how they clean the tunnels of the Maldonado stream so that the streets are not flooded

A few meters from the Río de la Plata, near the Fishermen’s Club, a large well serves as the entrance to one of the city’s most important infrastructure works: the relief tunnels of the Arroyo Maldonado. He is lowered into a basket hoisted by a large crane. In the background, dump trucks filled with garbage and sediment. And a group of workers entering one of the tunnels with a backhoe. Bugle accompanies them. The first impression inside one of these tunnels is a strong musty smell, which then mellows. The chin straps help.

The task they are leading was interrupted by the pandemic in 2020. So far, it has been decided to resume it despite the second wave, to avoid flooding due to overflows from the stream that passes under Avenue Juan B. Justo.

In order for water to flow without interference through these conduits and to flow into the Río de la Plata, they must be free of waste and sediment.

The Arroyo Maldonado rises in San Justo (La Matanza) and flows into the Río de la Plata. He was locked up in 1929, but with the growth of the city, this reliever was insufficient. And for decades, the stream was the martyrdom of thousands of families who lived near Avenida Juan B. Justo: when it rained a lot, overwhelmed.

The solution came with the construction of two tunnels, a short one, 4.5 kilometers and 6.9 meters in diameter, and a long one, 9.8 kilometers. Inaugurated in 2012, both run parallel to the stream and increase its drainage capacity.

Whenever a team from the Buenos Aires Ministry of Public Space and Urban Hygiene immerses themselves in this task, they find surprising things in the tunnels.

The typical appears, such as cans, bottles, bags and wrappers for cookies, snacks and candies, among other products. But they even found new generation cell phones, remote controls, lamps and small electrical appliances, such as radios. Among the most common are pieces of foam and plastic, a lot of plastic.

Before starting the cleaning, they close the doors at both ends of the tunnels, which they are emptied with very powerful pumps.

Once they are waterless, operators enter and walk every inch of the ducts, as cleaning is manual.

With backhoes, operators they collect garbage and sediment found at the base. This sediment is mainly composed of mud and remains of structures, for this reason we see stones and rubble.

Waste are placed in dump trucks like those used on construction sites. Finally, these dump trucks are pulled to the surface.

Right now they are cleaning the short lifter, who was born to Niceto Vega and Juan B. Justo. The task requires between 12 and 15 working days. The functionality, the cleaning of which would then be carried out, begins in Galicia and Juan B. Justo. The two flow into the Río de la Plata, between the Fishermen’s Club and Punta Carrasco.

According to the calculations of the Ministry of Public Space and Urban Hygiene, they will extract around 500 m3 of sediment, which equates to about 100 full dump trucks.

It is calculated that 50% of the collected materials contain recyclable materials (bags, foam, PET, etc.). The cleanable items are sent to the “El Ceibo” cooperative for classification and reuse.

“The recovered material is already committed to be delivered to our cooperative. Sewers and sewers that we receive around 600 kilos of PET every month, ”explains Cristina Lescano, while observing the tunnel cleaning process.

“We do these cleaning tasks to improve the flow of water to the river. But it’s a job that starts on the surface, with cleaning nearly 30,000 sewers. Every paper, packaging, bag and glass that ends up in the street ends up in these tunnels. This is why it is important to remember that the river begins in the public space, ”said Clara Muzzio, the city’s Minister of Public Space.

But in order for them to fulfill their function, they must remain free. “Respecting the periodic cleaning of the Maldonado allows us to avoid the accumulation of water and waste in the tunnels so that the city is not flooded”, explains the chief of staff of the government of Buenos Aires, Felipe Miguel.

The history of the Maldonado stream

The Maldonado stream has an extension of 21.30 kilometers. Born in San Justo (La Matanza), near the corner of Mármol and Coronel Lynch.

In the city, the stream passes under Avenida Juan B. Justo and crosses 10 neighborhoods: Versalles, Liniers, Villa Luro, Vélez Sarsfield, Floresta, Villa Santa Rita, Villa Miter, Caballito, Villa Crespo and Palermo.

At other times, a good part of its trajectory passed through areas considered the outskirts of town. This is because in the late 1800s, the old department was the only urban area in Buenos Aires.

But the city began to grow and the stream has become a dumping ground, dangerous and polluting for the families who live there.

With the need to solve a health problem, in the 1920s, a debate began to determine what would become of this current. The possibility of transforming it into a navigable canal or of channeling it, but without a roof, in the open air has been studied. Finally progress has been made with the idea of ​​tubing it and work began in 1929.

There are two other major rivers that run through much of the city; they are the Vega and the Medrano. Like the Maldonado, its waters flow towards the Río de la Plata.

The city’s rainwater system has an underground route of 840 kilometers of tunnels. Every sump, culvert and cover seen in the streets rejects rainwater into these tunnels.

NS