237

CHAPTER 5

RESULTS AND DISCUSSIONS

5.1 FIELD STUDY

Before going into the model prediction, the following paragraphs

brief about the existing groundwater quality and the Amaravathi river water

quality in the study area (i.e) in 320 sq.Km area. For this study purpose field

sampling was done.

5.1.1 Groundwater Quality along the Amaravathi River Basin

For primary data collection, 13 open wells were identified in the

study area spreading from Chinnadarapuram where river enters into Karur

district and upto Kattalai where the river confluence with river Cauvery. The

wells locations (B 1 to B 13) are given in Figure 4.1. All the wells are dug

wells, since this type is the most common in the area. Water level and water

quality was monitored for three seasons. Water samples were collected in pre

monsoon (14.9.2008), post monsoon (31.1.2009) and summer (29.5.2009).

During these sampling days, the climate was sunny. The water samples were

collected with a bucket and stored in 1 litre new plastic containers, which were

filled to the brim with water. The samples were transported to Tamil Nadu

Water Supply and Drainage Board Laboratory at Karur. The samples were

analyzed as per the standards methods of APHA (2005). The analysis was

carried out for physico chemical parameters (i.e) turbidity, total dissolved

solids, electrical conductivity, pH, total alkalinity, total hardness, calcium,

magnesium, iron, manganese, ammonia, nitrite, nitrate, chloride, fluoride,

sulphate and phosphate. The findings are discussed below.

238

The analysis results are given in Table.5.1. The values are

compared with BIS standards for drinking water IS: 10050: 1991. In general

the groundwater quality in the down stream of Karur is affected. Turbidity was

in the range of 1 to 18 NTU. Out of 13 locations turbidity exceeded the

desirable limit of 5 NTU in one location. Total Dissolved Solids was found in

the range of 630 – 4280 mg/L. All 13 locations exceeded the desirable limit of

500 mg/L. The highest value was recorded in well No.10. The reason is one

irrigation canal branching from Amaravathi river is passing at about 10 metres.

It carries river water mixed with dark brown colored high TDS wastewater of

textile processing units. Electrical Conductivity was in the range of 1030 –

6158 µmho/cm. The highest value 6158 µmho/cm was found in well No.B10.

The permissible level of pH in the drinking water is 6.5 – 8.5. All the samples

were within this range value. pH varies from 7.15 to 8.32. The high pH 8.32

was observed in well No.B3. This is due to alkaline nature of the soil. Total

alkalinity of water is due primarily to the salts of weak acids. Bicarbonates

represent the major form of alkalinity. Alkalinity of water has little public

health significance. Total alkalinity was in the range of 150 mg/L to 699 mg/L.

The highest value 699 mg/L was detected in well No. B6, whereas the

desirable limit is 200 mg/L. Hardness of water depends on the geological

formations. Total Hardness in the study area was in the range of 235 – 1627

mg/L, whereas the desirable limit is 300 mg/L.

Calcium was found to be in the range of 36 – 353 mg/L. Out of 13

wells, 12 wells were above the desirable limit of 75 mg/L. Magnesium was

detected in the range of 7 mg/L – 200 mg/L. Nitrate was measured in the range

of 2 – 65 mg/L. 7 sampling wells exceeded the desirable level of 45 mg/L. The

desirable limit of chlorides in drinking water is 250 mg/L. In field survey,

chloride was detected in the range of 48 – 1936 mg/L. Expect well at

Thokkupatti (well No.B2) all the sampling wells exceeded the desirable limit.

239

Fluoride in the sampling wells was in the range of 0.2 – 2 mg/L. Desirable

limit in drinking water is 1.0 mg/L. 8 wells exceed the desirable limit.

Sulphate in the groundwater of the study area was found in the range 40 – 343

mg/L. Desirable limit of sulphate in drinking water is 200mg/L. 5 sampling

wells exceeded the desirable limit.

From the above sampling it is concluded that the ground water is

not fit for human consumption. The analysis results are plotted in graph and

given in Figure 5.1 to 5.12. The study area is covered with the protected water

supply by the local bodies. However the people and their cattle living in the

farm houses depend on well water. The high concentration of TDS, EC, TSS,

Chlorides and sulphate will also affect the crop growth.

