Netherlands-based global design giant Arcadis has named Mary Ann Hopkins as executive to lead its Americas unit and, worldwide, its water and environment business, as of Sept. 26. She joins from a previous role as federal business group president at Parsons Corp., where she worked since 1989. Hopkins is based in Washington, D.C.

Arcadis Chairman Niek Hoek says the water-and-environment sector generates most company revenue. Replacing Hopkins at Parsons on an interim basis is Thomas Roell, who remains vice chairman and chief risk adviser. He joined in 2003.