The flood plains indicate the area of land inundated by runoff in a storm event that has a 1 percent or greater probability of occurring in any given year, assuming maximum probable development (MPD) and future climate change. The flood plains are mapped from hydraulic modelling results. Information specific to each flood plain is accessible using the Identify tool, including the flood report. This dataset is continually updated at catchment scale to reflect the best information available.This dataset is updated by the Heathy Waters team on a regular basis.Disclaimer: In using the Catchments and Hydrology data set, you acknowledge that you have read, understood and agreed to the disclaimers below.The flood plains and flood sensitive area data layers are generated from catchment level modelling based on the datasets, requirements and technology available at the time of model build. They are compiled regional layers with varied data uncertainty and currency, which may directly impact data accuracy for the area of interest. The information provided therefore does not preclude the need for appropriate site-specific assessment and cannot be construed as an endorsement or approval of any development by Auckland Council.The Catchments and Hydrology data set is updated regularly when new information becomes available. As such, downloading and copying activities may result in data invalidity.Whilst due care has been taken in producing the Catchments and Hydrology data sets, Auckland Council gives no warranty as to the accuracy and completeness of any information given and accepts no liability for any error, omission or use of the information.

This layer provides polygons of approximate flood areas derived from Sentinel-1 satellite radar imagery captured at various times on 14/02/2023 near the peak of the Cyclone Gabrielle event in the North Island of New Zealand. Areas of coverage for this layer include the Hauraki, Thames-Coromandel and Hastings Districts, and Napier City.

​(Note: More accurate and validated flood extent models for the Hawke’s Bay region can be obtained from Hawke’s Bay Regional Council - Flood Observation Extents.)

​This dataset was created by Toitū Te Whenua LINZ as part of its contribution to the emergency response, and is limited to areas that had a satellite pass over, and to the few areas of interest as we knew them at the time.

​**Accuracy** Users of this data should exercise caution . The accuracy of this data has not been validated. A subjective threshold was used to determine possible flood areas and eliminate false positives. Polygons in hilly areas or below a certain area size were excluded as likely false positives.

Please use this data as advisory only. The results have not been ground truthed and will contain errors and ommissions.

Waikato District Council - Proposed District Plan (Appeals version), released 8th August 2022. This layer is a spatial representation of an overlay in the Proposed District Plan and indicates where land use will be regulated by various associated rules. It will be used as a guide in the regulatory process of implementing the Proposed District Plan and managing land use, subdivision, the environment and economy. This dataset is subject to changes undertaken through the Resource Management Act. Note individual Proposed Plan rules can have different statuses, some may have current legal effect and others will not until the Proposed Plan becomes operative. This data is provided for use in the District Plan only.

Flood Risk Areas are shown on the planning maps but also apply to any other land that is subject to more than minor flood hazards. Waikato Regional Council information.

The Waikato District Council District Plan is has been produced under the Resource Management Act 1991, and has been distributed to allow better public access to the data underlying the Plan. While you are free to crop, export and repurpose the data, we ask that you attribute the Waikato District Council, link to this page, and clearly state that your work is a derivative and not the authoritative data source. Please include this statement when distributing any work derived from this data:

This work is a derivative of Policy Series, part of the Waikato District Council District Plan. You can find the full District Plan at Waikato District E-Plan (https://www.waikatodistrict.govt.nz/your-council/plans-policies-and-bylaws/plans/district-plan)

Gate opened and closed to admit or exclude water.

Data Dictionary for floodgate_pnt: https://docs.topo.linz.govt.nz/data-dictionary/tdd-class-floodgate_pnt.html

This layer is a component of the Topo50 map series. The Topo50 map series provides topographic mapping for the New Zealand mainland, Chatham and New Zealand's offshore islands, at 1:50,000 scale.

Further information on Topo50: http://www.linz.govt.nz/topography/topo-maps/topo50

