From Design to Implementation: Development, Calibration, Implementation and Lessons Learned from a Large-Scale Dripper-Based Rainfall Simulator for Experimental SUDS Evaluation

Sustainable Urban Drainage Systems (SUDS) are highly effective tools to mitigate the adverse impacts of urbanization on the urban hydrological cycle. To rigorously evaluate their performance, it is essential to have robust monitoring systems capable of quantifying their behavior under controlled conditions. In this context, the present study describes the implementation of a rainfall simulator developed for the SUDS pilot research project located in Meco (Madrid, Spain). The design and construction of the simulator were well aligned with the project objectives, as was the methodology applied for its calibration and implementation. Results indicate strong performance in both simulated rainfall intensity and spatial uniformity. The selected setup, a plastic mesh with 1.9 mm openings positioned 0.70 m below the drippers, successfully reproduced rainfall intensities between 5 and 70 mm/h with deviations below 3 mm/h across the full simulator surface during the implementation phase. Uniformity values reached approximately 95% during calibration and 80% during implementation. Overall, the simulator is considered validated for future experimental campaigns.