Preventing flooding in cities must be a constant priority.
As urban areas continue to expand, the risks associated with flooding also increase.
These natural disasters not only cause economic losses, but also endanger the lives of residents and affect critical infrastructure.
For this reason, it is essential to adopt preventive measures that minimise these risks, ensuring the resilience of cities to extreme weather events.
Main Causes of Flooding in Cities
Urban growth has been a major factor in the exacerbation of flooding.
The expansion of cities often leads to an increase in surface water transport and a significant decrease in groundwater recharge.
Soil sealing is another serious problem, as it reduces the capacity of the land to absorb rainwater, which in turn increases surface runoff.
This phenomenon, coupled with poor urban planning, exacerbates flooding during heavy rains.
The natural hydrological cycle, which includes water evaporation, precipitation and subsequent infiltration into the ground, has been drastically altered in cities.
The modification of this cycle causes an increase in surface flow and a reduction in infiltration rates, which increases the likelihood of both floods and droughts.
Urban Renaturation as a Prevention Strategy
Urban renaturation is presented as an effective and sustainable solution for flood prevention. This approach involves the reintegration of natural elements into urban areas, such as parks, gardens and, especially, green roofs on buildings.
These interventions not only help to mitigate flood risk, but also improve the quality of life in cities.
Green infrastructure, such as green roofs, acts as a sustainable urban drainage system.
These solutions increase infiltration rates and reduce the volume of surface runoff, partly restoring the natural hydrological cycle.
In addition, they contribute to the creation of green spaces that can be used for leisure and recreation, thus improving the urban landscape.
Green Roofs: A Sustainable and Effective Solution
One of the most promising solutions for flood prevention in urban areas is the implementation of green roofs on buildings.
These roofs not only improve the aesthetics of buildings, but also play a crucial role in stormwater management.
According to a study by Cézar Di Paula da Silva Pinheiro and Adriano Marlisom Leão de Sousa from the Universidade Federal Rural da Amazonia, and Joyse Tatiane Souza dos Santos from the Universidade Federal do Pará, published in the scientific journal Interspaço, green roofs can be considered a sustainable urban stormwater drainage system.
These structures increase the areas of infiltration, percolation and temporary storage of rainwater, helping to reduce surface runoff.
In cities such as Gandía, the implementation of green roofs has shown promising results.
These covers can retain up to 75% of rainwater, gradually releasing it through evaporation and transpiration, while retaining pollutants in the soil.
In addition, this system contributes to thermal comfort and improves air quality, making cities more sustainable and resilient to extreme weather events.
Complementary Flood Management Techniques
Although green roofs are an effective solution, they must be complemented by other techniques for integrated flood management.
Sustainable Urban Drainage Systems (SUDS) are one such alternative. These systems are designed to mimic the natural processes of water infiltration and storage, reducing the impact of heavy rainfall.
Another important technique is the increase of permeable areas in cities, such as the implementation of permeable pavements and the creation of green areas.
These areas help to reduce the volume of runoff and improve the infiltration of water into the ground, which contributes to the recharge of aquifers.
In addition, the storage and reuse of rainwater is becoming increasingly common practice.
This technique not only helps to reduce the risk of flooding, but also provides an alternative source of water for various urban activities.
Flood Risk Management and Flood Prevention Plans
Flood prevention cannot rely solely on technical solutions; a comprehensive approach is needed, including coordinated planning and management at local and national level.
In Spain, the Ministry for Ecological Transition and the Demographic Challenge (MITECO) has developed Flood Risk Management Plans, which have as their main objective the reduction of flood risk through the identification of vulnerable areas and the implementation of preventive measures.
These plans are fundamental for the protection of communities against floods, as they integrate risk management into territorial and urban planning.
Collaboration between different levels of government is essential to ensure the effectiveness of these strategies, promoting the adoption of green infrastructure and other sustainable measures.
Conclusions and Recommendations for flood prevention
Flood prevention is a complex challenge that requires a combination of technical, natural and political solutions.
Urban renaturation, through the implementation of green roofs and other green infrastructure, is presented as an effective strategy to mitigate flood risks in cities. These solutions need to be integrated into urban and water management plans, ensuring a holistic and sustainable approach.
It is crucial that cities adopt public policies that promote the implementation of green infrastructure, not only as a flood mitigation measure, but also to:
- Reduce the volume of surface flow through delayed or increased infiltration.
- Increase infiltration rates of stormwater.
- Conserve stormwater for later use in other activities.
- Expanding the creation of recreational areas and enhancing the landscape aspects of cities.
With proper planning and a commitment to sustainability, we can build more resilient and safer cities for future generations.
