Floodviewer

We’ve got an ongoing programme to help us understand what would happen in areas of Hamilton if we had a very large, and rare, amount of rain, and where stormwater is expected to flow when stormwater pipes become blocked, their capacity is exceeded or where there is no piped network. 

When we receive new or updated data about these potential flood effects on properties in the city, we’re required by law to make this publicly available upon request and we use an online tool, Floodviewer, to host Councils best available city-wide data and make it more accessible to the public.

The tool shows: 

  • Flood hazards/extent – this is the land that’ll be covered during heavy rainfall (one-in 100-year-event). We’ve currently got 70% of the city mapped for this with most of the rest of the city set to be completed in 2023.
  • Overland flow path - these are the paths water will try to flow when our piped network becomes blocked, is exceeded or where there is no piped network.
  • Flood Depression Areas – city wide information coming soon – these are the areas that have the potential to ‘fill up’ with water. 

You can search Floodviewer by property address but before you check it out, we recommend you read the below FAQs as the tool holds a lot of information and can seem quite complex for people not used to working with Council mapping systems. 

If you have any questions regarding your property or future plans for development, we’re here to help. Please contact one of our team to discuss it either by email at City.Development@hcc.govt.nz or by calling 07 838 6699 during business hours.

For information on being prepared for floods please visit Civil Defence.

View Floodviewer

Operative District Plan

The Resource Management Act 1991 makes the Council responsible for controlling any actual or potential effects of the use, development or protection of land to avoid or mitigate natural hazards.

The Operative District Plan (2017) identifies flood hazard areas and has objectives, policies and rules specific to each area. These rules in the Operative District Plan apply to new subdivision, use and development and guide the development of new buildings and extensions to existing buildings 

View the District Plan

Waikato Regional Hazards Portal

View the Waikato Regional Hazards Portal

To find out more about how you can project yourself, your family and your property visit Civil Defence.

Update: Overland flow paths

Overland flow paths are the latest information we’ve added to Floodviewer.

What is an overland flow path?

Overland flow paths show the way the water will flow based on ground levels. Effectively water flows downhill. These paths are where water will flow when stormwater pipes are blocked or full (or where there are no pipes for the water to flow into).

Why does it matter?

This information can help property owners consider where flood water would go. This is particularly important if you’re planning changes to your property including big changes, like building a house or basement garage, or small changes such as a raised garden, a shed or playhouse. It also helps inform development and consenting, allows us to appropriately plan and maintain the stormwater network and mitigate or reduce flood risk in these areas.

What do you need to do?

You don’t need to do anything with this information right now, but we do encourage you use the tool to find out more to be informed in case of a flood event. If you’re looking to develop your property, the Floodviewer tool can provide useful information for that process.

What’s next?

  • In the next few months we’ll add data around flood depression areas.
  • We’ll complete the flood hazard maps for a majority of the city in 2023.

 

Overland flow paths (OLFPs)

What is an OLFP?

OLFPs are a type of flood mapping tool. They predict the flowpath of water over the ground when the stormwater network is overloaded/ pipes become blocked, capacity is exceeded or where there is no pipe network.

Historically, development has relied on a piped network for stormwater management. Little consideration was given to what might happen if the piped network was exceeded or inlets became blocked.

What is currently being updated in the Floodviewer tool and why?

Council is updating Floodviewer to show OLFPs. The information will be published on Council’s Floodviewer and is expected to appear in the information supplied as part of any LIM request and considered as part of development proposals and consent applications.

Why is the OLFP data shown as a line?

The OLFPs are simply the predicted flowpath of water over the ground. They do not represent a specific flood event (e.g. it’s not a one in 100 year event). They are the centreline of the predicted OLFP and do not show the potential width of the OLFP, which could be much wider than what is represented.

Why is there an OLFP line through my building?

The OLFPs have been mapped based on ground levels captured using LiDAR (light detection and ranging data). The ground level data removes the effect of buildings so the OLFPs do not consider the possibility that buildings may divert the overland flow. However, most buildings usually do not completely divert overland flows as they would likely re-join the mapped OLFP further downstream.

What would I use this data for?

This information indicates where water might flow or pond in a flood event. This information should be considered when developing property.

What does major, moderate, minor OLFP mean?

OLFPs are categorised by the size of the upstream catchment area contributing (i.e. flowing) to that particular length of OLFP.

