Green and blue are two colors that may not seem to go together, but when you look around, they are the dominant colors of nature. Green represents our forests, parks, and gardens. Blue is the product of water reflecting in our retinas.

So, it’s possible to imagine that green and blue infrastructure concerns how we can live with greater respect for the environment and with less dependence on concrete and asphalt.

The so-called “Green and Blue Infrastructure” aims to solve the functional problems of a city in a more economical way, privileging environmental preservation and benefiting people.

Within this planning approach, built infrastructure works together with natural or semi-natural spaces, such as lakes, ponds, orchards, lawns, and watercourses. Together, they are important for situations like natural water retention from rain or tides, as well as drainage, mobility, sustainable food production, and, of course, recreation. The landscape thus becomes a new way of designing infrastructure, based on natural processes.

The traditional model of urban drainage consists of interconnected networks of underground channels. In large Brazilian cities, the high-cost investments in such sanitation works cannot handle all the necessary drainage. With heavy rains, flooding and runoff are constant.

The “green and blue” concept could complement the traditional and expensive strategy by creating landscaped green areas that also function as a natural drainage mechanism. It is a mixed system where common drainage is aided by nature.

This concept applies to other systems as well. Instead of relying on a model that only works with one mode of transportation – like roads, designed for motor vehicles – it’s possible to conceive a multifunctional infrastructure alongside the landscape, where parks accommodate other mobility flows, such as cycling.

Infrastructure, as seen in the case of the Netherlands, also provides conditions for using space for much more than just transportation. It can solve other urban planning problems. Along with cycling paths, a park can also improve urban drainage. Instead of just increasing underground piping, an expensive solution that closes the street, there are gardens and sports courts designed to eventually fill with water, preventing floods.

A Dutch project that advances significantly in this direction is the Water Squares project, which focuses on drainage but also offers leisure, sports, and health spaces for the population.

In Denmark, by federal government policy, cities had to make climate change adaptation plans. With major cities subject to rising sea levels and periods of heavy rainfall, they need to minimize losses from extreme water events. Studies commissioned showed that adopting green and blue infrastructure makes the necessary flood mitigation works much more economical. The cost is a quarter of the cost for all projects compared to the traditional model of urban drainage, according to researchers at the University of Copenhagen. There are other interesting situations involving contracts from companies hired for the service, such as the limit of ten centimeters in street flooding height, which cannot be exceeded in the capital Copenhagen. Thus, the public utility company opted for the most economical solution, involving green and blue concepts along with the traditional solution.

It’s curious how such a creative, cheap, and useful way of thinking still finds little echo in Brazil. The multifunctionality of green and blue infrastructure should be considered here. Adding environmental values, such as natural and landscaped areas, and social values, such as parks and courts, to a functional structure is also a more economical solution for Brazilian cities. This is solving problems sustainably through urban design.