Suitability of groundwater for Irrigation purpose in Ankasandra Watershed in parts of Tiptur and C.N. Halli taluks of Tumkur district, Karnataka, India

International Conference on Integrated Water, Waste Water & Isotope Hydrology, 25-27th, July 2013, Bangalore.

SUITABILITY OF GROUNDWATER FOR IRRIGATION

PURPOSE IN ANKASANDRA WATERSHED IN PARTS OF

TIPTUR AND C.N. HALLI TALUKS OF TUMKUR DISTRICT,

KARNATAKA, INDIA

G.R.C.Reddy*, S.S.Vittala, Rahul Vashista and K.Md.Najeeb

ABSTRACT

Ground water is the major source of irrigation in drought prone Ankasandra watershed which is

located in parts of Tiptur and C N Halli taluks of Tumkur district of Karnataka State. The main

livelihood of the people in the watershed is agriculture. The area underlain by Archaean group

of rocks and important litho units are granite, gneiss, dharwar schist and dolerite dykes. The

phreatic aquifer in most of the area is desaturated and groundwater is being drawn from

fractured aquifer. The major crops grown under irrigation through bore wells are coconut and

areacanut. The study was carried out under pilot project on aquifer mapping. To know the

groundwater quality, 52 samples collected during September 2011 and chemically analysed for

Hydrogen ion concentration (pH), specific conductance, calcium, magnesium, sodium,

potassium, total hardness, carbonate, bicarbonate, sulphate, chloride, nitrate and fluoride. Based

on the analysis, parameters like percent sodium, sodium absorption ratio (SAR) and residual

sodium carbonate (RSC) were calculated. The results revealed that, with respect to electrical

conductivity, it is found that about 10% of water samples fall in good category, 86% falling

under permissible limit and about only 4% fall under doubtful category. In case of percent

sodium analysis, about 58% fall under permissible category, 27% is under good category, 13%

fall in doubtful category and 2% fall in excellent category. The SAR values ranges from 1.82

to 9.12 and reveals that all 52 water samples (100%) fall under excellent category. The RSC

values shows that about 86% of water samples fall under safe category while 8% and remaining

6% fall under marginal and unsuitable type respectively. It is concluded from various methods

that the groundwater quality is mostly suitable for irrigation purposes.

Key words: Groundwater quality, Ankasandra watershed, Tumkur district

Materials and methods

Description of the study area

The Ankasandra watershed is a part of

4D3D8 watershed and falls in Tiptur and

Chiknayakanhalli taluks.

1

Central Ground Water Board, SWR, 27

th

Main, 7th Cross, H.S.R.Layout, Sector – 1,

Bangalore 560102. *E-

mail:[email protected]

The area falls in the Survey of India

toposheet no. 57 C/7 and 57 C/11 and lies

between north latitudes 13 15' 15" to 13

28' 30" and east longitudes 76 23' 00" to

76 39' 00". The total area of the watershed

is 375 sq. km and covers about 141

villages. The location map of the study area

is shown in Fig. 1. The present study has

been carried out under pilot project on

Micro Level Aquifer Mapping (MLAM)

study. The general ground elevation is

around 850 m in the southern part of the


watershed and the lowest elevation of 720

m above MSL at Ankasandra village in the

northern part of the watershed. The

watershed is drained by 1st to 5

th order

streams. The drainage is dendritic with

flow direction from south to north and

ultimately forms the Torehalla stream. The

drainage is part of the Krishna basin and

Vedavati sub basin. The average annual

rainfall in the study area is 680 mm.

The area exposes mainly rock types

belonging to the Peninsular Gneissic

Complex, Schistose rocks of Sargur group

and Dharwar super group, Younger

intrusive (basic dykes) and in thin patches

of Quaternary gravels. The Schistose rocks

occupy the NW to SE direction in the

central portion of the area. Granitic

gneisses occupy the north and southern part

of the area. Granite occurs as a small patch

in the south-eastern part of the study area

near Bande gate village.

