Go to http://www.hec.usace.army.mil/software/hec-hms/download.html and download an appropriate version of HEC-HMS for your operating system. The software is available for Windows, Linux and Solaris machines but not for MacIntosh. If you want to work in the LRC, the software is maintained in rooms ECJ 3.302 and ECJ 3.306. It could occur that you are the first user of the software on one of these machines, and if so, you’ll have to agree to the Terms and Conditions for Use, as described below