Abstract

Mining activities are usually placed in the upper basin regions, especially in developing countries, with economies that strongly rely on natural commodities. Although glaciers do not occupy a large area of these mountain ranges, they deliver vital water for downstream populations. This is especially relevant during drought periods, when winter precipitation is strongly diminished and ice melt becomes relevant. They are also a key resource for highland wetland ecosystems and paradoxically at the same time for the development of mega-mining projects. Regularly, for environmental impact assessments and relevant public consultations, it will be stated that water from glaciers does not constitute an important source within the basin system, even though this has not been accurately quantified. Different water sources, given by spatial, geological, and hydrological features, can be identified using a combination of ionic and isotopic information from water, thus allowing to establish their proportions downstream, where water from different origins is mixed, and also to track their evolution over seasons. This approach should be useful especially for basins with strong pressures for the exploitation and consumption of water in mountainous basins and also with special relevance for basins with little or no knowledge of their water system and reservoirs.