The biggest test of Allan Cook's working life was the 2004 floods and the $70 million capital works projects that came after them.
He retires this week, after 45 years as a river engineer and the last 15 as overall manager of river work for Horizons Regional Council.
The capital works after the February 2004 floods were mainly for Palmerston North and on the Manawatu flood plain, but they extended to Whanganui and Rangitikei. The council has a total of 35 schemes for flood control, erosion prevention and drainage across the region, from Taringamotu north of Taumarunui to Ohau-Manakau south of Levin.
The Rangitikei is the region's most difficult river, because it's steep and changes its bed.
Keeping it within stopbanks and preventing it from encroaching on productive land is a challenge.
With iwi and Whanganui Regional Council, Mr Cook has been part of the group investigating Whanganui's flood in June last year.
He said the community wanted answers about flood risk and mitigation - not only for the Whanganui River but for tributaries like the Matarawa and Awarua streams.
"I'm sorry to leave before that's finished. I'm a person who likes to see the job finished."
Overall, he said his job has been helping people, and people have been grateful.
"It's all about protecting people and property from floods and providing good land drainage and enhancing economic wellbeing. Economic wellbeing is the big thrust - protecting productive land from flooding or erosion and improving drainage."
He has liked working with others and formed some good relationships.
Whanganui's Balgownie Stopbank has come in for a lot of criticism from some Chronicle readers.
It was not put to the test in the June flood, he said, because there was no high tide or storm surges when the river peaked. But there could be next time.
"I'm absolutely certain that the work will prove its full value in time and at that time it will be appreciated by the community."
Climate change is real, he said, and having an increasing influence on river management.
"The challenge is responding to those impacts while also taking account of present affordability."
Retirement will be a big change for Mr Cook, and need some adjustment.
He's planning to stay in Marton and do some overseas travel, fish, tramp and make some furniture in his home workshop.
After leaving school he got a New Zealand Certificate in Engineering, mainly by correspondence, and worked for the Ministry of Works in Christchurch, on the West Coast and in Wellington before accepting a job with the Rangitikei/Wanganui Catchment Board.
It was based in Marton and he planned to stay a short time and broaden his experience - but got enmeshed in family and community.
In 1989, when two catchment boards merged to form Manawatu/Wanganui Regional Council, he became the senior engineering officer for Ruapehu, Whanganui and Rangitikei.
His successor at Horizons will be Ramon Strong, whose river experience comes mainly from work at Otago Regional Council.