What is the current (as of July 2018) password?
mft.esri.com (port 22)
But content is a bit stale. Looks like the team is keeping the Web site more current:
http://downloads.esri.com/archydro/ is the preferred location. We only keep the ftp site in cases when a user cannot access the http link. So the contents may not be up to date as noticed.
Esri Water Resources Team
Retrieving data ...