Nature-based Solutions (NbS) for increasing urban greening and reducing runoff flows in narrow streets

Abstract

When we explore Nature-based Solutions (NbS) and their implementation in small cities with narrow streets and sidewalks as a feature of their historical cores, we can discover several challenges in terms of sustainability and microclimate regulation. The small cities in the Global South differs significantly from that in the Northern Hemisphere, because their financial reality; it is critical for the community, public authorities, and academia to collaborate to find accessible and novel approaches. Fighting floods and enhancing the environment in these tiny cities can begin with the reintroduction of vegetated spaces and their integration with Blue and Green Infrastructures, thereby assisting grey infrastructures in urban landscape planning. This article is an exercise result of the insertion of NbS in Cachoeira do Sul (RS) - Brazil, city located in the Guarani aquifer zone. The use of NbS was intended to increase drainage area, reduce runoff flows, and provide others ecosystem services in an urban street with nearly no vegetation, or spaces for this. The efficacy of the concept was investigated through the LID-TTT program, allowing to suggest its application in others streets and avenues in the same city. We were also able to use it to model other scenarios in the studied section, seeking an increase in permeability, modifying street coverings and walkways. This surge could also occur by building eco-corridors to enhance connectedness among isolated remnant patches in the city (green areas in backyards, squares, and urban edges), resulting in an increase in biodiversity. This paper intends to propose tiny solutions to dealing with recent flooding caused by current extreme weather conditions.