Sahyadri Conservation Series - 4 ENVIS Technical Report: 21,  February 2012
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WATER, SOIL AND SEDIMENT CHARACTERIZATION: SHARAVATHI RIVER BASIN, WESTERN GHATS
 http://wgbis.ces.iisc.ernet.in/energy/
Ramachandra T V             Subash Chandran M.D             Joshi N.V.             Rajinikanth R.             Raushan Kumar
Energy and Wetlands Research Group, Centre for Ecological Sciences,
Indian Institute of Science, Bangalore – 560012, India.
*Corresponding author: cestvr@ces.iisc.ernet.in

RESULTS AND DISCUSSION OF THE WATER ANALYSIS

Temperature

The temperature of water in upper catchment ranged from 22°C to 34.5°C. In sampling site 8 (Linganamakki Reservoir), water temperature was higher than any other site (Min: 24.0°C Max: 34.5°C). This is a characteristic feature of a lacustrine ecosystem (Table 15).

Table 15. Temperature (°C) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 24.5 29.5 29 28     31 34.5   28.9            
Mar-01 30.1 30.5 30.1 31.6 30.6 28 26.5 34 27.9 29.2 29.6 28.3 29.1      
Apr-01 28.1 26.5 26.5 29 29 29.5 31 31.5 28 31 29 30.5 30.5      
May-01 30.1 30.5 30.1 31.6 31 30.5 29.2 34 29 27.5 31 28.9 30      
Jul-01 23.8 24 23.9 24.3 23.3 24.1 24.8 26 24.5 23.4 25.5 24.5   24.1 24.4 25
Aug-01 23.4 27 26 26 25.9 26 25.8 26 24.5 24 26 25   27 26.5 26
Sep-01 26 29 25.5 26.5 27 25.5 27 26.5 27.5 28 27 28 27.5 27.5 27 27
Oct-01 28 31 27 28 27 25 28.5 27 27 28 27.5 27.5 28 29 28 26
Nov-01 26 26 25 29 28 26 28 27 26 29 28 28 28 26 28 28
Dec-01 25.5 24 22 24 26 25 24 25 24 25 25 25.5 26 24 24 27
Jan-02 24 25 23 25 26 25 24 25 25 27 25   25 22 25 29
Feb-02 25 27 29 30 27 25 26 27 27 27 28   28     28
Mar-02 29 29 27 28 26 23 25 24.5 27 26 25   27      
Apr-02 30 29 28 28 27 25 27 26 28 27 26   28      

In downstream, water temperature ranged from 20°C - 36°C (Table 16). Values obtained are well within the limits provided by Indian Standards Specifications (NEERI).

Table 16. Water temperature in downstream localities.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02     28 29 28 28   27 27 27 26
Dec-02     28 27 28 28   27 27 27 24
Jan-03     28 26 28 28 27 29 27 29 28
Feb-03       30 30 29 28 29 29 31 32
Mar-03       33 33 32 30   31 34 33
April-03       33 34 33 31   31 31 34
May-03       32 32 31 30   35 31 33
Jun-03     29 29 29 29 28 28   28 28

Table 16. Water temperature in downstream localities (cont...).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 29 26 27 28 22 22 22     29 28 30
Dec-02 28 24 28 28 20         27 28 30
Jan-03 29 27 28 30 21 28   27   30 29 26
Feb-03 33 35 30 30 27 28   32 26   30 31
Mar-03 32 30 30   28 28   32 26   29 31
April-03 34 36 32   26 30   32 27   30 32
May-03 32 33 31   26     30 28   30 32
Jun-03 30 28 28   24     25 24   34 27

Transparency and Turbidity

In the upper catchment, transparency varied from 3 cm to 284 cm and turbidity values fluctuated from <5 –125 NTU (Table 17 and 18). Turbidity exceeded NEERI limits, mainly in Hosanagara and some part of Sagar due to agricultural runoff during monsoon.

Table 17. Transparency (cm) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 85 80 40 80     27.5 65   76            
Mar-01 80 100 124 74 92 59 73 98 73 93 57 47 56      
Apr-01 64 65 76 56 67 55 60 75 67 67 43 70 45      
May-01 65 43 89 65 92 59 73 70 73 65 67 60 56      
Jul-01 23 16 14 8 50 45 50 43 34 53 45 42   8 8 4
Aug-01 12 12 8 5 30 50 30 37 32 50 42 40   5 3 3
Sep-01 18 15 12 6 25 35 20 75 45 30 45 30 30 7 5 4
Oct-01 53 35 38 3 50 150 65 160 80 80 80 75 32 8 3 35
Nov-01 58 58 38 15 112 166 82 148 70 39 39 39 82 18 15 38
Dec-01 58 38 38 13 97 130 70 280 97 80 148 24 80 10 10 58
Jan-02 80 65 58 23 90 284 82 284 90 35 90   145 20 35 35
Feb-02 82 75 42 12 82 284 80 284 90 35 70   125     15
Mar-02 72 48 15 15 82 284 72 72 58 72 10   130      
Apr-02 75 50 18 15 80 284 70 75 45 70 12   110      

Table 18. Turbidity (NTU) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 <10 <10 <10 25     <10     <10            
Mar-01 <10 <10 <10 >50 <10 <10 <10 <10 <10 <10 <10 <10 <10      
Apr-01 <10 <10 <10 >50 <10 <10 <10 <10 <10 <10 <10 <10 <10      
May-01 25 <10 <10 >50 <10 <10 <10 <10 <10 <10 <10 <10 <10      
Jul-01 50 35 30 60 <10 <10 <10 <10 <10 <10 <10 <10   75 75 50
Aug-01 75 50 20 75 <5 <5 12 <5 <10 <10 <10 <10   125 100 50
Sep-01 25 25 20 75 <10 <10 <10 <10 <10 <10 <10 <10 <10 60 75 45
Oct-01 <10 15 20 20 <5 <5 <5 <5 <5 <5 <5 <5 <5 50 70 <10
Nov-01 <10 12 15 20 <5 <5 <10 <5 <5 <5 <5 <5 <5 30 30 15
Dec-01 <10 <10 15 20 <5 <5 <10 <5 <5 <5 <5 <5 20 25 20 15
Jan-02 20 <5 15 30 <10 <10 <10 <10 <10 <10 <10   <10 25 10 20
Feb-02 10 5 20 40 7 <5 5 <10 <5 <10 <10   <10     45
Mar-02 10 5 20 40 7 <5 5 <10 <5 <10 <10   <10     45
Apr-02 10 10 15 25 7 <5 <5 <10 <5 <10 <10   <10      

In lower catchment,turbidity was in the range of 10 - 100 NTU. At Dabbe [DS4], Joginamutt [DS5] and Jog upper [DS5] it was 25-50 NTU, <100 NTU and 10 – 25 NTU respectively and exceeded the standard limit of 10 NTU. It was due to runoff from the catchment area and also due to the obstruction of water for agriculture leading to the increased sediment loads and phyto-productivity in the stream.

Total Dissolved Solids and Total Suspended Solids

In Sharavathi upstream regions, the total suspended solids ranged from 21.3 to 110 mg/L and total dissolved solids 13.77 – 84.03 mg/L (Table 21 and 22). The results showed that TSS concentration exceeds the limits, due to siltation from storm and agricultural runoff (mainly at Hosanagara region) whereas TDS values are within the limits provided by NEERI.

Table 21. Total Suspended Solids (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 62 41.3 21.3 52     52 40   38.6            
Mar-01 40 54 30 41 32 50 26 32 40 64 60 35 40      
Apr-01 54 39 68 37 32 37 68 35 46 52 40 52 27.1      
May-01 82 80 74 67 40 26 67 74 32 48 71 57 85      
Jul-01 65 78 76 110 40 35 65 55 65 45 55 55   102 108 58
Aug-01 80 80 82 110 45 40 70 58 68 50 58 60   100 106 55
Sep-01 82 83 80 108 50 50 75 55 70 55 60 65 55 101 105 60
Oct-01 81 83 81 106 49 51 72 51 69 53 62 62 51 101 102 58
Nov-01 85 85 82 108 55 55 75 55 75 55 65 65 55 105 105 65
Dec-01 75 80 80 100 52 50 72 52 72 53 59 60 54 100 98 61

Table 22. Total Dissolved Solids (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Aug-01 26.12 36.76 35.8 46.24 20.99 23.85 27.3 16.32 16.12 17.2 18.59 20   44.3 18.16 18.5
Sep-01 28.14 30.95 37 45.3 14.5 15.95 17.85 17.9 18 15 18.9 18 20 57 36 18.5
Oct-01 28.38 30.69 36.97 46.4 17.5 15.2 20.3 17.65 17.6 14.25 17.5 20.56 22.48 44 42.65 41.71
Nov-01 31.27 32.98 41.38 53.56 15.37 16.63 21.31 18.12 18.38 15.41 18.19 40.72 16.62 60.58 60.93 42.2
Dec-01 33.1 35.1 41.85 56.13 16.11 17.39 18.75 19.09 19.05 21.8 19.1 19.23 17.99 64.03 64.45 42.18
Jan-02 26.95 22.95 42.15 57.1 15.55 16.9 17.8 21.07 21.65 27.5 24.9   20.37 52.95 54.9 45.5
Feb-02 21.85 27.83 41.75 59.94 13.77 14.47 15.07 15.08 21.73 25.5 17.96   16.25     40.13
Mar-02 26.85 33.05 78.34 84.03 19.2 20.34 20.09 22.29 30.51 26.29 24.17   30.25      
Apr-02 27.4 80.8 110 60.83 20.02 21.6 22.52 23.68 32.38 32.38 24.49 26.54 33.96      

In downstream, however, except in the sites in confluence of Sharavathi into Arabian sea (Haddinabal, Gudankateholé and Badagani), all other localities had TDS values in the stipulated USEPA range of 500mg/L (Table 23).  In Haddinabal, Gudankateholé and Badagani, TDS ranges between 24.81 – 15,090 mg/L. This indicated the brackish quality of water in the region.

