Higher streamflow - the water flow in streams, rivers and other watercourses - is associated with snowfall, reports a paper published online in Nature Climate Change this week. Increased surface temperatures will cause less precipitation in the form of snow, resulting in reduced streamflow.

The impact of decreased snowfall has previously been assumed not to influence streamflow significantly. Wouter Berghuijs and colleagues investigated this by applying a water-balance framework, a ratio of mean evaporation to mean precipitation, to 420 catchment basins in the United States during the period 1948-2001. The authors report that when there is an increase in the fraction of precipitation falling as snow, there is a higher mean streamflow, although the level of response varies between catchments.

These results suggest that further study is needed to understand the impacts of a shift to less snowfall on water availability and to facilitate water resource planning.