Water quality and geochemical facie of high-altitude lakes in Tawang, Eastern Himalaya, India

High-altitude lakes (HALs) can be used as a supplement or alternative source of water in areas where there is a water shortage. When these lakes are efficiently managed, they can supply more water resources to fulfil the increasing demand. Water quality assessment aids in the identification of adequate and safe drinking water sources. It minimizes threats to the public’s health by making sure that lake water extraction fulfills safety and health regulations. Water quality and hydrogeochemical study was conducted on six HALs of the Tawang district of Arunachal Pradesh during the year 2022. The water quality index (WQI) values varied from excellent to poor (33.87 to 101.95). Lake 6 stands out with its exceptional water quality as it had the minimum average WQI value of 52.98. In contrast, Lake 5 had the lowest water quality among the studied lakes with the maximum average WQI value of 95.31. However, the water might not be safe to drink due to the elevated levels of fluoride in these lakes. It is crucial to address and minimize the high fluoride levels to ensure the safety and acceptability of the water for consumption. The Piper diagram showed that Ca2+  > Mg2+  > Na+  > K+ and HCO3−  > Cl−  > SO42−, respectively, were the primary cations and anions present in these lakes. The Gibbs diagram also demonstrated the effect of rock weathering and precipitation dominance on the water chemistry in the research area. These results provide insightful information about the water quality of HALs, which is essential information for concerned government departments and agencies to manage water issues more efficiently. Based on current research, the HALs in this region have a lot of potential to meet the growing demand for drinking water.