Table 23. Total Dissolved Solids (mg/L) in the water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 18.83   22.27 20.26 21.72 20.62   24.31 22.22 24.81 25.95
Dec-02 19.99 30.22 21.78 20.38 21.68 21.22   26.01 23.83 26.34 25.04
Jan-03 24.52 30.9 24.33 29.32 24.26 36.14 23.95 29.53 31.64 1.21* 26.66
Feb-03 29.44     38.29 22 38.89 20.78 41.92 36.86 2.17* 28.53
Mar-03 25.97 36.3   37.26 25.97 39.9 20.93   45.81 1.43* 27.85
April-03 28.11 38.71   36.79 26.89 38.17 21.8   41.26 1.79* 25.7
May-03 29.22 57.95   42.93 23.36 40.44 24.2   77.37 2.20* 26.3
Jun-03 21.24   26.22 25.75 28.23 27.92 30.72 34.91   79.23 32.02

Table 23. Total Dissolved Solids (mg/L) in the water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 18.77 27.77 17.71 17.51 19.6 26.36 22.19     19.05 25.24 1.56*
Dec-02 18 30.2 16.2 16.8 21.4         19.71 27.04 6.35*
Jan-03 19.91 41.77 19.49 19.83 27.34 38.42   27.89   21.46 56.5 14.42*
Feb-03 21.14 51.28 20.13 21.45 28.13 43.3   31.95 30.44   95.31 14.32*
Mar-03 20.33 67.82 23.71   36.2 46.21   33.75 32.1   547.2 14.42*
April-03 20.34 72.88 21.23   33.51 46.88   34.07 31.41   1.047 * 15.09*
May-03 21.04 87.98 22.45   33.51     34.83 29.78   11.1 * 14.89*
Jun-03 20.53 39.34 22.32   25.36     31.71 21.45   224.3 5.04*
* expressed as parts per thousand or g/L

Colour

Pure water has no colour, but the presence of soluble or insoluble, organic or inorganic matter will impart greenish blue, green, greenish yellow, yellow or brown colour to water. Different species of phytoplankton and zooplankton also impart colour. A dark or blue green colour can be caused by blue green algae, yellow-brown by diatoms or dinoflagellates and red and purple by zooplankton such as Daphnia or Copepods. Colour must be removed to make water suitable for general and industrial applications.

In upstream, the water was colourless to brownish green. Brown and brownish green colours were recorded during monsoon due to colloidal suspension of silts from erosion (Table 14). Similar colouration was also observed in the downstream. In streams like Chandubanu, Vatahalla, Hennur, Hossagadde, Bhaskere, it was transparent, colourless and odourless, whereas in Haddinabal it was greenish due to stagnation. In Dabbod, generally water was transparent and colourless, but during agricultural activities it turned slightly turbid and exceeded the permissible limits for turbidity (February, March and April).

Table 14. Coloration of water samples from the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5
Feb-01 Colour less Colour less Colour less Colour less Colourless
Mar-01 Colour less Colour less Colour less Colour less Colourless
Apr-01 Colour less Colour less Colour less Colour less Colourless
May-01 Colour less Colour less Colour less Colour less Colourless
Jul-01 Brownish Brownish Brownish Brownish Colourless
Aug-01 Brownish Brownish Brownish Brownish Colourless
Sep-01 Brownish Brownish Brownish Brownish Colourless
Oct-01 Colourless Brownish Light brown Brownish Colourless
Nov-01 Colourless Colourless Light green Brownish green Colourless
Dec-01 Colourless Light Brown Light Brown Brownish Colourless
Jan-02 Greenish Colour less Light Brown Brownish green Colourless
Feb-02 Light Brown Colour less Light Brown Brownish Colourless
Mar-02 Slight Green Light Brown Brownish Green Slight green Colourless
Apr-02 Light Brown Light Brown Light Brown Slight green Colourless

Table 14. Colouration of water samples from the Sharavathi upstream. (Cont...)

Months  Sampling sites
6 7 8 9 10
Feb-01 Colour less Colour less Colour less Colour less Colour less
Mar-01 Colour less Colour less Colour less Colour less Colour less
Apr-01 Colour less Colour less Colour less Colour less Colour less
May-01 Colour less Colour less Colour less Colour less Colour less
Jul-01 Colour less Light brown Light brown Light brown Colour less
Aug-01 Colour less Light brown Light brown Light brown Colour less
Sep-01 Colour less Light brown Light brown Light brown Colour less
Oct-01 Colourless Colourless Green Colourless Colourless
Nov-01 Colourless Colourless Bluish green Colourless Colourless
Dec-01 Colourless Light Green Light Green Colourless Light Green
Jan-02 Slight green Greenish Colour less Colour less Brownish
Feb-02 Slight green Light brown Colour less Colour less Brownish
Mar-02 Greenish Greenish brown Light Green Brownish green Brownish
Apr-02 Slight green Light brown Light Green Brownish green Light brown

Table 14. Colouration of water samples from the Sharavathi upstream. (Cont...)

Months Sampling sites
11 12 13 14 15 16
Feb-01 Colour less Colour less Colour less      
Mar-01 Colour less Colour less Colour less      
Apr-01 Colour less Colour less Colour less      
May-01 Colour less Colour less Colour less      
Jul-01 Light brown Light Brown   Brownish Brownish Brownish
Aug-01 Light brown Light Brown   Brownish Brownish Brownish
Sep-01 Light brown Light Brown Light brown Light Brown Brownish Light Brown
Oct-01 Colourless Colourless Light brown Brownish Brownish Brownish
Nov-01 Colourless Colourless Colourless Green Brownish green Brownish green
Dec-01 Colourless Colourless Light brown Brownish green Brownish Light Brown
Jan-02 Light Green   Light brown Green Green Brownish green
Feb-02 Brownish   Colourless     Brownish green
Mar-02 Brownish   Colourless      
Apr-02 Light brown   Colourless      

Electrical conductivity

The electrical conductivity in the upper catchments of Sharavathi River ranged from 0.003 to 0.44 mS/cm (Table 19). Values obtained are well within the limits provided by Indian Standards Specifications (NEERI).

Table 19. Electrical conductivity (mS/cm) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8
Feb-01 0.042 0.039 0.070 0.077     0.022 0.034
Mar-01 0.064 0.089 0.089 0.089 0.025 0.032 0.025 0.032
Apr-01 0.064 0.096 0.076 0.070 0.057 0.034 0.031 0.283
May-01 0.058 0.040 0.102 0.005 0.096 0.440 0.063 0.003
Jul-01 0.030 0.044 0.040 0.061 0.021 0.027 0.029 0.025
Aug-01 0.027 0.043 0.042 0.055 0.018 0.023 0.027 0.025
Sep-01 0.041 0.042 0.051 0.060 0.202 0.022 0.024 0.026
Oct-01 0.042 0.044 0.052 0.064 0.024 0.022 0.029 0.026
Nov-01 0.042 0.045 0.056 0.070 0.021 0.022 0.028 0.025
Dec-01 0.044 0.048 0.056 0.070 0.058 0.014 0.024 0.025
Jan-02 0.046 0.035 0.064 0.09 0.024 0.025 0.028 0.028
Feb-02 0.035 0.048 0.070 0.09 0.026 0.026 0.025 0.028
Mar-02 0.039 0.051 0.115 0.122 0.031 0.027 0.029 0.032
Apr-02 0.058 0.066 0.22 0.11 0.044 0.041 0.042 0.045

Table 19. Electrical conductivity (mS/cm) in the water samples of the Sharavathi upstream (cont...).