Various soil types viz., clayey soil, clayey

skeletal, clayey mixed, sandy clay and

gravely clayey soils are found in the study

area. Agriculture is the main stay of the

people and the major crops grown are

coconut, areacanut and ragi.

Fig. 1: Location map of MLAM study

area.

Hydrogeology

Ground water is being extracted mostly

through bore wells in the area. Due to

increase in number of bore wells over a

period of time mostly for irrigation

purpose, the depth to ground water levels

have become deeper and deeper and

touched more than 70 m bgl at certain

locations. Ground water occurs mostly in

fractured system which is in semi-confined

to confined condition. However, ground

water around Halkurike village occurs in

phreatic condition where the depth to water

levels are shallow. The ground water is

mostly suitable for domestic and irrigation

purposes.

Ground Water Resources:

The annual replenishable ground water

resources are 2510 ha.m and total ground

water draft is 3974 ha.m as on March 2009.

The stage of ground water development is

calculated as 158% and the area is

categorized as” over-exploited”.

Sampling and analysis:

To study the suitability of ground water for

irrigation, 52 ground water samples were

collected mostly from existing bore wells

during 20 – 25, September 2011 and

analysed in the chemical laboratory of

CGWB, SWR, Bangalore and locations of

samples collected shown in Fig. 2.

Fig. 2: Location map of water samples.


Results and Discussions

The analytical results of chemical analysis

of ground water samples are given in Table

1.

General quality

From the Table 1, it is revealed that the pH

ranges from 7.2 to 8.5. The ground waters

are mostly alkaline in nature. The electrical

conductivity (EC) values of ground water

samples ranges from 630 to 2570 µS/cm-

25°C and mostly within permissible limits.

The total hardness ranges from 130 to 750

mg/l indicating ground waters are hard to

very hard type .The concentrations of Ca,

Mg, Na and K ranges from 12 to 200 mg/l,

2 to 138 mg/l, 58 to 265 mg/l, and 1.6 to

30.5 mg/l respectively. The concentrations

of Cl, SO4, NO3 and F ranges from 28 to

454 mg/l, 14 to 180 mg/l, 3 to 190 mg/l,

and 0.3 to 1.6 mg/l respectively.

Evaluation of irrigation quality

The chemical quality of ground water is

essential factor to be considered in

evaluating its suitability for irrigation use.

The authors considered various parameters

viz., electrical conductivity (EC), Percent

sodium (%Na), Sodium absorption ratio

(SAR) and residual sodium carbonate

(RSC) for determination of suitability of

water for irrigation purpose. The computed

values of percent sodium, SAR and RSC

are given in Table 2.

Electrical Conductivity

Electrical conductivity (EC) is the

measurement of conductance of water at

25°C. It depends on the amount of salts

dissolved in the water. Higher the

dissolution of salts, higher the value of EC.

The higher concentration of salts creates

saline soil, which affect soil structure,

permeability and aeration which indirectly

affect plant growth. Based on the values of

EC, ground waters are categorized into

excellent, good, permissible, doubtful and

unsuitable classes for irrigation purpose. If

the EC is lesser than 250, 250-750, 750-

2000, 2000-3000 and more than 3000

µS/cm respectively. In the study area out of

52 samples, no sample falls under excellent

category, five samples fall under good

category, forty five samples fall in

permissible category and remaining two

samples fall in doubtful category. The EC

more than 2000 µS/cm was noticed at

Kuppur and Gopalanhalli villages (Table

1).

Sodium hazard

Sodium concentration is very important in

classifying irrigation water because sodium

by process of base exchange replace

calcium in the soil thereby reduces the

permeability of soil which has greater

effect on plant growth. Sodium content in

chemical analysis is reported as percent

sodium which is computed with respect to

the relative propositions of cations present

in water and is determined by

Where, all ion concentrations are expressed

in equivalent per million (epm).

Based on percent sodium, the ground

waters are classified as excellent , good,

permissible, doubtful and unsuitable

categories if the percent sodium value is

<20,20-40,40-60,60-80 and > 80

respectively.

