• The average water temperature in the entire stretch of river Ganga varied from 7.22°C to 29.52°C. During the entire sampling, the lowest water temperature (3.21°C) was observed at Harshil, While the highest temperature of 36.6°C was observed at Buxar-Balia Stretch of the river Ganga.
• The average depth in the entire river stretch was estimated at 6.34 m. During the study period, lowest average depth of 0.69 m was observed at Harshil in upper hilly stretch, and whereas the highest average depth of 13.36 m was observed at Diamond Harbor, which is a tidal zone of the river.
• River flow in the upper stretch of the river, the highest average flow value of 1.09 m/sec was observed at Harshil, 0.63 m/sec in the middle stretch at Narora, and in the lower stretch highest average flow of 1.09 m/sec was observed at Tribeni.
• The average transparency in the entire river was estimated at 43.94 cm during the study period of 2016-2020. The highest average transparency value of 88.20 cm was observed at Tehri in the upper stretch of the river. In the middle stretch, the highest transparency (52.50 cm) was recorded at Buxar and in the lower stretch the highest average transparency (73.75 cm) was observed at Farakka. The lowest transparency value (17 cm)in the entire stretch was observed at Diamond Harbour. Significantly lower transparency was recorded during monsoon months as compared to non-monsoon period.
• The turbidity in the middle and lower stretch ranged from 3.7 NTU to 523 NTU. Average turbidity in the entire river was 99.64 NTU. Highest average turbidity value of 208.06 NTU was recorded at Diamond Harbour of lower stretch of river Ganga.
• The observed average pH value of water in the entire river is 8.12 and ranged from 7.2 to 9.51 indicates nutral to lightly alkaline condition through out the season. The highest average pH value of 7.9 was recorded at Narora, and the lowest pH value of 7.29 was recorded at Farrukhabad.
• The dissolved oxygen level was above 6 ppm in entire stretch of river Ganga during the study period. The highest average dissolved oxygen value of 9.04 ppm was observed at Harshil in the upper stretch of the river;7.66 ppm in the middle stretch at Prayagraj, and in the lower stretch observed highest dissolved oxygen was 6.64 ppm at Farakka.
• The highest average alkalinity value of 163 ppm was recorded at Buxar-Balia stretch of the river Ganga and highest average total hardness value of 1095.46 ppm was recorded at Fraserganj describe the low alkaline zone.
• The salinity was recorded between 0.01 ppt to 31.79 ppt in the entire river stretch. Harshil to Tribeni stretch being freshwater zone, salinity ranges 01 to 0.15 pptwhereas,0.19 to 2.5 ppt was found at Godakhali and Diamond Harbour stretch considered as brackishwater zone. Highest average salinity value of 28.73 ppt was recorded at Fraserganj as it is an esturine zone of the Ganga river stretch.
• Highest average total dissolved solid (40 g/l) and Total Solid value (50.62 g/l) was recorded at Fraserganj. In upper & middle stretch, significant improvement was observed at Haridwar (13.1 %), Narora (17.5%), Kanpur (17.4%), Prayagraj (32.71 %) and Varanasi (7.6 %). In lower stretch, improvement was observed at Buxar (6.9 %), Patna (21.8 %) & Bhagalpur (27.5 %). In estuarine stretch also, improvement was observed at Balagarh (46 %), Tribeni (44.9 %), and Godakhali (26.4 %). However, supersaturated condition of oxygen level was obtained at Buxar, Patna, Balagarh and Tribeni (middle to lower stretch) during pre-monsoon mainly due to Microcystis sp. (Blue green algae) bloom formation and at Balagarh and Tribeni in winter due to bloom by the diatom, Aulacoseira granulata. During July 2018, a thick scum Microcystis aerugenosa bloom was noticed first at Buxar 2245 unit/l and Bhagalpur 1012 unit/l stretch.
• The highest average total phosphorus value of 0.65 ppm was recorded at Bhagalpur.
• The highest average available nitrogen value of 1.18 ppm was recorded at Varanasi and Highest average Total Nitrogen value of 3.6 ppm was recorded at Godakhali
• The highest average Biological Oxygen Demand (B.O.D) value of 3.83 ppm was recorded at Kanpur followed by Varanasi 3.6 ppm and Prayagraj 3.36 ppm due to industrial belt area indicates pollution in Kanpur to Prayagraj stretch of river Ganga.
• The higher average free carbon dioxide value was observed at upper stretches as Harshil, Bijnor and highest of average free carbon dioxide 5.41 ppm was recorded at Haridwar stretch of the river Ganga.
• The average specific conductivity in the entire river was 5.16 mS/cm. Highest average specific conductivity value of 43.12 mS/cm was recorded at Fraserganj. In upper and middle stretch, significant lowering was observed at Harshil (38.16 %), Tehri (31.39 %), Narora (36.3 %), Farrukabad (32.03 %), Kanpur (32.4 %), Prayagraj (31.45 %) and Varanasi (18.33 %). In lower stretch, significant lowering was observed at Buxar (2.7 %) and Farraka (14.3 %) showing the betterment in the health status of the river during the study period.
• The average total chlorophyll in the middle and lower stretch ranges from 0.29 to 42.05 mg/m³. Highest average chlorophyll content in river water of 16.47mg/m³ was recorded at Tribeni.