There are very few diploma courses for civil engineers (as per my knowledge) in canada. There are, but very few.
1. Construction management diploma (1year) at centennial.
2. Environmental monetoring and impact assessment(1year) at cambrian college.
3. Project Management at University of winnipeg (this course is for every B.tech or B.E degree holder).
I would suggest you to go for masters.
Almost every canadian university offers master program in civil engineering. But at this time u cannot apply for january2015 intake. Apply for may2015 or sept2015.