Comparative water quality assessment of Central Himalayan Lake: Nainital

Abstract

The Nainital Lake, situated in the central Himalayas of India, is an important water body and a major tourist spot. This study aims to identify factors or processes that determine the water quality of the lake. For this purpose, different data of different years were compared with the data of present study. In order to assess the state of the lake’s water quality, the samples were compared with the standard water quality values. Turbidity, electrical conductivity, total alkalinity, and heavy metal (lead, iron, and copper) concentration were found to be above the desirable limit of the prescribed national and international standards in all four seasons at both Mallital and Tallital. Reasons affecting the water quality were found to be natural (thermal stratification and lead-bearing rocks) and anthropogenic (domestic sewage, runoff, and illegal construction activities in the vicinity of lake). Various lake restoration alternatives/interventions have been suggested that can lead to an improvement in the lake’s water quality, such as afforestation and phytoremediation.