Department Urban Water Management


Project description:

Blue-green infrastructures (BGI) increase the peaking time and reduce the peak intensity and runoff volume of surface runoffs for most storm events, thereby reducing the risk of flooding and sewer overflowing. BGI have been increasingly adopted for stormwater management in cities worldwide due to these hydrological benefits.

However, like any other urban water infrastructure, BGI require regular upkeep (sweeping, de-clogging, and replacing composite layers) to preserve their hydrological performance. This aspect is often overlooked and understudied.

We hypothesise that an unmaintained BGI will have reduced hydrological benefits and therefore this needs to be considered when planning and designing BGI for cities and modelling their long-term performance. While infrastructure maintenance is a big challenge all over the world, it is especially relevant in low-income regions, where urban (water) infrastructure management is hindered by practices such as the open dumping of solid wastes and irregular sweeping of streets that, in turn, clog the drainage system.

Low-income regions are also less equipped to deal with the consequences of floods and sewer overflows due to their socio-economic constraints.

As such, if BGI are to be implemented for stormwater management purposes, their maintenance should be prioritised to ensure optimal hydrological performance, thereby preventing the flood and overflow risks in the first place.


Figure 1 provides an overview of this project in which we will both run experiments and analyse secondary data to quantify the hydrological performance of BGI with different levels of maintenance. We will then use the insights in a long-term modelling exercise where the model parameters will be changed to simulate this dynamic performance for different BGI implementations, according to different maintenance scenarios.

Project team

Prabhat Joshi Tel. +41 58 765 5114 Send Mail
Dr. Joao Paulo Leitao Senior scientist (Group Leader) Tel. +41 58 765 6714 Send Mail