Hyder has a role for Plumb.
In his new role, he will be responsible for management and business development of the geosciences teams in Hyder's Cardiff, Bristol and Exeter offices.
Mr Plumb was previously a director at White Young Green Environmental, where he established the firm's Cardiff and Bristol operations.
He has more than 30 years' experience of working within the construction, mining, environmental and geotechnical industries. He is a chartered geologist and a fellow of the Geological Society.
David Renton-Rose, director of land development at Hyder Consulting said: "With the Government's plans to step up the redevelopment of brownfield public land, geosciences consultancy will see increasing demand over the coming years.
"Colin's breadth and depth of experience in geotechnical engineering and design - both in terms of technical expertise and commercial awareness - make him ideally placed to manage our geosciences team."