Thematic mapping of water extraction from the Alter do Chão Aquifer in the urban area of Santarém, PA

Abstract

This study is justified by the growing urbanization pressure on the Alter do Chão Aquifer (AAC) in Santarém, Pará, making it imperative to understand its exploitation status for sustainable management. The methodology consisted of a multicriteria spatial analysis using the Analytical Hierarchy Process (AHP) to weight data on specific flow, static level, and aquifer type obtained from 212 wells registered in the Groundwater Information System (SIAGAS). The results indi-cated static level as the most important factor (64.3%) and revealed a sectorization of exploi-tation directly linked to urban density. The areas were classified into four conditions: "critical" in the urban center's unconfined aquifer (16.03% of the area), "of concern" in the adjacent semi-unconfined aquifer (23.77%), "favorable" in the semi-confined aquifer (37.78%), and "excellent" in the confined aquifer (22.42%), located in more remote neighborhoods. The conclusion is that water sustainability is not homogeneous. There is water stress in the urban core, which demands urgent public policies, such as well-drilling control and inspection, while the peripheral areas, in better condition, require planning to ensure long-term sustainable exploitation. The results of this research constitute an essential tool for urban planning, high-lighting the need for water management policies targeted at each sector to ensure the sus-tainability of the AAC.