How do you get into central water commission, GOI?

I am a recently passed out civil engineer and wish to know about how does one get into Central Water Commission. I have deep interest in water resources engineering and want to work with GOI however the only department I could come across that offers these kind of jobs is CWC. If there's another, please let me know. Also, how does the CWC recruit? I heard somewhere that the recruitment is done through Engineering Sevices Examination however there were no mention of CWC in this years notification.