What requirements did the role have and what’s the salary range?
From what little I gather from online job listings, most foreign labor dependent positions are trying to pay 90K for a masters degree, maybe 120-140K Bay Area. Additionally, many of these job listings want extremely specific degrees or certifications that frankly are of little interest to US citizens - but F1 students will take any masters program despite the program having little salary benefit - the degree is a requirement for the visa.
I have a hard time believing you can’t find a US civil engineer who could learn the subject matter right out of college. Although saying that I know first hand low starting salaries have pushed students towards mechanical engineering or CS if inclined.