Both NIT surathkal and NIT calicut are very good institutions. Coming to to Dept. of Civil in NIT surathkal, it has very curicullum and acdamics are very easy. The dept. has very good faculty and the dept. had completed many prestigious projects showing that the dept. is very good in research and Development (R&D) (civilengg.nitk.ac.in/)
 
Coming to Dept. of CS in NIT calicut it has very good course plan and the academics are relatively a bit difficult. The Faculty is very good and has very good citations. The dept. has very good placements record.For more information you follow the above link(nitc.ac.in/nitc/dept/cse/public_html/index.htm)
 
I would suggest you to opt for CS in NIT calicut over civil. If you go by rankings, NIT suratkal may just have a edge over calicut. But the place will be with you for only next four years but the degree will be with you for the rest of your life. And moreover the campus lifes of all the NIT s are almost the same and CS always have a edge in campus placements over any other dept. Moreover CS dept will have many options for higher studies than civil.