Pukehina EcoVillage Development Natural Hazards Risk Assessment Property Seven Limited Reference: 502328 Revision: 2 2019-04-08

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Document prepared by: Aurecon New Zealand Limited Ground Level 247 Cameron Road Tauranga 3110 PO Box 2292 Tauranga 3140 New Zealand

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Report title Natural Hazards Risk Assessment

Document code 502328-0000-GG-0002[2] Project number 502328

File path \\Aurecon.info\shares\NZTRG\Projects\Projects\502328 - Property Seven - Eco Village, Pukehina\5 Deliver Design\501 Engineering\Ground engineering\Natural hazards risk assessment\Report\Rev2\502328-0000-GG-0002[2].docx

Client Property Seven Limited

Client contact Ben Turner Client reference Pukehina

Rev Date Revision details/status Author Reviewer Verifier Approver (if required) 0 2019-03-18 Report issue K. Altinkaynak R. Griffiths J. Kupec A. Collier CGeol TCC Cat 1 CMEngNZ CPEng 1 2019-04-03 Revision following comments K. Altinkaynak R. Griffiths A. Collier from BOPRC CGeol TCC Cat 1 2 2019-04-08 Final K. Altinkaynak R. Griffiths A. Collier CGeol TCC Cat 1

Current revision 2

Approval

Author signature Approver signature

Name Kim Altinkaynak Name Aaron Collier

Title Senior Geologist Title Project Leader

Project number 502328 File 502328-0000-GG-0002[2].docx 2019-04-08 Revision 2

Contents

1 Project Background ...... 1 1.1 Introduction ...... 1 1.2 Proposed Development ...... 1 1.3 Approach ...... 2 1.4 Report limitations ...... 3

2 Site Setting ...... 4 2.1 Site location and geomorphology ...... 4 2.2 Geological and hydrogeological setting...... 4 2.2.1 Geological setting ...... 4 2.2.2 Hydrological and hydrogeological setting ...... 5 2.3 Seismicity ...... 5

3 Natural Hazards ...... 7 3.1 Introduction ...... 7 3.2 Volcanic Activity ...... 7 3.2.1 Ashfall ...... 7 3.3 Earthquakes ...... 10 3.3.1 Liquefaction and lateral spread ...... 10 3.3.2 Tsunami ...... 11 3.4 Coastal inundation and erosion ...... 15 3.4.1 Coastal inundation ...... 15 3.4.2 Coastal erosion ...... 16 3.5 Extreme (prolonged or intense) rainfall ...... 16 3.5.1 Flooding ...... 16 3.6 Summary of hazards ...... 18

4 Risk Assessment ...... 19 4.1 Risk analysis and evaluation ...... 19 4.2 Risk treatment ...... 21 4.2.1 Earthquake (liquefaction and lateral spread) ...... 21 4.2.2 Tsunami ...... 21 4.2.3 Flooding ...... 22 4.2.4 Other ...... 23 4.3 Analysis and evaluation ...... 24

5 Conclusion ...... 26 6 References ...... 27

Appendices

Appendix A Site Plans

Appendix B ECoast Tsunami Maps

Appendix C Natural Hazard Risk Assessment

Figures

Figure 1 Site Location Plan (image from Western Bay of Plenty District Council 2011-2012) Figure 2 Masterplan showing of mixed residential and ecological wetland habitat development Figure 3 Volcanic ash fall zones for 100-year event Figure 4 Volcanic ash hazard map (contours in mm) for 500-year return period (Hurst & Smith, 2010) Figure 5 Liquefaction Hazard Map, the site is outlined in blue (from WBOP Lifelines Group, 2003) Figure 6 Liquefaction Ground Damage Map, the site is outlined in blue (from WBOP Lifelines Group, 2003) Figure 7 Modelled tsunami depth at the site for a 0.2% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ) Figure 8 Modelled tsunami depth at the site for a 0.1% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ) Figure 9 Modelled tsunami depth at the site for a 0.04% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ) Figure 10 Coastal inundation hazard zones, the site is to the right (SE) of the map (from Tonkin & Taylor, 2015) Figure 11 Coastal erosion hazard zones, the site is shown in orange (from Tonkin & Taylor, 2015) Figure 12 Flood hazard zone indicated in blue, the site is shown in green (from BOPRC) Figure 13 Tsunami evacuation map, the site is shown in the blue box (from BOPRC) Figure 14 Proposed flooding mitigation options (Aurecon, ref: 502328-0000-REP-CC-0000)

Tables

Table 1 Occurrence of natural hazards in the region (after RPS, 2016 Table 2 Likelihoods for risk assessment (from Appendix L, RPS, Table 20) Table 3 Risk rating pre-development Table 4 Risk rating post-development Table 5 Risk rating pre- and post-development

1 Project Background

1.1 Introduction Property Seven Limited (the ‘Client’) have engaged Aurecon New Zealand Limited (Aurecon) to undertake a Natural Hazards Risk Assessment (NHRA) of the Pukehina Eco-Village development. The study area, currently comprising ~165 hectares (ha) of vacant pastoral grazing land and will be re-developed for low- density residential lifestyle dwellings (137 in total) with adjoining specialised ecological wetland habitat. The proposed development site (the ‘site’) is located 33 km southeast of Tauranga in the Pukehina township, on the north-west side of Pukehina Beach Road between the Pukehina Canal and the township (Refer Figure 1). The approximate site boundary is shown in red and current land parcels in green.

Figure 1 Site Location Plan (image from Western Bay of Plenty District Council 2011-2012)

This NHRA is prepared to accompany Aurecon’s G1 geotechnical assessment report (502328-0002-REP- GG-0001[3]). The report presents our interpretation of the natural hazards and risk and how the hazards are being eliminated or managed to reduce the overall risk.

1.2 Proposed Development A low-density residential development with specialised ecological habitat areas (refer to Figure 2). The proposed ecological habitat will comprise two ponds, with a supporting network of public walkways and cycleways. The balance of the site will be converted to residential land use, with up to 137 residential lots 2000 m2 in size on elevated fill platforms. To construct the proposed landform the site will be subject to cut and fill earthworks. A masterplan sketch is presented in Figure 2.

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Figure 2 Masterplan showing of mixed residential and ecological wetland habitat development

The two wetland ponds are proposed, one 33.5 ha pond (maximum depth 6 m) occupying the northern half of the site and a smaller 4.5 ha pond (maximum 4 m deep) in the southern portion of the site, adjacent to Pukehina Beach Road. The ponds will be constructed at 0.55 m Reduced Level (m RL)1. The groundwater table will be maintained at 0.55 m RL for the wetland ecosystem and habitat. The groundwater table and surface water levels will therefore be controlled to remain static (accounting for sea level rise) over the design life. We understand that the Client wishes to use soils extracted from wetland pond excavation to raise the residential land to a design level of ~4.2 m RL. The proposed dwellings will comprise detached lightweight residential structures constructed in accordance with NZS:36042. Key lifeline services and utilities electricity, effluent and stormwater will be provided onsite, as opposed to being connected to council systems. The built infrastructure will be constructed at an elevation of 3.6 m RL or higher. The preliminary landform design (Drawing 502328-0000-DRG-CC-0005[B]) and indicative cut and fill contours (Drawing 502328-0000-DRG-CC-0020[B]) are presented in Appendix A.

1.3 Approach The operative Regional Policy Statement (RPS) natural hazards provisions have been designed to influence resource consents and the development of regional, city and district plans as they affect natural hazards. The RPS was made operative in 2014, with Change 2 (Natural Hazards) merged into the RPS and made operative from 6 July 2016. The proposed development does not include a plan change and as such is not formally required to give effect to the provisions of the RPS. Section 104 of the Resource Management Act (RMA) requires that for a resource consent, the development should “give regard” to the provision of the RPS only. The RPS considers eight natural hazards; not all of the natural hazards are considered relevant to the site.

1 Metres Reduced Level (m RL) relates to Vertical Datum Moturiki (1953) 2 New Zealand Standard 3604:2011; Timber Framed Buildings Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2 2

To support the resource consent application a NHRA has been requested by the Bay of Plenty Regional Council (BOPRC) to assess the risk posed to the development from natural hazards, and identify the mitigation measures proposed to limit the effect of the hazards to the built environment and reduce potential harm to users (determined to be residents, and members of the public using the wetland for recreational purposes. Giving regard to the RPS, and to meet the provision of the RPS, the following scope of works was undertaken:

 A desktop study, including but not limited to:

 available geomorphological, geological and hydrological conditions;  a review of the Western Bay of Plenty District Council (WBOPDC) and BOPRC online hazard maps;  reports and maps pertaining to the hazards on the site from publicly available sources;  review of Aurecon’s G1 Geotechnical Assessment Report (ref: 502328-0002-REP-GG-0001[3]), noting that the ground investigations were not completed to inform the NHRA. The NHRA was a later request from BOPRC through the s92 process.

 An assessment of existing natural hazards risks that affect the site, excluding those not relevant;

 A qualitative risk assessment, completed in accordance with Appendix L of the RPS. It should be noted that the NHRA does not supersede any process or function of the Building Act which also gives provision to natural hazards and regulates building work through the Building Code to protect loss of life and amenity.

1.4 Report limitations This report has been prepared in accordance with the brief as provided. The scope of this work is limited to meeting the provisions of the Bay of Plenty RPS. All other legislative statutes giving reference to natural hazards and their mitigation shall be adhered to within their respective relevant frameworks. The contents of the report are for the sole use of the Client. No responsibility or liability will be accepted to any third party. Data or opinions contained within the report shall not be used in other contexts or for any other purposes without prior written agreement of Aurecon New Zealand Limited. Only a finite amount of information has been collected to meet the specific financial and technical requirements of the Client’s brief and this report does not purport to completely describe all the site characteristics and properties. This report is not to be reproduced either wholly or in part without prior written permission from Aurecon New Zealand Ltd.

