I am not sure they are talking about graduate courses or not - the ASCE document mentions that some undergrad coursework would also be acceptable toward the 30.
Plus, the only substantive "reason" given for this so far is that the civil engineering field has expanded so much that a typical 4-year BS can no longer adequately prepare a civil engineer for the breadth of possibilities available in a career. Which, in my mind, would seem to argue more for a longer, broader BS program. OR: splitting civil engineering up - structural, transportation, construction, water/wastewater, etc.
Personally, I would prefer that the requirement remain a Bachelor's degree. Let ABET decide what the B.S. should consist of - with input from ASCE, NCEES, NSPE, etc. If academia, in consultation with the professional societies, agrees that 150 credits is required, then let a BS in civil engineering equal 150 credits.