There are technical reasons for the sizes of these catchment areas, but Council has also chosen to use the same definitions used in other parts of New Zealand, such as Auckland and Taranaki, so we are consistent with our neighbouring regions.

Categories

Contributing catchment area

Minor

2000 m2 – 4000 m2

Moderate

4000 m2 – 30,000 m2

Major

Larger than 30,000 m2

What the flood information means

Will the flood information affect my rates?

The flood information will not directly affect your rates. Any works Council undertakes to address flooding would normally be determined through the 10-Year Plan process and funded from either rates or a combination of rates and development contributions.

Will the flood information affect my rates?

The flood information will not directly affect your rates. Any works that Council undertakes to address flooding would normally be determined through the 10-Year Plan process and funded from either rates or a combination of rates and development contributions.

What does Floodviewer tell me?

Floodviewer shows whether properties within modelled areas are affected by flooding in a 100-year flood. In early 2023 we will be adding citywide information that shows OLFP and flood depression areas.

What use is 100-year flood information?

Flood information shows people whether their property is likely to flood during a 100-year flood. These floods have a 1% probability of occurring in any given year.

Why is this information important?

The information shows whether this is low, medium or high flood hazard and enables you to prepare an emergency plan. The flood information can also inform what you do on your property. For example, owners of properties with a flood hazard showing should consider where flood water will rise and flow on the property particularly if intending to develop. People must avoid making flooding worse on any other properties by blocking or diverting flood water. For example, this could happen by constructing a raised garden, garden shed or playhouse in a flood area. They should also take care when altering the level of their property that they do not inadvertently direct water where it is not wanted, such as towards the door of a building.

Will my house be flooded?

Flood maps can look like they show flooding on top of the buildings. In reality, the water may go under, through or around the building. Whether flood water gets into a building depends on how high off the ground the floors are compared with the depth of the surrounding flood water. Council is unable to provide floor levels of existing buildings but can supply detailed maps showing maximum flood depth and velocity and design flood level for individual properties in a 100-year flood for flood-modelled areas. These maps may be requested by:

Do I have to move out or raise the floor level of my house?

You may wish to understand the flood risk to your property and modify your property to reduce the risk. Flood hazard rules in the District Plan apply to new subdivisions, land use and development. The rules also guide the development of new buildings and extensions to existing buildings, but they don’t require you to modify your home.

What happens if my house or land is only partly in a flood hazard?

If any part of your property is shown in a flood hazard area in the District Plan, then the floors of any new buildings and extensions to existing buildings are required to be a minimum height above the floodwater level.

If Floodviewer updates the flood hazard area on your property from that shown in the District Plan, or if your property is in a flood hazard area not identified in the District Plan, then contact Council’s customer services on 07 838 6699. Staff will direct you to someone who can advise you of any relevant requirements for new buildings and extensions to existing buildings.

If no flooding is shown, is the property free of flooding?

Floodviewer shows best available flood information, but this does not mean there is no risk of flooding for the following reasons:

  • Some areas are yet to be modelled, so we don't have data available for them; these are greyed out in Floodviewer.
  • Because modelling relies on data inputs and assumption, the model may not predict the full extent of flooding.
  • Flood hazard mapping is for a 100-year event. A larger flood event could flood a larger area and/or to a greater depth than shown on the flood hazard maps.

What is the earthworks layer in Floodviewer showing?

The earthworks layer shows areas that have been affected by significant, consented earthworks. Within this area, the flood hazard mapping is no longer reliable because land contours and, as a result, flooding, may have changed. The earthworks layer will be updated at least annually.

What does the flood information mean for resource consents?

The District Plan identifies flood hazard areas and has objectives, policies and rules specific to each area. These provisions set out the requirements to be met, whether resource consent is required, and the criteria to be used to assess whether to grant or decline resource consent. When making decisions on resource consents, Council will also consider the flood information displayed on Floodviewer if the District Plan provides the discretion for this to happen. New subdivision, land use and development should avoid areas subject to flood hazards, if the level of risk is unacceptable. Refer to Chapter 22 and the features maps of the District Plan for details.

What does it mean if my land is not in a flood hazard in the District Plan?

The flood hazard information displayed on Floodviewer is the best available information. Whether a resource consent is required for any proposed activity on such a property depends on the requirements of the District Plan and whether the District Plan provides discretion for consideration of Floodviewer information with respect to the proposed activity. Best available information, regardless of whether it is shown in the District Plan, should be considered whenever planning development. For example, it is expected to be used as part of the Building Consent process.