Flood prone areas (FPA) are potential ponding areas that have no natural outlet and may flood frequently.FPA are topographical depressions. The areas occur naturally or are created by dammed gullies created by man-made features such as roads and railway embankments. The flood prone extent is the area water will pond up to in a 1% AEP extreme rainfall event (Maximum Probable Development (MPD) and climate change scenario) assuming the outlet to the topographical depression is blocked. All FPA were generated based on an existing development (ED) situation. The layer was created by WSP and is managed by the Healthy Waters Regional Planning team. It was updated in June 2021 and is an update of an existing layer that was created in 2013.The FPA layer was generated from Auckland Council’s latest LiDAR data, which was flown in 2016 and became available after processing in 2018. The 2016 LiDAR data had a much higher point density (4 points per m2) than previous versions, resulting in more spatially accurate flood prone areas. FPA will be updated on an ad hoc basis to align with updates to Auckland Council’s LiDAR data.Vertical Datum: NZVD1946A summary of the fields and their definitions is as follows:FieldDescriptionCatchmentArea / Catchment Area (m2)Catchment area upstream of the flood prone area.DepID / Depression IDDepression IDDepth100y / 100yr ARI Future Scenario ponding depth (m)Maximum water depth in the 100yr ARI Future Scenario rainfall event assuming the outlet is totally blocked.MaxDepth / Max ponding depth (m)Maximum ponding depth in the flood prone area (spill elevation minus minimum elevation).MinimumLevel / Minimum elevation of depression (m RL)Minimum elevation in the flood prone area.RainfallExisting / 100yr ARI Existing Scenario rainfall (mm)TP108 24hr 100yr ARI Existing Scenario rainfall depth (effective depth over entire catchment).RainfallFuture / 100yr ARI Future Scenario rainfall (mm)TP108 24hr 100yr ARI Future Scenario rainfall depth (existing rainfall depth multiplied by 16.8% to account for a 2.1-degree Celsius temperature rise due to climate change).RainfallRequired / Rainfall required to fill (mm)Rainfall required in the catchment to fill up the depression to the spill elevation.SpillElevation / Spill elevation (m RL)Spill elevation (m RL)Vol100yrm3 / 100yr ARI Future Scenario volume (m3)Volume stored in a 100yr ARI Future Scenario rainfall event assuming the outlet is totally blocked.VolumeM3 / Volume to spill elevation (m3)Max. volume that can be stored in the flood prone area.Dam / DamIdentifies if flood prone area is classed as a large dam.DamClass / Dam classificationIdentifies the classification of the dam (classifiable or referable)Level100y / 100yr ARI Future Scenario flood level (m)The level water will pond up to in a 100yr ARI Future Scenario rainfall event assuming the outlet is totally blocked.CanFill / Can fill in a 100yr ARI Future Scenario rainfall eventCan the depression area fill in a 100yr ARI Future Scenario rainfall event if the outlet was totally blocked -either Yes or NoSHAPE.STArea() / Max. flooded area in the 100yr ARI Future Scenario (m2)Surface area of the depression (up to the spill elevation).Disclaimer: In using the Catchments and Hydrology data set, you acknowledge that you have read, understood and agreed to the disclaimers below.The flood plains and flood sensitive area data layers are generated from catchment level modelling based on the datasets, requirements and technology available at the time of model build. They are compiled regional layers with varied data uncertainty and currency, which may directly impact data accuracy for the area of interest. The information provided therefore does not preclude the need for appropriate site-specific assessment and cannot be construed as an endorsement or approval of any development by Auckland Council.The Catchments and Hydrology data set is updated regularly when new information becomes available. As such, downloading and copying activities may result in data invalidity.Whilst due care has been taken in producing the Catchments and Hydrology data sets, Auckland Council gives no warranty as to the accuracy and completeness of any information given and accepts no liability for any error, omission or use of the information.

Waikato District Council - Proposed District Plan (Stage 2 Natural Hazards), Notified 27 July 2020. This layer is a spatial representation of an overlay in the Proposed District Plan and indicates where land use will be regulated by various associated rules. It will be used as a guide in the regulatory process of implementing the Proposed District Plan and managing land use, subdivision, the environment and economy. This dataset is subject to changes undertaken through the Resource Management act. Note individual Proposed Plan rules can have different statuses, some may have current legal effect and others will not until the Proposed Plan becomes operative. This data is provided for use in the District Plan only.

High Flood Risk Areas are identified as areas within the Flood Plain Management Area where the depth of flood water in a 1% Annual Exceedance Probability (AEP) flood event exceeds 1 metre and the speed of flood water exceeds 2 metres per second. This belongs to the series of data relating to Natural Hazards which includes the following groups - coastal erosion, coastal inundation, inland flooding, and land subsidence. This layer belongs to the inland flooding group. Use in conjunction with Flood Plain Management Area, Flood Ponding Area,and Defended Area.

Made available for NPDC GeoHUB (GIS Hub Site and Open Data Portal) :A full description is available in the Metadata. SeeTerms of Use.Notes:The "Updated" date, noted here in the item, does not accurately reflect the currency of the data within the Feature Layer.The data available for download on NPDC GeoHUB is updated daily, this results in differences between what is available online and NPDC's databases.