In the study area, out of 52 samples, only

one sample falls under excellent category,

14 samples fall under good category, 30

samples fall under permissible category and

remaining seven samples fall under

doubtful category (Table 3).The doubtful

category samples are located at Halkurike,

Rudrapura, Tammadahalli ,Melanahalli,

Byadarahalli ,Gotakanakere and

Dasanakatte villages

Wilcox diagram

In order to determine the suitability of

class of water for irrigation purpose,

Wilcox (1955) proposed a diagram in

which percent sodium is to be plotted

against electrical conductivity. Authors

prepared a Wilcox diagram which is

presented in Fig. 3.The diagram reveals

that five samples fall in excellent to good

(Class - I), thirty eight samples fall in good


Fig. 3: Classification of irrigation water quality, with respect to electrical conductivity

and sodium percent (Wilcox diagram).

to permissible (Class - II), seven samples

fall in permissible to doubtful (Class - III)

and only two samples fall in doubtful to

unsuitable (Class - IV) category. The

doubtful to unsuitable category samples are

located at Kuppur and Gopalanahalli

villages.

Sodium Adsorption Ratio (SAR)

The relative activity of sodium ion in the

exchange reaction with soil is expressed in

terms of a ratio known as Sodium

Adsorption Ratio (SAR) which is

determined by

Where, all ion concentrations are expressed

in epm.

Based on SAR values, the ground waters

are classified as excellent , good, fair and

poor if the SAR value is <10,10-18,18-26

and > 26 respectively. In the study area the

SAR values reveals that all 52 samples fall

in excellent category (Table 3).

US Salinity diagram

The US Salinity Laboratory staff (1954)

has constructed a diagram for classification

of irrigation water with reference to SAR as

an index for sodium hazard ‘S’ and EC as

an index of salinity hazard ‘C’. Based on

SAR values, sodium hazard is categorized

as low (S1:<10), moderate (S2:10-18),high

(S3:18-26) and very high (S4:>26). Based

on EC values, the salinity hazard is

categorized as low (C1:<250), moderate

(C2:250-750), high (C3:750-2250) and

very high (C4:>2250) .

In the US salinity diagram, the values of

SAR are plotted on arithmetic scale against

EC on log scale and different classes of

water have been marked and presented in

Fig. 4. From the figure it is concluded that

forty one samples fall in C3S1 (High

salinity-low SAR) category, five samples

each fall in C3S2 (High salinity-medium

SAR) and C2S1 (Medium salinity- low

SAR) categories and one sample fall in

C4S2 (Very high salinity- medium SAR)

category.


Fig. 4: Classification of irrigation water quality, with respect to salinity hazard and

sodium hazard (USSL diagram).

Bicarbonate hazard

The Bicarbonate concentration of water has

been suggested as additional criteria to

study the suitability of ground water for

irrigation purpose. If the water contains

high concentration of bicarbonate ions,

there is a tendency of calcium and

magnesium ions to precipitate as

carbonates. The convenient way of

expressing values of the water in terms of

Residual Sodium Carbonate (RSC) is as

follows.

Where all the ion concentrations are

expressed in epm

On the basis of RSC, the ground waters are

classified into safe, marginal and unsuitable

classes based on values of <1.25, 1.25-2.5

and >2.5 respectively and shown in Table

3. It shows that out of 52 samples, 45

samples fall in safe category, 4 samples in

marginal and 3 samples in unsuitable

category. The unsuitable categories of

samples are noticed at Byadarhalli,

Kallakere and Rudrapura villages.

