HCR is an extension of files associated with a specialized CAD tool called HydroCAD Stormwater Modeling System. HCR files are used to store data used in modeling rainwater runoff. This is rainfall information and includes e.g. rain intensity curves (IDF).

Technically, the HCR is a plain text file. It is an integral part of the hydrological project carried out in the program. This solution is most often used in construction engineering.