The hydrochemistry and water quality of glacierized catchments in Central Asia: A review of the current status and anticipated change

Abstract

Study region: Glacierized catchments in Central Asia Study focus: The literature on hydrochemistry and water quality was reviewed to identify gaps in knowledge required to understand and quantify the impacts of climate change and deglacierization. New hydrological insights for the region: The main knowledge gap was the characterization of hydrochemistry and water quality along the elevation continuum from glaciers to arid plains. The chemical composition of snow and glacier ice are understood relatively well but the pathways of pollutants stored in glacier ice and released with melt into the aquatic systems are not researched. There is a lack of publications on the release of organic carbon following deglacierization and element leaching from the exposed substrate, permafrost and rock glaciers. Snow and glacial melt dilutes pollutants along the river channels, reducing concentrations and mostly ensuring the compliance with water quality standards including downstream locations. Poor surface water quality is associated with irrigation, the practice of soil washing, and discharge of the untreated sewage. There is a notable lack of information about the links between snow and glacier melt, aquifer recharge and groundwater quality and this is a major gap in knowledge affecting environmental and health protection. Better understanding and quantification of factors and processes controlling hydrochemistry and water quality is needed to adapt to the impacts of the imminent deglacierization.

Keywords

• Glaciers
• Mountains
• Arid regionsWater quality
• Hydrochemistry
• Central Asia
• Endorheic basins