Purpose:The coastal inundation hazard layers map describes the areas exposed to extreme water levels caused by storm tides, wave setup and sea-level rise under the following scenarios (where AEP is the Annual Exceedance Probability or the chance of occurring each year, ARI is the Average Recurrence Interval):20% AEP (5 year return)5% AEP (20 year return)2% AEP (50 year return)1% AEP (100 year return): to demonstrate present day risk in alignment with the Auckland Unitary Plan activity controls2% AEP (50 year return) + 1m sea level rise2% AEP (50 year return) + 2m sea level rise1% AEP (100 year return) + 1m sea level rise: in alignment with Auckland Unitary Plan activity controls1% AEP (100 year return) + 2m sea level rise: to demonstrate longer term risk with ongoing sea-level riseThis is a generalised version of the data. Download the original full dataset with layer files here:https://data-aucklandcouncil.opendata.arcgis.com/datasets/coastal-inundation-hazards-geodatabase/aboutThe layer takes into account extreme sea levels calculated between 2013 and 2019, as compiled in Carpenter, N., R Roberts and P Klinac (2020). Auckland’s exposure to coastal inundation by storm-tides and waves. Auckland Council technical report, TR2020/24. Auckland’s exposure to coastal inundation by storm-tides and waves (knowledgeauckland.org.nz)Sea-level rise values applied currently align with the projections by the Intergovernmental Panel on Climate Change sixth assessment report (2021), and the Ministry for the Environment (2022) Interim guidance on the use of new sea-level rise projections, which updates the Ministry for the Environment Coastal Hazards and Climate Change Guidance for Local Government (2017). In MfE’s (2022) Interim guidance, (excluding vertical land movement) one metre sea-level rise is projected to occur between 2095 - >2200, depending on the emission scenario used. Two metre sea-level rise is projected to occur in the longer term (beyond 2150). MfE’s (2022) Interim guidance recommends the inclusion of vertical land movement (VLM) in relative sea level rise considerations. These are not included in the above sea level rise predictions due to the high VLM variability across the region. Vertical land movement is generally predicted to increase the rates of relative sea level rise for the Auckland region so should also be incorporated in planning and design.Refer to Interim guidance on the use of new sea-level rise projections | Ministry for the Environment for more information on MfE’s interim guidance on sea level rise and vertical land movement.Lineage:3Extreme sea levels for the Auckland region were derived by NIWA in 2013 (Part 1 of Technical Report 2020/24). From 2016-2019, additional extreme sea level data was gathered for:The east coast estuaries (NIWA, 2016; Part 2 of Technical Report 2020/24)Parakai/Helensville Harbour (DHI, 2019; Part 3 of Technical Report 2020/24)Great Barrier Island (NIWA, 2019; Part 4 of Technical Report 2020/24)In 2020, these levels were projected onto the land topography (derived from the 2016-2018 LiDAR survey) by Stantec to establish the extent of coastal flooding. Creation Date: 15/12/2020Update Cycle: Adhoc – when improved data becomes availableThis data is available to the public on the Geomaps viewer and is copied into LIMsContact Person: Natasha CarpenterContact Position:Coastal Management Practice Lead, Infrastructure and Environmental ServicesCouncil Contact:Natasha.Carpenter@aucklandcouncil.govt.nzConstraints – General:The Coastal Inundation data is subject to updates to reflect the latest, best available understanding of storm tides, waves and sea-level rise processes.The geodatabase contains a copy of the historic inundation mapping, which is superseded by the publication of the 2020 data. The superseded data is identified by having a validation state of 0, whereas the published data has a validation state of 3 (valid and public).Constraints – Legal: This data is available to the public on the Geomaps viewer and is copied into LIMsConstraints – Security: The Coastal Inundation data is available to the public Under Creative Commons license.
