CLIMATOLOGICAL WATER BALANCE OF THE COUNTY OF CACEQUI/RS FROM 1985 TO 2020: EFFECTS OF THE ENSO PHENOMENON AND CHANGE IN LAND COVERAGE

Abstract

The objective of this study is to analyze the impact of changes in land cover classes on the Climatological Water Balance (CWB) of the municipality of Cacequi/RS during the years 1985 to 2020, at intervals of 5 years, its correlation with a Principal Component Analysis (PCA) of the CWB, and its relationship with the ENSO phenomenon. The CWB and PCA results and slope, soil classification, and land cover parameters were correlated using the Pearson method and inserted into spreadsheets with a Southern Oscillation Index column. Given the results, the variability of the CWB can be explained mainly by changes in land cover, where agricultural areas fluctuate between two hydrological extremes (deficit and surplus). In contrast, areas of native vegetation promote regularization in the hydrological system, and the effects of ENSO act with the aggravation of extreme reactions within the CWB during deficit (La Niña) and surplus (El Niño) conditions. Thus, the importance of areas with native vegetation in regulating water availability is emphasized. Additionally, the aggravation of extreme events identified may have synergy with the effects of climate change, warranting further sequential studies to reduce uncertainty levels.