Conclusion

Based on the attempt made to study the

quality of groundwater, it is learned that the

ground water in the study area is generally

alkaline in nature and the pH varies from

7.2 to 8.5. The concentration of EC varies

from 630 to 2570 µS/cm-25°C and mostly

suitable for irrigation purpose. According

to percent sodium, two percent samples fall

in excellent category, twenty seven percent

samples fall in good category, fifty eight

percent samples fall in permissible category

and thirteen percent samples fall in

doubtful category. The doubtful category

samples are located at Halkurike,

Rudrapura, Tammadahalli, Melanahalli,

Byadarahalli, Gotakanakere and

Dasanakatte villages. According to sodium

absorption ratio all samples fall in excellent

category. As per RSC, eighty six percent

samples fall in safe category, eight percent

in marginal category and six percent in

unsuitable category. The unsuitable

category of samples are noticed at

Byadarhalli, Kallakere and Rudrapura

villages. From the above discussion on

chemical quality of ground waters, it is

concluded that ground water in the study

area in general is suitable for irrigation

purpose. It is also revealed from the present

study that the high values of certain


chemical constituents at certain locations

are highly localized in nature.

Acknowledgements

The study has been carried out under pilot

project on micro level aquifer mapping

studies in parts of Tiptur and CN Halli

taluks of Tumkur district. The authors are

very much thankful to Chairman and

Members CGWB, CHQ, Faridabad for

their encouragement and permission for

publishing the paper. The authors are also

thankful to Sri. D.Subba Rao, Supt.

Hydrogeologist, Dr.K.R.Sooryanarayana,

Scientist-D and other colleagues of CGWB,

SWR, Bangalore for their encouragement.

References

1. John, D. Hem, Study and interpretation

of the chemical characteristics of

natural water.

2. Ingermer Larson, Ground water in hard

rocks.

3. Karanth, K.R. 1989. Hydrogeology,

Tata McGraw Hill, New Delhi.

4. Wilcox, L.V. 1955. Classification and

use of irrigation waters. U.S.Dept.

Argiculture Circular.

5. Reddy, G.R.C and Reddy, C.H.R.K.

1998. Hydrogeology of Sangareddy

Revenue Division, Medak district,

Andhra Pradesh, India. Technical

report of CGWB, Southern Region,

Hyderabad.


Table 1: Chemical characteristics of groundwater in MLAM study area.

Sample

Id.

Location

pH

EC

(µS/cm-

25°C)

CO3-- HCO3

- CI

- NO3 SO4 F

- Ca

++ Mg

++ TH Na

+ K

+

(mg/l)

