Mr Rake, 40, announced on Friday that he would leave the authority on August 4 after almost five years in the role to become the chief operating officer of the Therapeutic Goods Administration.

‘‘I made a decision a while ago I wouldn’t seek a second term. I think chief executive officers have a shelf life and that is five to seven years,’’ he said.

The mild-manned executive applied for the TGA job, making no secret of the fact he wants to progress further in his career, not ruling out a job ultimately at the level of a department secretary.

‘‘I would like to make myself available to serve the government at higher levels in the future. I don’t know if I’ll ever get there but I have to develop my skills as far as I can. I’ve always done my best and I hope I continue to serve this community through the elected government of the day, ’’ he said.

Mr Rake said past budget cuts by the Labor Government which had reduced the size of the authority had not forced his hand. He said the Labor Government had more recently increased funding to the authority and he could not say either way if it would necessarily fare better under a Coalition government.

‘‘I’m extremely positive about the future of the organisation and that’s one of the reasons I’m confident now is the time to go,’’ he said.

Mr Rake has dealt with issues from preparing for royal visits to monitoring the water quality of Lake Burley Griffin; from overseeing the construction of the Kings Avenue overpass to weathering the storm of the Brodburger-by-the-lake stoush.

‘‘The highlight would be finding myself in situations that, frankly, a boy from Kambah never had a right to be in. MCing an event for a royal visit; giving short private viewings of the vista from Mount Ainslie to visiting dignitaries,’’ he said.

‘‘Some of the bigger challenges have been the sleepless nights that we had while we wondered just how bad the problem with Scrivener Dam was. That was pretty unpleasant. I’m glad we found a solution and I’m thrilled with the way the team is going about fixing the problem. But I was pretty scared for a while.

‘‘I was here at the time of the changes to the NCA budget and having to work with a relatively large number of people being forced to leave the organisation and find other jobs, that was pretty distressing for those people and us at the other end.

‘‘But I keep going back to the fact the people who work here are amazing. Their ability to create something out of nothing never ceases to amaze me.’’

A contractor uncovered corrosion in the anchor bolts securing the gates of Scrivener Dam in 2011, forcing the authority to lower the water level of Lake Burley Griffin by 50cm to undertake repairs. Mr Rake recently revealed the work had been revised from a cost of $14 million to $8 million.

Mr Rake said his anxiety at the time was fuelled by the fact in the early days no one could rule out the dam wall bursting.

‘‘I couldn’t get a dam engineer to tell me that it wouldn’t. They couldn’t tell us how bad the problem was. As we got a better handle on that, it became scarier but easier to manage,’’ he said.

‘‘As they got a better handle on it, they were able to say, ‘Yes, if we do nothing, there’s a high likelihood at some point part of the dam won’t work properly and it will lose water in a hurry’. Then we could say, ‘Great, let’s fix it’ and lowering the water level by just half a metre took the risk from being very high to being virtually zero.

‘‘But there was a period of a couple of weeks where we didn’t understand enough about the problem, how bad the risk was and when you’re dealing with community safety and people who might have been fishing or walking their dogs and not having any inkling, there is a pretty high responsibility to get things right.

‘‘Each of us went home at night and lay awake hoping that we’d done everything we could to manage the risk properly.’’

Mr Rake is a born and raised Canberran, educated at St Thomas the Apostle Primary School in Kambah, St Edmund’s College and Daramalan College as well as the Australian National University.

He said he had enjoyed ‘‘more joys and more challenges’’ than he could have imagined during his time with the authority and paid tribute to his staff.

‘‘In my letter of resignation to the Governor-General, one of the things I pointed out is that I’ve been supported by one of the most progressive, professional and dedicated teams in the public service and I couldn’t have possibly done my work without them,’’ he said.

Mr Rake was also pleased that during his tenure, he believed the authority had become more accessible and more responsive to the community.

‘‘That means we’re just as willing to talk to the community about the things we’ve done well as the things we’ve done not so well,’’ he said. ‘‘Every organisation makes mistakes, but if you’re willing to sit with the community and talk about the mistakes you’ve made, how you can work from it and what you can do better, the community at least comes to trust the intent of an organisation and I think we’re in that place now.’’

The authority’s chief planner Andrew Smith will be acting chief executive until a new appointment is made.