Methods to investigate the hydrology of the Himalayan springs: a review
Springs are the major source of freshwater in many small mountainous watersheds within the Himalayan region. In recent years, their flow rates have diminished, but the reasons for this are not self-evident. This paper reviews the methods that investigate the hydrology of springs, with a focus on the Himalayan region. The methods are classified as field-based empirical and desk-based analytical. Field-based empirical methods help to characterize geology, hydrology, climate and landuse patterns. Desk-based analytical methods guide quantification of fluxes and responses across watersheds, which are potential inputs to the development of hydrogeological maps, quantification of water balances, conceptualization of processes that control or influence the movement and storage of groundwater, and development of a mathematical model, which may guide further sustainable development of water resources. The review identified that there are a few detailed studies in the Indian Himalayas, but studies in Nepal are very limited. Due to the paucity of literature from the Himalayas, the review includes literature from other parts of the world, which may guide research on springs in the Himalayas. The paper recommends analysis of existing grey and published literature, and data first prior to embarking on costly field investigations.