1 Kuppuradoddahalli 7.2 1230 0 467 85 55 58 0.87 60 58 390 98 8.2

2 Timmalapura 7.3 1180 0 396 106 44 66 0.78 48 60 370 95 9.6

3 Vasudevarahalli 7.4 1050 0 384 78 10 76 0.92 36 53 310 87 18.3

4 Bhairanayakanahalli 7.2 1970 0 342 334 76 150 0.80 168 60 670 137 11.0

5 Alur 7.4 1090 0 335 114 30 70 0.70 52 41 300 100 19.7

6 Saratvalli 7.7 800 0 232 92 15 56 0.77 36 22 180 97 5.9

7 Halkurike 7.3 1860 0 390 312 12 140 0.98 120 10 340 264 11.3

8 Mayagondanahalli 7.5 850 0 281 85 20 48 1.15 52 19 210 94 7.6

9 Basavarajapura 7.3 1700 0 415 305 16 52 0.53 108 70 560 126 11.0

10 Bommanahalli 7.4 870 0 323 71 32 38 1.04 56 17 210 85 25.0

11 Balavaneralu 7.4 1430 0 445 170 36 68 1.20 116 31 420 127 12.6

12 Rudrapura 7.6 1820 0 616 206 15 94 1.50 32 58 320 265 2.3

13 Kamalapura 7.6 1020 0 396 92 34 20 1.00 60 48 350 72 2.1

14 Dugganahalli 7.5 1460 0 476 170 54 44 1.04 96 73 540 85 3.2

15 Bharanapura 7.9 1480 0 525 185 34 18 1.20 40 94 490 109 2.3

16 Khaimara Junction 7.8 830 0 354 64 10 16 0.89 72 17 250 72 5.9

17 Chattasandra 7.6 910 0 128 220 8 22 0.97 56 22 230 100 4.5

18 Banjara tanda 7.8 690 0 323 36 5 18 1.60 36 14 150 84 5.2

19 Kuppur 7.6 2070 0 238 454 28 160 0.30 112 102 700 151 2.9

20 Anekatte 7.5 1480 0 390 192 52 94 0.68 112 17 350 172 9.8

21 Aralikere 7.2 1870 0 122 341 190 180 0.70 200 29 620 136 13.0

22 Ankasandra 7.7 1320 0 213 256 58 66 0.80 108 24 370 128 7.4

23 Kallenahalli 7.7 820 0 323 57 6 48 1.10 44 27 220 82 7.9

24 Karehalli 8.2 630 0 274 28 4 38 1.20 48 14 180 58 5.5

25 Desihallipalya 7.7 690 0 274 57 5 30 0.94 52 12 180 69 6.4

26 Kodagihalli 7.7 1940 0 360 440 10 30 0.40 48 116 600 166 5.8

27 Tammadihalli 7.6 1740 0 372 348 7 50 0.61 60 46 340 237 8.3

28 Manchasandra 7.8 1030 0 140 227 18 56 0.85 56 24 240 124 2.6


29 Madihalli 7.6 1860 0 470 312 16 74 0.65 72 138 750 81 1.9

30 Dasikere 7.7 1960 0 549 213 77 140 1.14 104 63 520 208 4.9

31 Settikere 7.4 1030 0 178 192 32 64 0.81 64 22 250 117 7.4

32 Gaudanahalli 7.7 970 0 128 220 12 54 0.76 56 14 200 122 10.7

33 Hosur 7.4 1070 0 506 57 17 22 0.75 60 48 350 80 1.6

34 Somalapura 7.2 1490 0 329 262 5 86 0.68 108 43 450 131 6.9

35 Dugudihalli 7.7 760 0 104 170 6 42 0.93 40 29 220 68 8.4

36 Kedigehalli 7.3 1160 0 458 85 4 72 1.00 56 31 270 133 6.7

37 Melanahalli 7.6 1070 0 189 213 9 58 0.67 36 29 210 147 2.0

38 Savsettihalli 7.4 1260 0 397 121 60 70 1.04 90 14 290 156 7.0

39 Kadenahalli 7.4 1080 0 232 192 22 48 0.90 48 24 220 144 3.1

40 Tarabenahalli 7.3 1290 0 226 248 36 66 0.65 84 12 260 173 5.7

41 Agasarahalli 7.7 650 0 152 114 19 14 0.83 52 2 140 81 5.3

42 Garehalli 7.3 850 0 220 135 19 30 0.57 76 17 260 72 4.3

43 Sasalu 7.6 1670 0 311 248 88 140 0.73 148 10 410 176 30.5

44 Gopalanahalli 7.3 2570 0 518 398 150 160 0.69 108 111 730 238 27.4

45 Bandagate 7.5 860 0 238 128 15 34 0.79 52 17 200 104 1.9

46 Misetimmanahalli 7.6 1080 0 409 85 10 70 0.73 40 36 250 122 11.0

47 Kallakere 7.7 740 0 354 28 5 24 1.20 40 14 160 91 8.7

48 Timmarayanahalli 7.6 780 0 262 99 3 26 1.10 52 17 200 79 6.3

49 Byadarahalli 7.5 1600 0 482 213 34 80 0.90 68 24 270 230 20.4

50 Gotakanakere 7.6 970 0 183 199 15 30 1.10 28 17 140 156 3.8

51 Manjunathapura 7.9 840 0 220 135 29 24 0.3 48 17 190 100 4.3

52 Dasanakatte 8.5 900 15 140 170 25 36 1.5 12 24 130 142 7.5

Min. 7.2 630 0 104 28 3 14 0.3 12 2 130 58 1.6

Max. 8.5 2570 15 616 454 190 180 1.6 200 138 750 265 30.5


Table 2: Computed values of Percent sodium, SAR, and RSC in MLAM study area.

