What can engineering do to prevent flooding? What's up Engineering Lovers, my name is Igor Felipe, and today we are going to talk a little about the floods and floods that we see at certain times of the year. If you are aware of the news, you saw with sadness what happened in the south of Bahia and north of Minas with the floods and recent cases of torrential rains in the metropolitan region of Belo Horizonte, and we realized how very destructive water can be.
Flood and flood prevention remains a major concern, especially as we have weather events that become increasingly severe and often reveal infrastructure problems. When rainfall accumulation exceeds what the drainage infrastructure or even what the natural terrain can drain, the water also accumulates and gives rise to a huge problem. The point is that when it becomes evident that the infrastructure at a location will not be sufficient to support an estimated water flow, one must improve flood management methods, design new infrastructure and seek new ways out of this problem.
And it's not just solving the problem looking at what has already happened, but looking to the future and estimating what new problems may happen. But talking about the problem without giving a solution ends up looking like news and not an engineering solution, so I'm going to show you some possibilities for better management of stormwater resources. The first of these is the use of 3D models to guide efforts.
Flood models can reveal which areas of countries, states or communities are most at risk of severe water damage. We often see these models used in what we call ZAS, which stands for Auto Rescue Zones. A great example of ZAS is in dams, where 3d models indicate where it is safe and where we are at risk in the event of a dam failure, thus creating an area that we call ZAS.
But these models can also be created to guide flooding zones in the event of rainfall. These models should help engineers build new infrastructure or upgrade existing features. And most importantly, these models must be constantly reviewed.
The disorderly growth of cities and regions can lead to problems that are not so visible, and worse, can only become visible when the worst happens. So, knowing the places with the highest risk of flooding through these models can prevent growth and development in these risk areas. The second point is the use of water banks.
There are several models and techniques to manage river and storm floods, and one of them is what we call water banks. Imagine that in a region there will be a propensity to flood and that this flow of water cannot be vented. At strategic points, water banks can be provided as if they were reservoirs to receive the water, fill the reservoir, and only release the water gradually, avoiding flooding in inhabited places.
This method uses these water banks to increase what we engineers call retention time. In addition, in some countries, they bet on encouraging the population to capture rainwater. This model can be considered as a water bank, as the water that would fall from the roofs of the houses, run through the streets and which could cause flooding, would be stored inside the houses themselves.
This would not only help with flood control, but it would also help the environment with the possibility of reusing this rainwater. In some countries, such as Japan, they have underground systems that receive this rainwater, and later use this water to wash city streets or be sent to treatment plants. The third point is to recognize the potential of green infrastructure When we think of rain, we automatically think of so-called gray infrastructure as a kind of temporary patch for surface water problems.
For example, when water floods a city, we tend to choose a solution targeting new underground galleries, larger drains and even additional pumping stations with more robust pumps. However, it is time to pay more attention to green infrastructure options such as rain gardens and tree trenches. Especially in more remote areas, building concrete drainage works is much more difficult, and it would be much better to use retaining walls and the green areas themselves to manage flooding.
That's a goal of Philadelphia's Green City Clean Waters program, launched in 2011. So far, it's added green infrastructure at 800 locations across the city. They collectively prevented nearly 3 billion gallons of dirty water from cities from entering neighboring rivers.
Already in the city in Hull, a port city in East Yorkshire in England, it is believed that green spaces are also the way forward. Previous efforts, including the construction of new flood walls and a water storage pond , have failed to resolve the region's ongoing flooding problems. As a result, some of the future plans feature green areas that retain and release water after the rains as if they were water banks, but these areas also help with the percolation of water through the soil itself.
A fourth point is to focus on local emergencies. Managing current and future surface water floods requires making people aware of areas of greatest flood risk, providing the information people need to evacuate quickly and safely. Drwing up evacuation plans and strategies can be vital to preserving human lives.
In this case, there must be a study of the region and implementation of visual and even audible signaling systems that warn entire communities about the situation of increased water flow. And yes, installing alarms is sometimes essential, and not just putting up signs warning that flooding occurs there. Just remember that there are always those who are close to a flooded street and think: will my car pass here?
So to avoid this kind of questioning, we have to implement measures that literally warn and block these areas during these moments. This is, of course, combined with an effective evacuation and training plan that allows residents of the region to move to safe places, thus preventing them from putting their lives at risk. This method would not solve the problem of material losses, but would focus on the preservation of lives.
And like I said, this is an emergency solution, and it shouldn't be a permanent solution. A fifth point could be greater use of permeable concrete Concrete and asphalt are widely used in structures and roads, but they have known shortcomings. A great example is the impermeabilization of the areas and the difficulty of giving flow to the waters.
The use of porous concrete or permeable concrete can be an effective way to prevent surface water flooding. This type of concrete allows up to 25 millimeters of rain per hour to flow through its pores and with this a drainage system can be installed down the entire length of the structures. These pores in concrete can be the diameter of a hair and in laboratory tests, they have shown that they can also serve as a particulate filter, which can restrict about 80 percent of the pollution and particulate matter found in storm water.
Some analysts say that this type of material is already found in some cities, but they are not spread out enough. And the sixth point is to adopt a broader point of view on funding and project resources. When we talk about investment in drainage infrastructure, projects can be quite expensive.
But the point is that it is better to invest in a working system even if it is more expensive now than paying to fix things after the floods and having to redo the drainage system and the destruction of the streets again. This should not be a trial and error model, as sometimes it is necessary to spend better on better solutions, rather than doing it cheaper and wasting infrastructure resources poorly. But achieving that change requires a new mindset.
If a system that has been made is not enough, sometimes rebuilding the same system after it has been destroyed by the rains is not the solution. It is necessary to discuss the need to change resource plans and design considerations in areas that suffer from constant flooding. The responsible bodies need to be more attentive to the risk of floods, and it is indisputable that there is a bad approach to these problems, and they are often treated simply.
I will give you an example. In my city, I'm tired of knowing which regions suffer from flooding every year in January. And practically every year, there is a famous avenue here that floods, and all the asphalt on the avenue has to be redone.
Heck, isn't it better to invest in better drainage infrastructure than having to spend millions every year just to remake the asphalt? And it's just me who realizes this, but government agents too, they just choose to do the easiest thing! Well, every year it's the same thing and with climate change and global warming, these rains are likely to become more and more intense.
We have the torrential rains at the beginning of the year, flooding and then the works to rebuild what was destroyed. Would it not be better to invest better in works, acting on the causes of flooding and not on the effects? These suggestions highlight how there is no single solution to contain flooding and waterlogging, but yes, we do have options.
However, taking the time to analyze current and future needs is hard work, but it is essential to understand the impacts that these infrastructures can bring to society as a whole. Sometimes spending more is not the best option, but spending better together with a mentality that goes beyond the term of office of some politicians. I'll leave two videos on the side that complement the theme, so be sure to watch.
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