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2 Site Setting

2.1 Site location and geomorphology The site covers 165 ha of pastoral land and is bound by Pukehina Beach Road to the east, Pukehina Canal to the south and residential properties to the north. The site is roughly rectangular in shape with dimensions of approximately 1.9 km long and 1 km wide orientated north-west to south-east. The extent of the site is defined by the drawings presented in Drawing 502328-0000-DRG-CC-0005[B], Appendix A. There are six land parcels within the site, Section 33 – 36 BLK I Waihi South SD, Lot 1 DPS 51656 and Lot 2 DPS 65860, four of which contain residential dwellings and related farm buildings. Buildings include:

 239 Pukehina Beach Road – A residential dwelling and a shed;

 275 Pukehina Beach Road – A residential dwelling and shed. Approximately 75 m north, a farm shed and cattle yards;

 307 Pukehina Beach Road – A residential dwelling with multiple sheds;

 2 Gardiner Place – A residential dwelling and to the south, several large farm sheds including a milking shed.

The entire site is currently used for pastoral grazing / dairy. The land is low-lying and has a series of drains which divert water into the Pukehina Canal and effluent ponds. The site has a relatively flat topography, ranging in elevation from 0 – 2 m RL; the eastern and northern areas of the site are marginally higher than that of the balance. There is evidence of minor earthworks, and the land has been artificially risen to 2 m RL in places, including the stopbank along the Pukehina Canal. It is situated on the coastal lowlands behind coastal dunes and approximately 0.2 km from the sand-dune forefront and Pukehina Beach. The site adjoins an area to the north known as the “Pukehina Beach Settlement” which is a strip of residential properties located on elevated sand dune land ridge along a 5.2 km length of coastline which is raised to 2 – 12 m RL. To the east is Pukehina Beach Road and across of Pukehina Beach Road is rural farmland, to the south and west is further rural farmland. Topographic features in the wider area include, Waihi estuary 3 km northwest of the site, several alluvial terraces located to the east (up to ~30 m RL), and to the north is a coastal dune system.

2.2 Geological and hydrogeological setting

2.2.1 Geological setting The coastal Bay of Plenty (BOP) comprises a range of dunes, lagoons, swamps, estuaries and alluvial regimes. Together with changing sea levels and volcanic eruptions in the Pleistocene and Holocene, this has resulted in a thick sequence of soft and loose sediments and shallow groundwater. The coastline has been transformed through marginal marine and alluvial processes. Streams and rivers navigate through the area, transporting pumiceous tephras from Okataina and Taupo Volcanic centres to the coast. Material has accumulated at river mouths and been transported along the coast via longshore drift; leading to shoreline progradation and the formation of several low-lying alluvial plains along the BOP coastline. The lithology in coastal BOP varies laterally and vertically and depicts the environmental conditions at the time of deposition. Fluctuating sea level, migrating rivers and energy environments, has led to heterogeneous packages of coarser and finer materials. A review of the Institute of Geological and Nuclear Sciences (GNS) 1:250,000 geological map for Rotorua (Leonard et. al., 2010) indicates the site to be underlain by Holocene Tauranga Group deposits described as: dark brown to black organic mud, muddy peat and woody peat with minor overbank sand, silt and mud. Towards the coast, the geology is comprised of coastal beach deposits, described as: marine gravel, sand and mud on modern beach; these deposits have been mapped underlying the north-eastern edge of the site. These

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units are underlain by Quaternary alluvium, exposed to the east of the site, and described as: poorly to moderately sorted gravel with minor sand and silt underlying terraces; includes minor fan deposits and loess.

A ground investigation was undertaken between the 26 March and 12 April 2018 by Aurecon to establish ground and groundwater conditions across the site (refer to Aurecon’s Geotechnical Report; ref: 502328- 0002-REP-GG-0001[3]). Based on observed and inferred ground conditions, the site geology broadly reflects the published setting; comprising surface topsoil, underlain a thick sequence of alluvial and estuarine soils comprising a combination of silt, sand and gravel with interbedded organic layers. The geology is divided into three main units comprising upper and lower alluvial units (predominantly granular with lenses of soft silt and occasional peat horizons) separated by a layer of soft estuarine silt (with occasional sand layers). The relationship with between the lower alluvial and estuarine units is complex, with significant interbedding inferred. These units are capped by a thin layer topsoil or fill. It is anticipated that fill earthworks have been completed along farm drains, and the Pukehina Canal. More detailed information on the site ground conditions is included in Aurecon’s Geotechnical Report.

2.2.2 Hydrological and hydrogeological setting There are no natural surface water bodies on the site. In the mid-1900s a land drainage scheme was put into place which controlled flooding and allowed the conversion of flax growing land into pastoral land (Law, 2008). Several canals have been developed adjacent to the site, including the Kaikokopu, Wharere, Pongakawa and Pukehina Canal which runs along the southern boundary of the site. There are two main farm drains on site, and the site is actively pumped from a sump at its western boundary. Water drains, and is pumped, into the Pukehina Canal to the south of the site and eventually discharge into the Waihi Estuary approximately 2.5 km to the north west of the site. The pumping artificially lowers the groundwater table on the site. Heavy rain fall events and seasonal changes may result in variations to groundwater level and flow direction. A search of the BOPRC well bore database identifies one historical well (reference number: BH-1218) located at the north-eastern edge of the site. The bore is 36 m deep and water level recorded at 19.5 m bgl. Nearby bores within the alluvial plain have recorded the groundwater closer to the surface. Based on this information and the water level within adjacent drains and canals, the groundwater level is anticipated to be shallow. This is confirmed by reported groundwater levels in Aurecon’s Cone Penetrometer Tests (CPTs), hand augers and the rotary drilled borehole undertaken during ground investigation where groundwater level ranges between 0.20 and 0.99 m below current surface level (refer to Aurecon’s Geotechnical Report, ref: 502328-0002-REP-GG-0001[3]). In the test locations the groundwater was measured in the same geological unit; beach sand / upper Alluvium. Hand auger boreholes collapsed, due to the high-water content, between 1.2 and 2.2 m bgl. A regional groundwater flow to the north can be expected, however shallow groundwater flow may be affected by the artificial drains/canals, and the nearby Waihi Estuary.

2.3 Seismicity A review of the New Zealand Active Fault Database3 shows the nearest fault to the site, approximately 7 km southeast, is the Otamarakau Fault. The Otamarakau Fault is a normal fault with unknown rupture parameters. There are several more normal faults located approximately 14 km southeast of the site, and of the faults that have been investigated, they have recurrence intervals of ≤ 2,000 years. The Otamarakau Fault is not listed as a major fault in Table 3.6 of NZS:11704.

3 Data.gns.cri.nz. (2018). New Zealand Active Faults Database. [online] Available at: https://data.gns.cri.nz/af/ [Accessed Mar. 2018]. 4 New Zealand Standard 1170.5:2005 Structural Design Actions, Part 5. Earthquake Actions – New Zealand. Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2 5

A number of active fault sources have been identified and used as inputs for the probabilistic seismic hazard analysis (PSHA) (Stirling, et al. 2012). The site is within the Havre Trough – central Taupo Rift domain which is the continental arc and back-arc of the Hikurangi subduction margin; the domain widens northward as it transitions from the Taupo rift to the southern Havre Trough. There has been one major historical surface rupturing earthquake on land, and potentially another earthquake. The 1987 Mw 6.5 Edgecumbe earthquake ruptured the Edgecumbe fault, and several other nearby faults, and the 1992 Mw 6.3 Bay of Plenty earthquake potentially ruptured a fault in the offshore Whakatane Graben (Stirling, et al. 2012).

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3 Natural Hazards

3.1 Introduction Our present understanding of natural hazards that may affect the site come from sources including:

 Western Bay of Plenty hazard studies including liquefaction, flooding, coastal erosion and inundation, and tsunami;

 Site-specific investigations of stormwater and earthquake effects;

The Bay of Plenty Civil Defence Emergency Management (CDEM) Plan and the RPS identifies a wide range of natural hazards that affect the region and are presented in Table 1, with the hazards that are most relevant to the site shown in bold.

Table 1 Occurrence of natural hazards in the region (after RPS, 2016

Natural occurrence Resulting natural hazard

Volcanic activity  Ash fall  Pyroclastic and lava flow  Landslip, debris flow and lahar  Geothermal hazard  Caldera unrest Earthquakes  Fault rupture  Liquefaction and lateral spread  Ground shaking  Landslide and rockfall  Tsunami Coastal/marine processes  Coastal inundation  Coastal erosion Extreme (prolonged or intense) rainfall  Flooding  Landslide  Debris flow/flood

Climate change will exacerbate natural hazards with weather patterns likely to bring more intense rain, result in more frequent intensified flooding. Sea level rise could result in intensified coastal hazards, such as erosion and storm surge, flooding and higher groundwater tables. Sea level rise effects not considered as part of NHRA due to controls in place to artificially maintain at a relatively constant normal water level to preserve wetland.

3.2 Volcanic Activity

3.2.1 Ashfall At present, there is no published ash fall hazard information provided by regional and district councils for the coastal Bay of Plenty. Waikato Regional Council (WRC) engaged the Institute of Geological and Nuclear Sciences (GNS) to characterise the most relevant volcanic centres, along with the likely nature and extent of fall out following an eruption. The depth of ashfall, using prevailing wind directions, was mapped for a 100- year event and is presented in Figure 3.

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Figure 3 Volcanic ash fall zones for 100-year event5

Ash fall of between 0.1 to 1 mm could be expected for a 100-year event over the coastal Bay of Plenty. Conversely, the ash fall isopachs from the New Zealand ash fall Probabilistic Volcanic Hazard Map (Figure 4, Hurst & Smith, 2010) indicates that no ash fall would be expected in the coastal Bay of Plenty region from a 500-year event.

5 Waikato Regional Council. Volcanic ashfall zones map: https://www.waikatoregion.govt.nz/services/regional-services/regional- hazards-and-emergency-management/volcanic-activity/volcanic-ashfall-zones/ Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2 8

Figure 4 Volcanic ash hazard map (contours in mm) for 500-year return period (Hurst & Smith, 2010)

The consequences of between 0.1 to 5 mm of ash fall are (after Edbrooke, 2005):

 <0.1 mm ash thickness:

 Irritant to lungs and eyes;  Possible contamination to water supplies;  Minor damage to houses, vehicles and equipment caused by abrasive ash.

 1-5 mm ash thickness:  Possible crop damage;  Some minor effects of livestock (lack of feed, wear on teeth, possible water contamination);

 Water supplies may be cut or limited due to electricity failure;  Roads may need to be cleared to reduce dust nuisance and prevent storm water systems becoming blocked.

As the ash fall hazard is not well-defined for the site, it will not be considered further in agreement with BOPRC. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development.

