Development of River Bank Filtration (RBF) well in saline coastal aquifer

Abstract

Providing the safest potable water supplies is a challenging task in the coastal areas of India due to the high groundwater salinity and unreliable surface water supplies. One of the east flowing river basins in Andhra Pradesh State, India, namely Varaha river saline coastal tract has been identified for implementing the River Bank Filtration (RBF) technique for providing potable water to the rural population. This technique is focused on identifying low saline aquifer zone, which is connected to the river bed for establishing RBF well on Varaha river bank. Using Geophysical methods (Electrical Resistivity Tomography, Vertical Electrical Soundings) and hydrochemistry surveys, the river-aquifer interaction zones (low saline) are successfully identified and drilled the RBF well on the Varaha river bank up to the depth of 35 m below ground level. The RBF well yield and aquifer productivity are assessed during pumping test analysis. The comparison of hydrochemistry between river water, groundwater and RBF water further confirm that the RBF water is safe for drinking with minimum treatment like chlorination or ozonation. Hence the RBF technique is an alternative source of drinking water supply scheme in the saline coastal tracts of east flowing rivers of India.