240

Table 5.1 Physico-Chemical Parameters of Well Water Samples in Amaravathi River Basin

Well

No.

Village Season Turbidity TDS EC pH Tot.

Alka

Tot.

Hard

Ca+

Mg+

NO3

Cl F SO4 Water

levelamsl

B1 Bharathinagar Pre-mon 1 1460 2091 7.73 185 480 118 45 9 381 0.8 248 180

Post-mon 1 1880 2707 7.15 335 872 239 66 58 465 1 343 181

Summer 1 1470 2147 7.42 322 666 180 52 18 468 0.6 215 179

B2 Thokkupatti Pre-mon 1 720 1030 8.26 225 235 36 35 17 132 1.5 65 174.5

Post-mon 2 980 1431 7.88 406 439 63 68 65 162 2 40 175.6

Summer 1 630 946 7.73 342 361 58 52 16 48 1.2 24 173.2

B3 Senkalai

palayam

Pre-mon 2 960 1372 7.99 268 235 66 17 5 218 1.4 60 171.2

Post-mon 1 1150 1663 7.58 426 474 64 75 50 216 1.8 87 172.9

Summer 1 1520 2257 7.44 370 784 145 101 7 393 1.2 134 170.2

B4 Thumbivadi Pre-mon 1 1280 1836 8.32 335 314 55 42 17 249 1.8 139 155.2

Post-mon 2 1650 2389 7.91 418 519 78 78 58 495 1.8 233 157

Summer 1 2020 2990 7.57 422 784 110 122 10 527 1.4 235 153

B5 Andankovil Pre-mon 2 3620 5178 7.66 201 1215 285 120 9 1573 1.2 256 134

Post-mon 1 1530 2201 7.78 390 559 102 73 2 439 1.4 83 135

Summer 1 3120 4521 7.56 330 1411 243 193 15 1313 1 173 133

B6 Kollanda

goundanur

Pre-mon 18 3060 4381 7.99 339 510 125 47 4 1228 1.4 71 121.3

Post-mon 3 2860 4133 7.77 607 1156 282 108 38 869 0.8 99 122.1

Summer 9 2680 3897 7.45 699 960 223 96 3 900 0.4 38 120.8

B7 Arugam

palayam

Pre-mon 3 4080 5858 7.57 319 823 154 105 6 1776 1.2 183 115.5

Post-mon 1 1950 2806 7.55 378 500 212 7 21 662 1.4 99 116.9

Summer 1 3240 4697 7.38 438 706 169 68 17 1363 1 144 114

241

Table 5.1 (continued)

B8 Sanapiratti Pre-mon 1 3860 5533 7.9 150 1117 297 108 28 1736 1 176 107

Post-mon 1 3220 4652 7.66 351 1215 243 146 58 1252 1 167 108.5

Summer 1 3060 4492 7.49 277 1137 192 158 17 1294 0.8 156 106

B9 Nerur Pre-mon 1 3180 4548 7.34 205 784 188 75 22 1309 1 176 112

Post-mon 2 3100 4452 7.27 374 1490 353 146 58 1242 0.8 174 113

Summer 1 3080 4453 7.17 322 1568 294 200 15 1284 0.6 154 110.2

B10 Puliyur Pre-mon 1 4100 5927 7.79 154 1058 238 111 4 1939 1 238 105

Post-mon 1 4280 6158 7.31 351 1627 337 188 14 1889 1 211 107

Summer 1 3760 5858 7.42 277 1470 270 191 2 1821 0.8 182 104.5

B11 Renganathan

pettai

Pre-mon 1 1060 1523 7.72 229 363 74 43 9 270 0.8 79 99.5

Post-mon 1 1230 1790 7.6 323 451 110 42 11 323 0.8 88 100.1

Summer 1 1470 2127 7.34 370 617 118 78 19 403 0.4 100 98.5

B12 Uthukara

patti

Pre-mon 1 1370 1959 7.31 197 608 163 48 15 452 0.5 61 105

Post-mon 1 1250 1800 7.47 284 713 199 52 48 378 0.2 59 106

Summer 1 1400 2047 7.47 269 843 216 73 16 478 0.2 43 103

B13 Nataraja

puram

Pre-mon 1 1910 2736 7.99 276 412 66 59 5 584 1.6 198 99.4

Post-mon 2 3160 4532 7.57 390 1196 212 160 12 1232 1.2 215 101

Summer 1 2280 3322 7.51 446 715 137 89 12 761 1.2 159 98.2

IS 10500:1991

Drinking water

specifications

Desirable -

Limit

5 500 6.5-

8.5

200 300 75 45 250 1 200

Permissible- Limit

10 2000 6.5-8.5

600 600 200 100 1000 1.5 400

All parameters are in mg/L except EC, pH & Turbidity. EC is expressed in micromho/cm, Turbidity is expressed in NT. Water level in metres (above mean sealevel)

