A £7m flood defence scheme in Llanrwst and Trefriw in Conwy has been officially opened.
The scheme has been developed to allow the natural flood plain to protect 96 homes and businesses in the area.
It was successfully put to the test during construction when the area was hit by heavy rain last November.
Initial costs rose from £5.75m to £7m due to "unforeseen circumstances," and bad weather damaging partly-built defences during construction.
Environment Minister Jane Davidson said she was delighted to be returning to Conwy to open the flood defences.
"During my trip here last year I was able to see first-hand the need for a flood protection system to protect the community living in this beautiful part of Wales," she said.
"If we are to adapt successfully to climate change, the way we manage our shores and rivers will be critical," she added.
Natural flood plain
The Llanrwst and Trefriw scheme, which protected homes, businesses and jobs, did just that, she said.
The area is prone to flooding because it drains rain from the mountains in eastern Snowdonia.
It comes down the rivers Lledr, Llugwy and Conwy, which merge at Betws y Coed, before reaching the narrow part of the valley at Llanrwst and Trefriw.
The flood scheme allows the water to flow over man-made flood banks onto the natural flood plain of the valley floor.
It is then stored and drains away over a few days.
To allow for this the flood bank immediately upstream was lowered and a new flood bank built to protect homes in Trefriw.
Specialist temporary flood barriers will seal off vulnerable properties in Llanrwst.
David Edwell, the area manager for Environment Agency Wales, said the agency wanted to thank the community for their "input and co-operation".
"Our officers will be closely monitoring any risk of flooding and will respond to make sure the defences are doing their job protecting these communities," he added.