Autodesk no longer sells Hydraflow Express as a standalone product. Instead, the functionality is included in as a built-in add-on. For newer versions (Civil 3D 2019 and later), Autodesk recommends using the InfoWorks WS Pro or Storm and Sanitary Analysis tools, or installing the legacy extension if you have a valid subscription.
: Capacity and normal-depth rating curves for rectangular, trapezoidal, and user-defined shapes. Autodesk no longer sells Hydraflow Express as a
Hydraflow Express Extension for AutoCAD Civil 3D is a hydraulic and hydrologic calculation tool typically included by default Autodesk no longer sells Hydraflow Express as a
For a deep dive into specific hydraulic formulas and input methods, you can refer to the official Autodesk Hydraflow Express User Guide . Useres Guide - Autodesk Autodesk no longer sells Hydraflow Express as a