Sample Location

EC Percent SAR RSC

Id. (µS/cm-25°C) Sodium

1 Kuppuradoddahalli 1230 36 3.05 -0.13

2 Timmalapura 1180 37 3.05 -0.86

3 Vasudevarahalli 1050 41 3.04 0.12

4 Bhairanayakanahalli 1970 32 3.26 -7.74

5 Alur 1090 45 3.56 -0.49

6 Saratvalli 800 55 4.44 0.19

7 Halkurike 1860 63 8.79 -0.43

8 Mayagondanahalli 850 51 4.00 0.44

9 Basavarajapura 1700 34 3.28 -4.37

10 Bommanahalli 870 51 3.61 1.09

11 Balavaneralu 1430 41 3.82 -1.06

12 Rudrapura 1820 64 9.12 3.71

13 Kamalapura 1020 31 2.37 -0.47

14 Dugganahalli 1460 26 2.25 -3.02

15 Bharanapura 1480 33 3.03 -1.15

16 Khaimara Junction 830 40 2.80 0.80

17 Chattasandra 910 49 4.05 -2.52

18 Banjara tanda 690 56 4.25 2.34

19 Kuppur 2070 32 3.51 -10.11

20 Anekatte 1480 52 5.65 -0.61

21 Aralikere 1870 34 3.36 -10.39

22 Ankasandra 1320 44 4.10 -3.89

23 Kallenahalli 820 46 3.39 0.87

24 Karehalli 630 43 2.67 0.94

25 Desihallipalya 690 47 3.17 0.90

26 Kodagihalli 1940 38 4.17 -6.07

27 Tammadihalli 1740 61 7.91 -0.70

28 Manchasandra 1030 53 4.93 -2.49

29 Madihalli 1860 19 1.82 -7.28

30 Dasikere 1960 47 5.61 -1.40

31 Settikere 1030 51 4.54 -2.10

32 Gaudanahalli 970 59 5.33 -1.86

33 Hosur 1070 34 2.64 1.33

34 Somalapura 1490 40 3.81 -3.55

35 Dugudihalli 760 42 2.82 -2.69

36 Kedigehalli 1160 53 5.00 2.15

37 Melanahalli 1070 61 6.24 -1.09

38 Savsettihalli 1260 55 5.70 0.85

39 Kadenahalli 1080 59 5.98 -0.58

40 Tarabenahalli 1290 60 6.60 -1.49

41 Agasarahalli 650 57 4.24 -0.27

42 Garehalli 850 38 2.74 -1.60

43 Sasalu 1670 51 5.34 -3.13


44 Gopalanahalli 2570 43 5.42 -6.07

45 Bandagate 860 53 4.52 -0.10

46 Misetimmanahalli 1080 53 4.76 1.73

47 Kallakere 740 57 4.45 2.65

48 Timmarayanahalli 780 47 3.43 0.29

49 Byadarahalli 1600 66 8.62 2.52

50 Gotakanakere 970 71 8.10 0.20

51 Manjunathapura 840 54 4.46 -0.20

52 Dasanakatte 900 71 7.69 0.21

Table 3: Classification of Irrigation water

Parameter Min. Max. Category No. of No. of Water Class

Samples Samples (%)

EC 630 2570 < 250 - Nil - - Nil - Excellent

(µS/cm-25°C)

250 - 750 5 10 Good

750 - 2000 45 86 Permissible

2000 - 3000 2 4 Doubtful

> 3000 - Nil - - Nil - Unsuitable

Percent Sodium 19 71 < 20 1 2 Excellent

20 - 40 14 27 Good

40 - 60 30 58 Permissible

60 - 80 7 13 Doubtful

> 80 - Nil - - Nil - Unsuitable

SAR 1.82 9.12 < 10 52 100 Excellent

10 - 18 - Nil - - Nil - Good

18 - 26 - Nil - - Nil - Fair

> 26 - Nil - - Nil - Poor

RSC -10.39 3.71 < 1.25 45 86 Safe

1.25 - 2.5 4 8 Marginal

> 2.5 3 6 Unsuitable

Suitability of groundwater for Irrigation purpose in Ankasandra Watershed in parts of Tiptur and C.N. Halli taluks of Tumkur district, Karnataka, India

Documents