Our GIS team has completed a comprehensive case study on the impact of Cyclone Gabrielle on Te Awahōhonu Forest Trust lands. Proud of our team’s effort in blending traditional knowledge with modern technology to enhance Matāurangi Māori and support the Trust’s resilience against severe weather events. With the Trust permission we share the story of the project on the success of enabling trustees to access rich geospatial with ease.
Here is a quick summary and take a look for yourself at: Story Map – Te Awahohonu Trust Impact of Cyclone Gabrielle 2023
Background
The Te Awahōhonu Forest Trust is responsible for managing a significant expanse of land, including both farming and commercial forestry operations. In the wake of Cyclone Gabrielle’s destruction, the Trust sought Interpine’s expertise to evaluate the cyclone’s impact through the lens of modern GIS technology, complemented by traditional Matāurangi Māori insights.
The Challenge
‘Te mohoi ki te whenua’ (the return to the land)
The goals of this project were to:
- conduct a comprehensive damage assessment following Cyclone Gabrielle that caused unprecedented flooding and damage across parts of the North Island in early 2023;
- develop an interactive web interface that allows users to visualise the before-and-after impacts of the cyclone using satellite imagery and lidar data;
- provide a geospatial risk assessment for potential soil migration in the event of future severe weather events.
The assessment covers the entirety of Te Awahōhonu, including native forests, planted forests, and the steep hill-country farming area, highlighting the areas that have been severely affected. The before and after cloud free storm imagery that could be sourced were captured on 4 Dec 2022 and 14 March 2023 and includes Cyclones Hale and Gabrielle.
Innovative Approach
Interpine utilized a blend of satellite imagery, lidar data, and advanced geospatial analysis tools to conduct a change detection analysis. This approach pinpointed 226 hectares of impacted land, providing detailed visualizations of affected roads, forest cover loss, and areas at risk of soil migration. The dataset resulting from the change detection analysis was examined and refined to quantify the degree of soil movement. Additionally, a comprehensive desktop assessment was done to establish whether any of the observed damages were from windthrow trees, and if any roads were blocked or damaged.
Outcomes
The project yielded an interactive ESRI Story Map, enabling stakeholders to visually compare the pre- and post-cyclone scenarios. The analysis also led to strategic recommendations for the Trust’s sustainable land management and potential eligibility for carbon credit revenue through the Emissions Trading Scheme. This approach to leading trustees through a story of their land, while enabling them to also interact with rich 2D and 3D geospatial content in a manner that all trustees can accesseasily.
Conclusion
This case study showcases the transformative potential of GIS in analyzing disaster impacts and preparing for future environmental challenges. It highlights the synergy between traditional knowledge and state-of-the-art technology in effective land stewardship.
An example of one of the 3D datasets within the Story Map.
Take a look for yourself at: Story Map – Te Awahohonu Trust Impact of Cyclone Gabrielle 2023 or expand the view to full screen of the story map below.