I think it’s hard to compare “opportunities” unless one has extensive knowledge of both schools. You can still compare their academic offerings on their websites. I went to their websites and from the first glance, Northwestern has an industrial engineering & management sciences department and Rice doesn’t. I don’t know if that matters to you. As for civil engineering, it’s probably a toss up unless you are interested in transportation. Northwestern has probably one of the leading transporation research centers in the country, which offers an undergraduate minor program.