Açude Acaraú-Mirim is a historic reservoir located in the municipality of Massapê, in the state of Ceará, Brazil, nestled within the Brazilian semiarid region. Construction of the reservoir began in 1900 and was completed in 1907, funded by the Federal Commission of Dams and Irrigation, making it one of the older water infrastructure projects in the region. The reservoir serves as the primary surface water supply for Massapê and has demonstrated a strong historical record of water intake and overflow, maintaining adequate storage volumes even during drier periods. The surrounding landscape is predominantly rural, with the Riacho do Canto being one of the main tributaries feeding the reservoir, itself formed by several smaller streams including the Riacho Raiz and the Riacho da Onça, with headwaters originating in the residual massif of Meruoca. The reservoir sits in a warm, semiarid climate where temperatures regularly range from the low 20s°C in cooler months to above 30°C during the hottest periods, creating a year-round warm-water fishery typical of northeastern Brazil.