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