242

0

500

1000

1500

2000

2500

3000

3500

4000

4500

B ha ra thina ga r

T hokkupa tti

T humbiva di

Se nka lipa la ya m

A nda nkoil

K olla nda gounda nur

Aruga mpa la ya m

Sa na pira tti

N e rur

Puliyur

U thuka ra pa tty

R e nga na tha npe tta i

N a ta ra ja pura m

Well Location

T o ta l D issolve d Soilds (mg/L)

Pre-m

onsoonP

ost-monsoon

Sum

mer

Desirable lim

it

0

500

1000

1500

2000

2500

B h a ra th ina ga r

T ho kkup a tti

T hum biva di

S e n ka lip a la ya m

A n da n koil

K olla nda gou nda n ur

A ruga mp a la ya m

S a n a pira tti

N e rur

P uliyur

U thuka ra pa tty

R e nga n a th a npe tta i

N a ta ra ja pura m

Well Location

C h lor ide s (mg /L)Pre-m

onsoonPost-m

onsoon

Summ

erD

esirable limit

Fig

ure 5

.1 T

DS

in S

tud

y A

rea F

igu

re 5.2

Ch

lorid

e in S

tud

y A

rea

0 50

100

150

200

250

300

350

400

B ha ra th ina ga r

T hokkupa tti

T hum b iva d i

S e nka lipa la ya m

A nda nko il

K o lla nda gounda nur

A ruga m pa la ya m

S a na pira tti

N e ru r

P u liyu r

U thuka ra pa tty

R e nga na tha npe tta i

N a ta ra ja pu ra m

Well Location

S u lpha te s (m g /L )

Pre-monsoon

Post-monsoon

Summ

erD

esirable limit

5 6 7 8 9 10 11

B h a ra th in a g a r

T h okku pa tti

T h um b iva d i

S e nka lipa la ya m

A nd a nko il

K o lla n da go un da n ur

A ru g a m pa la ya m

S a n a p ira tti

N e rur

P u liyu r

U thu ka ra pa tty

R e ng a n a tha np e tta i

N a ta ra ja pu ra m

Well Location

pH

Pre-monsoon

Post-monsoon

Summ

erD

esirable lower lim

itD

esirable upper limit

Fig

ure 5

.3 S

ulp

hate in

Stu

dy

Area

Fig

ure 5

.4 p

H in

Stu

dy

Area

243

0

100

200

300

400

500

600

700

800

B ha ra th in a ga r

T ho kku pa tti

T hu m b iva d i

S e nka lip a la ya m

A n da nko il

K o lla n da gou nd a nu r

A ruga m p a la ya m

S a na p ira tti

N e ru r

P uliyur

U th uka ra pa tty

R e ng a n a th a np e tta i

N a ta ra ja pu ra mW

ell Location

T o ta l A lka lin ity (m g /L)

Pre-monsoon

Post-monsoon

Summ

erD

esirable limit

0

200

400

600

800

1000

1200

1400

1600

1800

B ha ra th in a ga r

T h okkup a tti

T h um b iva d i

S e n ka lipa la ya m

A n da n ko il

K o lla n d a g o u nd a nu r

A ru ga m p a la ya m

S a n a p ira tti

N e ru r

P u liyur

U th u ka ra p a tty

R e n ga n a tha n pe tta i

N a ta ra ja p ura m

Well Location

T o ta l H a rd ne ss (m g /L )