Months Sampling sites
9 10 11 12 13 14 15 16
Feb-01   0.023            
Mar-01 0.03 0.025 0.032 0.032 0.032      
Apr-01 0.03 0.044 0.44 0.096 0.32      
May-01 0.12 0.045 0.064 0.037 0.12      
Jul-01 0.023 0.02 0.025 0.026   0.06 0.067 0.029
Aug-01 0.022 0.02 0.025 0.026   0.028 0.054 0.027
Sep-01 0.026 0.02 0.026 0.023 0.020 0.038 0.064 0.049
Oct-01 0.249 0.02 0.025 0.023 0.021 0.063 0.061 0.059
Nov-01 0.024 0.021 0.024 0.031 0.022 0.077 0.077 0.059
Dec-01 0.023 0.028 0.026 0.024 0.023 0.077 0.09 0.058
Jan-02 0.029 0.033 0.03   0.016 0.083 0.09 0.064
Feb-02 0.038 0.032 0.031   0.028     0.064
Mar-02 0.039 0.037 0.035   0.043      
Apr-02 0.062 0.053 0.048   0.067      

In downstream regions, some localities were recorded with higher electrical conductivity. This is due to the salt-water intrusion by the Arabian Sea in these localities. Table 20 details the electrical conductivity of water samples from the downstream.

Table 20. Electrical conductivity (mS/cm) in the water samples of the Sharavathi downstream

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 0.04   0.05 0.04 0.05 0.04   0.05 0.05 0.05 0.05
Dec-02 0.04 0.06 0.04 0.04 0.04 0.04   0.05 0.05 0.05 0.05
Jan-03 0.05 0.06 0.05 0.06 0.05 0.07 0.05 0.06 0.06 2.35 0.05
Feb-03 0.06     0.08 0.04 0.08 0.04 0.08 0.08 4.35 0.06
Mar-03 0.05 0.07   0.08 0.05 0.08 0.04   0.09 2.84 0.06
April-03 0.06 0.08   0.07 0.05 0.08 0.04   0.08 3.56 0.05
May-03 0.06 0.12   0.09 0.05 0.08 0.05   0.16 4.41 0.05
Jun-03 0.04   0.05 0.05 0.06 0.06 0.06 0.07   0.16 0.06

Table 20. Electrical conductivity (mS/cm) in the water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 0.04 0.06 0.04 0.04 0.04 0.06 0.05     0.04 0.05 3.28
Dec-02 0.04 0.06 0.03 0.03 0.04         0.04 0.05 12.65
Jan-03 0.04 0.08 0.04 0.04 0.05 0.07   0.05   0.04 0.11 27.91
Feb-03 0.04 0.1 0.04 0.04 0.06 0.09   0.06 0.06   0.19 28.61
Mar-03 0.04 0.13 0.05   0.07 0.09   0.07 0.06   1.1 28.82
April-03 0.04 0.15 0.04   0.07 0.09   0.07 0.06   2.1 30.2
May-03 0.04 0.18 0.05   0.07     0.07 0.06   22.15 29.77
Jun-03 0.04 0.08 0.05   0.05     0.06 0.04   0.44 10.06

pH, Acidity and Alkalinity

In the upstream, pH ranged from 6.53 - 8.25 (Table 24). Acidity 2.5 –40 mg/L (Table 25) and alkalinity value ranged from 8 – 75 mg/L (Table 26), results well within the limits (NEERI and WHO standards).

Table 24. pH in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 7.4 6.9 7.3 7.5     7.5 6.53   6.7            
Mar-01 6.85 6.53 6.78 7.2 6.85 6.8 6.9 7.4 6.9 6.94 6.75 6.55 6.65      
Apr-01 7 7.2 7 7.4 6.72 6.94 6.94 6.94 6.55 7 7.4 7 6.72      
May-01 7.4 6.9 7.74 7 6.94 6.55 6.72 6.59 6.75 7 7 7.4 6.94      
Jul-01 7.09 6.89 6.97 6.98 6.95 7.22 6.94 6.65 6.6 6.93 6.8 6.99   7.01 6.98 6.85
Aug-01 6.98 7.03 7.15 7.05 7.24 7.07 7.21 7.06 6.69 6.99 6.85 7.03   7.03 6.94 6.83
Sep-01 7.3 7.12 7.17 7.03 7.01 6.64 7.01 7.13 6.75 6.53 6.88 7.27 6.88 7.02 7.53 7.07
Oct-01 7.5 7.43 7.85 7.58 7.12 6.9 7.21 7.38 7.33 7.34 7.33 7.45 7.02 7.9 7.7 7.83
Nov-01 7.35 7.25 7.26 7.55 7.19 7.01 7.27 7.1 7.06 6.99 7.03 6.56 6.96 7.2 7.5 7.34
Dec-01 7.4 7.71 7.59 7.86 6.98 7.76 7.36 7.26 7.01 7.45 7.46 7.43 7.45 7.55 7.81 7.28
Jan-02 7.25 7.2 7.1 7.38 7.08 7.09 7.07 7.01 7.9 7.05 6.69   7.03 7.25 7.48 7.18
Feb-02 7.62 7.7 8.25 7.75 7.7 7.47 7.13 7.38 7.36 7.01 6.93   7.04     7.25
Mar-02 7.27 7.25 7.01 7.73 7.45 7.45 7.58 7.62 7.48 7.38 7.32   7.25      
Apr-02 7.41 8.41 7.05 7.15 6.54 6.55 6.77 7.02 7.76 6.52 6.57   6.63      

Table 25. Acidity (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 16 20   8     8 8   12            
Mar-01 8 8 12 12 20 20 12 12 12 16 8 16 12      
Apr-01 6 12 8 12 8 8 8 8 12 8 8 12 12      
May-01 12 16 12 9 12 20 8 12 6 12 20 12 12      
Jul-01 5 5 5 5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5   2.5 2.5 12
Aug-01 10 5 5 10 10 5 10 10 10 5 10 10   10 15 10
Sep-01 15 15 15 20 20 10 15 30 15 10 15 15 10 15 20 20
Oct-01 12 12 10 15 18 8 12 15 12 8 12 12 8 12 18 18
Nov-01 12 12 12 12 15 10 12 12 12 10 15 12 8 12 15 15
Dec-01 17.5 17.5 17.5 17.5 10 12.5 12.5 12.5 12.5 12.5 15 15 12.5 25 30 20
Jan-02 20 17.5 20 20 12.5 15 15 12.5 12.5 15 15   12.5 25 30 25
Feb-02 20 20 20 20 10 20 10 10 20 30 20   10     30
Mar-02 30 30 40 30 20 30 30 20 30 30 30   30      
Apr-02 25 25 35 22 21 25 23 21 32 25 25   27      

Table 26. Alkalinity (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 48 40 28 68     24 38   34            
Mar-01 44 56 52 48 32 40 26 44 52 64 60 35 40      
Apr-01 60 40 44 48 36 44 38 32 49 48 36 32 48      
May-01 56 52 48 52 42 50 48 52 52 40 52 48 50      
Jul-01 35 30 35 45 20 20 20 30 20 20 25 25   55 50 32
Aug-01 45 45 50 45 45 45 30 35 20 20 25 24   30 30 30
Sep-01 40 40 45 40 45 35 35 35 20 20 24 28 24 28 30 28
Oct-01 45 40 50 20 20 25 30 30 25 20 25 25 25 55 55 60
Nov-01 45 45 55 25 25 30 30 35 30 25 25 30 30 60 65 55
Dec-01 48 48 59 30 30 30 35 35 32 28 26 32 35 55 68 58
Jan-02 16 12 8 20 8 8 16 8 8 12 8   8 24 8 20
Feb-02 32 16 12 20 16 12 24 20 8 12 8   12     12
Mar-02 75 50 50 50 25 25 50 25 25 25 25   25      
Apr-02 50 45 52 50 33 31 48 28 22 25 30   32      

In the downstream, pH value was generally in circum neutral condition of 6.5 – 7.5 and rarely exceeded 8.0 (Vatahalla: 8.67 in May 2003). Apart from this individual observation, all other localities had pH level within the permissible level of NEERI (Table 27). Tables 28 and 29 show corresponding alkalinity and acidity values of Sharavathi downstream. They were also observed within the permissible level of 100 – 250mg/L.

