Groundwater Chemistry of the River Terrace Springs along Himalayan Foothills in and around Pasighat, Arunachal Pradesh, India

Abstract

Springs present around Pasighat in the Himalayan foothill region are a major source of water for the local people. Study of groundwater chemistry of the river terrace springs of the Himalayan region is scarce. These springs tap the river terrace aquifers and have different chemical characteristics as compared to other types of springs present in the Himalayan region. This study aims to understand the chemical characteristics of the spring water in terms of water types and rock-water interaction. This study shows that the spring water has low concentration of dissolved ions and the pH is slightly acidic. Also, the groundwater of this area belongs to Ca-Mg-HCO₃ type and recharge water type. Principal component analysis, correlation matrix and scatter plots show that silicate weathering, weathering of Cl-rich amphiboles and biotites, weathering of feldspars and ferromagnesian minerals and ion-exchange are the major operational processes in the area. Low concentration of dissolved constituents within the desirable limits makes the groundwater suitable for drinking, and other household purposes. Also, due to geological similarity of terrace deposits along the Himalayan foothills it is inferred that river terrace springs in other parts of Himalayan foothills may have similar groundwater characteristics.