All UC’s are competitive, but you can apply as a Civil Engineer and then if possible, switch to CS. There are requirements that have to be fulfilled prior to switching majors. All engineering majors will be competitive, regardless if they are impacted are not. If CS is what you want, then I believe you should apply for CS. If you are unsure, then apply for Civil Engineering. Here is the requirements to switch majors:
http://student.engr.ucr.edu/policies/requirements/majorchange/cs.html