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3.3 Earthquakes

3.3.1 Liquefaction and lateral spread The New Zealand Active Fault Database shows the nearest fault to the site, approximately 7 km southeast, is the Otamarakau Fault. The Otamarakau Fault is a normal fault with unknown rupture parameters. There are several more normal faults located approximately 14 km southeast of the site, which have recurrence intervals of ≤ 2,000 years. The Otamarakau Fault is not listed as a major fault in Table 3.6 of NZS:1170. The Western Bay of Plenty (WBOP) Lifelines Group Report (2003) indicates that the site is underlain by material likely to undergo widespread liquefaction with the associated ground damage to be moderate with approximately 300 mm of subsidence possible. Major to extensive lateral spreading and subsidence could be expected adjacent to the adjacent rivers and canals. The hazard maps in relation to the site are presented as Figure 5 and Figure 6.

Figure 5 Liquefaction Hazard Map, the site is outlined in blue (from WBOP Lifelines Group, 2003)

Figure 6 Liquefaction Ground Damage Map, the site is outlined in blue (from WBOP Lifelines Group, 2003)

Further investigation into the liquefaction and lateral spread hazards associated with earthquakes related to the site were undertaken by Aurecon and reported in the Geotechnical Assessment Report (ref: 502328- 0002-REP-GG-0001[3].

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Aurecon’s geotechnical investigation across the site indicates two different ground profiles with different earthquake responses. Loose to medium dense sand and silty-sand (Units 2 and 4 alluvial layers) encountered on site are considered to be potentially liquefiable from a soil character and density perspective. In situ materials with higher fines contents (Unit 3 – Estuarine silts) are considered non-liquefiable. For the ground penetrated by the CPT profiles this non-liquefiable cut-off is assumed to be where the Soil Character Index, Ic, is greater than 2.6. Any horizons of peat or gravel are not considered to be liquefiable. The groundwater table is currently recorded at between 0 and 1 m bgl, though the actual water level may be affected by active pumping to the Pukehina Canal. Anticipating that the sea level is expected to rise up to a level of 1.2 m RL over the next 50 years the groundwater table, for the purpose of this analyses is set at 0 m bgl for each CPT location. Residential building structures such as those proposed for this development are classified as Importance Level 2 structures in accordance with NZS1170. Based on the inferred geological model the site is considered likely to have a site subsoil category of Class D (deep soil sites) in accordance with NZS 1170. As the maximum level of investigation extends to 15 m bgl, with areas of softer ground noted to the maximum depth investigated, it is possible that area of the site may comprise Class E ‘very soft soils’. The possible extent of Class D and E soils requires further investigation as part of detailed design. Based on the results of analyses completed as part of the Aurecon’s assessment a 1 in 1000 year earthquake event (0.1%) exceeds the maximum credible (worst case) event for vertical settlement effects, which is considered to be the point at which the maximum amount of liquefaction can be achieved (based on our analyses determined to be within a 1/100 to 1/150 year return period; or 1% to 0.67% AEP), which equates to a peak ground acceleration of between 0.13 to 0.15 g for an IL2 structure. A ULS building code event (1 in 500 year, or 0.2% AEP; 0.26g) for an IL2 importance level structure in accordance with NZS1170 in line with existing uses also exceeds the maximum credible earthquake event. In the event of a 0.1%AEP earthquake event, a free field settlement of ~310mm is currently predicted. The site is not currently expected to be effected by lateral spread based on the current landform. It is noted that the construction of new ponds will create a situation where lateral spread hazard is created. The Geotechnical Assessment Report notes that in a 1 in 500-year event (Ultimate Limit State) a lateral spread effect in excess of 400 – 600 mm is conservatively predicted at the edges of the ponds, in the absence of specific controls put in place. Based on the results of analyses completed to date more significant lateral spreading effects would be expected in a 1 in 3,030-year event, required to be considered by RPS.

3.3.2 Tsunami Tsunami modelling has been undertaken of the Pukehina area for WBOPDC (ref: ECoast Report, June 2017) to identify areas susceptible to tsunami inundation hazard. The inundation extents were determined for four different probability levels based on the National Tsunami Hazard Model of Power (2013). These are the 0.2% AEP (500-year recurrence interval [RI]), 0.1% AEP (1000-year RI) 0.04% AEP (2500-year RI) and the Maximum Credible Event (MCE). Further detailed information on the methodology and results are included in the ECoast Report. For Pukehina during the Mean High Water Spring tide (WHWS) plus Sea Level Rise (SLR) scenario, the entire area is flooded prior to any tsunami activity due to the low-lying topography. The narrow strip of land remaining along the Pukehina Spit is overtopped in several places by the 0.2% AEP event and completely over run in the 0.04% AEP and MCE scenarios. For all scenarios, the tsunami flood depth at the current land form is <0.5 m (refer to the ECoast maps included in Appendix B). GIS data provided by BOPRC was plotted to get an indication of Tsunami inundation depth across the site. The modelled flow depths for a 0.2% event are <0.5 m in the very northeast corner of the site whereas the 0.1% AEP event indicates a maximum depth of 1.5 m may be expected in the northeast portion of the site. The tsunami depth is generally <1 m over the site and inundation is not present outside the northeast corner. Tsunami inundation for a larger event (0.04%) covers the entire site, however the maximum depth of water still remains 1.5 m (predominantly in the NE portion of the site. Across the rest of the site tsunami depths are generally <1 m. A tsunami evacuation map has been produced by the WBOPDC based on the modelling undertaken, and is discussed further in Section 4.

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Figure 7 Modelled tsunami depth at the site for a 0.2% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ)

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Figure 8 Modelled tsunami depth at the site for a 0.1% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ)

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Figure 9 Modelled tsunami depth at the site for a 0.04% AEP event. Site boundary shown in black (data provided by BOPRC, aerial photo from LINZ)

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3.4 Coastal inundation and erosion The online BOPRC and WBOPDC hazard maps were used to identify potential coastal erosion and inundation hazards for the site. The Pukehina Coastline has been the subject of a detailed study to identify land at risk to these coastal hazards over two timeframes: 0-50 and 50-100 years. The study findings are reflected on the District Plan Maps through the identification of ‘Coastal Erosion Areas’ and ‘Coastal Inundation Areas’. Tonkin & Taylor (April 2015, ref: 851833) assessed the coastal hazard extent based on a method developed by Healy (1993), where both coastal erosion and inundation hazard have been assessed. Two timeframes were applied: 1) 50 year, and 2) 100 year.

3.4.1 Coastal inundation The Coastal Inundation Hazard Zone (CIHZ) was assessed over a 50 year and 100-year timeframe for Pukehina (Figure 10). The CIHZ was based on an inundation level derived from the combination of the following components:

 Storm tide;

 Wave set-up;

 Wind set-up;

 Sea level rise. The inundation components were calculated for the estuary coast environment at Pukehina (inner spit shoreline). The 2065 and 2115 CIHZ identify land susceptible to coastal inundation hazard over a 50 and 100-year planning timeframe respectively. The foredune heights at Pukehina are sufficient to mitigate any inundation hazard from the open coast, therefore the site is not affected by coastal inundation hazards.

Figure 10 Coastal inundation hazard zones, the site is to the right (SE) of the map (from Tonkin & Taylor, 2015) The assessment undertaken identifies that coastal inundation hazards do not affect the site, and therefore have not been considered further in the risk assessment.

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3.4.2 Coastal erosion The Coastal Erosion Hazard Zone (CEHZ) methodology used combines standard and well-tested approaches for defining coastal erosion hazard zones. The resulting distribution is a probabilistic forecast of potential hazard zone width. The method is further discussed in the Tonkin & Taylor Report. The 50-year CEHZ values for Pukehina range from 30 to 40 m, and from 50 to 80 m for the 100-year CEHZ (Figure 11).

Figure 11 Coastal erosion hazard zones, the site is shown in orange (from Tonkin & Taylor, 2015) The assessment undertaken identifies that coastal erosion hazards do not affect the site, and therefore have not been considered further in the risk assessment.

3.5 Extreme (prolonged or intense) rainfall

3.5.1 Flooding The online BOPRC flood hazard map to identifies a flood hazard applicable to the site (Figure 12). The flood mapping was derived from the Pukehina Catchment Management Plan - Floodable Areas Maps (Duffill Watts and King, 2006). The annual exceedance probability (AEP) used was 2% (i.e. equivalent to a 50-year return period) to determine potential areas of flooding.

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Figure 12 Flood hazard zone indicated in blue, the site is shown in green (from BOPRC)

Further investigation into the flood hazards related to the site was undertaken by Aurecon and reported in the Stormwater and Services Assessment (ref: 502328-0000-REP-CC-0000). The site is part of the catchment of the Pukehina Canal which runs alongside the full length of the south- western boundary and drains to the estuary. The site is connected to the canal by a flood pump located in the western corner of the block adjacent to the canal. There is no direct connection to the canal as there is a stopbank running the full length of the site to the estuary with the crest level at between RL 1.75 m and RL 2.0 m approximately. The canal is tidally affected but with a narrow tidal range from approximately RL 0.3m to RL 1.0m based on measurements taken between 15th and 19th March 2018. Land drainage pumps maintain a lower level of water within the internal land drains than the water levels within the canal. The catchment to the single drainage pump includes the site, the Pukehina Parade properties and road over the length of the site, and approximately 140 ha of upstream rural property – a total catchment of approximately 330 ha. A further drainage pump at the eastern extent of the Pukehina Canal services a further 140 ha of rural and residential land. These pumps are linked with a common central drain and during periods of extended rainfall, when flooding extends over the pastures, the two pumpstations will work together to lower the surface flooding. Approximately 46 ha of the upstream property is a continuation of the low-lying flood plain similar to the site with a network of farm drains providing connection to the culvert under Pukehina Beach Road for flood drainage and also to maintain lower ground water levels To determine the flood levels and flows a simplified stormwater model using Mike-Urban was developed to assess the impact in a 100-year event. The rainfall was input in a nested storm pattern which provides peak flows and maximum volumes for the range of durations within a 48-hour period. Rainfall depths included for 3°C of climate change in line with BOPRC’s Stormwater Management Guidelines for the Bay of Plenty region. The flood model also assumed no discharge out of the paddock areas to the Pukehina Canal (i.e. the pumps are not operating). The 100-year flood level over the site is RL 1.07m and extends beyond the existing site boundaries and covers the upstream and downstream farm properties, and the lower yard areas of the existing urban properties at 28 and 42 Pukehina Parade, and a portion of the Pukehina Campground. The ground level within the rural land is typically between RL 0.6 and RL 0.9m. Upstream of Pukehina Beach Road, the modelled 100-year flood level is RL 1.28 m. The capacity of the existing 1050 mm diameter culvert under the road also restricts the volume transfer required to balance the flood levels across the Pukehina Beach Road during the 100-year rainstorm event. The Pukehina Canal is separated from the site by a stopbank crest that is between RL 1.75 m and RL 2. 0 m adjacent to the site and above RL 1.5 m upstream of Pukehina Beach Road.