What happens if there is a difference between the District Plan and Floodviewer?

Council may consider the flood information displayed on Floodviewer when making decisions on building consents. The Building Act requires any building consent application for a site that has a flood hazard to demonstrate that the proposed buildings and site work will protect the outfalls of drainage systems and safeguard people from injury or illness, and other property from damage, caused by surface water. This includes demonstrating, amongst other things, that:

  • The disposal of surface water collected or concentrated by buildings or sitework will avoid damage or nuisance to other property in a 10-year event (an event having a 10% probability of occurring any year); and
  • Surface water resulting from a 50-year event (an event with a 2% probability of occurring any year) will not enter any housing, communal residential or communal non-residential buildings.
  • Adequate provision has been or will be made to protect the land, building work or other property from the likely flood hazard (considered as a 100-year event, i.e. an event with a 1% probability of occurring any year).

Does the flood information affect insurance?

Council cannot advise on how flood information affects insurance cover. If you have questions we recommend discussing this with an insurance provider. Insurance policies often require policy holders to advise the insurer of any new information about natural hazards on an insured property. The public, including insurance companies, can access Floodviewer.

Will the flood information affect property values?

Council is required to produce the best available flood information and make it available to the public on request, including anybody considering buying a property. Property valuations reflect sales evidence up to the valuation date. Over time, property sales evidence will reveal any effect the flood hazard information has on property values. If you are concerned about the potential impact of flood hazard information on property value, then you could seek advice from a registered valuer.

Will flood information appear on a LIM?

Yes. A LIM outlines all information a council holds on a property, including permitted land use, consents, stormwater and sewer drains, rating information and potential natural hazards including erosion and flood hazards.

What will a LIM say about flooding on a property?

Where the property that is the subject of the LIM lies within a flood hazard area identified in the District Plan, the LIM will simply state what types of flood hazard are present. That is, whether it is high, medium or low. Where the property lies in a flood area identified on Floodviewer, additional details of the flooding will be included in the LIM.

Why Council gets and publishes flood information

Why does Council map flooding?

The Resource Management Act 1991 makes Council responsible for controlling any effects of the use, development or protection of land to avoid or mitigate natural hazards. Council’s Comprehensive Stormwater Discharge Consent also requires Council to avoid or minimise adverse flooding of land and property. Mapping flood hazards helps Council fulfil these requirements.

Why is Council getting new flood information?

Council is getting new flood hazard maps to achieve flood hazard mapping coverage of the entire city. Council is preparing an Integrated Catchment Management Plan (ICMP) for each catchment to comply with Council's comprehensive stormwater discharge consent. New flood hazard maps are becoming available as each ICMP is developed.

The process Council follows to get and publish flood information

Will the flooding shown in Floodviewer for my property change in the future?

Flooding shown in Floodviewer is the best available information. Models will be created or updated from time to time. Updates may include changes to modelling methods, the inclusion of new infrastructure (e.g. new pipes), new or updated inputs and assumptions (e.g. how much allowance is made for climate change), and changes to landforms (e.g. from earthworks that may change the way water flows).

This means flooding shown on properties may change.

Why isn’t new flood hazard maps added to the District Plan right away?

Council will include in its District Plan only flood maps that are unlikely to be changed by development anticipated during the life of the plan. Such maps are included in the District Plan by way of a plan change or plan review, which is a lengthy and expensive process. Until this happens, new flood hazard maps must remain outside the District Plan.

As flood hazard modelling is useful to people planning or managing development, it is appropriate to make it available to the public by means other than the District Plan, such as Floodviewer.

Technical matters

My property is on a hill or a long way from the River, how can it flood?

A rising river is not the only source of potential flooding, it can also be caused by a pipe network blockage or overloading. Most flood hazard areas result from rain flowing downhill overland, through channels, waterways and gullies, or ponding in localised depressions or low points.

What is a 100-year flood event?

A flood event that is caused by extreme rainfall that, on average, would occur once every 100 years. Such an event has a 1% probability of occurring in any given year.

When did a 100-year flood event last occur in Hamilton?

The last widespread 100-year flood event in Hamilton occurred in 1958. The Waikato River was last at a 100-year flood level in 1998. Waikato River flooding is affected by rainfall upstream of Hamilton. Flooding in Hamilton, other than in the Waikato River Corridor, is affected by rainfall directly on the city. A 100-year flood event has a 1% probability of occurring any year.

