Quantitative assessment of the effects of climate change on water resources in the Huancané River basin, Peruvian Andes

Abstract

The purpose of this article is to evaluate the effects of climate change on surface runoff, aquifer recharge, percolation and renewable water resources in the Huancané River basin, Puno – Peru, using the SWAT hydrological model and the standardized precipitation index (SPI). The RCP 4.5, RCP 8.5, SSP1-2.6 and SSP3-7.0 climate scenarios of CMIP5 and CMIP6 were applied for the projected period 2025–2100. The model was calibrated and validated with historical data from the period 1981–2016. The results showed that surface runoff will decrease significantly in the most extreme scenarios, reaching only 8.09 m³/s in SSP3-7.0, while in RCP 8.5 a maximum of 12.59 m³/s is projected. The recharge of the aquifer will be reduced from 559.22 Mm³ to 179.09 Mm³ and the volume of renewable water will decrease by 51.2%, from 750 Mm³ to 366 Mm³. In addition, the average annual temperature in the basin could reach 14°C by the end of the 21st century, increasing evapotranspiration and further reducing water availability. The SPI index projects an intensification of droughts during the period 2025–2050. These scenarios show a growing vulnerability of the water system, which represents a critical challenge for agriculture, supply and sustainability. The integration of the SWAT model with climate projections is a key tool for water planning and adaptation in vulnerable Andean regions.