Tasman District Council invites feedback on the draft Tasman Inundation Practice Note (IPN) 2025.

The IPN was first adopted jointly by Tasman District and Nelson City Councils in 2019 to provide a consistent methodology for determining minimum ground and/or building platform levels for subdivision, new buildings, and major alterations in areas at risk of inundation from seawater (coastal) and freshwater flooding.

Since then, there’s been updates to both national guidance and local data and so here in Tasman we’re progressing with a Tasman-only update of the IPN. There are no changes to the fundamental purpose or approach of the IPN and these technical updates will ensure that the IPN remains fit for purpose and demonstrates current best practice.

What are we consulting on

The latest draft incorporates recent national guidance, including the Ministry for the Environment’s updated Coastal Hazards and Climate Change Guidance (2022, 2024) and MBIE’s 2023 Natural Hazards Provisions Guidance on complying with the Building Act. The latest climate change projections have been incorporated—including updated sea-level rise values as well as the effects of vertical land movement.

It also features the newest NIWA coastal calculator data, revised mean sea-level and high tide assessments, updated extreme sea level values for Waimea and Moutere Inlets, and refreshed flood modelling for local rivers and catchments. Other changes include refined technical definitions and minor amendments to improve accuracy and readability.

The draft IPN sets out a consistent, defensible methodology for determining minimum ground and/or building platform levels for subdivision, new buildings and major alterations in areas exposed to flooding or coastal inundation in Tasman District.

The aim is to support robust, future-focused resource and building consent processes, ensuring safe and resilient development across our region for the next 50–100 years. This document provides guidance to support the implementation of the Building Act 2004, the New Zealand Building Code, and the Tasman Resource Management Plan.

Consultation

We invite stakeholders, practitioners, and the wider community to provide feedback to help ensure the Inundation Practice Note meets local needs and reflects best practice. Feedback closes 17 December 2025.