Much of the settled Hawke’s Bay region is low lying and built on river flood plains. This brings the risk of flooding, which is our most common natural hazard - a severe storm or flood happens every 10 years on average. Major storms affect wide areas and can be accompanied by strong winds, heavy rain or snowfall, thunder, lightning, and rough seas. They can cause damage to property and infrastructure, affect crops and livestock, disrupt essential services and cause coastal inundation.Rivers normally flood every winter when a storm brings more rainwater than can soak into the soil. When floods threaten communities the flood become a hazard. In Hawke's Bay stop banks have been built alongside many of the rivers to hold in the extra flood water. However in a severe storm, rivers could breach stop banks and the flood waters may go through farms, homes, shops, schools and damage roads and other infrastructure.There have been significant flood protection systems completed on the Heretaunga Plains and the Ruataniwha Plains. Flood protection works in Hawke’s Bay are generally designed to contain a 1% annual exceedance probability (AEP) flood). These works have significantly reduced the effect of small to medium sized floods, but a large flood could overwhelm the works and have a devastating effect. Such a flood, which exceeds the design capacity of the flood protection system, is called a Super Design Flood. Flooding from localised downpours in urban areas can also overwhelm drainage systems, so events below the AEP can still be costly.With climate change, rainfall patterns in the Hawke’s Bay are expected to change over the next century; winters are predicted to become drier, but overall flood risk is expected to increase as single events may be more intense.

The East Cape has a history of “hits” from decaying tropical cyclones causing widespread flooding and disruption. There are also other events that are more localised and result from a weather system dumping a large volume of water in a small area. A recent study showed that there is a trend of less of these events, but when they occur more rain falls. Most areas north of Ruatoria have a higher average rainfall than the south of the district and can cope with high rainfall events. The Waikura Valley for example can get 200mms in a 24 hour period without any adverse effects. The populated areas likely to be worst affected in a large event are the Poverty Bay Flats, Te Karaka and the area just north of Tolaga Bay. More intense localised events such as the 1985 Ngatapa flood and the 1977 Glenroy flood also caused substantial damage. Most of the Poverty Bay Flats, during inundation, is not subject to fast flowing water but huge areas are subject to ponding, which after the water recedes, will leave thick layers of silt damaging pasture and fences. In the city a number of riverbank properties are at risk. Extensive flooding depends upon the tides, potential overflow from the Waipaoa River, storm surges and the flood-peak times of the Taruheru and Waimata Rivers.

Coastal Flood Hazard Zone 0 (CFHZ0) – the area potentially susceptible to coastal flooding in a 1% AEP event as of 2020

Coastal Flood Hazard Zone 1 (CFHZ1) – the area potentially susceptible to coastal flooding in a 2% AEP event in 50 years (including 0.6m of sea level rise)

Coastal Flood Hazard Zone 2 (CFHZ2) – the area potentially susceptible to coastal flooding in a 1% AEP event in 100 years (including 1.2m of sea level rise)

Coastal Flood Hazard Zone 3 (CFHZ3) – the area potentially susceptible to coastal flooding in a 1% AEP event in 100 years under a rapid sea level rise scenario (including 1.2m of sea level rise)

Coastal flood hazard zones were developed by 3 different external expert consultants in 2020. The layers are derived by advanced models using empirical calculations including tide gauge and extreme water level analysis, wind records and wave models, and used the 2019 LiDAR DEM. Three different models were used to construct the coastal flood layers: a full-coastline ‘bathtub model’ (Tonkin and Taylor, 2020), and two hydrodynamic models for Rangaunu (eCoast, 2020) and Kaipara (DHI, 2019) harbors. The reports detailing the methodologies can be accessed from the NRC website.

Waikato District Council - Proposed District Plan (Appeals version), released 8th August 2022. This layer is a spatial representation of an overlay in the Proposed District Plan and indicates where land use will be regulated by various associated rules. It will be used as a guide in the regulatory process of implementing the Proposed District Plan and managing land use, subdivision, the environment and economy. This dataset is subject to changes undertaken through the Resource Management Act. Note individual Proposed Plan rules can have different statuses, some may have current legal effect and others will not until the Proposed Plan becomes operative. This data is provided for use in the District Plan only.

