Green and blue infrastructure: a solution with multiple benefits

by David Lammers, MSc Environmental Studies and Sustainability Studies, Lund University

Water systems have a crucial function in many cities. Rivers and coastlines act as veins of life as they provide cities with a plethora of ecosystem services – water supply, income generation, relaxation and many more. At the same time, however, they can be the source of major threats: rivers can serve as breeding points for mosquitos and thus exacerbate the spread of malaria; both rivers and adjacent oceans can be the origin of major flood events.

Flood events pose a particular threat to cities below or marginally above sea level. In mitigating these, cities usually have the choice between two major pathways: a “grey infrastructure“ approach, building – for example – extensive drainage systems and dams, or a “green and blue infrastructure“ approach, which relies on natural elements to retain the water, like lowered parks that can serve as retention basins.

The session “River-revitalization and better use of green/blue infrastructure for urban resilience” revealed many promising examples for the latter approach. Projects in both cities in developed countries (Almada, Portugal) as well as developing countries (Beira, Mozambique; Dar es Salaam, Tanzania; Addis Abeba, Ethiopia and Lilongwe,Malawi) especially showed that an approach of this kind can serve multiple purposes at the same time. Next to water retention, the extension of green areas can help with local food production (e.g. 300 tons of fresh vegetables per year in Almada), create areas for local economic activities (e.g. local farmer markets in Beira) and serve as carbon sinks. River revitalization can further prevent mosquito breeding as their eggs get swept away (as experienced in Beira).

In carrying out these projects, all panelists emphasized the importance of running them in a participatory manner, where citizens are the main actors in both identifying locations for implementation. They can, for instance, identify spots most threatened by flooding within the project area and select measures most appropriate to them. While one might have the impression that participatory approaches are the standard these days, Kobie Brand, Regional Director of ICLEI Africa, expressed that participatory tools are not commonly employed.

A further commonality between panelists were the positive experiences with supporting technology. Robbert Snep from Alterra Wageningen reported about the benefits of the Adaptation Support Tool, while Kobie Brand and Ellika Hermansson Török (SwedBio at Stockholm Resilience Center) commended the App THRIVE that offers 60 nature-based adaptation solutions.

Financing multi-purpose solutions, on the other hand, still appears to be a challenge. According to session participants, donors often still apply traditional funding criteria where projects of this kind might have trouble fitting in. However, with the advance of green/blue infrastructure and multi-purpose approaches, it seems fair to be optimistic that this will change in the near future.