Pre-monsoon

Post-monsoon

Summ

erD

esirable limit

Fig

ure 5

.5 T

ota

l Alk

alin

ity in

Stu

dy

Are

a

Fig

ure 5

.6 T

ota

l Ha

rdn

ess in

Stu

dy

Are

a

0 50

100

150

200

250

Bharathinagar

Thokkupatti

T humbivadi

Senkalipalayam

Andankoil

Kollandagoundanur

Arugampalayam

Sanapiratti

Nerur

Puliyur

Uthukarapatty

Renganathanpetta i

Natarajapuram

Well Location

Magnesium (mg/L)

Pre-m

onsoonP

ost-monsoon

Sum

mer

Desirable lim

it

0 50

100

150

200

250

300

350

400

Bhara thinaga r

T hokkupatti

T humbiva di

Senkalipa la ya m

Anda nkoil

Kolla ndagounda nur

Arugampalayam

Sanapiratti

N erur

Puliyur

U thukara pa tty

Renganatha npetta i

Nata ra ja puram

Well Location

C a lcium (mg/L)

Pre-m

onsoonP

ost-monsoon

Sum

mer

Desirable lim

it

Fig

ure 5

.7 M

ag

nesiu

m in

Stu

dy

Area

Fig

ure 5

.8 C

alciu

m in

Stu

dy

Area

244

0 2 4 6 8 10 12 14 16 18 20

Bha ra th ina ga r

T hokkupa tti

T humbiva di

S e nka lipa la ya m

A nda nkoil

K olla nda gounda nur

Aruga mpa la ya m

Sa na pira tti

N e rur

P uliyur

U thuka ra pa tty

R e nga na tha npe tta i

N a ta ra ja pura m

Well Location

T urbidity (N T U )

Pre-monsoon

Post-monsoon

Summ

erD

esirable limit

0

1000

2000

3000

4000

5000

6000

7000

B h a ra th ina ga r

T h okkup a tti

T hu m biva d i

S e nka lipa la ya m

A nd a n koil

K o lla n da go un da n ur

A rug a m pa la ya m

S a na pira tti

N e rur

P uliyur

U thuka ra p a tty

R e ng a n a tha n pe tta i

N a ta ra ja p ura m

Well Location

E le ctrica l C o nd uctivity (M icrom h o/cm )Pre-m

onsoonPost-m

onsoon

Summ

er

Fig

ure 5

.9 T

urb

idity

in S

tud

y A

rea F

igu

re 5.1

0 E

C in

Stu

dy

Area

0 10 20 30 40 50 60 70

B ha ra thina ga r

T hokkupa tti

T humb iva d i

S e nka lipa la ya m

A nda nkoil

K olla nda gounda nur

A ruga mpa la ya m

S a na pira tti

N e rur

P uliyur

U thuka ra pa tty

R e nga na tha npe tta i

N a ta ra ja pura m

Well Location

N itra te s (m g/L)

Pre-m

onsoonPost-m

onsoon

Sum

mer

Desirable lim

it

0

0.5 1

1.5 2

2.5

B h a r a th in a g a r

T h o kku p a tti

T h u m b iva d i

S e n ka lip a la y a m

A n d a n ko il

K o lla n d a g o u n d a n u r

A ru g a m p a la ya m

S a n a p ira tti

N e ru r

P u liyu r

U th u ka ra p a tty

R e n g a n a th a n p e tta i

N a ta r a ja p u ra m

Well Location

F lu o r id e (m g /L )

Pre-monsoonPost-monsoon

Summer

Desirable limit

Fig

ure 5

.11

Nitra

te in S

tud

y A

rea F

igu

re 5.1

2 F

luorid

e in S

tud

y A

rea

245

5.1.2 Amaravathi River Water Quality

The treated effluent from the CETPs is finally reaching the river

Amaravathi. Though the dyeing industries effluent is treated, the TDS, Chlorides

in the effluent are not removed to the permissible level. Therefore river got

polluted while passing through Karur town. In this study in order to know the

quality of the river water, sampling was done at three locations C1). Andankovoil

– 3 Km upstream of Karur, C2) Pasupathipalayam - 0.5 Km down stream of

Karur, C3). Kattalai - 10 Km down stream - river confluence with river Cauvery.

