Hydrochemical Characterization of Surface Water in Phewa Lake, Gandaki Province, Nepal

Abstract

Abstract Securing water to satisfy the needs of humans and the ecosystem is one of the prime issues worldwide. This study aims to characterize the hydrochemical properties and water quality of Phewa Lake, Nepal. The mean pH and DO were found to be 7.98 and 6.08 mg/L, respectively. The ionic dominancy of water follows the order of Ca2+>Na+>K+>Mg2+, and HCO3−>SO42−>Cl−>NO3−. The Piper plot characterizes the Ca-HCO3 type of water facies, and the Gibbs diagram indicates the rock weathering as a major controlling mechanism. The high ratios of (Ca2+ + Mg2+)/TZ+, (Ca2+ + Mg2+)/(Na++ K+), Ca2+/Na+, and HCO3− /Na+, i.e., 0.84, 5.33, 6.48, and 5.36, respectively also confirmed the dominancy of carbonate weathering. The drinking and irrigational indices revealed that the lake water was relatively better in monsoon compared to the pre-monsoon season. The study provides new insights on hydrochemical characteristics which contribute to the sustainable management of Ramsar-listed lakes in the Himalayas.