Te Kāuru Upper Ruamāhanga Floodplain Management Plan

Consultation has concluded

Submissions closed 14 April 2019.

Download a copy of the Te Kāuru Upper Ruamāhanga Floodplain Management Plan.

Want to find out what proposals are near your property? Check out the Te Kāuru Interactive GIS map to find out.

We have received the final independent audit report on the Te Kāuru Upper Ruamāhanga hydraulic modelling.

Background

The Te Kāuru catchment includes the Upper Ruamāhanga River upstream of the Waiohine confluence, and its tributaries the Waipoua, Waingawa, Taueru, Whangaehu and Kopuaranga Rivers.

The catchment has a history of flooding, which can be dangerous and cause damage to private property and community assets.

Processes for managing flooding and erosion have been in place for some time. After working with community representatives we realised our plans could do more to reflect wider local values and we want to take a long-term view of managing the whole catchment’s flood and erosion issues.

The process for developing this Floodplain Management Plan (FMP) was done in three broad phases:

Phase 1

  • Establish the context
  • Define the issues, values and objectives
  • Identify the flood hazard
  • Collect information

Phase 2

  • Identify, assess and select management options through the Te Kāuru Subcommittee

Phase 3

  • Achieve sustainable solutions
  • Prepare Floodplain Management Plan

A Floodplain Management Plan

A floodplain management plan is a living document that describes the approach to flood and river management over the next 30 – 40 years. It describes various types of responses and methods that will be used for flood and erosion protection in the Te Kāuru catchment. The various responses and methods include both structural and non-structural measures. Periodically, we will assess the outcomes of this floodplain management plan and review our plan accordingly.

What are we doing? The Te Kāuru Approach

The proposed FMP will allow rivers more space to flow naturally and the freedom to move. We have been working with the community and its representatives for several years on a plan that not only helps to protect from current and future flood and erosion risks, but also better reflects local values.

A wide range of community values have been recognised in the plan and as part of that we are proposing to spread the share of the local costs of river management works across the wider community instead of asking neighbouring landowners to pay. Te Kāuru outlines how this change in costs may work.

A lot of the responses outlined in the proposed FMP build on what we are already doing to manage flood and erosion risks. It’s important to remember that the proposed Te Kāuru FMP outlines a long-term approach to flooding and erosion issues that could take decades to implement and changes will not be visible right away.

More information and reports can be found in the document library to the left. If you would like a hard copy of any of the documents, including the proposed Floodplain Management Plan, or would like more information contact us at TeKauru@gw.govt.nz.


Submissions closed 14 April 2019.

Download a copy of the Te Kāuru Upper Ruamāhanga Floodplain Management Plan.

Want to find out what proposals are near your property? Check out the Te Kāuru Interactive GIS map to find out.

We have received the final independent audit report on the Te Kāuru Upper Ruamāhanga hydraulic modelling.

Background

The Te Kāuru catchment includes the Upper Ruamāhanga River upstream of the Waiohine confluence, and its tributaries the Waipoua, Waingawa, Taueru, Whangaehu and Kopuaranga Rivers.

The catchment has a history of flooding, which can be dangerous and cause damage to private property and community assets.

Processes for managing flooding and erosion have been in place for some time. After working with community representatives we realised our plans could do more to reflect wider local values and we want to take a long-term view of managing the whole catchment’s flood and erosion issues.

The process for developing this Floodplain Management Plan (FMP) was done in three broad phases:

Phase 1

  • Establish the context
  • Define the issues, values and objectives
  • Identify the flood hazard
  • Collect information

Phase 2

  • Identify, assess and select management options through the Te Kāuru Subcommittee

Phase 3

  • Achieve sustainable solutions
  • Prepare Floodplain Management Plan

A Floodplain Management Plan

A floodplain management plan is a living document that describes the approach to flood and river management over the next 30 – 40 years. It describes various types of responses and methods that will be used for flood and erosion protection in the Te Kāuru catchment. The various responses and methods include both structural and non-structural measures. Periodically, we will assess the outcomes of this floodplain management plan and review our plan accordingly.

