Buller River Topographic, Rainfall, and Flow Stream Analysis in Correlation to Westport Flood Risk Management

Abstract

Floods frequently damage New Zealand settlements, and recently, one of the most significant flood events in the country destroyed a town known as Westport. While previous studies have examined multiple factors in Westport floodings, this research would traverse more. This paper analyzed Westport flooding cases connected to its topography, rainfall, and Buller River’s flow stream at Te Kuha. The research aims to characterize elements of flash flood hazards at Westport. The data is retrieved from New Zealand’s National Institute of Water and Atmospheric Research (NIWA) website and processed to produce daily mean flow, stage-discharge curve, and flood return period graphs. The graphs created in this research concluded that the 2021 Westport flooding was a 50-year extreme event, meaning Westport should expect a similar flood event to hit the city in 2070s, as it hit them previously in the 1970s. Finally, this research confirms that the Buller River’s flow stream at Te Kuha significantly affects flood events at Westport, and future flood management should consider climate change’s impact on flood risk at Westport.

Keywords: Topographic, Rainfall, River flow, Flash floods, Flood management, Flood risk, Westport New Zealand.