Blue-green infrastructure for climate change adaptation: Combining nature and semi-natural structures for water management an risk reduction in the Peruvian basins

By Sander Carpay, Sonja Bleeker, Pamela Quino Ramos, Constantino Aucca Chutas and Lukas Edbauer

What is blue-green infrastructure?

Blue-Green Infrastructure differs from the “grey” infrastructure or traditional engineering due to its natural elements, the network of measures that connect them, and the multiple ecosystem services that they provide. 90% of the world’s disasters are related to excess’ and shortages of water. These are worsened by climate change; effectuating changes in temperature, precipitation, storm frequency and intensity, as well as sea level rise. Adapting to the impacts of climate change and reducing water-related risk, requires a dynamic and adaptable infrastructure.

If we merge the dynamic and adaptable properties of natural areas (wetlands) with the semi-natural (linear parks with roads), that are interconnected (with drainage systems and green roof corridors), we end up with Blue-Green Infrastructure. This interconnected network allows the flow of persons, water and biodiversity. Additionally, the disaster risks related to climate change, such as floods, droughts and landslides, could be reduced. At the global level, there is increasing for well-managed Blue-Green Infrastructure is economical, scalable and sustainable. It could even contribute to the grey infrastructure. For example, preserving highland wetlands can contribute to the supply of water to a hydropower dam downstream.

[...]

Urban infrastructure: Floodplains

In the main densely populated cities, there are often established settlements in the marginal strip of rivers. These are in fact, floodplains. As such, infrastructure and people present in such areas are susceptible to flooding. Conventional engineering approaches or “grey” practice would be to channel the river to protect the banks. However, this leads to faster discharge of excess water, increasing the risk of lower basin flooding. On the other hand, the natural Blue-Green Infrastructure of floodplains can retard runoff due to their ability to temporarily store water (filling up and expanding the river); and lower the velocity of the river channel, thus controlling erosion. This means that, instead of limiting the river, you must give it the space to grow and shrink.

[...]