Found a bug:  When completing Tradition, the first four cities receive a Sewer not an Aqueduct. In addition, the Aqueduct is available to build (at Engineering).

FYI, having both leads to insane city growth. (Which can be a lot of fun, but really not very balanced.) I wonder if the AI would take advantage of this bug ...

How to recreate:
Start a game with this mod. (and IGE - see below)
Complete Tradition and Engineering. Build Aqueduct. 

Note: You can use IGE to complete the Tradition Tree on Turn 1 and there it is, a Sewer and not an Aqueduct.