Table 27.  pH in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 7.26   7 6.98 6.84 6.75   7.14 7.13 6.97 7.01
Dec-02 7.13 7.4 6.72 6.93 7.01 6.98   7.04 7.05 6.95 6.99
Jan-03 7.25 7.59 7.22 7.1 6.94 7.36 6.94 7.31 7.52 7.42 7.35
Feb-03 7.11     6.76 6.78 7.19 6.99 6.91 7.74 7.68 6.93
Mar-03 7.35 7.26   6.36 6.61 6.62 6.9   7.07 7.23 6.37
April-03 7.1 7.28   6.55 6.67 6.76 6.92   6.88 7.17 6.58
May-03 7.29 7.05   6.71 6.68 6.66 6.83   6.92 7.18 6.44
Jun-03 6.66   6.8 6.62 6.51 6.79 6.88 7.13   6.71 7.07

Table 27.  pH in water samples of the Sharavathi downstream (cont...).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 7.5 7.63 7.05 6.94 7.21 7.54 7.27     6.74 6.68 7.07
Dec-02 7.07 7.52 7.06 7.01 7.13         6.78 6.81 7.46
Jan-03 7.07 7.84 6.9 7.23 7.3 7.8   7.3   6.98 7.27 7.38
Feb-03 7.22 7.88 7.21 7.12 7.3 7.6   7.3 6.5   7.16 7.61
Mar-03 6.84 7.85 6.56   7.5 7.4   6.9 6.7   6.84 7.54
April-03 7.16 7.72 6.96   7.2 7.6   7 6.6   6.61 7.51
May-03 7.08 8.67 6.89   7.17     6.84 6.81   6.53 7.54
Jun-03 7.3 7.49 7.5   7.33     6.55 6.68   6.21 7.18

Table 28. Alkalinity (mg/L) in the water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 13.93   16.87 13.2 16.87 16.87   19.8 15.4 19.07 21.27
Dec-02 15.4 24.2 17.6 15.4 16.13 16.5   19.07 18.7 19.8 19.8
Jan-03 15.4 26.4 15.4 19.8 13.2 22 11 17.6 24.2 26.4 17.6
Feb-03 21.6     31.2 16.8 28.8 14.4 26.4 33.6 38.4 21.6
Mar-03 21.6 36   28.8 19.2 31.2 14.4   40.8 45.6 21.6
April-03 24 38.4   28.8 21.6 33.6 19.2   38.4 45.6 19.2
May-03 24 40.8   36 19.2 26.4 16.8   74.4 48 19.2
Jun-03 14.4   14.4 16.8 19.2 16.8 19.2 9.6   19.2 21.6

Table 28. Alkalinity (mg/L) in the water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 13.2 24.2 12.1 15.4 13.2 22 17.6     13.2 14.67 25.7
Dec-02 15.4 30.8 11 13.2 14.3         13.93 17.6 46.2
Jan-03 13.2 28.6 11 11 17.6 28.6   17.6   11 30.8 73.7
Feb-03 16.8 45.6 14.4 14.4 21.6 38.4   24 24   33.6 76.8
Mar-03 16.8 60 19.2   33.6 40.8   26.4 24   26.4 79.2
April-03 16.8 67.2 16.8   28.8 45.6   28.8 26.4   24 72
May-03 16.8 74.4 19.2   26.4     24 21.6   43.2 74.4
Jun-03 19.2 26.4 19.2   16.8     12 12   9.6 28.8

Table 29. Acidity (mg/L) in the water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 1.8   2.1 2.7 1.8 1.8   1.8 1.8 2.4 3.6
Dec-02 2.7 2.7 2.7 2.25 2.7 2.7   3 1.8 2.4 2.7
Jan-03 1.8 1.8 1.8 1.8 1.8 1.8 1.8 0.9 3.6 1.8 0.9
Feb-03 1.8     5.4 1.8 1.8 1.8 5.4 3.6 3.6 3.6
Mar-03 3.6 3.6   5.4 3.6 3.6 3.6   5.4 3.6 3.6
April-03 4 6   2 2 4 2   2 4 2
May-03 4 4   6 4 8 4   8 6 6
Jun-03 4   2 4 4 4 4 4   4 4

Table 29. Acidity (mg/L) in the water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 1.8 2.7 1.8 1.8 2.7 2.7 1.8     1.8 2.7 2.7
Dec-02 2.7 2.7 2.7 2.4 2.25         2.7 4.5 1.8
Jan-03 1.8 1.8 1.8 2.7 1.8 1.8   1.8   1.8 1.8 2.7
Feb-03 3.6 5.4 3.6 1.8 1.8 1.8   3.6 3.6   3.6 3.6
Mar-03 3.6 5.4 3.6   3.6 3.6   3.6 3.6   3.6 9
April-03 2 4 2   2 4   4 4   2 4
May-03 4 0 6   4     4 6   12 6
Jun-03 4 4 2   4     4 2   4 8

Dissolved Oxygen                                         

In the upstream region, dissolved oxygen ranged from 5 to 8.0 ppm (Table 30). This is within the range of NEERI standards.

Table 30. Dissolved oxygen (ppm) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 5 5.4 5.7 5.6     5.2 6   5.9            
Mar-01 6 5.6 5.8 4.8 6.2 5 6.4 5.2 6.4 4.9 5.3 6 5.2      
Apr-01 6.3 5 5.5 5.3 5.8 6 6.3 5.6 5.4 5.8 6.3 6 6.4      
May-01 6.5 4.9 6 6 6.8 6.4 7 7 7 6 7 6.5 7      
Jul-01 7.7 7.5 7.6 7.7 7.7 7.8 7.7 7.7 7.9 8 7.7 7.8   7.3 7.4 7
Aug-01 7.8 8 7.9 7.6 7.8 8 7.7 7.8 7.8 7.9 7.7 7.8   7.7 7.8 7
Sep-01 7.3 7 7.3 7.2 7.4 7.2 7 7.3 7 7.2 7.4 7.1 7.2 7.1 7.3 6.5
Oct-01 7.6 6.9 7.1 6.9 7.3 7.4 6.6 7.3 7 7 7.2 7 7.1 6.4 6.6 6.9
Nov-01 8 7.9 7.7 6.7 7.5 7.5 7.5 7.3 7.5 7.3 6.6 7.5 7 6.8 7.3 7.5
Dec-01 7.8 7.5 7.2 6.5 7.4 7.2 7.5 7 7.1 6.8 7 7.6 7.3 6.5 6.9 7.4
Jan-02 7.2 7.1 6.9 6.3 7 7 7.4 7.3 7.2 7 7.4   7.5 5.8 6.6 6.9
Feb-02 6.7 6.8 6.8 6.5 6.9 7 6.8 7 7.1 7.1 6.7   6.9     6.8
Mar-02 6.1 6.2 6.5 6.4 6.9 7.2 7.1 7.2 6.6 6.5 7.2   6.5      
Apr-02 6 6.3 6.2 6.1 6.3 6.5 6.4 6.5 6.1 6.2 6.5   6.3      

In downstream, DO at Chandavar [16.3 ppm], Gudankateholé [13 ppm], Dabbod [12.2 ppm], Hossagadde [12.2 ppm], Hennur [12.2 ppm] showed comparatively higher values due to high inflow and increased water turbulence in the region. Apart from these extremities, DO range was very much similar to upstream catchment.

Table 31. Dissolved oxygen (ppm) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02                      
Dec-02 8.1 7.3 12.2 12.2 11.4 12.2   9.7   7.3 6.5
Jan-03     6.5 5.2 6.2 5.9 6.8 8.6 7.9 7.5 6.9
Feb-03 6.3     4.1 6.1 4.5 6.9 5.1 7.7 5.3 6
Mar-03 6.2 6.8   4.2 6.4 5.8 6.9   6.6 6.7 5.5
April-03 6.8 7.1   4.6 5.6 6.7 6.9   6.6 5.9 5.5
May-03 7.4 6.6   4.7 6 6.8 7.1   6.2 6.1 4.9
Jun-03 7.2     6 6.6 6.4 6.7 6.7   6.5 6.6

Table 31. Dissolved oxygen (ppm) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02                        
Dec-02 8.9 8.1 11.4   7.3         16.3 13 7.31
Jan-03 7.1 8 8.2 7.3 9.6 6.4   6.3   7.4 5.6  
Feb-03 7.1 6.8 7.1 8.1 7.4 6.4   5.3 6.7   4  
Mar-03 6.9 6.7 7.9 6.6 7.2 6.3   5.5 6.8   5.7  
April-03 6.5 6.8 6.9   6.4 6.5   6.6 6.9   5.9  
May-03 6.9 9.1 6.9   6.6     6.5 7   6.1  
Jun-03 6.6 8.4 6.7   7.4     7.4 7.6   7.2  

Chloride

The chloride concentration fluctuated from 4.9 to 63.9 mg/L in the upstream region, well within the limits of NEERI (Table 32).

