflow to sea. Year wise surplus flow to sea is given in Table. 4.4. 75% &

50% dependable flow is “0” Mcm whereas 25 % dependable flow has been worked as 143.74 Mcm.

The 33 years average surplus flow to sea measured in this basin as 88.38 Mcm.

Table 12 Tanks in Vaigai River Basin

Sl. No. Name of Sub basin

System tanks Non System tanks Total

No. Capacity

in Mm3

Registered

ayacut in Ha No.

Capacity

in Mm3

Registered

ayacut in

Ha

No. Capacity

in Mm3

Registered

ayacut in Ha

1 Suruliyar 36 8.86 1889.16 4 0.74 180.57 40 9.60 2069.73

2 Theniyar 0 0.00 0.00 32 6.59 1703.61 32 6.59 1703.61

3 Varahanadhi 3 2.42 558.19 30 8.13 2089.80 33 10.55 2647.99

4 Varattar Nagalar 43 16.27 1985.01 17 4.68 606.04 60 20.94 2591.05

5 Upper Vaigai 0 0.00 0.00 13 2.40 531.74 13 2.40 531.74

6 Sirumalaiyar 23 19.99 3817.37 29 10.04 2253.97 52 30.03 6071.34

7 Manajalar 15 6.57 1176.15 11 1.78 886.18 26 8.35 2062.33

8 Sathaiyar 126 76.48 12744.10 62 6.10 1083.80 188 82.58 13827.90

9 Uppar 653 141.63 14466.70 129 44.18 7139.44 782 185.81 21606.14

10 Lower Vaigai 150 127.07 18662.04 35 30.45 3848.78 185 157.52 22510.82

I Total No. of tanks in

Vaigai basin

1049 399.29 55298.71 362 115.08 20323.92 1411 514.37 75622.64

a Vaigai system tanks in

Gundar basin

125 81.94 10811.62 0 0.00 0.00 125 81.94 10811.62

b Vaigai system tanks in

Pambar & Kottakaraiyar

basin

869 142.36 29005.45 0 0.00 0.00 869 142.36 29005.45

II

(a+b)

Total No. of Vaigai

system tanks outside

Vaigai basin

994 224.30 39817.07 0 0 0 994 224.30 39817.07

I+II Grand Total 2043 623.59 95115.78 362 115.08 20323.92 2405 738.67 115439.70

Surface Water Potential Assessment

The Surface Water Potential is assessed by using Monthly Runoff Simulation Model.

The Surface Water Potential is worked out for the 75% Dependable yield for South West, North

East and Non Monsoon periods. The influencing stations in the subbasin are given in Table 13.

Table 13 Rainfall Stations used in MRS Model

Sl.

No. Name of Sub-basins

Area

(Km2)

Rainfall Station and Share in the basin

area.

1. Upper Vaigai

822.02 Uthamapalayam, Veerapandi

2. Suruliyar 640.10 Thekkady, Gudalur, Periyar,

Uthamapalayam, Veerapandi

3. Theniyar 651.65 Bodinaikkanur

4. Varattar Nagalar 631.82 Vaigai Dam, Viralipatti

5. Varahanadhi 380.28 Periyakulam

6. Manjalar 612.74 Manjalar Dam

7. Sirumalaiyar 541.59 Nilakottai, Cholavandan,

Peranai, Andipatti

8. Sathaiyar 782.76 Mettupatti, Kallandiri, Madurai, Idayapatti

9. Uppar 882.29 Pulipatti, Melur, Chittampatti, Sivagangai

10. Lower Vaigai 1063.88 Manamadurai, Paramakudi,

Ramanathapuram

Total

7009.13

75% Dependable Surface Water Potential for each Subbasin of the Vaigai Basin shown in the

Table 14.

Table 14 75% Dependable Surface Water Potential for the Vaigai River Basin

Sl.

No.

Name of Sub basin

75% Dependable Surface Water Potential

in Mcm

SW NE NM Annual

1. Upper Vaigai 16.02 35.16 18.94 70.12

2. Suruliyar 8.82 39.35 16.70 64.87

3. Theniar 13.78 27.59 8.85 50.22

4. Varattar Nagalar 12.07 32.91 11.61 56.59

5. Varahanadhi 7.00 26.43 11.83 45.25

6. Manjalar 14.06 17.75 16.64 48.45

7. Sirumalaiar 17.39 32.59 15.26 65.25

8. Sathaiyar 25.83 30.16 20.19 76.18

9. Uppar

25.83 50.63 16.54 93.01

10. Lower Vaigai

22.84 83.75 30.61 137.19

Vaigai Basin as a Whole 163.64 376.32 167.17 707.13

South West Monsoon

Potential

North East Monsoon

Potential

Non Monsoon Potential

Annual Potential

163.64 (or) 164 Mcm

376.32 (or) 376 Mcm

167.17 (or) 167 Mcm

707.13 (or) 707 Mcm

Total Surface Water Potential in Vaigai Basin:

1. Vaigai basin - Surface Water Potential from its own catchment = 707

Mcm

2. Periyar release to Vaigai basin (75% Dependability) (1970-2010)= 529

Mcm

Total Surface Water Potential at 75% Dependability = 1236 Mcm

Total Surface Water Potential available including Periyar Release contribution is

1236 Mcm.

Comparison of the present results with the earlier study results:

The surface water potential assessment made by this Institute in the earlier Micro Level

Study in the Vaigai basin during 2003 is given below in Table 15 for comparing the values with

the present assessment. It is seen that the surface water potential derived from its own

catchments has been reduced due to decline in annual rainfall pattern.

Table 15 Comparison of Surface Water Potential in the years 2003 & 2011

Sl.

No. Name of Sub basin

75% Dependable Surface Water Potential in Mcm

2003 2011 2017

1. Upper Vaigai 149.12 112.83 70.12

2. Suruliyar 80.85 94.91 64.87

3. Theniar 43.42 74.72 50.22

4. VarattarNagalar 74.16 81.46 56.59

5. Varaghanadhi 72.48 74.48 45.25

6. Manjalar 63.89 61.26 48.45

7. Sirumalaiar 47.15 48.59 65.25

8. Sathaiyar 94.66 66.26 76.18

9. Uppar 114.44 104.13 93.01

10. Lower Vaigai 161.13 123.05 137.19

11. Total Surface Water

Potential 901.30 841.68

12. Periyar Release to Tamil

Nadu in Mcm 580 529

Inter basin transfer

1. Trasnsfer of water from Periyar Basin to Vaigai basin through a masonry gravity

dam and a tunnel of 1740 m long with a discharging capacity of 40.75 cumecs to

irrigate 84268.82 Ha. There is also a power station of 140 MW capacity.

2. Transfer of water from Vaigai to Guntar Basin to irrigate 4015.60 Hectares located

in Madurai, Virudhunagar districts.

3. Diversion of Surplus flood flow from Vaigair river Basin to virudhanagar and Upper

Guntarsubbasin.

4. From Vaigai basin to Pamabar and Kottakarayar Basin

Ground Water Potential

In the Vaigai Basin, groundwater occurs under water table condition and also under

leaky conditions with water from one aquifer flowing vertically into another. The appraisal of

groundwater occurrence is based on geological evaluation and on observation wells . An

inventory of about 52 observation wells spread over the entire Vaigai Basin has been scrutinised

and the periodical water level fluctuations were examined sub-basin and land classification

wise, to understand the hydrogeological nature and groundwater occurrence.

The appraisal of Ground water occurrence is based on the analysis of lithological log

data of the observation wells and other deep bore wells along with the water level fluctuation

data of the shallow observation wells and of the deeper bore wells.

In Hard Rocks

In the hard rocks the ground water occurs under water table conditions in the top loose

formations and weathered zones. It occurs under semi-confined conditions in the fractured and

fissured zones at deeper depths. Water-bearing zones are present in the formations with a

cumulative thickness ranging from 1 m to 21 m.

In Valley fill

The Valley fill sediments are distributed in the Valley portions of Cumbum,

Kadamalaigundu, Odaipatti and Palakombai areas in the western part of Vaigai river basin.

Ground water occurs under water table condition in general but semi confined condition has

been observed in clay and silt formations.

In Alluvium

In the alluvial patch, the ground water occurs under water table conditions as well as in

the semi-confined conditions. The alluvium is highly porous and permeable, developing into

potential zones.

In Sedimentary rocks

The sedimentary formations encountered in this basin area includes upper gondwana, shale, grit,

tertiary formations of sandstone and shale with recent to sub recent laterite and alluvium as the

top layer in general. Ground water occurs under pheratic conditions in the upper portions and

under semi confined conditions in the lower strata. The subbasin wise ground water fluctuations

are shown below in the Table 16.

Table 16 Sub Basin-wise Fluctuations

S.

No.

