Modelling Future Snow Cover and Runoff with Climate-Adjusted Parameters

The effect of a warmer climate on snow cover and runoff was evaluated in the Rio Grande Basin near del Norte (3416 km2, 2436-4229 m a.s.l.) using the reference hydrological year 2001 and an above average snow year, 1987, for comparison. The parameters of the SRM model were adjusted to the new climate for model runs. The depletion curves of the snow coverage for a temperature increase T+4°C show that the seasonal snow cover in 2001 has been melted away before 1 April in the lower half of the basin. In the snow-rich year (1987), the depletion of the snow coverage was also accelerated. Consequently, the runoff in the winter half year (October-March) was tripled in 2001 and doubled in 1987. The runoff in the summer half year was reduced correspondingly. Runoff peaks in 1987 were shifted to earlier dates. These predictions of the future snow cover and runoff in mountain basins are important for hydroelectricity production, flood control, and agriculture. (KEYWORDS: Snowmelt Runoff Model, climate change, Rio Grande, streamflow prediction)