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A greater level of flooding in a secondary event required by RPS cannot currently be achieved as the larger events will fill across the large floodplain and not be localised to the site and neighbouring properties. It is considered likely that the 0.2% AEP rainfall event will cover the area to a level greater than the stopbanks along the drainage canals (approximately 2.0m RL). This has not been modelled by the Regional Council, or District Council, to our knowledge. However due to the large floodplain area, relative to the total catchment area, and the direct connection to the tidal estuary the 0.2% AEP rainfall event is not considered to be significantly higher than the 1% AEP rainfall event and therefore would still be expected to be lower than the tidal inundation hazard. The increase in rainfall between the 1% and 0.2% AEP rainfalls for a 24hour duration event is about 175 mm. This would lead to an approximate increase in flood level of 300-400 mm only.

3.6 Summary of hazards After consideration of the natural hazards presented in Table 1, included in Section 2.11 of the RPS, and discussed in the subsections above, the following natural hazards will be assessed using the RPS risk assessment methodology (refer to RPS, Appendix L):

 Liquefaction and lateral spread;

 Tsunami;

 Flooding.

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4 Risk Assessment

4.1 Risk analysis and evaluation A NHRA has been undertaken for the site in line with the BOPRC RPS and natural hazard risk management policy framework for development proposals; this includes identifying the risk, risk analysis and evaluation, and risk treatment. A discussion of hazards relative to the region are presented in Section 3 and on evaluation the following hazards have been assessed specific to the site:

 Liquefaction and lateral spread;

 Tsunami;

 Flooding. Aurecon has undertaken a qualitative evaluation as per steps 1 to 4 of Appendix L of the RPS. Where required, secondary analysis has been qualitatively evaluated. Step 5 of the methodology has not been followed as this is requirement for calculating the Annual Individual Fatality Risk (AIFR). Calculation of the AIFR is inappropriate for this site as the hazard consequences only relate to building and lifeline functionality rather than health and safety risks post-development. The following likelihoods for risk assessment were considered (Table 2):

Table 2 Likelihoods for risk assessment (from Appendix L, RPS, Table 20)

Natural Hazard Likelihood for initial analysis Likelihood for secondary analysis AEP (%)1 AEP (%)1

Earthquake (liquefaction and lateral 0.1 0.2 spread) 0.033

Tsunami 0.1 0.2 0.04

Flooding 1 2 0.2

1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20)

The risk assessment and evaluation undertaken pre-development is included as Table C1 in Appendix C, with a discussion of the qualitative consideration and the effects of the hazard on the current site users. A summary is presented in Table 3.

Table 3 Risk rating pre-development

Natural Hazard Overall risk rating1 (AEP2 vs. consequence3)

Earthquake (liquefaction and lateral spread) High Risk

Tsunami Medium Risk

Flooding High Risk

1 Refer to Risk Screening Matrix, page 374 of RPS 2 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 3 Consequences (Refer Appendix L of RPS, Table 21,)

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A key consequence governing the outcomes of the risk assessments completed relates to the functionality of buildings in a post-event scenario. The performance requirement of the RPS considers is the likelihood of relevant buildings or structures being “functionally compromised” as a result of the earthquake event under consideration. Functionally compromised is defined by the RPS as a condition that “will generally occur when a building cannot continue to be used for its intended use immediately after an event.” Outside of the RMA framework, the Building Code objective B1.1(b) states that a building is to have a low probability of “loss of amenity” during its life, which is defined as “an attribute of a building which contributes to the health, physical independence and well-being of the building’s user but which is not associated with disease or a specific illness.” This concept is considered further in MBIE (2012), which ensures that amenity is maintained by ensuring that “all parts of the structure shall remain functional so that the building can continue to perform its intended purpose. Minor damage to structure. Some damage to building contents, fabric and lining. Readily repairable. Building accessible and safe to occupy. No loss of life. No injuries.” On this basis, we make the assumption that buildings design in accordance with this guideline will remain habitable in an immediate post event scenario. With on-site provision of lifeline utilities, as opposed to reliance on a less resilient network we could anticipate that amenity will be maintained to some degree in this scenario. Therefore, for the purpose of this report, we interpret “functionality compromised” as being equivalent to the loss of amenity definitions set out by MBIE. The term “readily repairable”, is defined by MBIE as a building that can be repaired without relocation of occupants for a period of more than four weeks. On this basis, we interpret that a functionally compromised building is one that cannot be repaired within four weeks. In a pre-development scenario covered by Table 3 (referencing Table C1, Appendix C) the high risk and medium risk ratings are in part due the catastrophic and major consequences of buildings which are old and not likely to have been constructed in accordance with the current building code and industry best practice. With four of the existing residences on the site at least 25% functionally compromised during a tsunami and at least 50% functionally compromised due to liquefaction, lateral spread and flooding. Further discussion is included in Table C1 in Appendix C.

In undertaking the risk assessment and evaluation for the post-development scenario, the following assumptions were made:

 Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC;

 Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833);

 Earthquake shaking is outside of the requirements of the RPS (but covered by the Building Code);

 Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development;

 Calculation of the individual fatality risk as per Appendix L is inappropriate for this site as the hazard consequences only relate to building and lifeline functionality rather than health and safety risks;

 The consequences were considered in the Table 21 in Appendix L of the RPS, and with reference to the Tonkin & Taylor (2018) Lifelines Consequence Assessment (ref: 1003468.vE).

Further assessment has been undertaken taking into account the risk treatment options below as part of the site development (refer to Section 4.3).

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4.2 Risk treatment The following treatments are proposed during site development and will mitigate the natural hazard risk to the site. Further discussion is also included as Table C2 in Appendix C.

4.2.1 Earthquake (liquefaction and lateral spread) As a result of Aurecon’s geotechnical assessment, it is considered that the site would be unavailable for residential development without any modification, ground improvement or engineering intervention. A summary of the risk treatment options is presented below, with further details discussed in Table C2 (Appendix C), and within Aurecon’s Geotechnical Report:

 Buildings will be standalone detached structures within large lots. Buildings shall be no greater than two stories in height, with use of lightweight cladding and roofing materials to be recommended;

 Foundations will be designed to meet TC2 ground performance requirements which can cope with a maximum displacement of 100 mm vertically or laterally under very high levels of shaking without causing significant superstructure damage. Structural collapse is unlikely to occur provided foundations remain tied together. Following guidance and objectives related to loss of amenity (as set out within MBIE, 2012) foundations designed in accordance with this guideline shall ensure that structures remain habitable and readily repairable, thus maintaining functionality and amenity. With potential for further loss of amenity reduced by implementation of on-site utilities;

 Tilting and differential settlement may occur but TC2 type foundations are able to cope with differential settlement as they are well tied together and can cantilever and span over sunken ground. Services connections can be readily repaired at the slab edges/boundaries;

 The building platforms will comprise at least 4m of compacted non-liquefiable fill and create a 'crust' that will reduce the impact of differential settlement arising from reconsolidation settlement. An intact 3m+ thick crust will provide sufficient robustness to support the building and prevent any significant damage to services (as observed from the Canterbury Earthquake Sequence);

 We consider that surface ejection of liquefied material through the crust is unlikely to occur even at maximum considered shaking intensities;

 The building platforms will be either sufficiently set back from any free edges to be affected by lateral spreading, or specific ground modifications or improvement will be provided at subdivision development stage;

 All horizontal infrastructure will be designed to cope with the expected differential settlement and use modern materials that are able to cope with vertical and horizontal deformations.

4.2.2 Tsunami A summary of the risk treatment options is presented below, with further details discussed in Table C2 (Appendix C), and within Aurecon’s Stormwater Assessment:

 Built infrastructure will be constructed at an elevation of 3.5 m RL or higher, and the design level for the construction of the proposed residential building platforms is currently 4.2 m RL, which is above the modelled tsunami level of 1.5 to 2.4 m RL for both a 0.1% AEP and 0.04% AEP event;

 A catchment separation bund height is proposed at RL 2.2 m. The level of the bund is lower than depth of the modelled 0.1% AEP tsunami and maybe overtopped at the current design height. The tsunami will not overtop the built infrastructure and residential building platforms and likely to be funnelled into the wetlands;

 Built infrastructure functionality will be increased further using standalone site-specific utilities (solar panels, rain collection systems and on-site effluent disposal) thus not reliant on the existing network;

 Additional mitigation measures include tsunami evacuation route signage for residents.

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 The site is located within the orange evacuation zone (Figure 13); a tsunami from regional or distant sources (further away than 1000 km) could take anywhere from 2 to 12 hours to arrive. The yellow zone represents an area impacted by the most devastating tsunami. After a major earthquake it would take about 50 minutes for this tsunami to reach the coast, and approximately another 30 minutes to flood the yellow zone.  The nearest “safe zone” as indicated by tsunami hazard mapping and evacuation zones is located approximately 1.2 km southwest along Pukehina Beach Road, or 500 m east of the site. These locations are less than a 15-minute walk from the site and therefore the site would be evacuate-able.

Figure 13 Tsunami evacuation map, the site is shown in the blue box (from BOPRC)

4.2.3 Flooding A summary of the risk treatment options is presented below, with further details discussed in Table C2 (Appendix C), and within Aurecon’s Stormwater Assessment:

 Approximately 40 ha of area will be elevated to create raised lot and access area platforms;

 The built infrastructure will be constructed at an elevation of 3.5 m RL or higher, and the design level for the construction of the proposed residential building platforms is currently 4.2 m RL, which is above the expected ground water level of RL 0.6 m to RL 1.0 m, and an internal 100-year flood level of RL 1.31 m;

 Water reticulation is not affected by flooding, and sttormwater will function again after the flood is gone. Power will be related to transformers only that need to be elevated above RL3.5 which is fine;

 The built infrastructure and building platform levels will also be above the Tauranga Harbour Inundation Levels the RCP 8.5 H+ value (the BOPRC Policy on this matter is yet to be finalised);

 Stormwater, wastewater and effluent will be managed on-site, and essential services will be elevated above the flood level (i.e. at least RL 3.5m). Each lot will install rainwater tanks for irrigation and possible potable uses. The single watermain supplying water for firefighting purposes is likely to be adjacent to access roading into the proposed development, which will also be raised above the flood level;

 The area outside of the building platform and lot areas are proposed to be lowered to allow a combination of shallow wetland areas, above water zones for different species, and deep-water zones within the site;

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 The bund will be constructed around the site to protect the external properties from flooding from within the site. The bund will also protect adjacent properties;

 Modelling shows that the site can accommodate increases in water levels within the site and is separated from the surrounding land by a bund so that external flood levels are not increased. The catchment separation bund height is proposed at RL 2.2 m (refer to Figure 14). The modelling has also shown that the construction of a bund will decrease the flood levels on the surrounding properties for many storm scenarios;

 The site will be separated from the existing land drainage pump that maintains a depressed water level within the drains; this will enable the normal water level within the site to be managed to a consistent level that is more appropriate for the final wetland design, and does not rely on mechanical systems to maintain the proposed hydrological regime;

 During detailed design, a longer period of canal water level and tidal level measurements will enable the final levels of the inflow weir and outflow floodgates to be more accurately determined to achieve the volume of tidal inflow and outflow and flood release to maintain a healthy wetland.