The sampling location is given in Figure 4.1. The samples were collected for

three seasons (i.e) pre monsoon (14.9.2008), post monsoon (31.1.2009) and

summer (29.5.2009). The results are given in Table 5.2

TDS at 3 Km upstream of Karur town (sampling point 1) was 230 -

590 mg/L, 0.5 Km down stream of Karur town (sampling point 2) was 430 – 5360

mg/L and 10 Km down stream of Karur town (sampling point 3) was 480 - 690

mg/L. Permissible level of TDS in class C surface water body as per IS 2296:

1982 is 500 mg/L. pH was in the range of 7.21 - 8.62. The permissible range is

6.5-8.5. It reveals that the alkaline effluent from bleaching and dyeing units

increase the pH level in the river water. Dissolved oxygen in the river upstream

was 5 - 6.7 mg/L, 0.5 Km downstream of Karur was 4.6 - 6.8 mg/L and, 10 Km

down stream of Karur was 5.2 - 6.6 mg/L. Minimum DO level in class C surface

water body is 4.0 mg/L. The results are given in Table 5.2 and pictorial form is

given in Figure 5.13-5.17. During summer there is no water flow in the river. The

river acts as drainage for dyeing effluent and domestic sewage.

246

Table 5.2 Amaravathi River Water Quality

S.No

.

Samplinglocation

Season Turbidity

TDS EC pH TotalAlkalinit

y

TotalHardnes

s

Ca

Mg

Fe NH

3

NO

2

NO

3

Cl F SO

4

PO4 DO

1 Andankoil(3 Km

upstream of

Karur)

78.0305E10.9568N

Pre-monsoo

n

2 230 3408.4

795 104 22 12

0.1

10 0 3 26

0.

811

0.0

65

Post-

monsoon

1 360 5238.6

2189 159 28 21 0 0 0 4 61

0.

815 0 6.7

Summer 1 590 8748.2

3197 114 16 17 0 0

0.0

32 135

0.

817

0.0

76.2

2 Pasupathipalaya

m

(0.5 Kmdown stream

of Karur)78.1708E

10.9736N

Pre-

monsoo

n

6 520 7528.19

134 129 27 150.17

0.55

0.09

4 910.4

200.14

4.6

Post-

monsoo

n

2 430 6438.2

2205 169 36 19 0 0 0 1 67

0.

618

0.1

36.8

Summer 17536

07789

7.21

515 568 90 820.14

1.23

0 22488

0.2

501.89

5.1

3 Kattalai

(10Kmdown stream

of Karur &

before

confluence withriver Cauvery)

78.1950E

10.9850N

Pre-

monsoon

1 480 6908.8

4138 167 31 21 0 0

0.0

33 128

0.

620 0 5.2

Post-

monsoon

1 490 7038.7

2165 141 24 20 0 23

0.0

53 105

0.

825

0.5

26.7

Summer 1 6901031

8.17

221 220 46 25 0 00.05

2 1750.2

200.06

6.6

IS:2296:1982 tolerance

limit for inland

surface waters (Class C)

1500

6.5-8.5

50 6001.5

4

Note: All parameters are in mg/L except pH, Turbidity & EC. Turbidity in NTU, EC micromho/cm

247

0

1000

2000

3000

4000

5000

6000

An

danko

vil

Pa

supath

ipala

yam

Katt

ala

i

Location

TD

S (

mg/L

)

Pre-monsonn

Post-monsoon

Summer

0500

10001500200025003000

Andanko

vil

Pasu

pa

thip

ala

yam

Kattala

i

Location

Chlo

ride

s (m

g/L

)

Pre-monsonn

Post-monsoon

Summer

Figure 5.13 TDS in Amaravathi Figure 5.14 Chloride in Amaravathi

012345678

And

ank

ovi

l

Pasu

path

ipala

yam

Kat

tala

i

Location

DO

(m

g/L

)

Pre-monsonn

Post-monsoon

Summer

00.10.20.30.40.50.60.70.80.9

An

da

nko

vil

Pa

sup

ath

ipa

laya

m

Ka

tta

lai

Location

Flu

ori

de

(m

g/L

)

Pre-monsonn

Post-monsoon

Summer

Figure 5.15 DO in Amaravathi Figure 5.16 Fluoride in Amaravathi

0

1

2

3

4

5

Andanko

vil

Pasu

path

ipala

yam

Kattala

i

Location

Nitr

ate

(m

g/L

)

