Avaliação da sustentabilidade do uso da água do Aquífero Alter do Chão na zona urbana de Manaus

Abstract

Manaus, the capital of the Amazonas State, is located at the confluence of the Negro and Solimões rivers, where the Amazonas River forms. The city is the most populous in the state of Amazonas, with 2,020,301 inhabitants, and a population growth of 33% in each decade, on average. In it, was established in the 1950s, the Free Trade Zone of Manaus, which made possible the structuring of an expressive industrial pole. Currently, this polo has 488 industries, according to the Superintendência da Zona Franca de Manaus (SUFRAMA), mostly technology and motorcycle manufacturers, responsible for the generation of approximately 110 thousand direct jobs, collaborating with 1.4% of National GDP. Under all this activity is the Alter do Chão Aquifer (ACA), inserted in the Alter do Chão Formation, consisting of intercalations of sandy, silty, clayey and conglomeratic layers. The ACA has a varied thickness and permeability, reaching, in Manaus, a maximum thickness of 190 m. The city of Manaus has almost 3,000 wells registered in the Sistema de Informação de Águas Subterrâneas (SIAGAS), and are estimated more than six thousand clandestine wells. Several factors led to the intensive use of groundwater: the intense use by the industry of the Manaus Industrial Pole; water distribution network that does not fully cover the city; faults and interruptions in supply; the former water poor quality distributed by the public system (problem currently healed); an intense increase of the population of the city allied to the deficit network. These factors lead to the discussion about the sustainability of the current use of ACA in Manaus. The main objective of this work was to understand the current panorama and dynamics of the uses and groundwater flow, evaluated possible changes caused by anthropic factors, such as the increase and decrease in the number of wells, and by natural factors such as the occurrence of climatic extremes and the decrease trend in annual rainfall.