Dinâmica hidrogeomorfológica e vulnerabilidade hídrica em diferentes sistemas hidrogeológicos na Bacia do Rio Cabaçal-MT

Abstract

The dynamics of the hydrological cycle and water availability are conditioned by the complex interaction between environmental components and anthropic activities. In this sense, this dissertation's main objective was to evaluate the dynamics of surface and groundwater in different litho-hydrogeological systems through hydrogeomorphological characterization. The research sought to answer which environmental factors and processes control the hydrological cycle and how the physical properties of each component, associated with anthropogenic factors, determine the levels of water vulnerability and water availability in the landscape. The central hypothesis maintains that geological units, by conditioning morphogenesis and pedogenesis, are the determining component of the cyclical dynamics of water, and that indicators such as the Curve Number (CN), Available Water Capacity (AWC), and Total Soil Moisture Storage Capacity (STC), and water balance, associated with processing techniques, have predictive potential for patterns of water availability. To test the hypothesis, the methodology integrated the analysis of primary and secondary data, with office and field work, between 2023 and 2024. Three sub-basins with distinct hydrogeological characteristics in the headwaters of the Cabaçal river basin (MT) were analyzed: Piraputanga (granular-fissured), Cachoeirinha (fissured), and Corgão (mixed). The procedures included geological, geomorphological, pedological, and climatic characterization, monitoring of streamflow and the water table, and analysis of land use and land cover. The Analytical Hierarchy Process (AHP) method and Geographic Information System (GIS) tools were used to create the hydro geomorphological vulnerability map. The results revealed distinct patterns of hydrological response. The Piraputanga sub-basin demonstrated low water vulnerability, with high infiltration and storage capacity, attributed to the predominance of porous rocks (Utiariti Formation) and deep soils (Quartzarenic Neosols), resulting in greater water resilience. The xiii Cachoeirinha sub-basin showed moderate vulnerability, with infiltration limitations due to the dominance of crystalline rocks and intensive land use for cattle ranching, which aggravates sensitivity to dry periods. The Corgão sub-basin exhibited the most critical scenario, with high vulnerability resulting from the combination of a low-porosity substrate, shallow soils, and intense anthropic intervention, such as a high density of dams, resulting in an intermittent flow regime and severe water fragility. The research concludes that the interactions between geological and pedological components are determining factors of the hydrological cycle and that vulnerability mapping, validated by field data, constitutes an effective tool for the diagnosis and management of water resources in river basins.