Soil, water & Engineering would point to Civil 3D. You might want 3dsMax if you want high end visualization at end of project. If so, check out Autodesk Infrastructure Suite.
Particularly, if you are motivated to do so
Civil 3D is based on AutoCAD. So everything you learn in Autocad will be available in Civil 3D. But Civil is much more complicated and requires additional learning.
BTW What do you mean by AutoCAD 2D? Basic AutoCAD is a 3D program. It just isn't focused on a specific discipline. Are you talking about AutoCAD LT?
Log into access your profile, ask and answer questions, share ideas and more. Haven't signed up yet? Register
Start with some of our most frequented solutions to get help installing your software.