Groundwater recharge potential and its interaction with soil physical quality in Brazil

Abstract

In the face of increasing global water scarcity and the complex process of climate change, groundwater emerges as a fundamental resource to ensure water quality and availability. Thus, the present study investigates the role of soil attributes in groundwater recharge potential by developing and evaluating Soil Quality Index (SQI) using data from the Hydrophysical Database for Brazilian Soils (HYBRAS). Initially, a Soil Quality Index for Groundwater Recharge Potential (SQIra) was developed based on the evaluation of eleven physical soil attributes, employing the Supervised Principal Component Analysis (SPCA) tool to select the main indicators: Saturated Hydraulic Conductivity (Kslab_log), Drainable Porosity (DP), and Silt content. The SQIra proved effective in highlighting differences in soil quality among land uses and soil classes. The index was validated with Basic Infiltration Rate (BIR) data and baseflow data, emphasizing its usefulness for sustainable watershed management. Furthermore, the pattern of the SQI created, along with other indices available in the literature for recharge potential, was evaluated for the influence of soil class, textural class, functional structure, land use, and biomes. The Amazon and Atlantic Forest biomes showed higher recharge potential, while the Pampa biome exhibited lower values. Native vegetation areas showed greater recharge potential. Although soil texture is a relevant factor in water conduction through the soil and, therefore, in groundwater recharge, the combination of soil texture and soil classification proved more satisfactory for mapping recharge potential in Brazil.