Harrison, S.E.; Pastor-Paz, J.; Vinnell, L.; Scheele, F.R.; Nguyen, Q.; Paulik, R.; Johnston, D.M. 2024 An overview of available frameworks and data requirements to account for direct, indirect and intangible flood costs for business-case development. Lower Hutt, N.Z.: GNS Science. GNS Science report 2024/45. 70 p.; doi: 10.21420/JKCS-P558
Abstract
This report was prepared by a joint research team from GNS Science, Massey University and National Institute of Water & Atmospheric Research (NIWA) for the Greater Wellington Regional Council and the River Managers’ Special Interest Group (SIG) of Te Uru Kahika Regional and Unitary Councils Aotearoa. The project was funded by the Ministry of Business, Innovation & Employment (MBIE) Extreme Weather Recovery Advice Fund. The report provides a ‘cookbook’ of the various methods and frameworks that are commonly used both internationally and within Aotearoa New Zealand to account for direct, indirect and intangible flood costs to support business-case development for flood mitigation in Aotearoa New Zealand. It highlights that most estimates only capture direct, insured, damages, potentially under-estimating the full economic and social costs, and discusses the challenges of quantifying indirect and intangible losses, including social and cultural impacts and data-accessibility issues. A case-study application of the April 2017 Edgecumbe Flood is also presented to demonstrate the data requirements and aspects of modelling to estimate some indirect and intangible costs relating to housing and habitability. The summary herein is presented in reverse order of the report sections so that key findings from the review of methods and results for measuring intangible losses is presented first, as this was of most interest to Greater Wellington Regional Council and the River Managers’ SIG. (auths)
