Lally originally joined Barhale in 2011 becoming senior general foreman after his work on the London Olympics projects and his leadership of the Optimise teams in the Thames Water, AMP5 programme.
He was promoted to Southern Region operations manager in 2015 and supervised the delivery of the Thames Water, AMP6 framework for eight2O.
Lally will report directly to the new Barhale CEO, Martin Brown, who joins the business in September.
Barhale director, Andy Flowerday said: “With more than 20 years in civil engineering, including 10 years at Barhale, David fully understands the delivery challenges we face and the core values that the company pursues in all of its projects.
“David’s primary responsibilities will be maximising productivity and resource utilisation, programme achievement and “Right First Time” delivery, together with supporting and responding to operational needs to mitigate issues and maximise opportunities.”