Análise da vulnerabilidade hídrica subterrânea no município de Itacoatiara/AM

Abstract

Groundwater represents the main source of water supply in several municipalities of Amazonas State, whose dependence on this resource may be vulnerable due to limitations in basic sanitation and the presence of potentially polluting activities. This study analyzed groundwater vulnerability by integrating two well-established aquifer vulnerability assessment methods, GOD and POSH, combined with geoprocessing tools and a spatio-temporal analysis of land use and land cover for the years 1990, 2008, and 2023. The research was based on secondary data from SIAGAS, IBGE, MapBiomas, and field observations, enabling the identification of critical areas. The results showed that shallow dug wells (poços amazonas) presented the highest susceptibility to contamination, with vulnerability indices ranging from moderate to extreme (0.24 to 0.72) using the GOD method, while the POSH method indicated higher risk associated with urban areas and the municipal center, mainly due to the precariousness of sanitation and the presence of point sources such as dumps, gas stations, fish farming, cemeteries, and industries. The multitemporal analysis revealed a reduction in forest cover and an expansion of pasture areas from 272,710 hectares (1990) to 562,810 hectares (2023), an increase of 106.38%, while urban areas grew from 12,522 hectares (1990) to 19,082 hectares (2023), a 53.39% increase, compromising aquifer recharge and intensifying pressure on groundwater resources. The overlap between highly permeable soils and pollution sources reinforces the condition of hydraulic overload in the municipality. It is concluded that unplanned land use expansion and weak environmental management increase groundwater vulnerability, highlighting the need for integrated public policies on sanitation, monitoring, and territorial planning to ensure the sustainability of groundwater resources in the municipality