9.4 Policies

Policy 9-1: Responsibilities for natural hazard^ management

In accordance with s62(1)(i) RMA, local authority^ responsibilities for natural hazard^ management in the Region are as follows:

The Regional Council and Territorial Authorities^ must be jointly responsible for:
1. raising public awareness of the risks of natural hazards^ through education, including information about what natural hazards^ exist in the Region, what people can do to minimise their own level of risk, and what help is available.
The Regional Council must be responsible for:
1. developing objectives and policies for Region-wide management of activities for the purpose of avoiding or mitigating natural hazards^,
2. developing specific objectives, policies and methods (including rules^) for the control of:
  1. all land^ use activities in the coastal marine area^,
  2. erosion protection works that cross or adjoin mean high water springs,
  3. all land^ use activities in the beds^ of rivers^ and lakes^, for the purpose of avoiding or mitigating natural hazards^, and
3. taking the lead role in collecting, analysing and storing regional natural hazard^ information and communicating this information to Territorial Authorities^.
Territorial Authorities^ must be responsible for:
1. developing objectives, policies and methods (including rules^) for the control of the use of land^ to avoid or mitigate natural hazards^ in all areas and for all activities except those areas and activities described in (b)(ii) above, and
2. identifying floodways* (as shown in Schedule J¹) and other areas known to be inundated by a 0.5% annual exceedance probability (AEP) flood event² on planning maps in district plans^, and controlling land^ use activities in these areas in accordance with Policies 9-2 and 9-3.

¹    Schedule J is not a component of Part I - the Regional Policy Statement. It is a component of Part II - the Regional Plan.
²    Flood event does not include the effects of stormwater which are managed byTerritorial Authorities^ under different
     criteria including engineering, subdivision and design standards/manuals.

Policy 9-2: Development in areas prone to flooding

The Regional Council and Territorial Authorities^ must not allow the establishment of any new structure^ or activity, or any increase in the scale of any existing structure^ or activity, within a floodway* mapped in Schedule J unless:
1. there is a functional necessity to locate the structure^ or activity within such an area, and
2. the structure^ or activity is designed so that the adverse effects^ of a 0.5% annual exceedance probability (AEP) (1 in 200 year) flood event2 on it are avoided or mitigated, and
3. the structure^ or activity is designed so that adverse effects^ on the environment^, including the functioning of the floodway, arising from the structure^ or activity during a flood event² are avoided or mitigated,
in which case the structure^ or activity may be allowed.
Outside of a floodway* mapped in Schedule J the Regional Council and Territorial Authorities^ must not allow the establishment of any new structure^ or activity, or an increase in the scale of any existing structure^ or activity, within an area which would be inundated in a 0.5% AEP (1 in 200 year) flood event2 unless:
1. flood hazard avoidance* is achieved or the 0.5% AEP (1 in 200 year) flood hazard is mitigated, or
2. the non-habitable structure^ or activity is on production land^, or
3. there is a functional necessity to locate the structure^ or activity within such an area,
in any of which cases the structure^ or activity may be allowed.
Flood hazard avoidance* must be preferred to flood hazard mitigation.
When making decisions under Policies 9-2(a) and b(i) regarding the appropriateness of proposed flood hazard mitigation measures, the Regional Council and Territorial Authorities^ must:
1. ensure that occupied structures have a finished floor or ground level, which includes reasonable freeboard, above the 0.5% AEP (1 in 200 year) flood level.
2. ensure that in a 0.5% AEP (1 in 200 year) flood event² the inundation of access between occupied structures^ and a safe area where evacuation may be carried out (preferably ground that will not be flooded) must be no greater than 0.5 m above finished ground level with a maximum water velocity of 1.0 m/s, or some other combination of water depth and velocity that can be shown to result in no greater risk to human life, infrastructure^ or property*,
3. ensure that any more than minor adverse effects^ on the effectiveness of existing flood hazard avoidance* or mitigation measures, including works and structures^ within River and Drainage Schemes, natural landforms that protect against inundation, and overland stormwater flow paths, are avoided,
4. ensure that adverse effects on existing structures^ and activities are avoided or mitigated,
5. have regard to the likelihood and consequences of the proposed flood hazard mitigation measures failing,
6. have regard to the consequential effects^ of meeting the requirements of (d)(ii), including but not limited to landscape and natural character, urban design, and the displacement of floodwaters onto adjoining properties*, and
7. have regard to the proposed ownership of, and responsibility for maintenance of, the flood hazard mitigation measures including the appropriateness and certainty of the maintenance regime.
Within that part of the Palmerston North City Council district that is protected by the Lower Manawatū River Flood Control Scheme to a 0.2% AEP (1 in 500 year) standard, including the Mangaone Stream stopbank system, additional flood hazard avoidance* or mitigation measures will generally not be required when establishing any new structure^ or activity or increasing the scale of any existing structure^ or activity.
Despite Policy 9-2(d)(i) and (ii), within that part of the Whanganui central city bounded by Bates Street, Ridgway Street and Victoria Avenue, flood hazard mitigation measures will not be limited to considering flood height and flow but will include such methods as resilient construction and emergency management systems.
This policy does not apply to new critical infrastructure*.

Policy 9-3: New critical infrastructure*

The placement of new critical infrastructure* in an area likely to be inundated by a 0.5% AEP (1 in 200 year) flood event² (including floodways mapped in Schedule J), or in an area likely to be adversely affected by another type of natural hazard^, must be avoided, unless there is satisfactory evidence to show that the critical infrastructure*:

will not be adversely affected by floodwaters or another type of natural hazard^,
will not cause any adverse effects^ on the environment^ in the event of a flood or another type of natural hazard^,
is unlikely to cause a significant increase in the scale or intensity of natural hazard^ events, and
cannot reasonably be located in an alternative location.

Policy 9-4: Other types of natural hazards^

The Regional Council and Territorial Authorities^ must manage future development and activities in areas susceptible to natural hazard^ events (excluding flooding) in a manner which:

ensures that any increase in risk to human life, property or infrastructure^ from natural hazard^ events is avoided where practicable, or mitigated where the risk cannot be practicably avoided,
is unlikely to reduce the effectiveness of existing works, structures^, natural landforms or other measures which serve to mitigate the effects^ of natural hazard^ events, and
is unlikely to cause a significant increase in the scale or intensity of natural hazard^ events.

Policy 9-5: Climate change^

The Regional Council and Territorial Authorities^ must take a precautionary approach when assessing the effects of climate change and Msea level rise* on the scale and frequency of natural hazards^ with regard to decisions on:

stormwater discharges^ and effluent disposal,
coastal development and coastal land^ use,
activities adjacent to rivers^,
water^ allocation and water^ takes,
activities in a Hill Country Erosion Management Area*,
flood mitigation activities, and
managing storm surge.

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Chapter 9: Natural Hazards