An Integrated Catchment Management Plan (ICMP) was recently developed for the Mangere Inlet catchment,in Manukau City,Auckland.Flood risk analysis was one of the critical factors in the assessment and management of future land use and district planning;both significant features of the ICMP.Flood mapping was considered a conventional part of the ICMP,however flood risk management was more challenging and required the prediction of flood risk levels and the associated damage to affected properties.In order to achieve this,it was essential to predict flood extents,depths and velocities accurately.In reality,this was very difficult to achieve using the traditional one dimensional pipe network with an overlay of overland flow paths as defined based on the ground/terrain model.To avoid the uncertainties inherent in a one dimensional (1D) model,a 1D pipe network model and a two dimensional (2D) shallow water,ground surface flow model were combined to model stormwater flows within the study catchment.Overland flow direction,flow depth and velocity were automatically predicted using the dynamic 2D model.A flood risk assessment was then processedbased on the accurate modelling results.Flood reduction options were developed from a good knowledge of the catchment and understanding of the risk categories.This paper demonstrates the success of flood mapping using a 2D approach and the production of results which are clear,understandable and useful for both the public and the council.This has proved to be an important step forward from the traditional flood maps.