Civil servants who have served in the federal government for decades said that the efforts by the Trump Administration to roll back environmental regulations were sharply different from those of previous administrations.“In previous administrations, we did not always agree with the policies, but when we did new rules, we spent years reviewing the data, the science, the economics, as the law says to do,” said Elizabeth Southerland, who joined the E.P.A. during the first George Bush administration and resigned in 2017 from her position as a senior official in the agency’s clean water program. “But what these guys have done is come in and repeal and replace, without relying on data and science and facts.”