What do the different flood hazard areas mean?

There are three categories of flood hazard - high, medium and low. The following figure shows how the modelled maximum flood water depths and speeds resulting from overland flow and ponding determine the hazard category applying at any location, except within the Waikato River corridor.

Figure 35.1: Flood hazard areas, except within the Waikato River Corridor

Figure 35.1: Flood hazard areas, except within the Waikato River Corridor

 Flood hazard areas in the Waikato River corridor are defined using the following figure.

Figure 35.2: Flood hazard areas in the Waikato River Corridor

Figure 35.2: Flood hazard areas in the Waikato River Corridor

What the flood hazard categories mean for people and property

 

Flood Hazard Category

Floodwater depth

Floodwater speed
(metres per second)

Depth x speed

Effect on people and property

(None)

0 to 10cm

Any velocity likely to occur in a flood

-

Surface water is unlikely to be a hazard to people and unlikely to cause damage to property.

Low

10 to 50cm

< 1.0m/s

-

Emergency vehicles will usually be able to drive through the flood water. Damage to property will be minor to moderate. Damage will be more severe if the flood level is above floor level. Scour or erosion of building foundations is unlikely to occur. People can usually stand up in and wade through the flood water, but more vulnerable people (e.g., children, elderly, injured and physically disabled) may not be able to do this.

Medium

50 to 100cm

< 2.0m/s

<1

People may not be able to stand up. Damage to property can be financially significant.

High

>100cm

> 2.0m/s

>1

Flood water can scour building foundations, resulting in buildings becoming unstable. Significant damage to buildings and risk to life are very likely.

Notes: During a flood, buildings with floors that have adequate freeboard above floodwater are unlikely to suffer significant flood damage, whereas buildings with floors below the floodwater level are likely to suffer damage from water and silt.

Being in a Low Flood Hazard Area does not automatically mean existing development is at a low level of risk, nor that existing development within a High Flood Hazard is at a high level of risk. The level of risk associated with the flooding of an existing development or land use depends upon how often the flooding would occur and its consequences. It is recommended you consider seeking expert stormwater engineering / risk assessment advice, if you require an assessment of this risk. Such an assessment should consider the floor levels of buildings in relation to the modelled flood water depth, the effects of water getting into the building, whether the building has been constructed to withstand the force of the flood water expected, and whether it will be safe for people to get into or out of the building during a flood.

The District Plan uses the Low, Medium and High Flood Hazard Areas to determine whether new subdivision, new use or new development should be assessed through a consent process to identify the level of risk and whether this is acceptable or not. If the level of risk is unacceptable, then consent for the new subdivision, new use or new development may be refused.

Floodviewer uses the same Low, Medium and High flood hazard categories. Flood hazard information from Floodviewer, which is not in the District Plan, can be considered by Council as part of determining whether to grant, or impose conditions on, a subdivision consent.

Is all flooding in Floodviewer the same accuracy?

The flood data on Floodviewer is best available information. Council's flood data is based on models that vary in age and levels of accuracy. This means some flood information can be used directly, while other information requires interpretation by a suitably qualified person to ensure its limitations are understood and the information is correctly applied. For example, whether an old model is accurate enough to set the height of a habitable floor in a new house. Council's flood modelling information has been assigned an information level which relates to the current assessment of each model's level of accuracy. There are five information level categories generally based on Waikato Regional Council's classifications. Floodviewer shows model data that has been assessed as level 1, 2 or 3. Information level 5 is not considered accurate enough to be displayed in Floodviewer. Level 4 is general information which may be included later. Anyone can request data that informs the flood maps (the maximum depth and velocity and design flood level) and the information level associated with that data by:

  • Phoning (during normal business hours) 07 838 6699, or
  • Emailing development@hcc.govt.nz.

Information Levels shown in Floodviewer

Information ​level

Level Description

1​

Property Scale

  • Information is suitable for determining floor levels and/or Building and Resource Consent applications.
  • Input data is accurate/best available and consistent with current guidelines.
  • Modelling process is detailed and robust.

2

Local Scale

  • A suitably qualified person will need to assess whether the information is suitable for determining floor levels and /or Building and Resource Consent applications.
  • Input data is accurate but not consistent with current guidelines.
  • Modelling process is detailed and robust.