Pre-monsonn

Post-monsoon

Summer

0123456789

10

And

an

kovi

l

Pa

sup

ath

ipa

laya

m

Ka

tta

lai

Location

pH

Pre-monsonn

Post-monsoon

Summer

Figure 5.17 Nitrate in Amaravathi Figure 5.18 pH in Amaravathi

248

5.2 MODEL PREDICTION

The validated MT3D model is used to simulate the TDS concentration

in the study area under various stress conditions. Prediction is done for next 15

years (i.e) 2010 to 2024. For model prediction purpose, two PWD monitoring

wells (i.e) Chinnadharapuram (A1 – well No. 14022 ), Kakkavadi (A4 – well No.

14012D), and six wells from which primary data is collected (i.e),

Kolladanagoundanur (B6), Arugampalayam (B7), Sanapiratti (B8), Puliyur (B10),

Renganathanpettai (B11), and Natarajapuram (B13) were selected along the 40

Km stretch of river Amaravathi. The reason for selection of more wells towards

the down stream of Karur is that this area is severely affected by textile effluent

discharge. Groundwater flow is also towards northeast along the direction of river

flow. In case of any improvement in the effluent treatment and disposal system,

the impact will be felt in the down stream. The model was run for the following

scenarios.

i. If the present scenario continues (i.e) CETPs discharging the partially

treated effluent with TDS in the range of 5000-10,000 mg/L., what will be

the impact on the groundwater quality?

ii. If the CETPs meet the TDS discharge standards of 2100 mg/L and

discharge the effluent into river, what will be the impact in the ground

water quality?

iii. If the quantum of effluent discharge is doubled with TDS level of 2100

mg/L, what will be the impact on groundwater quality?

iv. If the dyeing units go for reverse osmosis plant and recycle the entire

effluent and achieve zero discharge, what will be improvement in the

groundwater quality?

249

v. If the groundwater recharge is increase by 1.5 times from year 2009 and

the dyeing units adopt zero liquid discharge concept, what will be the

improvement in the quality of groundwater?

The simulated results for five scenarios are plotted for TDS verses

Year for eight monitoring wells located on either side of Amaravathi river which

are influenced by the discharge of dyeing effluents. The starting point for the

change in stress for the various scenarios is considered as year 2009. Because, the

CETPs have not yet met the TDS standards and still continuing discharge the

effluent into river Amaravathi with TDS range of 7000 – 10000 mg/L, chloride

4000 – 5000 mg/L. As explained in Chapter-4 input parameters (i.e), recharge,

recharge concentration are altered for each scenario. All other input parameters

were remains the same. The MODFLOW and MT3DMS were run for a total

period of 10950 days (year 1994 – 2024). The model out gives the TDS vs time

plots. These out puts are consolidated and presented below.

5.2.1 Groundwater Quality at Chinnadarapuram

Chinnadapuram is located at about 30 Km on south west direction

from Karur and at the upstream side of the Karur town. From the MODFLOW

model simulations, it is understood that the groundwater flow is towards north

east direction. The surface water drainage is also towards north east direction.

Therefore the impact of textile dyeing industries effluent is not noticed in

Chinnadarapuram area. As per the model prediction, the TDS in groundwater will

reach to a level of 2900 mg/L (Figure 5.19). This may be due to lowering of water

table due to increase of agricultural activities, domestic consumption and soil

weathering. However when groundwater recharge is increased to 1.5 times, TDS

250

level is towards declining trend. Even then it will not meet the permissible level

of 500 mg/L.

0

500

1000

1500

2000

2500

3000

3500

1994 1999 2004 2009 2014 2019 2024

Year

TD

S m

g/L

Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Figure 5.19 TDS Profile of Well at Chinnadarapuram (A1 – Well No. 14022)

5.2.2 Groundwater Quality at Kakkavadi

Kakkavadi is located at about 6 Km on south west direction from

Karur town at it is on upstream side of Karur. This area is at higher elevation

compared to Karur and the Amarvathi river. There is no textile processing

industries in this area. This area is a dry area. There are no wet agricultural

activities using river or canal water. However dug well framing activity is taking

place on selected spots. Even though, this area is not influenced by the textile

industrial activity, the TDS in groundwater is in rising trend and reach a level of

2200 mg/L in year 2024 (Figure 5.20). For the scenario 5, the TDS well is

declined to 1000 mg/L due to groundwater recharge thereby raising the water

table. The villages in the area are provided with piped water supply from the

head works at river Amaravathi.