Table 32. Chloride concentration (mg/L) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 17.9 12.9 14.9 13.9     10.9 8.9   9.99            
Mar-01 4.9 6.9 12 11 6.9 7.5 6.9 7.9 7.1 5 10.9 8.9 12      
Apr-01 15 9.9 10.9 8.9 9.9 11 8.9 9.9 8.9 11.9 12.9 9.9 12      
May-01 33 23 21.8 23 16 22 18 23 14 18.5 20.8 19.7 21.2      
Jul-01 19.9 14.9 14.9 14.9 14.9 19.9 14.9 14.9 14.9 19.9 14.9 14.9   19.9 24.9 12.99
Aug-01 14.99 19.99 14.99 9.99 14.99 9.99 14.99 14.99 14.9 19.9 14.9 13.9   9.99 14.99 14.99
Sep-01 14.99 14.99 14.99 12.99 12.49 14.99 14.99 14.99 9.99 14.99 9.99 12.9 14.99 12.9 19.99 14.99
Oct-01 24.9 19.99 19.99 24.9 14.99 24.99 14.99 19.99 19.99 19.99 19.99 14.99 19.99 14.99 19.99 19.99
Nov-01 24.99 14.99 14.99 14.99 9.99 14.99 9.99 14.99 14.99 14.99 9.99 14.99 14.99 14.99 14.99 14.99
Dec-01 24.9 24.9 29.99 34.98 34.98 29.99 29.99 29.99 29.99 29.99 29.99 24.9 39.98 34.98 34.98 34.98
Jan-02 17.04 22.72 22.72 25.56 25.56 22.76 25.56 22.72 25.56 25.56 28.4   25.56 28.4 31.24 25.56
Feb-02 19.88 25.56 19.88 22.72 19.88 17.04 17.04 17.04 25.56 31.24 17.04   19.88     19.88
Mar-02 42.6 63.9 63.9 56.8 42.6 56.8 35.5 42.6 49.7 49.7 49.7   42.6      
Apr-02 17.49 42.48 22.47 24.99 14.99 22.49 17.49 19.99 19.99 22.49 19.99   24.99      

In Haddinabal, Gudankateholé and Badagani of downstream, Chloride concentration was comparatively higher (range: 3.19 – 13320.9 mg/L; Table 33) than other sites (both in upstream as well as in downstream). Intrusion of salt-water in the above regions is the main reason for higher chloride concentration.

Table 33. Chloride concentration (mg/L) in Sharavathi downstream water samples.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 1.91   2.87 4.47 3.19 3.51   3.83 2.55 3.19 5.1
Dec-02 2.87 2.39 4.79 4.79 4.15 4.31   4.47 4.31 4.79 2.87
Jan-03 6 6 6 8 6 8 6 16 6 655.8 6
Feb-03 7     11 6 8 6.5 11 7 50.98 7
Mar-03 7 7   8 7 10 6   7 782.75 7
April-03 7 6   9 6 8 6   7 1017.68 7
May-03 7 6   9 6 11 7   31 3049.1 7
Jun-03 5   9 7 8 8 10 9   37.99 8

Table 33. Chloride concentration (mg/L) in Sharavathi downstream water samples (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 2.87 4.15 2.87 1.91 3.19 3.83 3.83     3.19 4.47 871
Dec-02 2.87 3.35 3.83 2.9 3.35         4.79 6.7 5344.1
Jan-03 4 6 6 6 6 6   8   6 16 12371.2
Feb-03 6 8 5 6 7 7   8 7      
Mar-03 6 7 7   7 7   9 9      
April-03 6 8 5   7 7   9 8   570.82 13320.9
May-03 6 9 6   8     10 8   364.89 523.8
Jun-03 5 34.99 5   7     9 6   130 3573.9

Sulphate

The sulphate concentration in the representative samples from the upstream catchment ranged from 0.34 to 32.02 mg/L, within the limits given by NEERI (Table 34).

Table 34.  Sulphate concentration (mg/L) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 19.42 16.05 20.12 32.02     15.28 17.2   16.4            
Mar-01 14.22 16.22 14.89 25.77 13.17 23.35 18.62 14.89 24.81 14.89 20.5 18.29 16.65      
Apr-01 11.3 22.32 24.52 14.65 6.99 12.5 7.15 20.11 14.5 11.87 10.05 10.05 13.79      
May-01 13.27 9.52 15.23 9.24 10.04 15.23 12.4 9.32 12.51 7.39 10.93 12.4 14.21      
Jul-01 4.96 11.28 9.47 22.1 7.44 2.93 4.51 11.28 10.15 7.44 7.66 6.76   21.2 20.07 24.36
Aug-01 13.26 10.38 6.34 15.86 0.86 0.86 0.86 7.86 8.99 6.34 6.53 5.86   19.86 29.9 32
Sep-01 4.76 11.9 9.52 14.86 2.3 4.28 3.33 2.38 3.8 3.33 4.76 3.33 4.76 17.86 15.7 4.76
Oct-01 1.76 4.47 1.76 11.94 1.49 1.19 2.38 2.69 6.86 1.79 1.19 1.49 1.79 9.25 22.3 3.88
Nov-01 7.46 8.06 8.65 9.55 8.06 8.06 9.55 8.36 8.65 10.15 9.85 10.44 11.64 12.53 14.92 13.13
Dec-01 10.46 9.69 11.59 12.56 7.58 9.25 10.25 11.25 12.58 13.01 9.89 11.49 12.59 17.58 18.59 16.48
Jan-02 5.07 1.33 4.53 8 5.87 2.67 2.67 2.13 7.2 22.66 9.33   4.27 7.466 12 13.66
Feb-02 2.99 2.45 4.89 4.89 0.54 3.53 5.17 4.35 2.18 8.16 9.25   5.44     9.25
Mar-02 2 4 9.33 5 0.34 0.67 0.34 0.67 0.67 3.33 0.67   0.67      
Apr-02 2.51 3.24 8.99 6.21 1.24 1.25 1.65 1.22 1.54 2.13 2.01   0.99      

In downstream, apart from Haddinabal, Gudankateholé and Badagani, all other sites had low sulphate concentration, but within NEERI’s specification (Table 35).

Table 35.  Sulphate concentration (mg/L) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 3.78   3.62 2.5 2.18 2.57   2.07 1.87 3.2 3.43
Dec-02 1.93 1.29 1.47 1.64 1.6 2.52   1.33 2.05 1.68 1.35
Jan-03 4.44 2.46 2.22 4.33 2.57 2.34 3.63 2.46 2.22 79.29 3.51
Feb-03 1.99     2.69 1.64 1.87 1.29 1.87 1.75 117.53 1.29
Mar-03 2.34 2.57   2.69 2.81 3.39 4.56   1.52 84.2 1.52
April-03 1.87 2.11   1.87 1.52 1.99 1.99   1.64 113.21 1.05
May-03 2.22 2.46   1.64 1.52 2.46 2.57   2.34 93.56 1.87
Jun-03 5.61   13.57 1.52 1.99 1.99 1.05 3.51   3.63 2.11

Table 35.  Sulphate concentration (mg/L) in the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 3.39 2.73 3.12 1.64 3.08 2.69 3.98     2.77 2.49 123.8
Dec-02 1.52 1.82 1.64 1.29 1.41         1.75 2.34 224.2
Jan-03 2.11 2.22 3.74 1.99 2.34 2.69   4.44   3.51 3.16 837.4
Feb-03 1.64 2.22 1.4 1.87 1.75 2.69   1.99 1.99   2.92  
Mar-03 1.4 2.57 1.75   2.22 2.57   2.34 1.29   38.13 456.1
April-03 2.46 3.63 1.52   1.75 2.22   2.69 1.64   48.89 1765.9
May-03 2.11 3.98 1.64   2.11     3.39 2.57   1090.6 1754.3
Jun-03 1.4 3.51 1.4   1.75     5.15 8.07   12.16 321.6

Total Hardness

In the water samples of upstream, total hardness ranged from 27.25 to 148.29 mg/L (Table 36). Except four incidences from Sharamanavathi, Haridravathi, Keshawapura and Sampekai, where total hardness reached beyond 120mg/L, all other sites had very low hardness. The reason for higher concentration could not be substantiated.

Table 36.  Total Hardness (mg/L) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 59.95 27.25 49.05 27.25     30.12 30.35   32.7            
Mar-01 54.4 49.05 81.7 76.3 49.05 43.6 49.5 76.3 54.5 49.5 38.15 40.9 54.5      
Apr-01 43.6 43.3 39.24 52.32 37.5 49.7 43.6 30.52 50.7 43.6 48.8 39.24 34.48      
May-01 52 43.6 56.6 56.6 50.2 54.3 60.9 65.4 58.2 56.6 58.9 58.2 54.3      
Jul-01 59.5 59.9 76.3 82.2 82.3 49.5 40.9 38.15 54.5 49.5 49.05 43.6   54.5 54.5 40.6
Aug-01 39.24 39.24 43.6 43.6 47.96 34.88 30.52 30.52 46.32 46.35 45.63 40.56   56.68 78.48 39.24
Sep-01 61.04 43.6 56.68 56.6 43.6 52.32 30.52 61.04 39.24 47.96 69.76 78.48 47.9 78.89 122.08 78.48
Oct-01 65.4 49.05 49.05 54.5 43.6 54.5 49.05 49.05 59.95 59.95 43.6 59.95 49.05 70.85 59.95 59.95
Nov-01 78.48 52.32 143.88 122.08 78.48 52.32 87.2 61.04 43.6 39.24 47.96 52.32 56.68 148.24 82.84 65.4
Dec-01 43.6 39.24 47.96 52.32 43.6 30.52 30.52 56.68 65.4 52.32 61.04 43.6 65.4 126.44 95.92 47.96
Jan-02 28 36 68 80 40 32 32 36 32 28 28   32 76 76 44
Feb-02 60 32 52 88 40 20 32 36 44 22 92   32     64
Mar-02 60 50 50 60 50 50 30 30 70 40 30   40      
Apr-02 58 42 55 55 48 50 35 38 68 54 28   38      

Similar to upstream, generally all the sites in downstream exhibited low hardness concentration (Table 37). The reason for higher concentration in Haddinabal, Gudankateholé and Badagani could be due to salt-water intrusion in these regions.