Figure 14 Proposed flooding mitigation options (Aurecon, ref: 502328-0000-REP-CC-0000)

4.2.4 Other The following considerations are also made for reducing the natural hazard risk on the site:

 The current proposed minimum floor level maintains a compliant freeboard from estuary inundation levels;

 BOPRC advised (ref: email from Pam Crabbe dated 11 March 2019) that in the current study on Tauranga Harbour Inundation Levels the RCP 8.5 H+ value adopted is 1.6 m. This increases the design 1% AEP level for this development to around 4.0 m. The BOPRC Policy on this matter is yet to be finalised however, the proposed minimum Building Platform Level of 4.2 m RL is above this level;

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 Groundwater table is to be controlled to be in the order of 0.55 m to 0.65m RL for the wetland. The current design for the eco-village and wetlands will control the water levels on the site (including sea level rise) to ensure that the ground/surface water control mechanisms work, and are in place. Increases in wetland level will be in response to a rainfall event or a significant tide event which is managed by the significantly elevated Building Platform level;

 Due to the shallow groundwater table, the final earthworks design will incorporate separation and drainage layers under fills;

 Stormwater, wastewater and effluent will be managed on-site so there is no impact on the public services. In addition, Aurecon’s Stormwater Assessment found that the proposed development will have a less than minor effect on the public water supply and a negligible effect on any public stormwater or wastewater system;

 Each lot will install rainwater tanks for irrigation and possible potable uses, reducing demand on the Council potable supply compared with conventional residential developments. A single watermain supplying water for firefighting purposes and a trickle feed in periods of drought if required;

 Aurecon’s Traffic Assessment (ref: 502328-0006-REP-CC-0001) found the proposed development complies with the Western Bay of Plenty District Plan traffic requirements and the impact to the existing key intersection of SH2/Pukehina Beach Road results in minimal change in level of service. The New Zealand Transport Agency (NZTA) considered the proposed development and does not have any concerns regarding the capacity of the Pukehina Beach Road / SH2 intersection. The analysis used was conservative, having used 150 dwellings as opposed to the 137 in the development proposal and assuming that all are permanent residents.

4.3 Analysis and evaluation

Further assessment considering the risk treatment options above is presented in Table 4. Further assessment has been undertaken taking into account the risk treatment options below as part of the site development. Calculation of the individual fatality risk as per Appendix L is inappropriate for this site as the hazard consequences only relate to building and lifeline functionality.

Table 4 Risk rating post-development

Natural Hazard Overall risk rating1 (AEP2 vs. consequence3)

Earthquake (liquefaction and lateral spread) Low Risk

Tsunami Low Risk

Flooding Low Risk

1 Refer to Risk Screening Matrix, page 374 of RPS 2 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 3 Consequences (Refer Appendix L of RPS, Table 21,)

Further discussion is included in Table C1 in Appendix C.

In undertaking the risk assessment and evaluation, the following assumptions were made:

 Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC;

 Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833);

 Earthquake shaking is outside of the requirements of the RPS;

 Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development;

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 Calculation of the individual fatality risk as per Appendix L is inappropriate for this site as the hazard consequences only relate to building and lifeline functionality rather than health and safety risks;

 The consequences were considered in the Table 21 in Appendix L of the RPS, and with reference to the Tonkin & Taylor (2018) Lifelines Consequence Assessment (ref: 1003468.vE). ‘

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5 Conclusion

Aurecon was engaged to undertake a NHRA of 165 ha of land located approximately 33 km southeast of Tauranga in the Pukehina township, on the north-west side of Pukehina Beach Road between the Pukehina Canal and the township. The proposed development is for low-density residential development of up to 137 residential lots approximately 2000 m2 in size, with specialised ecological wetland habitat, as part of the proposed ‘Pukehina Eco-Village’. The residential units will comprise lightweight residential structures constructed in accordance with NZS:3604, and it is anticipated that the effluent and stormwater will be managed onsite. A NHRA has been undertaken for the site in line with the BOPRC RPS and natural hazard risk management policy framework for development proposals; this includes identifying the risk, risk analysis and evaluation, and risk treatment. Liquefaction and lateral spread, tsunami and flooding hazards were assessed specific to the site using the methodology presented in Appendix L of the RPS. The overall risk pre- and post-development were identified as presented in Table 5.

Table 5 Risk rating pre- and post-development

Natural Hazard Overall risk rating1 (AEP2 vs. consequence3)

Pre-development Post-development

Liquefaction and lateral spread High Risk Low Risk

Tsunami Medium Risk Low Risk

Flooding High Risk Low Risk

1 Risk rating (refer to Risk Screening Matrix, page 374 of RPS) 2 Probability (refer to Appendix L of RPS, Table 20) 3 Consequences (refer to Appendix L of RPS, Table 21,)

The main reasons for the decrease in risk post-development is that with risk treatment the following will be achieved:

 All residential allotments will be outside lateral spreading that would compromise TC2 type foundations (0.033% AEP);

 All residential allotments will be engineered and constructed to provide TC2 level or equivalent ground performance at ULS levels of shaking;

 All residential allotments will be above any potential tsunami inundation hazards (0.04% AEP);

 All residential allotments will be above the considered flood event (1% AEP), and the Tauranga Harbour Inundation Levels of RCP 8.5 H+ (the BOPRC Policy on this matter is yet to be finalised);

 Services may progressively lose the ability to service the allotment but will be designed with sufficient resilience to continue to operate after significant earthquake events. Services will be located above tsunami and flood inundation levels.

 The target for proposed earthworks and foundation design will be to achieve no loss of amenity (buildings remain habitable and can be repaired within 4 weeks) as defined by MBIE (2012) and the Building Code, as such 0% loss of function within residences on site. We conservatively allow for up to 10% of buildings to be compromised, owing for time taken to achieve repairs. Lifeline utilities supporting individual dwellings are on-site structures that can be easily repaired with no reliance on a less resilient inground council owned network.

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6 References

Aurecon. 2019. EcoVillage Pukehina: G1 Geotechnical Assessment report. Property Seven Limited. March 2019; ref: 502328-0002-REP-GG-0001[3]. Aurecon. 2018. Eco-Village Pukehina: Stormwater and Services Assessment. Property Seven Limited. July 2018, ref: 502328-0000-REP-CC-0000. Duffill Watts & King Ltd. 2007. Pukehina Stormwater Catchment Management Plan. Western Bay of Plenty District Council. P7.43091, 55027/1/2/24. eCoast Limited. 2017. Probabilistic Tsunami Inundation Assessment for the Western Bay of Plenty District. 26 June 2017. Edbrooke, S.W. 2005. Geology of the Waikato area: scale 1:250,000. Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences 1:250,000 geological map 4. 68 p. + 1 folded map. Healy, T. 1993. Coastal erosion, setback determination and recommendations for management of the Waihi Bowentown and Pukehina Beach and dunes. A report of the Western Bay of Plenty District Council. Hurst, T., Smith, W. 2010. Volcanic ashfall in New Zealand – probabilistic hazard modelling for multiple sources, New Zealand Journal of Geology and Geophysics, 53:1, 1-14. Law, G., 2008. Archaeology of the Bay of Plenty. Science and Technical Publishing, Department of Conservation. Leonard, G.S.; Begg, J.G.; Wilson, C.J.N. (comps) 2010 Geology of the Rotorua Area: Scale 1:250,000 Institute of Geological & Nuclear Sciences 1:250,000 geological map. 5. Ministry of Business Innovation & Employment (MBIE), 2012. “Repairing and rebuilding houses affected by the Canterbury Earthquakes”. New Zealand New Zealand Standard 3604:2011; Timber Framed Buildings. New Zealand Standard 1170.5:2005 Structural Design Actions, Part 5. Earthquake Actions – New Zealand. Power, W. L. 2013. Review of Tsunami Hazard in New Zealand (2013 Update) GNS Science Consultancy Report No. 2013/131, 238 pages. Stirling, M., et al., 2012. National Hazard Seismic Model for New Zealand: 2010 Update.” Bulletin of the Seismological Society of America, 102 (4), pp. 1514-1542. Tonkin & Taylor. 2015. Coastal Protection Areas Re-assessment, Stage Two. Western Bay of Plenty District Council. April 2015, Ref: 851833. Tonkin & Taylor. 2018. Lifelines Consequence Assessment – Guidance. Bay of Plenty Regional Council. December 2018, ref: 1003468.vE. Western Bay of Plenty Lifelines Group (2003) Microzoning for Earthquake Hazards for the Western Bay of Plenty. Prepared by Opus International Consultants.

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A

Site Plans

Appendix A Site Plans

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2 LEGEND PROPOSED SITE BOUNDARY EXISTING MAJOR CONTOUR 2.50 AT 2.5m INTERVALS EXISTING MINOR CONTOUR AT 0.50m INTERVALS PUKEHINA PARADE PUKEHINA PARADE BOREHOLE - CPT ONLY

BOREHOLE - CPT AND

ROTARY DRILLED 0.00 COSTELLO CRESCENT

GARDINER PL 0. 0.00 BOREHOLE - CPT AND HAND 0.00 AUGER HA-CPT21 CPT20 DATUM INFORMATION:

· VERTICAL DATUM: MOTURIKI 1953.

