Further north, connecting Rio de Janeiro to the Baixada Fluminense, the watersheds of the Pavuna, Acari, Meriti, and Sarapuí rivers open up over a vast area, like true lines of force crossing the municipality of Rio de Janeiro, tracing an intimate relationship between the terrain, land use, and dense urbanization over time.
Image description: This is an aerial photograph of a densely populated urban area. On the left, there is a large parking lot full of white vehicles. In the center, there is a green area with trees and a soccer field. On the right, there are residential and commercial buildings close to a road. In the background, there is a range of hills covered with vegetation. The sky is partly cloudy.Rio Acari, channeled through the urban landscape, shortly before flowing into the Rio Pavuna in the background.
These rivers flow down from the northern slope of the Maciço da Pedra Branca and the southern slope of the Maciço do Gericinó-Mendanha. On the still-deforested, North-facing slopes of the Maciço da Pedra Branca, the waters of the Piraquara River rise, joining the waters of the Realengo lowlands, which form the Merinho River, to form the important Rio Acari, a tributary of the main collector, the Pavuna River, one of the largest in the North Zone. Several river toponymies have been lost amid intense urbanization and channeling, sadly and commonly referred to as valões. People no longer even remember the name of the River that was once there.
Image description: This is an aerial photograph of an urban area with a large factory on the left and another on the right. The factory on the left has a light gray roof and a blue structure. On the right, there is a factory with a blue and white roof. Between them, there is a green area with trees and a river cutting across the image. In the background, we see a densely populated city with many colorful buildings. There are also green areas and areas of construction under development. The sky is partly cloudy, and in the background, we see mountains.CEASA Canal meeting Rio Acari amid the urban density of the suburbs of Zona Norte
The lack of sanitation infrastructure contributed fatally to these erasures, remembered only on flood days. Rio Quitungo, Rio Lucas, Rio das Pedras, Rio Ninguém, Rio das Ostras, Rio dos Afonsos, Rio Caranguejo, Rio Marangá — all subsumed beneath concrete walls or culverts under the hot asphalt of the suburban lowlands. Crossing the neighborhoods of Realengo, Deodoro, Vila Militar, Madureira, Irajá, Cordovil, Anchieta, and Pavuna, the waters merge to form the Arapogi, Acari, Meriti, and Pavuna Rivers. The latter traces the municipality's northern boundary and its border with São João de Meriti. Today, with their murky, sediment-laden waters, these channels recall what was wrought by the neglect of public authorities in neighborhoods where the old quality of life and the richness of neighborly relations and collaboration of the Rio suburbs were once their socio-spatial hallmark.
Image description: This is an aerial photograph of an urban and natural area. On the left side, we see a river flowing parallel to the main road. The road is wide and has several traffic lanes, with cars circulating. Along the river, there are dense green areas, forming a green strip that extends to the horizon. On the right, there is a densely populated city with buildings of various sizes and colors. In the background, we see a line of distant mountains under a blue sky with a few clouds.Rio Pavuna with some remaining meanders and the channelized Rio São João de Meriti forming the municipal boundary
The Sarapuí river, in turn, receives contributions from the Maciço de Gericinó and has its most distant headwaters on the slopes of the Maciço da Pedra Branca, starting from the Serra do Viegas, draining the neighborhoods of Senador Camará, Bangu, and part of Realengo. It is an important river of the Baixada Fluminense, flowing out of the municipality of Rio toward the municipalities of Nilópolis, São João de Meriti, and Duque de Caxias. The largest extent of its basin spreads across lower-lying topographies, draining former marsh areas and floodable environments along the coast of Guanabara Bay. Such ecosystems, which once reached extensive mangroves and sandy restingas, were destroyed and subjected to extreme paving over. Of course, the river's responses still occupy the floodable areas during the strongest events of the rainfall regime, but now flooding houses, streets, and other occupied spaces. This is an unnecessary situation in a city that was supposedly, as mentioned, planned to house the working class encouraged to live near factories and workplaces. Squeezed between densely urbanized areas, the Campo do Gericinó, under the administration of the Brazilian Army, still preserves remnants of that landscape -- much altered, of course, but maintaining conditions similar to past landscapes. Lowland forests and marsh systems are used there for the training of enlisted personnel and officers. These rivers are, in fact, witnesses to how geography and history intertwine, shaping the urban space with their flows, landslides, and floods, reminding us of how much water still disturbs the boundaries with the artificialized space, between the old and the current Rio de Janeiro.
