Many things may hold up applications. First, the Graduate School must receive your application, GRE score, application fee, transcripts, and TOEFL score for international applicants. It is your responsibility to ensure that these materials arrive at the Graduate School. Secondly, your reference letters may not have been received at the Department of Civil & Environmental Engineering. You should check with your references to ensure they have written a letter on your behalf, and that they submitted it on-line or mailed it to the Department.