Case Study: Understanding Secondary Overland Flowpaths in the Urban Catchments

Secondary overland flowpaths are a key design component of an urban stormwater catchment's response to storm rainfall that engineers take account of in the provision of stormwater infrastructure. However, the complexity, function and effects of secondary overland flowpaths are not generally communicated effectively to non-technical audiences, e.g. non-technical professionals and the wider public.

This paper presents a case study of a residential subdivision in Palmerston North where the independent quantification of secondary overland flowpaths by the author assisted in the resolution of a dispute (that was to be litigated in the High Court) about the effects of overland flowpaths paths on adjacent property.

It is intended that the case study highlight the importance of stormwater managers and technical professionals understanding and communicating the extent and effects of overland flowpaths in urban catchments.