Two aspects of hydraulic design are addressed: the determination of a design peak flood flow rate; and the estimation of channel flow resistance. Existing practice on these two topics is reviewed by surveys of practicing engineers and university lecturers in engineering and geography departments. A review of existing scientific knowledge on both topics is also presented, with an emphasis on any recent research developments.
For both flood flow rates and channel resistance, limited site data have been obtained to indicate which of the methods used for ungauged New Zealand sites appear to be the most valid, and therefore may justify continued development.
Keywords: floods, rivers, channel resistance, flood frequency prediction