Areas adjacent to the 100yr ARI floodplain that are within 0.5m of the predicted 100yr ARI flood level. These mapped areas are to ensure the appropriate planning rules are considered for properties developing adjacent to the floodplain Created by the Stormwater Hydraulic Modelling Team Last Update 23 May 2013Disclaimer: In using the Catchments and Hydrology data set, you acknowledge that you have read, understood and agreed to the disclaimers below.The flood plains and flood sensitive area data layers are generated from catchment level modelling based on the datasets, requirements and technology available at the time of model build. They are compiled regional layers with varied data uncertainty and currency, which may directly impact data accuracy for the area of interest. The information provided therefore does not preclude the need for appropriate site-specific assessment and cannot be construed as an endorsement or approval of any development by Auckland Council.The Catchments and Hydrology data set is updated regularly when new information becomes available. As such, downloading and copying activities may result in data invalidity.Whilst due care has been taken in producing the Catchments and Hydrology data sets, Auckland Council gives no warranty as to the accuracy and completeness of any information given and accepts no liability for any error, omission or use of the information.

This layer contains the index tiles for LiDAR data for the Nelson - Tasman region, captured between 23 August 2022 and 6 September 2022.

• The DEM is available as layer Nelson and Tasman - Top of the South Flood LiDAR 1m DEM (2022).

• The DSM is available as layer Nelson and Tasman - Top of the South Flood LiDAR 1m DSM (2022.

• The LAS point cloud and vendor project reports are available from OpenTopography.

LiDAR was captured for Nelson City Council, Tasman District Council, Waka Kotahi NZ Transport Agency and the National Emergency Management Agency by Aerial Surveys Ltd between 23 August 2022 and 6 September 2022. These datasets were generated by Arial Surveys Ltd and their subcontractors. Data management and distribution is by Toitū Te Whenua Land Information New Zealand. Coverage includes Nelson to Brightwater, including the Waimea River, State Highway 6 from Hira to Rai Valley and Ōkiwi Bay access road, plus Abel Tasman Drive, Bird Hill and Takaka Hill in Golden Bay.

Data comprises:

• DEM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout

• DSM: tif or asc tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout

• Point cloud: las tiles in NZTM2000 projection, tiled into a 1:1,000 tile layout

Pulse density specification is at a minimum of 2.8 pulses/square metre.

Vertical Accuracy Specification is +/- 0.2m (95%) Horizontal Accuracy Specification is +/- 1.0m (95%)

Vertical datum is NZVD2016.

Orthophotography within the West Coast Region captured in the flying season of 2020-2021.

Imagery was captured for Toitū Te Whenua Land Information New Zealand by Aerial Surveys Ltd, Unit A1, 8 Saturn Place, Albany 0632, New Zealand.

Data comprises: • 105 ortho-rectified RGB GeoTIFF images in NZTM projection, tiled into the LINZ Standard 1:1000 tile layout. • Tile layout in NZTM projection containing relevant information.

The supplied imagery is in terms of New Zealand Transverse Mercator (NZTM) map projection. Please refer to the tile index layer for specific details, naming conventions, etc.

Imagery supplied as 12.5cm pixel resolution (0.125m GSD), 3-band (RGB) uncompressed GeoTIFF. The final spatial accuracy is ±0.25 at 95% confidence level in clear flat areas.

Also available on: • Basemaps • NZ Imagery - Registry of Open Data on AWS

Index tiles for this dataset are available as layer Westport Flood 0.125m Urban Aerial Photos Index Tiles (2021)

This modelled fluvial flood depth data was created for the 0.1% annual chance of flooding situations and was produced as a by-product from the 2004 generalised modelling project. The purpose of the generalised modelling project was to fill the gaps where there was no detailed local modelled data in 2004, in order to define the extents of Flood Zones for spatial planning.

A two-dimensional hydrodynamic model called JFlow was used to produce this modelled fluvial flood depth data on a 5x5m grid.

Since 2004, local detailed modelling has been used to replace this generalised modelling in many areas to define the extents of Flood Zones. However this depth dataset has not been updated.

INFORMATION WARNING: This data is not suitable for identifying whether an individual property will flood, for detailed decision making or for use in site specific Flood Risk or Strategic Flood Risk Assessments. Where this data is used for anything other than broad catchment or Shoreline Management Plan scale further evidence, verification and studies should be undertaken.

More recent, accurate and local detailed modelling depth data is available for many places. Please contact your local Environment Agency office to see if detailed modelling is available for your area of interest.

