Dr Paul Leinster has been appointed chief executive of the Environment Agency and will take up the post on 1 November.
Leinster joined the Agency in 1998 and has been acting Chief Executive since May 2008. His appointment completes the change of both top jobs at the Agency.
Engineers had previously appealed for the chief executive to have technical experience, and Leinster seems to fit the bill.
Dr Leinster said: "I am delighted to be leading the Environment Agency at such an important time. We have achieved much for people and the environment in the last decade and are well placed to face the challenges of the future.
"We will ensure that we maintain the focus of business and the public on environmental protection and climate change, even in a difficult financial climate, and provide a more effective, efficient service through better regulation.
"Expectation levels about the environment are higher than ever before. We have many big challenges to address including flooding, pollution, water quality and resources, waste and climate change and will use our expertise, experience and influence to deliver the necessary changes. And we will continue to do so by cutting bureaucracy and maximising the environmental improvements for every pound we spend," he said.
Environment Agency chairman, Lord Chris Smith, said: "We face a defining moment in our history and our actions now will determine the environmental impact of climate change for future generations.
"Now is the time for bold decisions to protect our land, air and water. Throughout his time at the Environment Agency, Paul Leinster has consistently shown himself to have the skills and experience needed to ensure the Environment Agency can meet the challenges we face and create a better place."
Leinster has more than 30 years experience in health and environmental safety, and has held the roles of had director of environmental protection and director of operations at the Agency.