The east-west part of Wacker replaced South Water Street. River Street was the short NE-SW diagonal approach to the Rush Street Bridge, where Heald Square is now.
South Water Market was relocated to W. 14th Street, but the produce merchants wanted to keep their old addresses, so those blocks ignored Chicago's addressing system from 1925 until 2004, when the produce market relocated yet again to 29th & Ashland, and the buildings were converted into University Commons.
Incidentally, we have a thread for
Historic Chicago photos.