· 202 0.00 HORIZONTAL DATUM: NZGD2000 BAY OF PLENTY. 2.50

16.6 ha

CPT11 0.00 0.00 0.00 CONSERVATION AREA 3 19 0 20 2001m² 2001m² 21

2002m² 22 2.50 2001m² 400 3.51ha

HA-CPT19 23

2000m² 300 2.50 24 2016m² LOCAL2500m² 25 2009m² PURPOSE

120 0.00 HA-CPT18 2002m² 124 BUILDING PLATFORM 121 122 2013m² RESERVE 119 2003m² 2002m² 26 2002m² 123 2001m² 125 LEVEL RL 4.2M 2000m² 2014m² HA-CPT06 11 10 9 2.50 118 126 13 12 2017m² 2005m² 8 2004m² 2007m² 127 2038m² 2036m² 2004m² 7 0.00 2005m² 2001m² 128 27 2002m² 6 2 2002m² 2004m² 5 129 2002m² 2000m² 1 2006m² 2000m² 4 3

28 14 HA-CPT05 2000m² 130 2004m² 2047m² 2023m²

2002m² CPT10 15 2017m² 2.50 2.50 29 2022m² 131 2000m² 117 2006m² 2.50

2050m² 132 2.50 2000m² 30 2053m² 16 133 2000m² 2000m² 2.50 17 134 2000m² -2.50 2000m² 31 -5.00 116 CPT28 2007m² BUILDING PLATFORM 2003m² 135 18 2000m² BUILDING PLATFORM HA-CPT29 2000m² -2.50 LEVEL RL 4.2M 136 113 2.50 2003m² LEVEL RL 4.2M 114 2000m² 112 137 115 111 110 2015m² 2.50 2001m² 2010m² 2000m² 2000m² 2000m² 109 2000m² 108 2000m² 107 2002m² BUILDING PLATFORM LEVEL RL 4.2M PUKEHINA BEACH ROAD CPT14 106

0.00 2006m² 105 2021m² 104 2.50

HA-CPT17 2019m²

-5.00 32 CPT01 2016m² 103 2.50 2.50 2011m²

0.00 WL 102 2000m² 33 RL 0.55m 101 2002m² 2001m² 100 HA-CPT27 2004m² 99 34 CPT08 2001m² HA-CPT07

2000m² 98 0.00 2000m² 97 2.50 -2.50 2000m² 301 CPT12 35 2005m² BUILDING PLATFORM 4003m² HA-CPT30 LOCAL 2.50 201 LEVEL RL 4.2M PURPOSE 96 36 200 2006m² 2001m² 29.8 ha WL

-5.00 87.0 ha RESERVE RL 0.55m 37 CONSERVATION AREA 2 0.00 CONSERVATION AREA 1 95 2000m²

2004m² -2.50 38 BUILDING PLATFORM -2.50 2028m² BUILDING PLATFORM 94 39 LEVEL RL 4.2M

0.00 LEVEL RL 4.2M 2025m² 2024m² 2.50 BASE OF -2.50 -2.50 93 40 -5.00 2019m² 2000m² POND RL-3.5M 41 0.00 92 2012m² 2031m² 42

-5.00 2011m² 43

91 2003m² 2030m²

-2.50 44 0.00 90 2001m² 45 CPT09 2021m² 89 2004m² 2016m² HA-CPT04 -5.00 BH01/CPT26 CPT02 0.00 BASE OF POND 88 HA-CPT13 2000m² RL-5.5M 2.50 87 2008m² 86 BUILDING PLATFORM HA-CPT23 2000m² 85 LEVEL RL 4.2M -5.00 2006m²

-5.00 84 2001m² 2.50

0.00 -2.50 46 2000m² 0.00 47 2.50 0.00 2000m²

48

2026m² -2.50 2.50

-5.00 -2.50 49

83 2027m² 0.00 2000m²

-2.50 -2.50 82 50 CPT22

HA-CPT24 2001m² 2014m²

-5.00 51

2002m² 0.00 0.00 81 2013m² 52 BUILDING PLATFORM

80 2010m²

1993m² 54 LEVEL RL 4.2M 53 2.50 CPT15 2048m² 59 2002m² 56 57 2008m² 79 2005m² 2018m² 58

2001m² 55 2002m² -5.00 78 2008m² 60 2068m² 2006m²

CPT25 61

77 2.50 2006m² 2079m² 0.00 76 BUILDING PLATFORM 2116m² 62 HA-CPT03 2007m² LEVEL RL 4.2M 75 2037m² 74 HA-CPT162.50 2003m² 63 2001m² P:\PROJECTS\502328 - PROPERTY SEVEN ECO VILLAGE, PUKEHINA\5 DELIVER DESIGN\503 CADD\DRAWINGS\CIV\502328-0000-DRG-CC-0005.DWG

2.50 73 70 2000m² 72 2027m² 64 PUKEHINA CANAL (STOPBANKED) 2005m² 71 2000m² 2012m² 66 69 2011m² 2073m² Filename: 68 67 2021m² 65 2009m² 2000m² NZTRG Office:

25 0 50 100m 25/2/2019 8:56:59 AM SCALE 1:2500 Plot Date: CLIENT REV DATE REVISION DETAILS APPROVED SCALE SIZE CONSENT PROJECT PROPERTY SEVEN - ECO VILLAGE A PRELIMINARY ISSUE AS SHOWN A1 NOT FOR CONSTRUCTION B 25.02.19 CONSENT ISSUE A.COLLIER PUKEHINA DRAWN APPROVED E.ALVAREZ . DATE TITLE PROPOSED LANDFORM CONTOURS PROPERTY SEVEN LIMITED DESIGNED 25.02.19 D.KALISCH A.COLLIER REVIEWED PROJECT No. WBS TYPE DISC NUMBER REV N.RAYNOR A.COLLIER DRAWING No. 502328 0000 DRG CC 0005 B LEGEND PROPOSED SITE BOUNDARY CUT CONTOUR AT 0.5m -0.50 INTERVALS FILL CONTOUR AT 0.5m 0.50 INTERVALS PUKEHINA PARADE PUKEHINA PARADE 0.00 ZERO CONTOURS

BOREHOLE - CPT ONLY COSTELLO CRESCENT BOREHOLE - CPT AND ROTARY GARDINER PL 1-2. DRILLED 0.00 -1.00 -0.50 0 HA-CPT21 0.00 1.00 0.00 0.50 0.50 -0.50 5 1.00 BOREHOLE - CPT AND HAND . 0.00 -0.50 -1.00 0 1.00 0.50 AUGER CPT20 0.50 0.50 0.50 0.00 1.00 DATUM INFORMATION: 0.00 0.00

-1.00

0.00

0.50

· VERTICAL DATUM: MOTURIKI 1953. .

1.00 0.50

1.00 CPT11 -1.000 · HORIZONTAL DATUM: NZGD2000 BAY OF PLENTY. 0.00 1.00 - 0.00

-0. 0.000.50 2.50 3.00 0.00 1.00 0.50 1.00-0.50 -1.00 -0.50 0.50 0.50 0.00 0.50 -0.50 1.00 -0.500.501.50 1.00 0.00 0.00

1.00 1.00 0.50 1.50 1.000.50 0.00 2.00 0.50 0.00 0.00 0.00 1.50 0.00 1.50 2.00 1.000.50 0.00 1.502.00

0.00 HA-CPT19 0.50 0.50 0.00 0.00 2.503.00 1.50 1.00 3.50

0.000.501.00 3.00 0.50 2.50

0.50 HA-CPT18 0.00 2.00 2.00

-0.50 0.50 3.50 0.00 1.50

3.00 HA-CPT06 0.00 2.50

-1.00 0.00 3.50 2.00 2.00 1.00 -2.50 -1.50 3.00 2.50 1.50 0.50 3.00 3.00 2.50 2.002.50 HA-CPT05

2.50 3.00 1.00

-2.00 2.50 1.00 1.00CPT10 1.50 0.00 0.00 -3.50 -0.50 3.00 -3.00 1.50 1.00 0.50 -4.00 2.000.50 2.50 1.00 -5.50-4.50 0.00

0.50 -6.00 0.00 3.00 2.50 3.50 2.50 3.50 0.50 0.00

-0.50 -5.00 3.00 0.00

0.50 0.50 1.50

0.50 0.00 1.50 CPT282.00 3.50 3.00 3.00 3.50 0.00 0 1.50 2.50 0.00 HA-CPT29 3.50

0.00

-5.50 0.00

0.00 0.50 3.00 0.00 1.00

0.00 0.50 0.50 0.00 1.50

-1.50 3.00 2.00 2.00 PUKEHINA BEACH ROAD

-2.00 -3.00 2.50 3.00

1.00 0.00 CPT14 0.50 2.50

-1.00 0.00 0.50

-5.00

1.50 0.00 0.50 0.00

-2.50 0.50

-6.00 0.00 -6.00 HA-CPT172.00 2.00

-5.00 CPT01 1.00 2.50 -3.50 2.00

0.00 0.00 2.50 3.00 0.00 1.00 1.501.00 -2.50

-1.50 1.50 2.50 -3.00-2.00 -4.50 -1.00 HA-CPT27

0.00 -4.50 -6.00 1.00 3.50 CPT08 -4.00 0.00

0.50 -6.00 3.50 1.50 HA-CPT07 -5.50

1.00 -0.50

0.50

-4.00 -5.00 0.50 1.00 -5.50 -6.00-5.50 -5.50-6.00 -1.50 -6.50 CPT12 -1.00 -5.50 -5.00 3.50 0.00 HA-CPT30 -0.50 0.00 0.00 1.00 2.00

-6.50 0.501.00 0.50 3.00 -6.00 0.00 0.00 0.50 1.00 -3.00

-0.50 0.00 2.00 1.50

-6.00 0.50 0.001.00 -2.00

0.50 0.00 -0.50 1.00 0.00 -6.00 0.00 0.00 0.50 1.00 0.50 0.00 0.00 0.00 -6.00 -5.50 3.003.003.50

-6.00 0.00 2.50 2.50

0.50 0.00

-3.50 1.00 0.50 -3.00-2.00 3.00 0.50 0.500.00

0.00 -6.00 -6.00 -0.50 0.500.00 -4.00-3.50

-5.50 -1.00 0.00 -3.50 -1.50 1.50 -2.50 -2.00 0.00 1.00 0.50 -5.00 -4.00 -3.00 -2.50 2.50 -0.50 -4.50

