HEC-HMS is a Free Windows program in the Other category, developed by Hydrologic Engineering Center. The current version is 4.13; you can download it safely from its official source with the download button above.
📝 Release notes (4.13)
HEC-HMS 4.13
SHA-256: 309BB87EF05CCC8E57CF9557BFDA9E711510AFC6929CF6ECBE36EAD0A6F063B8