A Scalable and Computationally Efficient Approach for Green Infrastructure Layout Optimization

Abstract Submission: Green infrastructure (GI) strategies offer a compelling alternative to traditional stormwater drainage systems for mitigating urban flooding. In the current context of climate change and increasing land development, causing non-stationarity in hydrologic extremes, these distributed approaches—designed to locally retain and delay stormwater runoff—emerge as more resilient and less invasive solutions for urban environments. Their effective implementation entails the simulation of a range of scenarios, where the effects of alternative GI measures and layouts are tested under precipitation forcings. However, this is a cumbersome task because of the preliminary, site-specific model calibration efforts, and the large computational times needed for multiple simulations. There is a compelling need for more standardized, scalable, and computationally lighter methods for GI optimal implementation, that can be easily streamlined at different locations. Our “HydroDisconnect” methodological framework, based on evaluating the reductions in hydrologic connectivity effected by different GI implementation scenarios, provides a powerful alternative to address this demand. The proposed methodology, validated against physically based simulations, relies on established connectivity measures, accounting for how the stormwater surface runoff occurring in a watershed interacts with the distinct land-use/land-cover (LULC) patches. The adopted indices display sensitivity to the relative extents and spatial arrangements of the different LULC patches, both developed and natural, making them ideal metrics to compare the effectiveness of candidate GI scenarios. The methodology can optionally be implemented without considering information on the existing stormwater network, at the cost of potentially less accurate optimal solutions, offering great flexibility also in cases of data scarcity.

Learning Objectives/Expected Outcome (Optional) : Advancing the state-of-the-art in effective implementation of green stormwater infrastructure (GSI) strategies, by proposing alternative methods for GSI optimal layout implementation.