What are we doing? The Te Kāuru Approach

The proposed FMP will allow rivers more space to flow naturally and the freedom to move. We have been working with the community and its representatives for several years on a plan that not only helps to protect from current and future flood and erosion risks, but also better reflects local values.

A wide range of community values have been recognised in the plan and as part of that we are proposing to spread the share of the local costs of river management works across the wider community instead of asking neighbouring landowners to pay. Te Kāuru outlines how this change in costs may work.

A lot of the responses outlined in the proposed FMP build on what we are already doing to manage flood and erosion risks. It’s important to remember that the proposed Te Kāuru FMP outlines a long-term approach to flooding and erosion issues that could take decades to implement and changes will not be visible right away.

More information and reports can be found in the document library to the left. If you would like a hard copy of any of the documents, including the proposed Floodplain Management Plan, or would like more information contact us at TeKauru@gw.govt.nz.


Consultation has concluded
  • Proposed approach to flood management in Masterton

    8 months ago

    Rivers are the lifeblood of our community.

    In fact, the name Wairarapa means ‘glistening waters’. However, sometimes our greatest assets can cause our biggest risk. Masterton District Council and Greater Wellington Regional Council (GWRC) are currently looking at options for managing the current and future flood hazard to Masterton from the Waipoua River. This is being done through the Te Kāuru Floodplain Management Plan.

    New to this project? Check out the FAQs to learn more.

    As part of the process, draft flood hazard maps have been jointly released by the Councils. The draft flood maps will be finalised following...

    Rivers are the lifeblood of our community.

    In fact, the name Wairarapa means ‘glistening waters’. However, sometimes our greatest assets can cause our biggest risk. Masterton District Council and Greater Wellington Regional Council (GWRC) are currently looking at options for managing the current and future flood hazard to Masterton from the Waipoua River. This is being done through the Te Kāuru Floodplain Management Plan.

    New to this project? Check out the FAQs to learn more.

    As part of the process, draft flood hazard maps have been jointly released by the Councils. The draft flood maps will be finalised following an independent audit, at which point they will replace the current flood hazard maps for Council.

    We're proposing a staged approach to managing the flood and erosion risks over the next 30 years. This will allow a better understanding of the current and future risks to Masterton, prior to a large financial investment. We will communicate and engage with the community during each stage of the process.

    The flood management responses developed for the urban reach of the Waipoua River include a combination of non-structural measures, increased river channel capacity, and new and upgraded stopbanks. However, these will depend on the information collected during the first stage of the process.

    Staged Approach

    We are proposing a staged approach, which will first focus on gathering more information and then addressing today’s risk. The first stage includes gathering some more data, undertaking geotechnical investigations on the existing stopbanks and the surrounding environment, considering detailed alignments for potential stopbank improvements, and raising community awareness and preparedness. The later stages will address the future risk of flooding that includes allowing for predicted climate change. A preferred option will be developed with the community and key stakeholders. Following that we will address the areas at immediate risk of a 1% annual chance flood (Oxford Street), then the Akura Road area. It should be acknowledged that all stages following Stage 1 will be dependent on the outcome of the previous stage.

    Often this size of flood is referred to as a 1-in-100 year flood, we call it a 1% annual chance flood; it means there is a 1% chance of this sized flood occurring in any given year. It does not mean that there is exactly one of these floods every 100 years. It is also important to remember that several big floods could happen in quick succession.

    One of the following stages, in 10-20 years’ time, will look to further review and understand the future flood risk and then a plan to manage that future risk.

    The staged approach is to ensure we are not doing unnecessary work and spending money if it is not needed.

    The approach of increased channel capacity and stopbanks was agreed as the most viable, supported by non-structural responses such as encouragement of wetland establishment upstream. The increased channel capacity is being considered in order to minimise stopbank heights, but it will have medium-term impact on the look and feel of the river channel and berms. A staged approach has been developed to try to manage the affordability.

