Matías Rodríguez Obón. Student Civil Engineering Degree at Universidad Politécnica de Madrid.

In a world where climate change is creating an environment that is constantly being altered and suffering abrupt changes, we need to implement innovative solutions to create resilient cities (ONU, 2018). This refers to cities capable of adapting to harsh and constant change, maintaining the population that resides within them protected. 

A way to achieve this is through sponge cities. Sponge cities are an innovative solution that looks towards increasing the absorption, storage and reusage of water imitating the processes seen in natural ecosystems. This reduces the runoff in cities that can provoke damages, floods and dangerous conditions towards circling people. 

It is achieved substituting the traditional structural elements by green alternatives (Sostenibilidad para todos, n.d.). This implies making improvements such as increasing the number of gardens, using permeable pavements and improving the draining of rivers. As a collective this makes water enter the ecosystem naturally filtered which protects it and facilitates its reusage. 

PREVENTION OF FLOODS

The drainage systems have proven not to be enough to face the high intensity, long duration precipitation that we see becoming increasingly frequent. Sponge cities increase the permeability of the terrain, reducing the runoff and increasing the water retention in the terrain.

REUSE AND REDUCTION OF WATER SCARCITY

An important aspect of sponge cities is the increase in water retention within the ecosystem. The water is filtered through the vegetation in green areas and through the pavements and is then retained in natural aquifers and underground water storage tanks (Argudo García, 2020). 

This increases the amount of water available to the population, allowing it to be used for urban services, reducing the demand of water that has been processed for sanitation. Additionally, it is reused naturally to maintain the ecosystems hydraulic cycles, recharging aquifers and river systems. The benefits generated by these phenomena include the improvement and preservation of natural green spaces and the vegetation within them and the regulation of urban temperatures. 

WATER FILTRATION

Nowadays precipitation collects contaminants from the atmosphere and the city surface before reaching the natural bodies of water. It has been seen that water from precipitation can have higher levels of contamination than normal residual water, showing a higher DBO, DQO and solids in suspension (Canal Isabel II, n.d.). 

The type of infrastructure that sponge cities promote filters the water reducing the contaminants that it may have along with the sediments and heavy metals. This ensures that water entering the ecosystem is cleaner and less damaging to the flora and fauna. 

CONCLUSION

Sponge cities present themselves as one of the best measures for the creation of resilient cities generating numerous benefits. They significantly mitigate a lot of the effects caused by global warming and the contamination that cities generate. It prevents flooding, allows the reuse and reduction of water scarcity, and increases the filtration of water. 

Additionally, it presents itself as an optimal solution for the Sustainable Urban Drainage Systems (SUDS) given that the techniques promoted by sponge cities are highly aligned with those promoted by the SUDS. Incorporating this into cities can achieve the benefits mentioned beforehand while supporting urban biodiversity and resilience. 

BIBLIOGRAPHY

Organización de las Naciones Unidas. (Octubre, 2018). Ciudades Resilientes. https://onu-habitat.org/index.php/ciudades-resilientes

Sostenibilidad para todos. (n.d.). Cómo Actúan las Ciudades Esponja para prevenir Sequías e Inundaciones. Acciona. https://www.sostenibilidad.com/agua/ciudad-esponja/#:~:text=Estas%20ciudades%20utilizan%20sistemas%20de,debe%20gestionarse%20como%20una%20esponja

Argudo García, Juan Jose. (Mayo, 2020). El Futuro de las Ciudades (IV): Ciudades Esponja. Cada gota de agua cuenta. Iagua. https://www.iagua.es/blogs/juan-jose-argudo-garcia/futuro-ciudades-iv-ciudades-esponja-cada-gota-agua-cuentaCanal Isabel II. (n.d.). ¿Está Contaminada el Agua de Lluvia?. https://www.canaldeisabelsegunda.es/-/esta-contaminada-el-agua-de-lluvia