Reservatório Dionísio de Araújo Machado is an artificial reservoir located in the municipality of Lagarto, in the Centro Sul region of Sergipe, Brazil. It was formed by damming the confluence of the rio Piauí and the rio Jacaré, with construction carried out by the state government between 1985 and 1987. The reservoir has a total storage capacity of 15,000,000 cubic meters, making it one of the largest water bodies in the Lagarto area.

The reservoir's primary purposes are human water supply and agricultural irrigation, with the facility accounting for approximately 80% of the city of Lagarto's water supply. Over time, the site has also developed into a recreational area, attracting visitors for swimming, fishing, and general water-based leisure. The Prefeitura de Lagarto has coordinated with the Polícia Militar and Corpo de Bombeiros to manage safety and organization at the reservoir's recreational zone, indicating an active effort to regulate use of the area.

Water quality is a relevant consideration for paddlers. Microbiological studies of the reservoir found thermotolerant coliform concentrations ranging from 17 to 49 NMP/100 mL during the rainy season and below 1.8 to 2 NMP/100 mL during the dry season. While these values fall within the CONAMA Resolution 357 classification for Class 1 freshwater, the water is unsuitable for direct human consumption without treatment. Paddlers should be aware of this distinction, particularly regarding incidental water contact.

The reservoir is situated within the bacia do rio Piauí, which has a surface water availability of 27.12 million cubic meters per year, though regional demand exceeds this figure. The broader region is subject to prolonged drought periods typical of the Northeast of Brazil, and the reservoir's water level drops significantly during extended dry spells. This is a practical consideration for trip planning, as low water levels can affect access and navigable area.

The surrounding area includes bars and recreational facilities that have developed along the shoreline over the years, and the site functions as a balneário — a bathing and leisure destination — for local residents and visitors alike. Water temperatures in the reservoir reach 31°C and 33°C, reflecting the warm climate of the Sergipe interior.