    Increased Channel Capacity

    The majority of vegetation would need to be removed to achieve the greater channel capacity so the river area would change significantly in the medium term until new trees are established. In doing this, it also creates the opportunity to enhance the recreational and amenity values of the river corridor, including improved spaces for walking, running, cycling, and other leisure activities.

    View the full image.

    River Corridor Proposal

    View the full image.

    Alternative Approaches

    A range of approaches have been considered including upstream storage and the removal of at-risk property. Both of these approaches had significantly higher costs (greater than $30 million) and were not considered further. The approach of increased channel capacity and stopbanks was agreed as the most viable.

    However, other forms of storage such as wetlands further up in the rural reaches of the Waipoua River are included in the proposed approach to help with the flood management.

    What does this mean for you?

    This proposed approach aims to provide flood hazard and erosion protection for the Masterton urban community while enhancing the environmental and cultural values of the river. During Stage 1, we will ensure we are doing this in a sustainable and economical way. Stage 2 may require a flood protection investment in the vicinity of $8 million, however, this will be assessed and confirmed during Stage 1. Funding will be loan based as these projects are long term and have a long-term benefit. Repayment of the loan (borrowed money) will be via a rates increase, similar to how ratepayers in the Carterton area are paying for their new Wastewater Treatment Plant.

    The cost estimates and timeframes of the plan are indicative only. They will be reassessed at the end of each stage and will be balanced with other council priorities.

  • Te Kāuru Upper Ruamāhanga Floodplain Management Plan - current and future flood hazard to Masterton

    8 months ago
    Waipoua high flow

    Masterton District Council and Greater Wellington Regional Council are currently looking at options for managing the current and future flood hazard to Masterton from the Waipoua River. This is being done through the Te Kāuru Floodplain Management Plan. As part of this process, draft flood maps have been developed jointly by both Councils.

    Check out our summary document for all you need to know about Waipoua River flood hazard maps.

    Want to find out what the draft flood hazard maps for Masterton look like? Have a look at the maps with different scenarios here.

    Masterton is a town with the...

    Masterton District Council and Greater Wellington Regional Council are currently looking at options for managing the current and future flood hazard to Masterton from the Waipoua River. This is being done through the Te Kāuru Floodplain Management Plan. As part of this process, draft flood maps have been developed jointly by both Councils.

    Check out our summary document for all you need to know about Waipoua River flood hazard maps.

    Want to find out what the draft flood hazard maps for Masterton look like? Have a look at the maps with different scenarios here.

    Masterton is a town with the Waipoua River running through our urban area. It’s an important natural asset that gives us identity and connection to our environment. It also means Masterton faces a risk of flooding.

    A key role of local authorities is to work with communities to protect them from the effects of hazards including flooding. To do this, we all need to understand the flood risk, put affordable and acceptable flood protection in place and ensure inappropriate development doesn’t create new problems.

    A note on terminology

    Our focus is on understanding the spread and depth of flood waters in an infrequent flood. Often this size of flood is referred to as a 1-in-100 year flood, we call it a 1% annual chance flood; it means there is a 1% chance of this sized flood occurring in any given year. It does not mean that there is exactly one of these floods every 100 years. It is also important to remember that several big floods could happen in quick succession.

    Updated information

    In 2014, Greater Wellington Regional Council shared its understanding of the spread of flooding across urban Masterton in one of these 1% annual chance floods.

    Thanks to access to better information, technology and local knowledge we now have a more accurate picture of what a significant and infrequent flood would look like in Masterton. The modelling has been revised and updated in collaboration with Masterton District Council.

    The new modelling now available shows a future 1% annual chance flood is likely to have less impact on the Masterton urban area than initially thought. The modelling is still in draft stage pending an independent audit.

    The maps, which are still in draft stage, show some areas of the Masterton urban area are likely to experience flooding in a 1% annual chance flood. This is mainly around Oxford Street and areas bordering Akura Road. The depth of flooding varies depending on the scenario being considered; most is likely to be below 30cm, but some areas experience flooding up to two metres.

