Abstract:
In place of direct pumping, river bank filtration (RBF) is increasingly being used for collecting surface
water for municipal supplies. However, as each site is different, every such scheme needs evaluation
and adds to our knowledge about RBF. This work aimed at evaluating the efficacy of a well commissioned
in May 2010 on the bank of River Alaknanda in Srinagar (Uttarakhand), India. The well water was
monitored for coliform removal and mineral content with reference to the river and surrounding
groundwater since the construction of the well. Study showed that the well water is much better in terms
of bacteriological quality and turbidity, but is highly mineralized with respect to the river water. The ionic
concentrations in the well water were comparable to the groundwater in the region. Stable isotope d2H
and d18O values, however, showed that the well water is predominantly river bank filtrate. In
addition, the water from the well has been containing unusually high concentrations of nitrate
(53–138 mg/L)—much higher than permissible limit for drinking water supply while the river water
had much lower concentrations (0.3–4.2 mg/L). Investigations were conducted on groundwater, wastewaters,
soils, and rocks in the area to identify the source of excess nitrate. The results suggest the
occurrence of phyllite and quartzite bedrocks as the origin of nitrate. These findings underline the need
for extensive hydrogeochemical studies before designing a RBF scheme.
