Synthesis of the hydrogeological studies in the sedimentary basins Amazon and Solim es: the Aquifers Systems I á-Solim es and Alter do Ch o

Geological maps and stratigraphic charts of the Amazon and Solim es sedimentary basins were reviewed, emphasizing the formations Alter do Ch o, I á and Solim es, the largest reserves of fresh groundwater in these basins. The lack of information on these formations was minimized by sample probe and stratigraphic profiles of construction, lithological and geophysical water and oil wells, obtained in the Base Operacional Geólogo Pedro de Moura, Urucu region, about 650 km southwest of Manaus (AM). In the Amazon Basin, the Aquifer System Alter do Ch o is characterized by unconfined and confined aquifers, with transmissivity between 1.5 and 9.1 x 10-3 m2/s, indicated for public supply. In the Solim es Basin, this system is confined by Aquiclude Solim es, recovered by the I-Solim es Aquifers. The reserve is estimated as 33,000 km3. The Aquifer System I á-Solim es, in Urucu, is unconfined-confined, with two aquifers hydraulically connected: the superficial, with top and bottom at depths near 20 and 70 m, respectively; and the deeper, between 50 and 120 m. With an outcrop area of 948,600 km2 in the Solim es Basin, the reservation of this system was estimated as 7,200 km3, less expressive than the Aquifer System Alter do Ch o. The average hydrodynamic parameters were: T = 3 x 10-3 m2/s, S = 5 x 10-4 and K = 1 x 10-4 m/s, orders of magnitudes similar to those found in the aquifer Alter do Ch o. Assessing the interrelationships and potential of these two regional aquifers sought to contribute to the hydrogeological knowledge in the Amazon Basin region, where researches on groundwater are still incipient.