Açude Coremas (officially known as Açude Engenheiro Estevam Marinho) is a massive reservoir located in the city of Coremas, within the Piancó microregion of Paraíba state in northeastern Brazil. Constructed by DNOCS between April 8, 1937 and May 8, 1942, the project was overseen by engineer Estevam Marinho (1896–1953), after whom it is formally named. At the time of its completion, it was considered the largest dam in Brazil — a distinction it held until 1960 when the Barragem de Orós was inaugurated. The reservoir is formed by the damming of the Rio Piancó, while the adjacent Açude Mãe d'Água was created by damming the Rio Aguiar. The two reservoirs sit so close together that they effectively form a single, continuous water surface connected by a 237-meter spillway channel, earning the local nickname "mar no sertão" — a sea in the sertão. Together, the Coremas-Mãe d'Água system holds a maximum storage capacity of 1.358 billion cubic meters and drains a watershed of 8,700.34 km², making it the largest water reserve in Paraíba state and the fifth largest in all of Brazil. The reservoir serves 112 municipalities across the Mesorregião do Sertão Paraibano, underscoring its immense regional importance. For anglers, this vast inland sea set against the dramatic semi-arid landscape of the northeastern sertão offers a truly unique and expansive fishing environment unlike anywhere else in the region.