Coastal hazards in Selwyn

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As part of the Selwyn District Plan Review, the Council has identified areas that may be at risk from coastal erosion and inundation (flooding by the sea) and developed proposed rules for how to manage that risk.

On this website you can find all relevant information on identified coastal hazards in Selwyn and how we propose to manage them in the new District Plan.

Background

Selwyn has a relatively small coastal environment with limited development opportunities, given the rural zoning of the area. The exceptions are the residential part of the coastline at Rakaia Huts, and the proposed Māori Purpose

As part of the Selwyn District Plan Review, the Council has identified areas that may be at risk from coastal erosion and inundation (flooding by the sea) and developed proposed rules for how to manage that risk.

On this website you can find all relevant information on identified coastal hazards in Selwyn and how we propose to manage them in the new District Plan.

Background

Selwyn has a relatively small coastal environment with limited development opportunities, given the rural zoning of the area. The exceptions are the residential part of the coastline at Rakaia Huts, and the proposed Māori Purpose Zone at Taumutu with the Ngāti Moki marae.

When reviewing coastal hazards as part of the Selwyn District Plan Review, we have considered the following hazards:

  • coastal inundation (flooding by the sea of low-lying coastal areas; this is particularly likely when high tides and extreme weather occur at the same time);
  • coastal erosion (where the shoreline retreats on a temporary or permanent basis); and
  • tsunami.
  • Key proposed changes for coastal erosion hazard in the new District Plan

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    3 months ago

    • Proposing to replace the existing map of the Coastal Hazard 1 line in the current District Plan with the newly identified coastal erosion area and map it in the Proposed District Plan as a Coastal Erosion Overlay.
    • This proposed coastal erosion area extends approximately 120 metres inland from the current shoreline and includes productive land, coastal wetland areas, coastal drainage systems and important coastal culvert structures. The area is similar to the existing Coastal Hazard 1 line for much of the district’s coastline, but extends further inland in some areas. The seaward boundary is the district boundary. The...

    • Proposing to replace the existing map of the Coastal Hazard 1 line in the current District Plan with the newly identified coastal erosion area and map it in the Proposed District Plan as a Coastal Erosion Overlay.
    • This proposed coastal erosion area extends approximately 120 metres inland from the current shoreline and includes productive land, coastal wetland areas, coastal drainage systems and important coastal culvert structures. The area is similar to the existing Coastal Hazard 1 line for much of the district’s coastline, but extends further inland in some areas. The seaward boundary is the district boundary. The different coastal processes at Rakaia Huts mean that the proposed Coastal Erosion Overlay doesn’t extend into private property in the township.
    • Subdivision, use and development within the Coastal Erosion Overlay would be subject to rules broadly equivalent to current requirements of the Canterbury Regional Coastal Environment Plan, which landowners already have to comply with. However, once the Proposed Plan becomes operative all resource consents in relation to coastal hazards will be processed by Selwyn District Council and not ECan.
    • For properties in the Rural Zone, any subdivision or building a new dwelling in an area at risk from coastal erosion would be a non-complying activity. This means that a resource consent would be required and would be difficult to get.
    • Work on an existing building would be permitted under certain circumstances, ie as long as the risk from coastal hazards wouldn’t increase with the work.

  • Key proposed changes for coastal inundation hazard in the new District Plan

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    3 months ago

    • Map low-lying coastal areas that may be susceptible to coastal inundation over the next 100 years: land that is less than four metres above sea level in rural areas and 5.8 metres above sea level in Rakaia Huts township. The different level for Rakaia Huts reflects the different coastal processes that take place within this township.
    • This new coastal inundation area is shown on the map in the Proposed District Plan as a Coastal Inundation Overlay.
    • For properties in the Rural Zone, any subdivision or building a new dwelling in an area at risk from coastal inundation would...

    • Map low-lying coastal areas that may be susceptible to coastal inundation over the next 100 years: land that is less than four metres above sea level in rural areas and 5.8 metres above sea level in Rakaia Huts township. The different level for Rakaia Huts reflects the different coastal processes that take place within this township.
    • This new coastal inundation area is shown on the map in the Proposed District Plan as a Coastal Inundation Overlay.
    • For properties in the Rural Zone, any subdivision or building a new dwelling in an area at risk from coastal inundation would be a non-complying activity. This means that a resource consent would be required and would be difficult to get.
    • We are considering slightly less stringent rules for properties in Rakaia Huts that have areas at risk from coastal hazards, when wanting to subdivide or building a new dwelling. This is to recognise that Rakaia Huts township has an existing residential zoning.
    • Work on an existing building would be permitted under certain circumstances, ie as long as the risk from coastal hazards wouldn’t increase with the work.


  • Managing coastal hazards in the current District Plan

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    3 months ago

    The current District Plan identifies and manages an area outlined on the planning map as Coastal Hazard 1 line for Selwyn District. Any development on land between the line and the sea requires a resource consent to enable an assessment of natural hazard risk.

    At Rakaia Huts, building any new dwelling or other principal building, and working on an existing dwelling on the lower river terrace is a non-complying activity. Non-complying activity status is a way for a council to signal that when processing a resource consent for an activity, it will be subject to a greater degree of scrutiny...

    The current District Plan identifies and manages an area outlined on the planning map as Coastal Hazard 1 line for Selwyn District. Any development on land between the line and the sea requires a resource consent to enable an assessment of natural hazard risk.

    At Rakaia Huts, building any new dwelling or other principal building, and working on an existing dwelling on the lower river terrace is a non-complying activity. Non-complying activity status is a way for a council to signal that when processing a resource consent for an activity, it will be subject to a greater degree of scrutiny. In particular the applicant must establish that the adverse effects of the activity on the environment will be minor or that the activity will not be contrary to the objectives of the relevant plan or proposed plan.

    Key issues with the current District Plan

    • The current mapped area at risk from coastal hazards is over 10 years old and pre-dates the national requirements, including taking into account the effects of climate change and future sea level rise scenarios.
    • The current District Plan doesn’t manage coastal inundation other than at Rakaia Huts, and tsunami risk is not addressed at all.