Updated rainfall data free to use
An updated version of a widely used rainfall dataset will be free to use thanks to funding from the Ministry of Cities, Environment, Regions and Transport (MCERT).
About the High Intensity Rainfall Design System
The High Intensity Rainfall Design System (HIRDS), developed by Earth Sciences New Zealand, helps planners and engineers estimate how much rain could fall at a location, over different durations, and how frequently rainfall of that magnitude might occur.
It supports decisions ranging from sizing culverts and stormwater drains to designing flood protection and other major infrastructure.
Following the July announcement of free access to HIRDS, a version 5 update has been released.
MCERT funding once again means the tool and underlying datasets can be accessed free of charge, including for commercial use, under a creative commons (CC BY) license.
Commercial use of the dataset, including for engineering design and consultancy for public infrastructure, previously attracted a charge.
About the update
HIRDS version 5 includes around 10 more years of rainfall observations. This means more recent extreme rainfall events are included in the analysis.
Previous versions assumed rainfall patterns remained stable over time. Version 5 instead accounts for observed changes in extreme rainfall.
Why this data matters
Access to up-to-date rainfall information helps councils, engineers and infrastructure planners understand extreme rainfall and plan for the future.
This work builds on MCERT’s broader efforts to make natural hazard information more accessible. HIRDS data also informs flood hazard information used in the New Zealand Flood Map.
The New Zealand Flood Map will provide a trusted picture of flood hazards across the country. It is a key component of the National Adaptation Framework, the Government’s long-term and strategic approach to climate change.
Explore HIRDS rainfall data (NIWA website)(opens in new tab).