Building a Community on a Foundation of Flood Management

The topography and climate of the Kapiti Coast makes it particularly vulnerable to flooding. This natural hazard combines with one of the most rapidly developing regions in New Zealand to make the management of flood risk an imperative that influences almost every aspect of the core functions of the District Council (KCDC). Over the past 6 years SKM has worked closely with KCDC to model the majority of the open channels and stormwater pipe network in the district. This work involved the development of 5 large integrated models of the network, streams and floodplains within the urban centres on the Kapiti Coast. These 1D-2D coupled models have been used as the foundation for analysis to guide the decision and policy makers in their planning to address existing flood risks and guide future development.

This paper discusses how hydraulic modelling has been developed and utilised to inform floodplain planning including flood damage assessments, engineering upgrades, prioritising response, planning controls, community consultation, effects assessment and planning for climate change impacts. KCDC have applied a detailed understanding of flooding risk developed through hydraulic modelling as a powerful tool to shape the future of the Kapiti Coast.