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1994 1999 2004 2009 2014 2019 2024

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Figure 5.20 TDS Profile of Well at Kakkavadi (A4 – Well No. 14012D)

5.2.3 Groundwater Quality at Kolandagoundanur

Kolandagoundanur village is located at 0.5Km down stream of Karur.

This village is located on the bank of Amaravathi river. The dyeing units are

located in this village and the surrounding area. Some of the dyeing units in this

area who have IETPs are utilizing the treated effluent with TDS of 10,000 mg/L

on land for irrigation. Stagnation of effluent as a pond in the river bed is a usual

phenomena here. Domestic sewage is also get stagnated in the river bed. At

present the TDS level in groundwater is 2750 mg/L. The ground water is unfit for

irrigating the crops. The wells are abandoned. The model prediction clearly

indicates the built-up of TDS in groundwater over a period of time. If the existing

discharge continuous (scenario 1), TDS will rise to 7500 mg/L in year 2024

(Figure 5.21). Even the effluent meets the TDS discharge standard of 2100 mg/L,

there is no improvement in the groundwater quality. If the entire effluent

discharge into the river is stopped (secraio-4) from year 2009 onwards, then the

TDS is getting leached out and it will reduced to a level of 1670 mg/L. When the

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recharge is increased to 1.5 times (sceraio-5), the TDS will be around 1350 mg/L

in year 2024.

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1994 1999 2004 2009 2014 2019 2024

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Figure 5.21 TDS profile of Well at Kolandagoundanur (B6)

5.2.4 Groundwater Quality at Arugampalayam

Arugamapalayam village is located on the northern bank of river

Amaravathi and at 1 Km down stream of Karur. The sampling well is located

nearer to a unlined canal which carries treated effluent from CETP namely Karur

Vanchi Dyeing Enviro Tech Ltd. Previously (until 1996), this well was used to

supply of water to the Karur Municipality. But it is now abandoned, due to high

TDS level. If the present system continues (senaraio-1), in year 2024, the TDS

level in groundwater of this area will be 8000 mg/L (Figure 5.22). If zero

discharge is implemented, then there will be an improvement in groundwater

quality and TDS will be around 2240 mg/L. If groundwater recharge is enhanced

as per scenario 5, then the quality will be improved and TDS will be reduced to

1750 mg/L in year 2024.

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Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Figure 5.22 TDS Profile of Well at Arugampalayam (B7)

5.2.5 Groundwater Quality at Sanapiratti

Sanapiratti village is located at 3 Km down stream of Karur town. The

village is about 2 Km away from the southern bank of river Amaravathi. Until

1990, this area is wet agricultural area producing paddy, turmeric, sugarcane

using Amaravathi river water. But now, the farmers have leased out the lands for

removing the top soil (2 m deep) for brick chambers. Some of them have sold the

land for housing plots. The remaining land is become barren land used for cattle

grazing. The model predicts that TDS will rise to a level of 9300 mg/L under

secraio-1(Figure 5.23). Whereas, the TDS will be reduced to a level of 2150 mg/L

in the next 15 years when the dyeing units in the Karur adopts ZLD system and

the ground water recharge is increased to 1.5 times (scenario-5).

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Figure 5.23 TDS Profile of Well at Sanapiratti (B8)

5.2.6 Groundwater Quality at Puliyur

Puliyur is located at about 5 Km on eastern side and at down stream of

Karur. The village is about 1.5 Km away from the southern bank of Amaravathi

river. An irrigation canal branching from Armaravathi at Karur is passing though

this village. This canal water carries dark brown coloured textile dyeing effluent

along with river water. Since, 1990 the dug wells located along the traverse of this

canal have become unfit for irrigation due high TDS and colour in the well water.

The farmers in this area forms co-operative societies and provided well on the

bank of Amaravathi and irrigate the fields. This is also affected for past ten years.

At present the TDS level in these wells are nearer to 3600 mg/L. The MT3D

model predicts that the TDS will rise to 8100 in the next 15 years. Even the

dyeing units treat the effluent to the standards, it will not solve the problem. The

only option is ZLD and groundwater recharge to bring down the TDS level to the

original level of 1800 mg/L (Figure 5.24).

