Where and when was the 100-year flood protection standard first used in New Zealand?

I answer this question in an article published in the Issue 52 - September FLOW Newsletter of the NZ Rivers Group. It is the first of the three questions I consider in the paper I presented at the Water New Zealand Stormwater Conference 2026 in May. My conference paper provides more detail on the research I undertook, and the other two questions:

• What influence did central government part-funding, through subsidies and loans, have on the selection of design standards for schemes?

• How did the standard become to be used as a reference scenario in floodplain mapping, and in urban settings?

Lower Manawatu River upstream of Fitzherbert Bridge, Palmerston North, 17 February 2025