Snowfall Affects the Amount of Water Rivers Discharge, Study

The amount of precipitation falling as snow governs the amount of water that flows through rivers in snow-affected regions, indicating less snowfall means less water discharged by rivers, a new study reveals.

In a collaborative study, researchers at the University of Bristol and Delft University of Technology revealed for the first time how snow affects the amount of water in rivers.

 To investigate the effect of snow on the amount of water that rivers discharge, the researchers worked on the historical data retrieved from several hundred river basins spread across the United States.

Despite plenty of studies done, the mechanism behind how river flow is generated in snowy areas is not fully known. This is mostly due to lack of apt measurements. Studies conducted earlier mostly looked at the role of snowfall within-year distribution of streamflow i.e. the amount of water in the river during the specific period of the year and believed that there existed no crucial effect of snow on the average streamflow.

This current study for the first time focuses on the role of snow on the average amount of water available in rivers.

Based on data of 420 catchments in the U.S., the researchers realized that in order to have an average river discharge, snow fall is a crucial factor.

The amount of snow in the snow-affected catchment will drop drastically due to the rise in global warming. The drop will occur even if temperatures soar by just two degrees Celsius.  In the current study, the researchers suggest that the amount of water in a river will reduce due to the drop in snow.

The authors of the study said: "With more than one-sixth of the Earth's population depending on meltwater for their water supply, and ecosystems that can be sensitive to streamflow alterations, the socio-economic consequences of a reduction in streamflow can be substantial. Our finding is particularly relevant to regions where societally important functions, such ecosystem stability, hydropower, irrigation, and industrial or domestic water supply are derived from snowmelt."

Researchers suggest further studies in order to respond to the consequences of temperature-induced precipitation shift from snow to rain.

The study was published in Nature Climate Change.