This metadata record is for Approval for Access product AfA238 Flood Zone Depth Grid Dataset 2004

Modelled fluvial flood depth data are available for the whole of England, however this data is for the 100x100km squared Ordnance Survey National Grid reference NZ. If you are interested in data for another grid reference refer to the Ordnance Survey National Grid document linked below to find the relevant referencing code and search on Data.gov.uk again to download the data. https://www.ordnancesurvey.co.uk/docs/support/national-grid.pdf

The map shows the 1% AEP RCP 8.5+. This is a representation of severe flood hazard exposure, with significant climate change impacts. The undefended case removes levees from the model. This gives a representation of the population at risk. Defences can be breached, which is why this is important to consider for exposure analysis for planning and emergency management. The ground survey or Digital Elevation Model (DEM) used in this model is derived from LiDAR captured in 2013/2014 with a 1m horizontal resolution. Modelling accuracy is expected to be reduced around features (channels, embankments) smaller than 20m, and is mapped to a 5m resolution. The model does sample the LiDAR at a higher resolution to conveyance characteristics of the higher resolution LiDAR. A static tidal boundary has been adopted for this assessment which does not take varying tidal conditions into consideration, but does consider extreme sea level impacts like storm surge. The model includes stormwater flooding but is less accurate in urban catchments. This model considers all catchments not just those with Greater Wellington flood protection schemes in place.

The Coastal Storm Inundation dataset maps the extent of sea water coverage expected around the Auckland Region during sustained coastal storm-tide flooding events. Elevated storm-tide sea levels are predicted based on the joint probability of a high tide, a storm surge (which is the rise in sea-level caused by wind action and low barometric pressure related to storm events), and wave setup. (Wave setup is the elevation of the mean sea level at the shoreline due to breaking waves. Larger dynamic wave processes like wave runup and overtopping are not included in this mapping so should be considered on top of these water levels. Rainfall and freshwater flooding are also not included in this data, but are available separately in other geomaps layers e.g. ‘Flood Plains’, or on the Auckland Flood Viewer). Coastal inundation (or coastal flooding) is mapped for a range of Annual Exceedance Probability (AEP) events, where the AEP is the % probability of an event occurring each year. Extreme events can also often be referred to by their return period, or Average Recurrence Interval (ARI). The table below gives the conversion between the two terminologies:AEP (%)ARI (yr)18.154.9202.0501.0100The extreme sea level events were 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)Increments of sea level rise have been applied on top of storm-tide sea level events in order to assess the increasing coastal flooding hazard into the future. 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 Environmentand NZ Sea Risefor more information on MfE’s interim guidance on sea level rise and vertical land movement.The inundation mapping is based on the Digital Elevation Model ground levels surveyed by aerial LiDAR between 2016-2018. Coastal inundation mapping is not available for some scenarios for the Parakai-Helensville area as this area’s complex dynamics requires hydrodynamic modelling to accurately assess the coastal storm inundation extent. Hydrodynamic modelling has not yet been carried out for all scenarios (e.g. 1.5m sea level rise) but is available for most 2% & 1% AEP scenarios and all tidal (MHWS) scenarios. Please see technical report 2020/024for information on the hydrodynamic modelling. Extreme 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. Additional coastal flooding scenarios (annual exceedance probability events + sea level rise) were mapped in 2023 by Watershed Engineering and mean high water spring tides + sea level rise were mapped by NIWA.(Note: The studies informing this mapping of coastal inundation generally used Auckland Vertical Datum 1946. Auckland Council is now transitioning to using New Zealand Vertical Datum 2016.)Update Cycle:Adhoc when improved data becomes available.This data is available to the public on the Geomaps viewer and on Auckland Council Open Data portaland some coastal flood mapping is copied into LIM reports.

Greater Wellington provides flood hazard advice to people across the Wellington Region, helping you to identify potential flood hazard on your property, and provide advice on appropriate development in flood hazard areas. This app helps people understand if they live in an area that could be impacted by flooding. It’s also used to inform district planning.We also provide flood hazard information for the rivers and streams we maintain, and local councils also hold flood hazard information. Wellington Water holds stormwater flooding models for areas of Porirua, Wellington, South Wairarapa and Upper and Lower Hutt. Note that local district plan rules apply when buying, selling, or developing in a flood hazard area.

Made available for NPDC GeoHUB (GIS Hub Site and Open Data Portal) :A full description is available in the Metadata. SeeTerms of Use.Notes:The "Updated" date, noted here in the item, does not accurately reflect the currency of the data within the Feature Layer.The data available for download on NPDC GeoHUB is updated daily, this results in differences between what is available online and NPDC's databases.