The Jacuí Delta (Portuguese: Delta do Jacuí) is a hydrographic complex of islands (archipelago), canals, swamps and ponds in Rio Grande do Sul, Brazil, formed by the meeting of the Jacuí, Caí, Sinos and Gravataí rivers, whose waters constitute Lake Guaíba.Politically, the delta is a state environmental protection area that overlaps with a state conservation unit, the Jacuí Delta State Park. The Jacuí Delta Environmental Protection Area (APAEDJ) is located in the municipalities of Porto Alegre, Canoas, Nova Santa Rita, Triunfo, Charqueadas and Eldorado do Sul and totals 22,826.39 ha, while the park totals 14,242 hectares.The Jacuí Delta State Park has the Jacuí Delta State Park Management Plan (PEDJ), published in 2014 and approved by SEMA Ordinance No. 20 of February 22, 2017.The Jacuí Delta includes areas of the Pampas and Atlantic Forest biomes and plays an important role in regulating the water regime of the Jacuí and Guaíba rivers. According to the PEDJ: "The wetlands inside the park are part of a larger set of humid areas that, especially in the central area of Rio Grande do Sul, form a strip of marshes and floodplains in a westerly direction, reaching up to the Ibicuí River, next to the Uruguay River, and in the east, northeast and southeast directions form the system of marshes and lagoons of the coastal plain".The eastern areas of the delta are urbanized. The urban centers of the municipalities of Triunfo, Eldorado do Sul and Charqueadas are located on the banks of the delta. Urban areas are also found in Porto Alegre, in the islands of Flores, Grande dos Marinheiros and Pintada. The Humaitá and Navegantes neighborhoods of the municipality of Porto Alegre were part of the deltaic system, but the implementation of the flood protection system in the 1970s (of which the Mauá Wall is part) eliminated their exposure to the deltaic water regime.