3

Regional Scale

  • Information is generally not suitable for determining floor levels and /or Building and Resource Consent applications.
  • A suitably qualified person will need to assess for which purposes the information can be used.
  • Could be used for high-level constraints mapping, emergency management or future mitigation scenarios.
  • Input data is not consistent with current guidelines and contains minor errors that impact model accuracy, but the information has some value.
  • Modelling process is robust.

On what climate change assumptions are the flood models based?

Each flood model used to produce the information shown on Floodviewer is based on one of three climate change assumptions described below. There are three different climate change assumptions because the flood models have been developed at different times and the understanding of climate change and its effects on flooding, and the recommended approach to modelling these effects, have changed over time.

  1. No allowance for climate change. (This applies to the 100-year Waikato River Flood model only).
  2. Increase of 2.1 degrees Celsius average to 2090 relative to 1980 – 1999.
  3. Increase of 3.1 degrees Celsius average to the period 2081 – 2100 (RCP8.5) relative to 1986 – 2005.

What can be done about flooding

Is the stormwater system inadequate?

No.

Whenever stormwater runoff exceeds the drainage capacity of the stormwater network, ponding and/or overland flow is expected. It would be extremely expensive to provide a drainage network that avoids all ponding and overland flow. Council first set design levels of service for the stormwater network in Hamilton in the 1980s but has since amended them.

As at 2018, different design levels of service have applied to existing and new development. For existing development, Council plans to maintain the following levels of service for the stormwater system: 2-year event for residential, 5-year event for commercial, and 10-year event for industrial (page 123 of the 2021-2051 Infrastructure Strategy).

For new development, the Regional Infrastructure Technical Specifications (the RITS) requires new primary stormwater systems for residential, industrial and commercial areas to be designed for a 10-year rainfall event.

These stormwater systems may include (but are not limited to) wetlands, ponds, lakes, rain gardens, swales, filters, pipelines, inlet/outlet structures and soakage areas (RITS, updated May 2018, page 15).

What will Council do to fix the flooding or make sure it doesn't get worse?

Council will consider flood information when managing its assets and planning future stormwater network improvements. These improvements could include increasing culvert or stormwater pipeline sizes or constructing stormwater detention facilities. Council may also require developers to install on-lot stormwater devices in new developments. Decisions on the priority and timing of stormwater upgrades are made via Council's Annual Plan and 10-Year Plan processes.

What can I do to reduce the effects of flooding on my property?

We encourage you to seek professional advice (e.g. from a stormwater engineer) about ways you can reduce the risk of flood damage to your property. Reducing the risk of flooding on your property must not make the flooding of any other property worse.

What is freeboard?

Freeboard is the vertical distance between the modelled top level of flood water and the underside of a concrete floor slab, or the underside of a floor joist.

Why is freeboard required?

Minimum freeboard provides a safety factor to reduce the risk a building will be flooded in a 100-year event.

The freeboard allows for:

  • the predicted flood level
  • some uncertainty in the energy of flowing water (think of how water “breaks” or “climbs” up an obstacle placed in flowing water)
  • waves created as water passes around or over obstacles
  • the wake of people or vehicles moving through flood water.

The freeboard may also provide a margin of safety should the flood be greater than the 100-year event.

When is freeboard required?

Where any part of a property is within a flood hazard area, then all new buildings and extensions to existing buildings must comply with the minimum freeboard.

Types of flood information and how to access it

What flood information is available for Hamilton?

Type of flood information

Description

Is it included on the Operative District Plan (2017) planning maps?

How you can see or get the information

Earthworks Area

Significant earthworks have occurred that mean that the mapped flooding within this area is no longer reliable. The flooding may be remodelled in the future to update the flood information.

No

On Floodviewer

100-year Flood Hazard

This layer shows the flood hazard that is predicted to occur on average once in 100 years. This hazard has a 1% probability of occurring in any year. Any flood water shallower than 10cm is not shown because it is not considered a significant hazard. Flood hazards are shown as low, medium, or high.  

"Yes" for some areas, "no" for others. To determine which, you will need to compare the 100-year flood information on Floodviewer for your area of interest with the flood hazard mapping in the District Plan. The next column to the right shows how to see or get that information.

  • All available 100-year flood information (including that in the District Plan) is shown on Floodviewer.
  • Flood hazard mapping included in the District Plan can be viewed on the Features Map of the District Plan GIS Map Viewer – click here.

Detailed 100-year flood hazard data for individual properties

For each 2m x 2m area of a property the following information for a 100-year flood is available:

  1. Flood hazard categories (low, medium and high)
  2. Maximum flood depth
  3. Maximum flood velocity
  4. Design flood level.

