A new $150 million road from the Northwest Coastal Highway, near Karratha, through the Millstream-Chichester National Park, to the Nanutarra-Munjina Road intersection (north of Tom Price) has been implemented and is part of a broader freight route that supports the mining industry.

This vital infrastructure project reduces travel time, improves safety and reliability, and enhances access to the Tom Price iron ore mine, as well as helps to facilitate other economic opportunities.

BG&E provided flooding and drainage services, specifically, detailed hydrology and hydraulic analysis of two major crossings – Harding River and Western Creek – for the new road alignment. Using HEC-RAS software, our technical team modelled water surface profiles of the upstream and downstream reaches of the rivers.

The Harding River site is adjacent to the two existing Hamersley Iron railway bridges and involved a difficult crossing at a sharp bend in the river. Various floodway, culvert and bridge options were investigated for each crossing, including detailed analysis of the stream flow hydrographs for the period of inundation and time of closure. BG&E’s report provided structure options and performances.