Stormwater New Zealand Conference 2025 Rotorua
Over the years residential development has been allowed in many of New Zealand’s towns and cities in sub-optimal locations such as overland flow paths and flood prone areas. Initially houses in such areas may have been on piles and on large lots with room for overland flow between them. Over time, lots have been infilled and increasingly houses are built on concrete slab close to ground level. Other houses have had open sided basements closed in and turned into living space. These factors have led to pluvial flooding issues in our urban areas being exacerbated. Generally in NZ the traditional approach to ‘solving’ existing flooding problems in residential areas is to try to reduce the flooding – usually by a piped solution.
This case-study looks at an example in the Matua suburb of Tauranga which has a history of flooding and most recently experienced flooding in March 2023. Currently there is a sag point in the road, and once the pipe and pit capacity here is exceeded, stormwater ponds in the road before flowing down through the adjacent properties which are all well below road level. An infrastructure solution was sought by Tauranga City Council (TCC) for current and future residents.