    Work has also been done to model what a flood would look like in the future (2090) with the impacts of climate change factored in. In this scenario, the flooding spreads across the urban area to the south west of the Waipoua River, including the central business district. However, this flood spread is smaller than what was initially thought in 2014.

    Community feedback

    Over the next few days we will start meeting with members of the Masterton community to provide answers to questions that you may have on the new flood hazard maps that are still in draft. GWRC is happy to provide more detail on a site-by-site basis to assist conversations with insurers. Note that the regulatory implications (e.g, new building levels) will be confirmed prior to final flood maps being produced.

    For more information download a copy of:

    Keen to talk to someone about Waipoua Maps

    You can email the project team at TeKauru@gw.govt.nz or phone them on 0800 496 734


  • Te Kāuru Upper Ruamāhanga Floodplain Management Plan - Phase One

    8 months ago

    Your feedback is important to us — we want to know if Te Kāuru is heading in the right direction.

    Check out our summary document for all you need to know about Te Kauru.

    Want to find out what proposals are near your property? Have a nosy at our Te Kāuru Volume 2 Interactive GIS map.

    Have your say on Te Kāuru by Sunday 16 September 2018.

    The upper Ruamāhanga catchment has a total area of 1560km². The catchment is made up of the Ruamāhanga River upstream of the confluence with the Waiohine and its tributaries the Waipoua and...

    Your feedback is important to us — we want to know if Te Kāuru is heading in the right direction.

    Check out our summary document for all you need to know about Te Kauru.

    Want to find out what proposals are near your property? Have a nosy at our Te Kāuru Volume 2 Interactive GIS map.

    Have your say on Te Kāuru by Sunday 16 September 2018.

    The upper Ruamāhanga catchment has a total area of 1560km². The catchment is made up of the Ruamāhanga River upstream of the confluence with the Waiohine and its tributaries the Waipoua and Waingawa rivers (which flow from the eastern side of Tararua Range), and the Kopuaranga, Whangaehu and Taueru rivers (which have their sources in the eastern Wairarapa hills). The catchment has a history of flooding, causing damage to private property and community assets.

    Processes for managing flooding and erosion – through our river schemes – have been in place for some time. Our draft plan takes a long-term view of the whole catchment. We have been working with representatives from the community to develop a long-term approach to managing the flood and erosion issues. This work has resulted in the development of the draft Te Kāuru Upper Ruamāhanga Floodplain Management Plan (Te Kāuru).

    Community feedback – Stage 1

    We are currently seeking feedback on Te Kāuru for all areas except the Waipoua Masterton urban area. Feedback for the Waipoua Masterton urban area will be requested at a later date. Your feedback is important because we want to find out if the Te Kāuru is heading in the right direction.

    A shift in approach is being proposed in Te Kāuru, which will give the rivers more space to flow naturally and carry out their natural processes within the channel and defined buffers.

    If this shift in approach is adopted, it will mean people who own land along the river will have a level of protection and certainty from river erosion outside of the buffers. However, there may be erosion to their land within the buffers from time to time.

    This shift reflects what your community representatives have told us is important to you. It also takes into account values that are important to the entire catchment, not just those factors that are flood related.

    This is a long term project that will be implemented over decades.

    Te Kāuru seeks to recognise a wide range of the community’s values in how we manage the rivers. Therefore, we are proposing that the local share of costs be spread across the wider community rather than falling mainly on adjacent landowners.

    Download a copy of the different volumes

    We’ve have separated the plan intothree volumes to make it easier to read.

    Volume 1: Background and overview

    Volume 2: Location specific values, issues and responses

    Section 1: Introduction

    Section 2: Ruamāhanga River

    Section 3: Waipoua River

    Section 4: Waingawa River

    Section 5: Eastern Rivers

    Appendix

    *Volume 3: Values, issues and responses for the Waipoua Masterton urban area.

    Keen to talk to someone about Te Kāuru?

    You can email the project team at TeKauru@gw.govt.nz or phone them on 0800 496 734