GeoSWMM for ArcGIS Pro, version 5.3, was officially released on October 13, 2025. This version introduces new features, major workflow enhancements, and key bug fixes aimed at improving the performance, usability, and hydrologic-hydraulic modeling capabilities within the ArcGIS Pro environment. Whether you're performing stormwater management, urban drainage analysis, or flood risk analysis, GeoSWMM 5.3 provides a more streamlined, integrated, and reliable modeling experience for engineers and GIS professionals alike.

New Features

Seamless Integration of Preprocessing Tools

GeoSWMM 5.3 now embeds all preprocessing tools directly within the modeling environment, eliminating the need for multiple transitions across different data layers and reducing potential data mismatches. For example, when using the Percent Imperviousness Calculator, the tool now automatically computes imperviousness values for each subcatchment and updates them directly in the model. Previously, users had to manually select the subcatchment layer as an input; now, it is seamlessly integrated with the GeoSWMM project. This integration ensures consistency across all modeling stages, from raw data preparation to simulation execution, and replaces previously manual steps with a unified, transparent workflow.

Updated UI/UX of Preprocessing Tools

This release features an updated UI/UX for all preprocessing tools, aligned with ArcGIS Pro standards. Users can dock or float tool panes, rearrange windows, and work in a more flexible layout. A refreshed icon set and simplified navigation make tools easier to use, while contextual tooltips and inline help links provide quick guidance. Overall, the new design offers a modern, intuitive, and efficient user experience for both new and experienced users.

Watershed Delineation Tool

The Watershed Delineation Tool introduces a structured, step-by-step workflow that guides users from data input to model integration. Users can specify input datasets such as project outfalls, Digital Elevation Models (DEMs), stream networks, minimum headwatershed area, and outlets—either by browsing file paths or by drawing interactively within the ArcGIS Pro map. Intermediate layers generated during processing are automatically organized in a dedicated geodatabase, ensuring clean data management and easy updates. The Import to Model option enables seamless integration of all generated features into the GeoSWMM model with a single click. This redesigned workflow enhances both efficiency and user experience, streamlining the entire process of watershed and stream delineation within the GeoSWMM environment.

Land Use/Land Cover Properties Tool

The Land Use/Land Cover (LULC) Properties Tool has been updated with a new reclassification process and enhanced data handling capabilities to improve modeling accuracy. Users can now easily import reclassification templates and take advantage of flexible, intuitive configuration options. The tool also introduces dedicated windows for assigning roughness (N-values) and depression storage (D-values), with the ability to import templates for quick and consistent parameter setup. Additionally, users can import custom reference tables containing predefined parameters, allowing roughness and depression storage values to be assigned or adjusted more efficiently. These enhancements simplify scenario management, reduce manual errors, and ensure full compliance with SWMM parameterization standards.

Modeling Dual Drainage Stormwater System

Dual drainage modeling allows the simultaneous simulation of surface (overland and street) and subsurface (pipe network) flows to more accurately represent urban flooding behavior. GeoSWMM 5.3 introduces a new feature called the Surface Flow Path (SFP) Tool, which delineates overland flow paths that develop when manholes surcharge during high-intensity rainfall events. Using a Digital Elevation Model (DEM), the tool traces terrain-guided flow paths from surcharged or selected nodes, directing surface runoff along streets or other low-lying areas. Traditionally, SWMM treats overflow from surcharged nodes as lost water. The SFP Tool addresses this limitation by routing excess water across the surface, maintaining realistic hydraulic continuity between underground and surface systems. As a result, overflow volumes remain within the model domain, providing a more accurate and complete representation of urban flood dynamics.

Enhanced Data Import Workflow

The Import to Model feature now streamlines the transfer of hydrologic and hydraulic features generated by the Watershed Delineation (WSD) and Surface Flow Path (SFP) tools directly into the GeoSWMM database. In the WSD Tool, features such as streams, outlets, outfalls, and watersheds are automatically mapped to GeoSWMM components—Conduits, Junctions, Outfalls, and Subcatchments—with key parameters auto-populated to match the existing model network. Similarly, SFP-derived features, including surface flow paths and inundated nodes, are imported with elevation and connectivity attributes preserved. This enhancement reduces manual data handling and ensures seamless consistency between GIS-based preprocessing and SWMM simulation layers.