Modelling urban stormwater and irrigation management with coupled blue-green infrastructure in the context of climate change

Urban planners must consider stormwater infrastructure to prevent floods, enhance resilience and promote sustainability, ultimately benefiting cities by minimizing damage and fostering sustainable growth. This is leading cities to consider the implementation of blue-green urban infrastructure (BGI) as an integrated approach to stormwater management. An urban irrigation model, blue-green infrastructure irrigation (B-GRIIN), has been developed that incorporates BGI and the possibility of reusing stormwater for irrigation to facilitate the design of zero-runoff urban blocks. Simulations based on rainfall time series, including an extremely dry year, have shown that it is possible to achieve a zero-water balance and provide sufficient water for irrigation by implementing coupled BGI. However, water availability in extremely dry years may limit the full irrigation of all green areas. The results have also shown that the evapotranspiration scaling factor kc has a large influence on the predicted irrigation volume and thus on the overall water balance. The B-GRIIN model makes it possible to couple the rainwater management functions of different BGIs, determine their water requirements and provide sufficient irrigation water. As a result, it can serve as a basis for holistic planning and operation of BGI in order to achieve a zero urban water balance.