Table 37.  Total Hardness (mg/L) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 16   19.33 14.67 17.33 16.67   18 17.33 21.33 22
Dec-02 17 23 17 15 18.67 19   20 19 18.67 20
Jan-03 16 24 16 20 16 24 12 24 24 232 18
Feb-03 18     24 12 22 12 20 26 400 18
Mar-03 14 24   24 14 20 10   32 272 14
April-03 18 26   24 14 22 10   28 336 14
May-03 18 28   28 12 18 12   64 400 6
Jun-03 12   14 14 18 16 16 20   28 20

Table 37.  Total Hardness (mg/L) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 14 22 16.67 16 16 22 16     14 14.67 1676.7
Dec-02 12 23 16 13.33 16         12.67 18 1866.7
Jan-03 12 26 12 12 22 32   16   16 32  
Feb-03 12 34 10 10 16 30   18 16   32 3800
Mar-03 10 44 10   26 32   16 18   116 4100
April-03 10 52 10   36 36   20 16   196 4300
May-03 6 52 6   8     6 10   3050 4200
Jun-03 12 22 14   16     16 12   52 1250

Calcium Hardness

In downstream sites, Calcium hardness ranged between 4 – 38 mg/L (excluding Haddinabal, Gudankateholé and Badagani). Table 38 details the Calcium hardness in Sharavathi downstream.  

Table 38.  Calcium hardness (mg/L) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 8   8 8 8 8   8 8.67 9.33 10
Dec-02 8 12 8 8 8 8   10 10 10 9
Jan-03 8 12 8 12 8 12 6 12 12 48 8
Feb-03 10     14 6 14 6 10 14 100 8
Mar-03 8 16   14 8 12 6   18 58 10
April-03 10 18   14 10 12 8   16 68 8
May-03 10 18   16 8 12 6   38 100 8
Jun-03 8   8 8 10 8 8 12   12 10

Table 38.  Calcium hardness (mg/L) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 8 11.33 8 6 7.33 12 8     6 7.33 66.7
Dec-02 8 12 6 6.67 8         6.67 8 366.7
Jan-03 6 16 6 4 8 14   10   8 14  
Feb-03 6 24 6 6 10 16   10 10   16 600
Mar-03 6 36 6   18 18   10 10   36 700
April-03 8 42 8   20 18   8 10   56 700
May-03 8 50 8   10     8 12   500 700
Jun-03 8 16 10   8     10 8   16 200

Magnesium Hardness

In downstream, magnesium hardness was within the permissible level (30 mg/L) in almost all sites (except sampling site 10, 22 and 23). Table 39 shows the magnesium hardness recorded from the downstream localities.

Table 39. Magnesium hardness (mg/L) in water samples of the Sharavathi downstream (cont…).
Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 8   11.33 6.67 9.33 8.67   10 8.67 12 12
Dec-02 9 11 9 7 10.67 11   10 9 8.67 11
Jan-03 8 12 8 8 8 12 6 12 12 184 10
Feb-03 8     10 6 8 6 10 12 300 10
Mar-03 6 8   10 6 8 4   14 214 4
April-03 8 8   10 4 10 2   12 268 6
May-03 8 10   12 4 6 6   26 300  
Jun-03 4   6 6 8 8 8 8   16 10

Table 39. Magnesium hardness (mg/L) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 6 10.67 8.67 10 8.67 10 8     8 7.33 1610
Dec-02 4 11 10 6.67 8         6 10 1500
Jan-03 6 10 6 8 14 18   6   8 18  
Feb-03 6 10 4 4 6 14   8 6   16 3200
Mar-03 4 8 4   8 14   6 8   80 3400
April-03 2 10 2   16 18   12 6   140 3600
May-03                     2550 3500
Jun-03 4 6 4   8     6 4   36 1050

Sodium and Potassium

Sodium concentration in upstream sites fluctuated between 2.1 to 101.4 mg/L (Table 40) and potassium values ranged between trace amounts to 9.5 mg/L (Table 41). The observed values are well within the limits given by NEERI. Concentration of potassium was much less compared to sodium, as it is not very abundant in natural waters.

Table 40.  Sodium concentration (mg/L) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 16.05 11.74 16.4 16.4     14.28 15.25   17.21            
Mar-01 7.81 9.99 10.44 15.57 12.53 9.8 11.4 12.3 11.5 12.34 12.64 12.97 13.5      
Apr-01 18 18 17 17.4 17.21 14.28 15.25 16.5 13.9 19 32.02 21 16.4      
May-01 12.52 12.64 12.25 11.4 12.3 17.5 15.75 11.5 12.4 9.99 10.53 10.44 7.3      
Jul-01 8.31 13.77 11.33 17.66 4.43 5.63 5.92 5.82 5.24 4.46 5.71 6.04   18.46 29.22 9.23
Aug-01 6.9 11.73 9.27 9.49 2.1 2.61 2.67 2.80 2.53 4.12 5.10 4.03   9.82 9.41 8.24
Sep-01 10.58 12.6 14.07 10.49 3.68 4.22 4.34 4.28 4.38 3.53 4.68 4.7 3.53 10.25 24.5 14.24
Oct-01 9.86 12.36 13.95 15.28 4.15 5.2 4.99 5.69 4.56 4.28 5.1 4.86 4.12 15.6 28.8 20.1
Nov-01 8.63 11.64 14.5 38.08 4.73 5.19 5.73 6.13 5.5 4.61 6.14 6.32 4.64 39.04 40.04 28.04
Dec-01 8.95 10.76 10.54 65.4 4.58 5.15 5.10 5.59 4.96 5.50 5.56 5.48 4.79 85 101.4 34.5
Jan-02 11.23 10.8 15.99 55.36 5.47 6.04 6.46 6.52 5.82 6.68 6.49   5.81 85.27 89.64 35.01
Feb-02 13.33 16.78 12.30 43.54 6.53 7.10 7.31 2.3 9.13 8.53 4   8.07     30.49
Mar-02 9.20 4.36 4.00 49.25 6.68 9.49 9.30 9.39 9.59 8.52 8.91   9.29      
Apr-02 10.21 5.321 3.68 47.86 5.69 10.25 10.25 9.37 9.46 8.65 8.64   10.25      

Table 41.  Potassium concentration (mg/L) in water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 0.4 0.8 0.7 0.8     ND ND   ND            
Mar-01 0.039 0.039 0.156 ND ND ND ND 0.078 0.039 ND 0.039 ND 0.039      
Apr-01 0.08 1.4 1.2 0.84 0.43 0.67 0.34 0.43 0.34 1.4 0.91 1.2 0.67      
May-01 0.039 0.56 1.4 0.91 0.22 1.4 0.43 0.1 1.2 1.2 0.84 0.91 0.34      
Jul-01 1.134 2.151 1.564 2.151 0.195 0.743 0.86 0.743 0.391 0.235 0.704 0.899   1.447 2.503 0.169
Aug-01 0.116 0.232 0.116 0.232 ND 0.116 0.116 1.96 0.291 0.203 0.502 0.775   0.155 0.193 0.193
Sep-01 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.013 0.03 0.04 0.01
Oct-01 0.95 0.98 0.88 1.1 0.099 0.098 0.15 0.2 0.298 0.258 0.35 0.42 0.199 0.56 0.33 0.99
Nov-01 1.076 1.35 1.35 1.55 0.3 0.478 0.59 0.59 0.478 0.3 0.59 0.59 0.398 1.435 1.91 1.395
Dec-01 0.3 0.348 0.503 0.465 0.077 0.116 0.116 0.15 0.116 0.116 0.15 0.15 0.077 0.54 0.69 0.348
Jan-02 2.7 2.156 4.156 4.274 0.919 1.216 2.039 1.647 1.176 1.294 1.686   0.941 2.94 4.039 3.25
Feb-02 0.883 0.803 1.225 3.214 0.281 0.361 0.401 0.401 0.321 0.562 0.321   1.285     4.416
Mar-02 3.518 2.345 7.818 9.508 5.863 1.564 4.691 1.173 0.782 0.782 0.782   1.564      
Apr-02 1.025 1.365 4.256 8.25 4.35 2.317 3.214 2.154 1.255 1.256 2.351   2.155      

In downstream localities, the lowest concentration of 0.1 mg/L of sodium was recorded at Dabbe falls and Joginamutt and was highest with 36.60 mg/L at Chandubanu (Table 42). High sodium concentrations were attributed to seawater intrusion. The permissible range of sodium concentration for surface water is <1 - > 300 mg/L. Similarly, potassium concentration in the downstream sub-basins ranged between 0.09 – 6.4mg/L (0.7 – 1.80 mg/L [DS 4], 0.09– 2.50 mg/L [DS 3], 0.09 – 6.4 mg/L [DS 2], 0.46 – 2.6 mg/L [DS 5]).

