Press Release – NIWA Flood flows on the Buller River this month were the largest of any river in Aotearoa New Zealand in almost 100 years, NIWA measurements show. NIWA hydrodynamics scientist Richard Measures says records show even larger flooding of the Buller River in 1926. … Flood flows on the Buller River this month were the largest of any river in Aotearoa New Zealand in almost 100 years, NIWA measurements show. NIWA hydrodynamics scientist Richard Measures says records show even larger flooding of the Buller River in 1926. “It’s not the largest river in New Zealand but it does experience the biggest flood flows. The flood levels through the Buller gorge are incredible” he said.