0.00 -6.00 -5.50 -5.00 -0.50

-1.50 -6.00 -2.50

-3.50 3.00 2.00 -0.50

-2.50

1.00 -5.00 -5.00 -5.50 1.00 -5.50 -1.50 0.00

0.00 -6.00 -6.00 -3.50 -3.00 -5.50

-1.00 -6.00 -1.00 0.00 -1.50 -2.00-2.50 -1.00 3.00 0.00 -

-4.00 3.50 0.00

-5.00 -4.50 0.00

-3.00 -1.50 2.00 -4.00

0.00 0.00 CPT09 3.50 -2.50 -6.00 -6.00 -4.00

-6.00 BH01/CPT26 CPT02 HA-CPT04

-4.50 HA-CPT13 0.00

-6.00 0.00 -3.50 -4.00 0.50

-6.00 -6.00 0.00 0.00 -2.00-0.50 -4.50 3.00 0.00

-5.50 0.50 0.00

-5.50 0.00 0.00

2.00 -1.50 0.00 -6.00 1.00 -1.00

-6.00 1.50 2.50

-4.50

-4.00 -0.50 0.00

HA-CPT23 -6.00 -6.00 3.00 3.50

0.50

-5.50

-0.50 1.50 -4.00 0.50

-5.50 0.50

-1.00 1.50

-6.00 -3.000.00 -0.50 1.00 -2.00 2.50

-5.00 -5.00

0.00 -5.00-5.50-3.50 2.00

-6.00

-5.00 -6.00 -2.00-2.50 3.50 -0.50 0.00

-3.00 0.50

0.00 0.00 0.00 -3.50 3.00

-3.50 -5.50 -6.00 0.50 -5.50

-5.50 0.00

0.00 0.00 2.50 -6.00 -5.50 -1.50 -1.50

0.50 -1.00 -5.00 -3.50 -1.00 CPT22 0.00 -4.50-4.00 0.00 0.00

-1.50 -4.50 -6.00 1.00

0.50 2.50 0.00 -3.00 -4.00 -1.50 HA-CPT24 -5.50 -3.00-2.00-2.50 0 -1.00 -2.50 -1.00 0.00 0.

0.00 -0.50 0.00 1.50 -2.00 -3.00 1.00 0.50 -2.00-2.50-5.00 -3.50 0.00 0.00 0.00 0.00

-0.50 -4.50 0.00 3.00 3.50 0.00 0.00

1.00 -4.00 -1.50-1.00 -5.50 CPT15 1.00 0.00 -4.50 0.50 -4.00 -6.00 1.50 2.50 1.00 -0.50

-5.00 0.50 3.00 2.00

0.50 3.00 0.00 0.50 0.00

-0.50 0.00 3.00 0.50 0.00

0.50 0.00 0.00 CPT25-3.50 1.00

0.00 2.00 -2.50

-3.00 3.50 0.50

-1.50 -2.00 3.50

1.50 0.00 -1.00 2.00 1.50 0.00 2.50 0.00 3.000.50 2.50 HA-CPT03

-0.50 -0.50 0.00

0.00 3.50

0.00 3.50 0.00 3.00 0.00 HA-CPT16 2.50 2.00

0.00 1.00

-0.50

0.50

0.00 3.50 0.500.00 2.50 1.00 P:\PROJECTS\502328 - PROPERTY SEVEN ECO VILLAGE, PUKEHINA\5 DELIVER DESIGN\503 CADD\DRAWINGS\CIV\502328-0000-DRG-CC-0020.DWG PUKEHINA CANAL (STOPBANKED) .0 3.50 0 0.50

Filename: 0.50

0.00 0.00

0.00 2.501.000.50 1.50 0.00

NZTRG 0.00 3.00 2.00

Office: - 0.

25 0 50 100m 25/2/2019 8:58:57 AM SCALE 1:2500 Plot Date: CLIENT REV DATE REVISION DETAILS APPROVED SCALE SIZE CONSENT PROJECT PROPERTY SEVEN - ECO VILLAGE A PRELIMINARY ISSUE AS SHOWN A1 NOT FOR CONSTRUCTION B 25.02.19 CONSENT ISSUE A.COLLIER PUKEHINA DRAWN APPROVED E.ALVAREZ . DATE TITLE CUT AND FILL CONTOURS PROPERTY SEVEN LIMITED DESIGNED 25.02.19 D.KALISCH A.COLLIER REVIEWED PROJECT No. WBS TYPE DISC NUMBER REV N.RAYNOR A.COLLIER DRAWING No. 502328 0000 DRG CC 0020 B

B

ECoast Tsunami Maps

Appendix B ECoast Tsunami Maps

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN SEA LEVEL

2500-year RI 2500-year RI Tsunami Height Overland Flood Depth

MCE MCE Tsunami Height Overland Flood Depth

Figure 4.8 Maximum computed tsunami height (left) and overland flow depth (right) for the 2500-year event (top) and the maximum credible event (bottom) at Maketu at MSL.

48 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN HIGH WATER SPRING: MAXIMUM TSUNAMI HEIGHT

500-year RI 1000-year RI Tsunami Height Tsunami Height

2500-year RI MCE Tsunami Height Tsunami Height

Figure 4.9 Maximum computed tsunami height at Maketu for the 500-year, 1000-year (top L, R) 2500-year and maximum credible events (bottom L, R) at MHWS.

49 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN HIGH WATER SPRING + SLR: MAXIMUM TSUNAMI HEIGHT

500-year RI 1000-year RI Tsunami Height Tsunami Height

2500-year RI MCE Tsunami Height Tsunami Height

Figure 4.10 Maximum computed tsunami height at Maketu for the 500-year, 1000-year (top L, R) 2500-year and maximum credible events (bottom L, R) at MHWS + SLR.

50 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN SEA LEVEL 2500-year RI 2500-year RI Tsunami Height Overland Flood Depth

MCE MCE Tsunami Height Overland Flood Depth

Figure 4.11 Maximum computed tsunami height (left) and overland flow depth (right) for the 2500-year event (top) and the maximum credible event (bottom) at Pukehina at MSL.

51 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN HIGH WATER SPRING 500-year RI 1000-year RI Tsunami Height Tsunami Height

2500-year RI MCE Tsunami Height Tsunami Height

Figure 4.12 Maximum computed tsunami height at Pukehina for the 500-year, 1000-year (top L, R) 2500-year and maximum credible events (bottom L, R) at MHWS.

52 Tsunami Inundation Assessment for the Western Bay of Plenty District

MEAN HIGH WATER SPRING + SLR 500-year RI 1000-year RI Tsunami Height Tsunami Height

2500-year RI MCE Tsunami Height Tsunami Height

Figure 4.13 Maximum computed tsunami height at Pukehina for the 500-year, 1000-year (top L, R) 2500-year and maximum credible events (bottom L, R) at MHWS + SLR.

53

C

Natural Hazard Risk Assessment

Appendix C Natural Hazard Risk Assessment

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

Table C1 Natural hazard risk assessment (pre-development)

Consequences2 Overall risk Social / Buildings Critical Lifelines Health and 3 Pre-development Scenario Probability rating Natural Hazard Cultural Buildings Utilities Safety Qualitative Consideration (current site use) 1 (% AEP) Buildings (AEP vs. consequence)

Ground investigations completed by Aurecon have demonstrated the development site to be underlain by saturated soils considered susceptible to liquefaction in the event of an earthquake. Based on the results of analyses completed as part of the G1 geotechnical assessment a 1 in 1000 year earthquake event (0.1%) exceeds the maximum credible (worst case) event, which we consider to be the point at which the maximum amount of liquefaction can be achieved (based on our analyses determined to be within a 1/100 to 1/150 year return period; or 1% to 0.67% AEP), which equates to a peak ground acceleration of between 0.13 to 0.15 g for Site is an agricultural property an IL2 structure. A ULS building code event (1 in 500 year, or 0.2% AEP; 0.26g) with four residential buildings, for an IL2 importance level structure in accordance with NZS1170 in line with ancillary farm buildings and existing uses also exceeds the maximum credible earthquake event. pastoral grazing land. High Risk In the event of a 0.1 %AEP earthquake event, a settlement of ~310mm is Assumed population of 10 (2.5 Earthquake 0.1 (1 in 1000 (on the basis that currently predicted. Lateral spread is not anticipated to be a significant hazard persons per household). Site (Liquefaction / year earthquake Insignificant Catastrophic Insignificant Moderate Insignificant >50% buildings given lack of significant water bodies with unrestrained free face. Some elevation typically 0 - 1 m RL, Lateral Spread) event) have been localised instability may occur around the farm drains, but no buildings or though locally elevated along functionally infrastructure would be compromised. northern site boundary (~2 m compromised) In the event of an 0.1% AEP earthquake, which equates to a MCE liquefaction RL) where the existing farm event it is not anticipated, based on the elevation and age of the buildings, that a buildings are located. design has been achieved that would maintain function of site buildings. There Existing access from northern are less than 10 buildings on site, and only one residence, exacerbating the site boundary and along overall 'high risk' rating. There are no social, cultural, or significant buildings on Pukehina Beach Parade. site. The current utilities are not fully understood but conservatively, we Pukehina Beach Road and anticipate that they could be repaired for a single residence within 6 weeks of the Pukehina Canal are located event occurring. along the south-eastern and While not within the development site, it is anticipated that adjacent infrastructure south-western boundaries (Pukehina Beach Road and Pukehina Canal) would be damaged to some respectively. degree, and repair or replacement would be required. Low lying areas of the site are actively drained to maintain grazing land. Groundwater level, Tsunami modelling has been undertaken of the Pukehina area for WBOPDC as measured by recent (ref: ECoast Report, June 2017). The modelled flow depths for a 0.1% AEP investigations, is taken to be ~0 event indicates a maximum depth of 1.5 m may be expected in the NE portion of to -1 m RL. the site. The tsunami depth is generally <1 m over the site and inundation is not present outside the NE corner. Medium risk There are less than 10 buildings on site, including 4 residences. This 0.1 (1 in 1000 (on the basis that exacerbates the overall 'high risk' rating with 1 of the 4 residences located within Tsunami year tsunami Insignificant Major Insignificant Moderate Insignificant >21-49% the tsunami flood inundation area. In addition, whilst the flood levels are event) buildings have been functionally relatively shallow i.e. <1 m and may not enter the homes - any water ingress is compromised) considered by BOPRC as deeming the building functionally compromised. There are no social, cultural, or significant buildings on site. The current utilities are not fully understood but conservatively, we anticipate that they could be repaired for the residences onsite within 6 weeks of the event occurring.