Table 42. Sodium concentration (mg/L) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 5.46   6.57 6.53 6.38 6.52   7.08 6.73 6.92 6.98
Dec-02                      
Jan-03                      
Feb-03 17.79     17.59 17.88 15.75 17.88 5.73 17.5   17.3
Mar-03 17.88 16.52     17.69 11.86 17.79   17.4   17.3
April-03 17.59 17.01   16.33 17.3 14 17.88   17.3   17.5
May-03       5.03 3 11.9 3.8   36.6 5356.8 3.87
Jun-03 0.1   0.6 0.7 0.8 0.7 2.29 1.6   20.54 1.1

Table 42. Sodium concentration (mg/L) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 5.8 7.38 6.07 5.57 6.19 6.38 6.95     7.16 8.53 1339.8
Dec-02                   7.16   1339.8
Jan-03                       1339.8
Feb-03 17.69 10.11 17.69 17.79 17.5 17.2   14.29 17.3   53.36  
Mar-03 17.79 6.12 17.59   16.72 17.2   12.44 15.75      
April-03 17.79 3.6 17.88   16.33 16.62   7.78 15.84      
May-03 2.42 13.6 2.5   4.5     12.08 4.06      
Jun-03 0.02 2.19 0.4   0.8     1.2 0.1   70.58 1908

Table 43. Potassium concentration (mg/L) in water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 0.51   0.07 0.24 0.13 0.44   0.31 0.33 0.24 0.4
Dec-02                      
Jan-03                      
Feb-03 1.8     1 0.9 1.5 0.9 2.2 1   0.7
Mar-03 0.9 0.7     0.9 1.6 0.8   1   0.9
April-03 1 1.3   1.2 1.3 2.5 0.8   1.2   0.9
May-03       0.09 0.09 0.09 0.09   0.09 0 0.09
Jun-03 1.29     0.89 1.09 0.8 0.89 1.49   1.89 0.89

Table 43. Potassium concentration (mg/L) in water samples of the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 0.4 0.84 0.81 0.79 0.31 0.46 0.4     0.04 0.22 186.9
Dec-02                   0.04   186.9
Jan-03                       186.9
Feb-03 1.1 4.5 0.8 0.8 1 2.2   1.7 2.3   4.7  
Mar-03 0.9 5.8 1.2   1.3 2.6   2 1.7      
April-03 0.9 6.4 1   1.3 2.6   2.4 1.7      
May-03 0.09 1.74 0.09                  
Jun-03 0.6 2.09 0.6   0.8     1.79 1.69   3.18 82

Nitrate Nitrogen

In Sharavathi upstream, Nitrate nitrogen concentration in water samples ranged from trace to 1.622 mg/L (Table 44).

Table 44. Nitrate concentration (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 0.161 0.167 0.12 0.154     0.147 0.141   0.134            
Mar-01 0.004 0.024 0.007 0.014 0.012 0.01 ND ND 0.024 0.028 ND ND 0.012      
Apr-01 0.013 0.073 0.213 0.34 0.01 0.04 0.06 0.006 0.067 0.033 0.053 0.06 0.006      
May-01 0.1 0.14 0.02 0.42 0.012 0.01 ND 0.14 0.024 0.16 0.13 0.4 0.14      
Jul-01 ND ND ND ND ND ND ND ND ND ND ND ND   ND ND 0.099
Aug-01 0.015 0.05 0.01 0.01 0.015 0.075 0.01 0.095 0.1 0.015 0.075 0.074   0.11 0.12 0.095
Sep-01 0.045 0.075 0.15 0.15 0.022 0.15 0.12 0.15 0.15 0.03 0.105 0.095 0.095 0.14 0.157 0.105
Oct-01 0.052 0.079 0.155 0.168 0.066 0.099 0.085 0.13 0.056 0.098 0.256 0.099 0.101 0.169 0.561 0.589
Nov-01 0.055 0.086 0.162 0.199 0.092 0.087 0.098 0.092 0.105 0.159 0.361 0.134 0.198 0.235 0.942 0.789
Dec-01 0.061 0.101 0.188 0.254 0.15 0.025 0.056 0.075 0.213 0.312 0.587 0.857 0.534 0.654 1.023 0.954
Jan-02 0.083 0.139 0.251 0.307 0.279 ND ND 0.008 0.335 0.587 0.979 0.712 0.979 0.979 1.259 1.623
Feb-02 0.042 0.063 0.021 ND ND ND 0.056 ND ND 0.416 0.071   ND     ND
Mar-02 0.09 0.128 0.308 0.142 0.160 0.038 0.257 0.039 0.071 0.192 0.769   0.026      
Apr-02 0.076 0.099 0.125 0.125 0.099 0.036 0.354 0.047 0.075 0.231 0.564   0.055      

In downstream sites, nitrate concentration was higher at Hossagadde, Bhaskere and Mavinaholé with 1.011 mg/L, 1.208 mg/L and 1.114 mg/l respectively (Table 45). Comparatively, downstream sites had low nitrate concentration than upstream sites.

Table 45. Nitrate concentration (mg/L) in the water samples of the Sharavathi downstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 0.149   0.203 0.146 0.134 0.173   0.094 0.113 0.153 0.097
Dec-02 0.144 0.146 0.12 0.178 0.15 0.142   0.153 0.165 0.12 0.142
Jan-03 0.231 0.231 0.206 0.343 0.253 0.793 0.326 0.253 0.279 0.206 0.214
Feb-03 0.317     0.308 0.214 0.27 0.24 0.249 0.219 0.206 0.236
Mar-03 0.27 0.279   0.176 0.21 0.227 0.244   0.223 0.249 0.219
April-03 0.047 0.099   0.06 0.064 0.06 0.051   0.039 0.06 0.021
May-03                      
Jun-03 0.63   1.011 0.716 0.908 0.951 0.176 1.208   0.788 1.114

Table 45. Nitrate concentration (mg/L) in the Sharavathi downstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 0.103 0.103 0.21 0.2 0.13 0.1       0.12 0.32 0.13
Dec-02 0.13 0.12 0.17 0.183 0.155         0.13 0.18 0.11
Jan-03 0.27 0.3 0.39 0.43 0.24 0.26   0.3   0.21 0.29 0.25
Feb-03 0.29 0.21 0.27 0.21 0.27 0.24   0.27 0.28   0.24 0.19
Mar-03 0.2 0.2 0.19   0.24 0.21   0.23 0.24   0.27 0.19
April-03 0.05 0.04 0.12   0.13 0.09   0.09 0.06   0.14 0.04
May-03                        
Jun-03 0.154 0.24 0.206   0.163     0.514 0.65   0.48 0.18

Phosphate

The values ranged from non-detectable (ND) to 0.0929 mg/L (Table 46). The occasional rise in concentration can be attributed to the agricultural runoff getting into that water.

Table 46.  Phosphate concentration (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Feb-01 0.007 0.009 0.009 0.008     0.006 0.018   0.007            
Mar-01 0.008 ND 0.012 0.009 0.004 ND 0.002 ND ND 0.005 ND 0.012 0.004      
Apr-01 0.004 0.01 ND 0.004 0.004 ND 0.002 0.005 0.002 0.003 0.003 0.001 ND      
May-01 0.002 0.003 0.001 0.01 ND 0.004 0.004 0.004 0.002 ND 0.004 0.014 ND      
Jul-01 0.014 0.014 0.014 0.02 0.005 0.01 0.011 0.019 0.01 0.015 0.01 0.02   0.018 0.032 0.003
Aug-01 0.017 0.008 0.012 0.018 0.012 0.009 0.02 0.005 0.012 0.015 0.010 0.02   0.013 0.017 0.002
Sep-01 0.004 0.007 0.004 0.005 0.003 0.002 0.01 0.001 0.004 0.007 0.005 0.01 0.005 0.005 0.005 0.004
Oct-01 0.022 0.015 0.053 0.012 0.025 0.008 0.008 0.032 0.008 0.028 0.023 0.011 0.007 0.092 0.003 0.036
Nov-01 0.009 0.005 0.008 0.007 0.012 0.011 0.014 0.008 0.016 0.014 0.010 0.01 0.011 0.014 0.013 0.014
Dec-01 0.014 0.010 0.017 0.005 0.004 0.003 0.014 0.038 0.022 0.07 0.014 0.017 0.007 0.048 0.051 0.021
Jan-02 0.001 0.005 ND 0.009 0.008 0.003 0.007 0.004 0.003 0.004 ND   ND 0.004 0.001 0.002
Feb-02 ND 0.046 ND 0.057 ND ND 0.009 ND ND ND ND   ND     ND
Mar-02 0.003 0.002 0.006 0.018 0.006 0.017 0.017 0.014 0.005 0.001 0.004   0.001      
Apr-02 0.002 0.002 0.004 0.026 0.005 0.021 0.015 0.015 0.005 0.002 0.004   0.002      

Contrasting to upstream, the downstream localities generally had low phosphate concentration (trace to 0.025 mg/L) and fluctuations were also very less (Table 47).

