International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 08 Issue: 01 | Jan 2021
p-ISSN: 2395-0072
www.irjet.net
Table-4: Relative weight (Wi) & WQI calculation for the samples SI (qi x Ci) for each sample (sample W1-W9) pH TDS HCO3SO42NO3ClTH Ca2+ Mg2+ Na+ K+ Po43F-
wi 4 4 3 4 5 3 2 2 2 3 2 3 4
Wi Si (BIS) 0.097561 7 0.097561 500 0.073171 244 0.097561 200 0.121951 45 0.073171 200 0.048780 600 0.048780 75 0.048780 30 0.073171 200 0.048780 25 0.073171 0.03 0.097561 1 WQI
SIW1 10.45 1.99 3.30 0.36 0.11 1.46 1.54 1.04 3.90 0.21 0.07 50.73 1.00 76.18
SIW2 10.59 3.38 5.55 0.38 0.39 1.10 1.46 2.34 3.51 0.39 0.18 50.24 1.63 81.13
SIW3 10.59 2.40 4.20 0.28 0.41 1.46 1.38 1.82 3.90 0.18 0.09 88.54 0.98 116.22
SIW4 10.73 2.61 4.20 0.39 0.24 2.93 1.87 1.82 6.24 0.19 0.08 86.83 1.13 119.26
SIW5 10.87 3.16 5.55 0.38 0.16 1.83 1.79 2.60 4.68 0.21 0.08 71.22 0.76 103.29
SIW6 10.73 3.16 4.95 0.41 0.27 1.46 1.54 2.08 4.29 0.21 0.08 125.12 0.82 155.13
SIW7 11.57 3.00 5.70 0.30 0.32 1.46 1.71 2.08 5.07 0.16 0.05 80.73 1.42 113.59
SIW8 11.15 3.04 6.60 0.79 0.33 2.38 2.28 1.82 8.20 0.20 0.06 47.07 0.91 84.82
SIW9 11.01 3.00 6.00 0.30 0.25 1.28 1.71 2.08 5.07 0.22 0.08 49.76 1.30 82.06
For computing the WQI, the SIi is first determined for each chemical parameter, which is then used to determine the WQI as per the following equations (Table-4) ...........................(3) .............................(4) The WQI are generally classed into five categories, excellent water to unsuitable for drinking [8], [9]. In the present study, the WQI values ranges from 76.18 to 155.13. WQI for samples from Lokchao River, Tisa Lok, Maha River and Tuivai Lok are less than 100 and falls under good water category while others are poor water category (Table-5). The higher WQI values are mainly attributed to the high values of phosphate in the water samples. Table-5: Water quality classification based on WQI values River Name Tisa Lok Maha River Khumji Lok Sekmai River Chakpi River A Chakpi River B Wangphu Lok Lokchao River Tuivai Lok
WQI value 76.18 81.13 116.22 119.26 103.29 155.13 113.59 84.82 82.06
Water quality Good water Good water Poor water Poor water Poor water Poor water Poor water Good water Good water
WQI range
Water quality class
<50
Excellent water
50-100
Good water
100-200
Poor water
200-300
Very poor water
˃300
Unsuitable for drinking
3.2 Irrigation quality The water quality suitability for irrigation purposes, the irrigation indices -Electrical Conductivity (EC), Soluble Sodium Percentage (SSP) and Sodium Absorption Ratio (SAR) are considered. The EC, TDS and SSP concentrations in water influences the irrigation water quality as these parameters represent the measure of salinity or salt concentration that have profound effects on soil osmotic pressure. The irrigation water quality parameters (EC, TDS, SSP and SAR) for the water samples are listed in table -6. EC concentration ranges between 171-288 µS/cm which falls under excellent to good water quality classes according to Richards [10]. All the samples are fresh water as TDS is less than 1000 mg/l [11]. SSP values vary from 12.03 to 4.19 which fall under excellent category [12]. According to Bouwer [13], SAR values of all the water samples fall in the category of less alkali hazards problem (SAR<6). Table-7 shows the classification of the water samples of the study area for irrigational uses based on EC, TDS, SSP and SAR. © 2021, IRJET
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