After a heavy rain caused floodingcollapses and left people stranded in Belo Horizonte on Tuesday (January 23), experts argue that the city needs to be rethought in the face of the increasingly common occurrence of this type of storm. On Wednesday morning (January 24), the mayor of the capital, Fuad Noman (PSD), classified the storm as a “new normal” and considered that the volume of water was a phenomenon rooted in climate change.
PhD in engineering and working in the areas of engineering expertise and asset assessments, Clémenceau Chiabi emphasizes that if the intensity and frequency of rainfall is no longer the same, then it is time to think actions for this “new normal”. As he explains, engineering projects are designed for a certain number of years, according to the historical average of storms. Thus, projects of more than 50 years may be entirely at odds with current days.
“From a practical point of view, we’ve seen heavier rains in a shorter period of time. Just saying that the rain will happen is a bit simplistic,” he says.
The solution, according to the professional, involves in-depth studies of what can be done in each location. More dams to control the volume of water are one of the solutions, as well as raising roads, if possible, given the constructions around. Additionally, expanding green areas is also a solution, since the removal of them over time causes the water, which should ‘stop’ in these places, to flow down the streets.
“The city is not static. It grows, becomes populated, neighborhoods occupy. Occupations have consequences for the drainage network. When new neighborhoods are approved, more streets are paved, the effect of this urbanization is felt, and it is necessary to think about drainage routes,” he says.
Furthermore, population education is very important, according to the engineer. The amount of garbage that accumulates over time in storm drains and sewers acts as a kind of ‘cap’, preventing water from entering and causing flooding, as he explains.
“There needs to be awareness, thinking about this starting in schools and showing how harmful it is,” he says.
Dams
The presence of more dams is also advocated by the urban planner and professor at the Federal University of Minas Gerais (UFMG), Roberto Andrés. However, he states that they must be made without creating degraded spaces in the city, “as happens in some of these large pools”.
“It is necessary to make dams in the mold of the Santa Lucia dam, with landscaping, with urban quality. And it is possible to distribute these small containments, draining gardens, throughout the territory. You do not need to focus on one dam. How does a draining garden or other water absorption structure work? You conduct the water from part of the basin of a few streets to a structure, a garden, a part that has a topography that causes the water to enter there and penetrate the ground in that place,” he explains.
In addition, it is also possible to work on each property in the city, as the professor explains. “It is possible, for example, to do a large subsidy work in the IPTU so that each lot can insert its water collection system, which can be a cistern, a draining garden, a green roof. There are several systems that can store rainwater instead of each lot throwing water into the street. This is something that the city hall can do and can also monitor the mandatory soil permeability rate. Municipal laws require that each lot have at least 20% of permeable area. This permeable area, a lawn or flooring, causes the rainwater, part of it, to enter the soil,” he details.
Despite the possible solutions pointed out, experts emphasize that none of them is easy or quick, and that it is not possible to do something “overnight”.