Table 47.  Phosphate concentration (mg/L) in the water samples of the Sharavathi upstream.

Months Sampling sites
1 2 3 4 5 6 7 8 9 10 11
Nov-02 0.01   0.01 0.01 0.01 0.02   0.01 0.01 0.01 0.01
Dec-02 0.01 0.01 0.01 0.01 0.01 0.01   0.01 0.01 0.01 0.01
Jan-03 0.017 0.014 0.016 0.016 0.016 0.016 0.015 0.015 0.017 0.014 0.016
Feb-03 0.016     0.014 0.013 0.012 0.014 0.012 0.016 0.009 0.014
Mar-03 0.017 0.02   0.025 0.015 0.018 0.022   0.017 0.016 0.015
April-03 0.003 0.004   0.003 0.003 0.006 0.003   0.003 0.003 0.003
May-03 0.004 0.004   0.003 0.003 0.006 0.003   0.003 0.003 0.003
Jun-03 0.014   0.016 0.013 0.015 0.015 0.016 0.012   0.014 0.014

Table 47.  Phosphate concentration (mg/L) in the Sharavathi upstream (cont…).

Months Sampling sites
12 13 14 15 16 17 18 19 20 21 22 23
Nov-02 0.01 0.01 0.01 0.01 0.01 0.01 0.01     0.01 0.01 0.01
Dec-02 0.01 0.01 0.01 0.01 0.01         0.01 0.01 0.01
Jan-03 0.016 0.017 0.015 0.012 0.016 0.016   0.016   0.01 0.02 0.01
Feb-03 0.014 0.018 0.013 0.013 0.013 0.021   0.014 0.014   0.013 0.01
Mar-03 0.01 0.02 0.03   0.01 0.02   0.02 0.02   0.02 0.01
April-03 0.003 0.003 0.003   0.003 0.004   0.003 0.003   0 0
May-03 0.003 0.003 0.003   0.003     0.004 0.003   0.003 0
Jun-03 0.009 0.013 0.01   0.014     0.012 0.015   0.013 0.013

Iron

Iron concentration in all upstream sampling points was <0.3 mg/L, within the limits of NEERI and APHA (drinking water 0.3mg/L and freshwater bodies 1.0mg/L).

Ammonia

In upstream sites, concentration of ammonia ranged between <0.2 to 3 mg/L.

Fluoride

In downstream, fluoride concentrations in all sub-basins were 0.6 mg/L which falls within the standard limit of 0.6 – 1.2 mg/L for drinking water.

Coliform Bacteria

In upstream, water samples taken during monsoon had coliform bacteria at Sharavathi 1 and 2, Sharmanavathi, Haridravathi and its nearby streams (Keshawapura and Nandiholé). This is due to human or animal interference with the waterbodies of the region. Other sampling sites showed occasional presence of coliform bacteria.

In downstream localities, coliform bacteria were found in almost all the samples. This could be due to human faecal matter or due to aquatic or terrestrial animal wastes. As per the permissible limits for drinking water, there should not be any coliform bacteria in the water.

1.    Comparison with NEERI and WHO Standards

Table 48 details the comparison of the study with NEERI and WHO standards. Only those parameters having permissible levels according to NEERI are considered here. A few parameters have exceeded the stipulated limits, but they require continued monitoring.

Table 48. Obtained values vs. standard values of NEERI and WHO

Variables Permissible Limits Upstream Downstream
Turbidity (NTU) Not more than 10 <5 – 125 10 – 100
Total Dissolved Solids (mg/L) 100 13.77 – 110 16.2 – 15,090 mg/L
Colour Colourless Colourless – Brownish green Colourless – Brownish green
pH 6.5-8.5 6.52-8.41 6.21-8.67
Conductivity (mS/cm) 0.05-1.5 0.003-0.44 0.03-30.20
Alkalinity (mg/L) 200 8 -75 9.6-79.2
Dissolved oxygen (ppm) Not less than 3.0 4.8-8 4.0-16.3
Total Hardness (mg/L) 300 27.25 - 148.29 6-4300
Sulphate (mg/L) 150 0.34-32.02 1.05-1765.3
Chloride (mg/L) 250 4.9-63.9 1.91-13320.9
Sodium (mg/L) 200 2.1 - 101.4 0.1-1908
Potassium (mg/L) - Trace - 9.508 0.09-186.9
Nitrates (mg/L) 45 Trace - 1.623 0.021-1.114
Phosphates (mg/L) 0.03 Trace - 0.092 Trace – 0.025
Coliform Bacteria Should be nil Nil - Present Nil – Present

2.    Comparison between Sampling Sites in Upstream

The upper catchment area was divided into three categories based on the their disturbance level. Group A was classified under most disturbed area (agricultural activities, siltation process, etc), whereas Group B and Group C come under comparatively less disturbed area. Table 49 gives the classification of groups based on their disturbance level.

Table 49. Classification of study area (upstream)

Group A Group B Group C
Sharavathi [1] and [2]
Sharmanavathi [3]
Haridravathi [4]
Nandiholé [14]
Keshavapura [15]
Sampekai [16]		 Muppane [5]
Talakalale dam [6]
Dam outlet [7]		 Linganamakki Reservoir [8]
Valagere [9]
Yenneholé [10]
Hurliholé [11]
Nittur [12]
Madenur [13]

Table 50 gives the comparison of water quality variables between sampling sites under each group.

Table 50. Comparison between sampling sites.

Variables Group A Group B Group C
Transparency (cm) 3 – 124 20 – 284 24 - 284
Turbidity (NTU) 10 – 125 <5 – 12 5 - 20
Colour Light Brown - Brownish green Colourless - Brownish green Colourless - Brownish
Total Dissolved Solids (mg/L) 18.16 – 84 13.77 - 27.3 14.25 - 40.72
Total Suspended Solids (mg/L) 21.3 – 110 26 – 75 26 - 85
pH 6.53 - 8.25 6.54 - 7.757 6.53 - 7.76
Ammonia (mg/L) <0.2 - >3.0 <0.2 – 3.0 <0.2 - 3.O
Total Hardness (mg/L) 27.25 - 143.88 20 – 87.2 22 - 78.48
Sulphate (mg/L) 1.76 - 32.02 0.34 – 23.35 0.67 - 17.2
Nitrates (mg/L) ND - 1.6229 ND - 0.279 ND - 0.979
Phosphate (mg/L) ND - 0.0929 ND - 0.0174 ND - 0.0699
Coliform Bacteria Almost Present in all sampling sites ND- Slightly Present ND-Slightly Present

The results show that the physico-chemical and biological variables under group A is comparatively polluted than group B and group C in terms of transparency, turbidity, suspended solids, phosphate and coliform bacteria.

The tributaries flowing through the sub-basins Nandiholé (US1), Haridravathi (US2), Sharavathi (US4), Mavinaholé (US3) and Hilkunji (US8) (Group A) are relatively more polluted  (in terms of transparency, turbidity, suspended solids, phosphates and coliform) than the tributaries in the sub-basins Yenneholé (US5), Linganamakki (US9), and Hurliholé (US6) (Group B and C) in the Sharavathi upper catchment. The reason for higher pollution in the above said sub-basins is due to agricultural and other anthropogenic activities in the catchment area.

3.    Comparison between Sampling Sites in Downstream

Stagnant waters especially at Dabbod, Gudankateholé show low DO values in comparison to flowing waters of Vatahalla, Chandubanu. Drastic changes were observed in the water quality during the months of January, February, March and April in the Haddinabal stream due to seawater intrusion as evident by high conductivity and total dissolved solids with corresponding increase in values for all other parameters. Generally, the water is saline only upto Badagani. The seawater intruded backwards upto Hablikapu nearly one and a half km away from Gudankateholé passing through 4 dams/obstructions. Farmers in the nearby areas have noticed crop damage i.e. stunted growth due to saline water usage.

In the coastal belt three locations of a major stream were monitored at Chandavar, Gudankateholé and Badagani. Badagani showed high salinity during all months. Gudankateholé showed freshwater characteristics during November, December, and January. But during the months February, March and April the water turned saline. This has led to the contamination of nearby wells and rendered them unfit for drinking.

Turbidity levels at Dabbod a stream located at the southern end of Sharavathi downstream catchment exceeded the limits during the months of January and April. The reason for this abnormality can be attributed to the damming of this stream where the water was retained for agricultural purposes. Alkalinity levels have also shown substantial increase in the values similar to TDS values. All streams except Chandavar started flowing in June due to rains. There are natural variations and trends in the water quality that the waterbodies are usually bound to experience over a period of time or season. Apart from Haddinabal, Gudankateholé and Badagani, all other sites had the water parameters within the stipulated range of Indian standards for drinking and agriculture except for turbidity and coliform bacteria.

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