On request Council can supply these for areas where flood modelling has been completed.

No

These maps may be requested by:

100-year Flood Extent

This layer shows the full extent of flooding likely to occur on average once in 100 years. This flooding has a 1% probability of occurring in any year and includes flooding less than 10cm deep.

Currently this information is only available for parts of the city.

No

On Floodviewer

100-year Waikato River Flood Area

This information is provided by Waikato Regional Council to show the extent of Waikato River flooding likely to occur on average once in 100 years.

Only the depth of flood water is used to determine the flood hazard.

Yes

  • On Floodviewer
  • On the Features Map on the left-hand side of the District Plan GIS Map Viewer – click here; or
  • On the Waikato Regional Hazards Portal – click here – on the "River Flooding" tab – see "Waipa and Waikato 1% AEP flood extent"

Design flood levels for the Waikato River

The locations of surveyed cross-sections and their identification numbers and a form for requesting the design flood level at a cross-section.

No

On the Waikato Regional Hazards Portal – click here – on the "River flooding" tab

Karapiro dam break

The predicted extent and depth of flooding if Karapiro Dam were to break

No

On the Waikato Regional Hazards Portal– click here – on the "Karapiro dam break" tab

Drainage scheme boundaries

Waikato Regional Council's drainage scheme boundaries

No

On the Waikato Regional Hazards Portal– click here – on the "Flood management" tab

Temple View Flood Hazard Area

These areas are susceptible to flooding associated with small-scale farm dams and secondary flow paths that are part of the Waipa Flood Prevention Scheme. The extent of this hazard area is based on a 100-year event.

Yes

On the Features Map of the District Plan GIS Map Viewer – click here.

Culvert Block Flood Hazard Area

This applies upstream of significant culverts in the gully system. It represents the maximum effect of a culvert becoming blocked and water backing up the gully until it eventually flows over the accessway or road above the culvert.

Yes

On the Features Map of the District Plan GIS Map Viewer – click here

Flood hazard maps included in the District Plan

Flood hazard mapping included in the District Plan is based on computer modelling. In the near term, no development is expected to change it.

In some areas, the flood hazard mapping included in the District Plan has been superseded by more recent flood modelling that has yet to be included in the District Plan. In all instances, the best available information will be that shown on Floodviewer.

To determine whether the flood hazard mapping for your area of interest has been superseded, you will need to compare the two sets of flood hazard information or contact Council at 838 6699.

The boundary of the area modelled is shown as a dashed line labelled "Flood Hazard Subcatchment Boundary" on the District Plan planning maps.

Yes

  • On Floodviewer
  • On the Features Map on the left-hand side of the District Plan GIS Map Viewer – click here.
  • Detailed flood hazard maps for individual lots showing the design flood level and maximum flood depth and velocity on each 2m by 2m grid are available on request from the Council: phone 07 838 6618 or email districtplan@hcc.govt.nz.

Ground contours from LIDAR data

LiDAR stands for "Light Detection and Ranging". It is an aerial surveying method that measures distance to the ground by illuminating the ground with laser light and measuring the reflected light with a sensor. LiDAR works in a similar way to radar and sonar, but uses light waves from a laser, instead of radio or sound waves. LiDAR data is used to create ground surface maps, such as contour maps, and digital terrain models that are used for flood modelling.

No

  • On Floodviewer
  • The ground contour data is available from the Council on request. A time-based charge may apply. Email your request to: gis@hcc.govt.nz.

 

For which parts of the city has flood modelling been completed?

Suitably detailed flood modelling has been completed for the unshaded areas shown on Floodviewer, when none of the layers on the Layer List are ticked. However, the flood modelling will not be reliable for properties that lie within an Earthworks Area.

Why is flood modelling only available for parts of the city?

Flood modelling is expensive. Council prioritised the catchments for modelling. Those catchments that initial screening indicated had the highest number of flood-affected properties were modelled first. Catchments proposed for large scale development were the next priority.

Can I talk to someone at Council about the flood information?

Yes. Call one of the following during normal business hours:

  • Regarding flood data: 07 838 6699
  • Regarding resource consents: Duty Planner via Customer Services 07 838 6699
  • Regarding building consents: Building Call Centre 07 838 6677
  • Other enquiries: City Planning 07 838 6478
  • Customer Services: 07 838 6699
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Last updated 16 January 2023