Estimation of the Climate Change Impact on the Hydrological Balance in Basins of South-Central Chile

Rebeca Martínez-Retureta,Norberto J Abreu,José-Miguel Sánchez-Pérez,Iongel Duran-Llacer,Lien Rodríguez-López,Alejandra Stehr,Mauricio Aguayo,Sabine Sauvage

doi:10.3390/w13060794

Abstract

In this study, the SWAT (Soil Water Assessment Tool) hydrological model is implemented to determine the effect of climate change on various hydrological components in two basins located in the foothills of the Andes: the Quino and Muco river basins. The water cycle is analyzed by comparing the model results to climatic data observed in the past (1982–2016) to understand its trend behaviors. Then, the variations and geographical distribution of the components of the hydrological cycle were analyzed using the Representative Concentration Pathway (RCP)8.5 climate scenario to model two periods considering the immediate future (2020–2049) and intermediate future (2050–2079). In this way, in the study area, it is predicted that yearly average temperatures will increase up to 1.7 °C and that annual average precipitation will decrease up to 210 mm for the intermediate future. Obtained results show that the analyzed parameters presented the same trend behavior for both periods of time; however, a greater impact can be expected in the intermediate future. According to the spatial distribution, the impact worsens for all the parameters as the elevation increases in both basins. The model depicted that yearly average evapotranspiration would increase around 5.26% and 5.81% for Quino and Muco basins, respectively, due to the large increase in temperature. This may cause, when combined with the precipitation lessening, a decrease around 9.52% and 9.73% of percolation, 2.38% and 1.76% of surface flow, and 7.44% and 8.14% of groundwater for Quino and Muco basins, respectively, with a consequent decrease of the water yield in 5.25% and 4.98% in the aforementioned watersheds, respectively.

Highlights

This study focuses on understanding the impacts of climate change on the components of the hydrological cycle in basins of south-central Chile
The decreasing trend is consistent in both river basins, indicating an intensification future, the model suggests the slightest changes in the lower and intermediate zone of highest changes in percolation are expected to occur in the intermediate future with of the trend observed since the historical period analysis
It could be expected that, by incorporating the precipitation and temperature anomaly from a future climate scenario (RCP8.5), the remaining water cycle components become modified, since precipitation is the main component of change in the hydrological cycle and basically confers it mobility [51,52,53]

Summary

Introduction

The temperature increases and rainfall fluctuations predicted could have an effect on evaporation from the soil and plant transpiration, contributing to the emission of water vapor into the atmosphere. This increase in water vapor could change the frequency and distribution of rainfall, affecting surface runoff and groundwater recharge regimes in the future [5,6]. Such changes could increase the vulnerability of water systems, known as their susceptibility to damage or lack of adaptation capacity [4]. The understanding of present and projected global climatic conditions becomes relevant in the determination of vulnerabilities and the development of adaptation strategies to climate change

Methods

Results

Discussion

Conclusion