Name of Sub

Basin

Highest fluctuation

(Seasonal)

Minimum

in m

During

the year

Maximum

in m

During

the year

1 Lower Vaigai 2.47 93-94 7.38 04-05

2 Manjalar 3.05 02-03 21.70 10-11

3 Sathaiyar 4.02 01-02 7.95 01-02

4 Sirumalaiyar 3.95 98-99 7.65 93-94

5 Suruliyar 3.40 84-85 9.50 89-90

6 Theniyar 6.58 03-04 7.53 75-76

7 Uppar 3.80 97-98 8.50 94-95

8 Upper Vaigai 6.49 87-88 16.23 06-07

9 Varahanadhi 6.30 94-95 9.20 73-74

10 VarattarNagalar 8.10 77-78 22.80 10-11

The sub basin-wise groundwater potential and draft were calculated on pro-rata basis i.e

based on the percentage of block area falling in the sub basin. The total ground water extraction

of the basin is given in Table 17. Classification of the Blocks based on the level of Ground

Water Development as on 2009 is shown in the Table 18. The balance groundwater potential

available for further development was arrived by deducting the total groundwater extraction

from the net groundwater recharge. The categorization of block is also presented it is

understood that further groundwater development is possible in many blocks in Lower Vaigai,

Sathaiyar, Uppar sub basins since many of the blocks in these sub basins were categorized as

safe. In this study report, it was concluded that groundwater is the major source of irrigation in

Lower Vaigai, Sathaiyar, Uppar sub basins, which indicates that groundwater development is

already taking place in these three sub basins.

Surface Water Quality

The main factors responsible for increasing water pollution are exponential growth of

population, urbanization, industrialization and agricultural revolution. Even though Vaigai

Basin consists of seasonal rivers, dumping of solid wastes of domestic and industrial origin in

the river path would adversely affect the eco system. In the rainy season the water flowing in

the river is affected by the solid wastes dumping in the river and causes floods in adjacent areas.

Also during the rainy season the chemicals present in the solid wastes are dissolved in the rain

water and carried by drains and streams which affect both surface and ground water quality. The

perennial domestic sewage disposal into the rivers causes bad smell and creates many diseases

in and around the location.

In Vaigai Basin, surface water pollution occurs only around Madurai city because of

letting in untreated domestic sewage, agricultural wastes and industrial effluents. In Nilakottai

and Periyakulam taluks domestic pollution is more. The quality of water in Vaigai reservoir is

good both for human consumption and irrigation use.

Table 17 Ground Water Potential Calculation as on Mar 2013

Name of District

covered

Area

covered

in %

Net water

available

Ground

water

potential

District

wise

Theni district 35.9 38685.27 13888.01

Dindigul district 21.18 58016.67 12287.93

Madurai district 22.08 63797.96 14086.59

Sivagangai 9.85 90618.63 8925.94

Ramanathapuram 10.99 51962.52 5710.68

Total 54899.15 Ha.m

548.9915 M.cum

Table 18 Classification of the Blocks based on the level of

Ground Water Development as on 2009

Sl. No. Name of Block District Level of Exploitation

1 Aathoor

Dindigul

Over-exploited

2 Dindigul Over-exploited

3 Kodaikanal Safe

4 Natham Semi-critical

5 Nilakottai Over-exploited

6 Reddiyarchatram Over-exploited

7 Sanarpatti Over-exploited

8 Vathalakundu Over-exploited

9 Alanganallur

Madurai

Semi-critical

10 Chellampatti Over-exploited

11 Kottampatti Safe

12 Madurai East Safe

13 Madurai West Safe

14 Melur Safe

15 Sedapatti Over-exploited

16 Thiruparankundram Semi-critical

17 Usilampatti Over-exploited

18 Vadipatti Safe

19 Bogalur

Ramanathapuram

Safe

20 Mandapam Safe

21 Nainarkoil Safe

22 Paramakudi Safe

23 Ramanathapuram Safe

24 Thirupulani Poor quality

(Salinity)

25 Ilayankudi

Sivagangai

Safe

26 Kalayarkoil Safe

27 Manamadurai Safe

28 Sivagangai Safe

30 Andipatti

Theni

Over-exploited

31 Bodinayakanur Critical

32 Chinnamanur Critical

33 Cumbam Critical

34 K.Myladumparai Critical

35 Periyakulam Critical

36 Theni Critical

37 Uthamapalayam Over-exploited

Sedimentation in Reservoirs

Sedimentation in each reservoir is shown in the following table 19, 20, 21 & 22 and the

details of the sand quarries are given in the Table 23.