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1994 1999 2004 2009 2014 2019 2024

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Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Figure 5.24 TDS Profile of Well at Puliyur (B10)

5.2.7 Groundwater Quality at Renganathanpettai

Renganathanpettai village is located at about 10 Km on eastern side

and at the down stream of Karur. It is located on the northern bank of river

Amaravathi. This is the area where the river Amaravathi joins with river Cauvery.

This area is a highly fertile land with intensive wet agricultural activities taking

place. Mainly paddy, turmeric, sugarcane and corai grass are cultivated using

Cauvery river water. During this study, filed visits were carried out on several

times. It was discussed with the local village people and farmers. During the

enquiry with the farmers, it was under stood that this area (Renganathanpettai) is

not influenced by the discharge of dyeing effluent into the river Amaravathi.

Because the irrigation canal branching from river Cauvery and irrigates in these

surrounding villages. This irrigation canal also carries Tamilnadu News Print and

Paper Mills Ltd coloured effluent. However the TDS level in the groundwater is

in the range of 1500 mg/L. The model predicts that in year 2024, the TDS will

reach to a level of 2400 mg/L (Figure 5.25). The farmers are using extensive

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chemical fertilizers to the crops. This also contributes to the rising of TDS level.

There is no much influence due to increase of groundwater recharges. Because

already the groundwater table in this area is at higher level.

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1994 1999 2004 2009 2014 2019 2024

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S m

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Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Figure 5.25 TDS profile of Well at Renganathanpettai (B11)

5.2.8 Groundwater Quality at Natarajapuram

Natarajapuram village is located at about 10 Km on eastern side and at

down stream side of Karur. It is located 1.5 Km away from southern bank of river

Amaravathi. Here the groundwater got affected due to the influence of textile

dyeing effluent discharge. During the filed visit, it was reported by the villagers

that for the past 10 years the surrounding well water quality gets deteriorated

gradually and become unfit for human consumption. Even though the dug wells

are having water at higher level, it is unfit for rising crops due to high TDS level.

Compared to northern bank villages, southern bank villages of river Amaravathi

are worstly affected. The model predicts that TDS level will be around 9500 mg/L

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after 15years (Figure 5.26). Under scenario 4 & 5, the TDS level gets reduced to

below 2000 mg/L.

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1994 1999 2004 2009 2014 2019 2024

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Scenario 1 Scenario 2 Scenario 3 Scenario 4 Scenario 5

Figure 5.26 TDS Profile of Well at Natarajapuram (B13)

5.3 LIMITATION OF THE STUDY

The reliability of the model depends on the accuracy of the data used

for calibration and validation. The following are the limitations.

i. The model is developed with the secondary data obtained from various

Government Departments. Groundwater quality is monitored by PWD

once in six months in selected points. This will not give a true picture on

the entire system.

ii. The aquifer properties such as permeability, transmissivity, specific yield,

and specific storage are taken from the literature available. However it is to

be verified by filed study, like pumping test, tracer study, lab scale

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hydraulic conductivity study. These studies involves expensive and longer

time duration.

iii. With the bore hole sampling at the selected locations of CGWB, the

litholgy is assumed. This needs a detailed investigation by having more

exploratory wells.

iv. The drains, recharge, evapotranspiration rate are assumed based on the

secondary data. It needs filed study and primary data collection.

v. The grid size is assumed as 200m x 200 m and homogeneous. But in field

it is no so. Small grid size with appropriate input parameters will give

reliable predictions.

5.4 SUMMARY

Visual MODFLOW prediction study indicates that in the next 15 years,

the TDS level in groundwater will further increase to the level of 7000 – 9000

mg/L in the villages located at the down stream side of Karur. This study

establishes that there is a direct relation ship between the effluent discharge and

the TDS built-up in the groundwater of Amaravathi river basin. This was also

observed by the Loss of Ecology (P&PC) Authority during their study in year

2003. The study also establishes that the TDS level can be brought down by

adopting ZLD system by the textile dyeing units. From the study, it is under stood

that the villages at the upstream side are not affected by the way of discharge of

effluent by textile dyeing units in Karur.