EVALUATION OF THE HYDROLOGICAL RESPONSE TO CLIMATE AND LAND USE CHANGE IN A WATERSHED

Abstract

Climate change and land-use change influence hydrological processes in a basin, thereby affecting water production. The Cañar River basin originates in the Andean moors and flows into the Pacific Ocean, covering areas of great importance for conservation and agriculture. The basin exhibits a high degree of climatic and ecosystem variability. Two scenarios were proposed and studied using a semi-distributed hydrological model: a) a future climate scenario based on the projection of historical precipitation and temperature trends observed from 1985 to 2010 at 9 stations distributed throughout the basin, and b) a future soil use scenario derived from a multi-temporal analysis of land use, explanatory variables, and transition models. The analysis revealed an increase in precipitation during the rainy season and a decrease in precipitation during the dry season, resulting in a slight reduction in annual precipitation. During the study period, an increase in temperatures is observed in the low and high zones, while in the middle zone, there is a slight reduction in temperatures. The most significant land use changes were observed in natural vegetation, which experienced a significant reduction in area. If the observed climatic trends persist, precipitation would be expected to be concentrated mainly in the rainy season, leading to increased water availability during that period and a significant decrease during the dry season.