Proprietary software capable of performing 1D/2D hydraulic modeling often presents a significant financial barrier for individuals, researchers, and public institutions, limiting accessibility and hindering hydrological studies. To overcome this challenge, we have developed Digital RAIN (DRAIN), an open-source QGIS plugin designed to facilitate 1D/2D hydraulic modeling in urban environments.

DRAIN leverages the combined strengths of EPA SWMM and Iber, two widely used hydraulic modeling tools, to simulate rainfall events and their impact on drainage systems. The tool provides detailed simulation results, including calculated hydrodynamic parameters for each element of the hydraulic infrastructure (processed by SWMM) and high-resolution raster outputs that depict accumulated rainfall and surface flow over time (generated by Iber).

At the core of DRAIN, a GeoPackage-based data model ensures seamless integration between Iber and SWMM, incorporating triggers and constraints to maintain data consistency and accuracy. The plugin also features an intuitive graphical interface with interactive GIS tools, allowing users to efficiently manage spatial data, define modeling parameters, and execute simulations directly within the QGIS environment.

By offering a free, open-source alternative to proprietary hydraulic modeling software, DRAIN promotes accessibility, reproducibility, and innovation in urban hydrology studies. This tool has the potential to support decision-making processes related to flood risk management, stormwater infrastructure design, and climate resilience planning in urban areas.