2024 Unsealed Roads Project for Auckland Council

This project uses high spatial and temporal resolution satellite imagery alongside machine

learning techniques to identify “bare earth” and unsealed roads across the Auckland region, specifically using Maxar 0.3m RGBI imagery from March/April 2023 (post cyclone Gabrielle).

The model analysis defines areas of bare earth as gravel, exposed soil, and sand.

GIS (Geographic Information System) processing techniques were used to consider key features, in conjunction with bare earth and unsealed roads, including intersections with overland flow pathways, river networks, and steep slopes.

The recently developed Sediment Sources Rapid Identification and Management System

(SSRIMS) method, piloted on the Rodney region in 2023 (this is basically a set of scripts and GIS tools customised for Auckland Council), was used to score and rank unsealed roads for purposes of management. This has the potential to inform compliance, management, and monitoring across Auckland, utilising near real-time satellite imagery.

These resulting datasets can be used to provide further understanding and monitor the complex interactions of sediment within sensitive receiving environments and waterways.

Additionally, the identification of unsealed roads, within high-risk environments, can be used to prioritise sealing works and road improvement works, such as through the Unsealed Roads Improvement Framework that Auckland Transport leads or to support the strategic management of potential sediment generating areas, across the entire Auckland region.