Table 19 Sedimentation in Vaigai Reservoir

Year Original Capacity

(Mm3)

Present

Capacity (Mm3)

Capacity

Loss

(Mm3)

Capacity

Loss

%

Rate of

Siltation

1976 194.785 178.191 16.594 8.52 0.473

1981 194.785 172.439 22.346 11.47 0.499

1983 194.785 172.380 22.405 11.50 0.460

2000 194.785 167.21 27.575 14.16 0.337

Source: I.H.H Reports and Watershed management Board Division, Pollachi

Table 20 Sedimentation in Marudhanadhi Reservoir

Year

Original Capacity

(Mm3)

Present

Capacity (Mm3)

Loss of

Capacity

(Mm3)

Capacity

Loss

%

Percentage

Loss in

Capacity

1998 5.3377 5.2197 0.118 2.21 0.116

Source: I.H.H Report No.14/99

Table 21 Sedimentation in Manjalar Reservoir

Year Original Capacity

(Mm3)

Present

Capacity (Mm3)

Loss of

Capacity

(Mm3)

Capacity

Loss

%

Percentage

Loss in

Capacity

1992 13.7594 10.6316 3.1278 22.73 0.9092

1996 13.7594 10.3042 3.4548 25.109 0.8658

Source: I.H.H Report No. 4/96 and 4/97

Table 22 Sedimentation in Berijam Reservoir

Year Original Capacity

(Mm3)

Present

Capacity (Mm3)

Loss of

Capacity

(Mm3)

Capacity

Loss

%

Percentage

Loss in

Capacity

1987 2.19455 1.80442 0.39013 17.78 0.234

Table 23 Details of Sand Quarries

Sl.No Name of Sand

Quarry

River Survey No. Possible Quantity to be

quarried (m3)/ year

1 Soodiyur Vaigai 255 102480 (18100 Loads)

2 Perungarai Vaigai 1-Jan 43500 (7685 loads)

3 Urapuli Vaigai 349 24000 (4240 loads)

4 Gangaikondan Vaigai 318, 107/1 120000 (21200 loads)

5 Oriyur Pambar 219 44500 (7862 loads)

6 Marungur Pambar 1 63500 (11200 loads)

Domestic water demand

Year Population Demand

2011 Urban 2780000

MLD MCM

Rural 2010000

2011

(as given by local bodies)

Urban 2316523 241.139 119.42

Rural 2151022 86.0409

2017 Urban 2608781 272.277

133.32

Rural 2324350 92.974

2020 Urban 2768459 288.676

140.64

Rural 2416183 96.6473

2030 Urban 3374737 351.89

168.58

Rural 2749314 109.973

2040 Urban 4113785 428.96

202.24

Rural 3128375 125.135

2050 Urban 5014681 522.9 242.83

Rural 3559699 142.388

Industrial water demand

WATER DEMAND CALCULATION FOR SMALL, MEDIUM AND LARGE INDUSTRIES BASED ON INDUSTRY CENSUS AS TAKEN

FROM IWS

Sl.

No.

Type of

industry

Average

Rate of

Water

consumption

as given in

IWS m3/day

2014 2017 2020 2030 2040 2050

No. of

industry

as per

IWS

Water

Demand

No. of

industry

Water

Demand

No. of

industry

Water

Demand

No. of

industry

Water

Demand

No. of

industry

Water

Demand

No. of

industry

Water

Demand

1

Small

scale

industry 2.5 67711 61.79 85296 77.83 107449 98.05 231974 211.68 500814 456.99 1081221 986.61

2

Medium

& large

scale

industry 2500 195 177.94 246 224.48 309 281.96 668 609.55 1442 1315.83 3114 2841.53

Total

Demand

in M.Cum 239.73 302.31 380.01 821.23 1772.82 3828.14

Water Balance

Water balance for Vaigai basin at 75% dependability is shown in Table 28.

Table 28 Water balance for Vaigai basin

Sl.

No

Name

of the

basin

Area

of the

basin (in

Sq.Km

)

No. of

Sub

basins

Year

Demand of water in various sectors (MCM) Water availabilty (MCM)

GAP

Remark

s-sewage

MCM Irrigatio

n

Domestic

s

Industr

ies

Live

stocks

Other

s Total

Surface

water

potentia

l

Ground

water

potentia

l

Quantit

y of

recycled

water

from

Effluent

Quantit

y of

water

from

desilting

Total

1 VAIGA

I 6823 10

2017 1802.00 133.32 302.31 35.57 0.00 2273.2

0 1371.00 548.99 0.00 32.01

1952.0

0

-321.20

0.08

2020 1802.00 140.64 380.01 35.67 0.00 2358.3

2 1371.00 548.99 0.00 32.01

1952.0

0

-

406.32 0.08

2030 1802.00 168.58 821.23 36.40 0.00 2828.2

1 1371.00 548.99 0.00 32.01

1952.0

0

-

876.21 0.08

2040 1802.00 202.24 1772.82 37.66 0.00 3814.7

2 1371.00 548.99 0.00 32.01

1952.0

0

-

1862.7

2

0.08