Still seems like a wide range. Does like ASCE have any resources?Have you checked glassdoor.com? I think you may have to set up an account (it's free), but I've gotten some good input from there. You can also put in your anonymous salary info to help others in the future.
Otherwise, you can check the threads here: http://engineerboards.com/forum/140-ebcom-salary-surveys/
They do not, however, encompass all the fields of civil engineering and some have more participants than others. Bear in mind that salaries are also, in my opinion, highly dependent on location.
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