IMPACT OF GLACIER DISAPPEARANCE ON RUNOFF FROM A GLACIERIZED CATCHMENT IN THE ANDES

Abstract

We predicted the hydrological impact of glacier retreat in the glacierized catchment located in Bolivian Andes by applying a grid-based physically distributed runoff model. The capability of the model was improved by including snow and ice melt processes, in which temperature, solar radiation and humidity were taken into accounts based on our field observation. Runoff retarding by the freezing soil was also considered. Given hourly meteorological conditions and spatial distributions of land cover, precipitation and air temperature, the model result agreed well with observed flow rates. After the full glacier retreat, the flow rate is estimated to be significantly reduced in the dry season while the impact is less in the wet season. We found that glacier melts mostly occurred in the early stage of the wet season. In addition to glacier disappearance, the rise in air temperature increased the discharge during major precipitation events but reduced the amount of snow accumulated over the catchment.