Notes/References 1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 2 Consequences (Refer Appendix L of RPS, Table 21) 3 Overall risk rating (Refer to Risk Screening Matrix, page 374 of RPS) Risk assessment completed in accordance with Appendix L of BOPRC Operative Regional Policy Statement Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833) Earthquake shaking is outside of the requirements of the RPS Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

Table C1 Natural hazard risk assessment (pre-development)

Consequences2 Overall risk 3 Pre-development Scenario Probability (% Social / rating Natural Hazard 1 Critical Lifelines Health and Qualitative Consideration (current site use) AEP) Cultural Buildings (AEP vs. Buildings Utilities Safety Buildings consequence)

Aurecon (report ref: 502328-0000-REP-CC-0000) modelled pre-development flood levels and flows to assess the impact in a 100-year 48-hour event (1% AEP). The rainfall was input in a nested storm pattern which provides peak flows and maximum volumes for the range of durations within the 48-hour event. Site is an agricultural property Rainfall depths included for 3°C of climate change in line with BOPRC’s with four residential buildings, Stormwater Management Guidelines for the Bay of Plenty region. The flood ancillary farm buildings and model also assumed no discharge out of the paddock areas to the Pukehina pastoral grazing land. Canal (i.e. the pumps are not operating). Assumed population of 10 (2.5 The modelled 100-year flood level over the site is RL 1.07 m, and extends persons per household). Site beyond the existing site boundaries and covers the upstream and downstream elevation typically 0 - 1 m RL, farm properties, and the lower yard areas of the existing urban properties at 28 though locally elevated along and 42 Pukehina Parade, and a portion of the Pukehina Campground. The northern site boundary (~2 m ground level within the rural land is typically between RL 0.6 and RL 0.9m. RL) where the existing farm Therefore, the depth of flood modelled across the site is a maximum depth of 0.5 buildings are located. High Risk m. Existing access from northern (on the basis that Upstream of Pukehina Beach Road, the modelled 100-year flood level is RL 1.28 site boundary and along 1 (1 in 100 year Flooding Insignificant Catastrophic Insignificant Moderate Insignificant >50% buildings m. The capacity of the existing 1050 mm diameter culvert under the road also Pukehina Beach Parade. rainfall event) have been restricts the volume transfer required to balance the flood levels across the Pukehina Beach Road and functionally Pukehina Beach Road during the 100-year rainstorm event. The Pukehina Canal Pukehina Canal are located compromised) is separated from the site by a stop bank crest that is between RL 1.75 m and along the south-eastern and RL 2. 0 m adjacent to the site and above RL 1.5 m upstream of Pukehina Beach south-western boundaries Road. respectively. There are less than 10 buildings on site, including 4 residences, exacerbating Low lying areas of the site are the overall 'high risk' rating. In addition, whilst the flood levels are relatively actively drained to maintain shallow i.e. <0.5 m and may not enter the homes - any water ingress is grazing land. Groundwater level, considered by BOPRC as deeming the building functionally compromised. There as measured by recent are no social, cultural, or significant buildings on site. The current utilities are not investigations, is taken to be ~0 fully understood but conservatively, we anticipate that they could be repaired for to -1 m RL. the residences onsite within 6 weeks of the event occurring. In a 0.2% AEP rainfall event the flood levels are expected to be consistent across the whole floodplain at a level approximately 300-400mm above the 1% AEP level.

Notes/References 1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 2 Consequences (Refer Appendix L of RPS, Table 21) 3 Overall risk rating (Refer to Risk Screening Matrix, page 374 of RPS) Risk assessment completed in accordance with Appendix L of BOPRC Operative Regional Policy Statement Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833) Earthquake shaking is outside of the requirements of the RPS Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

Table C2 Natural hazard risk assessment (post-development)

Consequences2 Overall risk Development 3 Natural Probability Social / rating What additional mitigation effects could be Scenario (proposed 1 Critical Lifelines Health and Qualitative Consideration Hazard (% AEP) Cultural Buildings (AEP vs. implemented? site use) Buildings Utilities Safety Buildings consequence) Ground investigations indicate the development site to be underlain by More robust building design or use of more saturated soils considered very susceptible to liquefaction in the event of even resilient materials to maintain function of dwellings A lifestyle block a moderate earthquake. To provide context the 1/100-year earthquake event post-earthquake event, possible use of development is currently predicts about 310 mm green field settlement. relocatable or recoverable structures (Refer proposed, with When considering the RPS secondary analysis (0.1% AEP and 0.033%AEP), Appendix M of the RPS - adjacent ecological https://cdn.boprc.govt.nz/media/782173/operative- wetland habitat and and based on the results of analyses completed as part of the G1 geotechnical assessment we believe the majority of the site soils will liquefy if earthquake rps-1-october-2014-incorporating-change-3- walking trails. Two appendix-m.pdf) ponds will be shaking exceeds 1/100 event. Earthquake shaking beyond a 1/1000-year event constructed within the will not significantly increase the effective liquefaction settlement, i.e. a 1/3030 Ensuring that footpaths are located outside of wetland, to depths event will provide no better or worse ground damage than a 1/1000 event. areas determined to be highly susceptible to ranging between 4 m We consider that the site would be unavailable for residential development lateral spread hazard. and 6 m bgl (-0.35 to - without any modification, ground improvement or engineering intervention. Our Undertake ground improvement and earthworks 0.55 m RL). ground assessment, analysis and design as per our G1 report proposes the design with the objective that IL2 buildings can Residential building construction of residential building platforms using engineered fill that will remain serviceable in a ULS event (max vertical platforms will be provide an equivalent ground performance to TC2 MBIE (2012). and lateral displacement of 100 mm, in constructed on Foundations designed to meet TC2 ground conditions can cope with a accordance with MBIE). engineered fill maximum displacement of 100 mm vertically or laterally under ULS levels of embankments to a shaking without causing significant superstructure damage. The building minimum RL of 4.2 m. platforms will comprise at least 4m of compacted non-liquefiable fill and create The residential lots will a 'crust' that will reduce the impact of differential settlement arising from not be connected to reconsolidation settlement. We consider that surface ejection of liquefied town supply, and material is unlikely to occur even at maximum considered shaking intensities. reliant on solar power, The building platforms are either sufficiently set back from any free edges to be in addition to rain Earthquake 0.1 (1 in affected by lateral spreading, or specific ground modifications or improvement (Liquefaction 1000 year will be provided at subdivision development stage. collection tanks and Insignificant Minor Insignificant Minor Insignificant Low Risk individual effluent / Lateral earthquake In line with observations from the Canterbury Earthquake Sequence we believe disposal fields. No Spread) event) that an intact 3m+ thick crust will provide sufficient robustness to support the social, cultural or building and prevent any significant damage to services. Structural collapse is critical buildings are unlikely to occur provided foundations remain undamaged. Tilting and currently proposed. differential settlement may occur but TC2 type foundations are able to cope Low-lying areas will with differential settlement as they are well tied together and can cantilever and remain drained to span over sunken ground. Services connections can be readily repaired at the maintain slab boundaries. ground/surface water In ground infrastructure may progressively lose the ability to provide service to levels at ~0.6 m RL for dwellings, but all horizontal infrastructure will be designed to cope with the protection of wetland expected differential settlement and use modern materials that are able to cope habitat which are likely with vertical and horizontal deformations. to rise as an ongoing Beyond the residential buildings, it is anticipated that some damage may be effect of predicted incurred within new roads, Pukehina Road and Pukehina Canal and that repair climate change. Bunds will be required. We anticipate that works to repair these roads would be will be constructed straight forward and could be achieved within a few days of a significant around the perimeter of earthquake event occurring. Access across the damaged sections of road is the development site to likely to be available after the event. help limit risks from In summary, the target for proposed earthworks and foundation design will be flooding. Existing land to achieve no loss of amenity (buildings remain habitable and can be repaired drains will be filled in. within 4 weeks) as defined by MBIE (2012) and the Building Code, as such 0% Pukehina Beach Road loss of function within residences on site. We conservatively allow for up to and Pukehina Canal 10% of buildings to be compromised, owing for time taken to achieve repairs. will remain. Lifeline utilities are on-site structures that can be easily repaired with no reliance on a less resilient inground council owned network

Notes/References 1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 2 Consequences (Refer Appendix L of RPS, Table 21) 3 Overall risk rating (Refer to Risk Screening Matrix, page 374 of RPS) Risk assessment completed in accordance with Appendix L of BOPRC Operative Regional Policy Statement Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833) Earthquake shaking is outside of the requirements of the RPS Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

Table C2 Natural hazard risk assessment (post-development)

Consequences2 Overall risk rating3 Development Scenario Natural Probability Social / What additional mitigation effects could be 1 Critical Lifelines Health and (AEP vs. Qualitative Consideration (proposed site use) Hazard (% AEP) Cultural Buildings implemented (not currently proposed)? Buildings Utilities Safety consequence) Buildings The pre-development tsunami modelling (ref: ECoast Report, Additional risk mitigation measures could include June 2017) for a 0.1% AEP event indicates a maximum depth of tsunami evacuation route and information A lifestyle block 1.5 m may be expected in the NE portion of the site. The signage for residents and visitors to the development is tsunami depth is generally <1 m over the site and inundation is wetlands. proposed, with adjacent not present outside the NE corner. Tsunami inundation for a ecological wetland The site is located within the orange evacuation larger even,t as per the likelihoods considered in the RPS habitat and walking trails. zone (refer to WBOPDC Tsunami evacuation secondary analysis (0.04% AEP), covers the entire site, however Two ponds will be map), whereby a tsunami from regional or the maximum depth of water still remains 1.5 m (predominantly constructed within the distant sources (further away than 1000 km) in the NE portion of the site). Across the rest of the site tsunami wetland, to depths could take anywhere from 2 to 12 hours to depths are generally <1m. ranging between 4 m and arrive. The yellow zone represents an area 6 m bgl (-0.35 to -0.55 m The built infrastructure will be constructed at an elevation of 3.6 impacted by the most devastating tsunami. After RL). m RL or higher, and the design level for the construction of the a major earthquake it would take about 50 proposed residential building platforms is currently 4.2 m RL, minutes for this tsunami to reach the coast, and Residential building which is well above the modelled tsunami level of 1.5 to 2.4 m approximately another 30 minutes to flood the platforms will be RL for both a 0.1% AEP, 0.2%AEP and 0.04% AEP event yellow zone. constructed on (likelihoods used for initial and secondary analysis as per the engineered fill The nearest “safe zone” as indicated by tsunami RPS). embankments to a hazard mapping and evacuation zones is minimum RL of 4.2 m. The catchment separation bund height is proposed at RL 2.2 m; located approximately 1.2 km southwest along higher than the Pukehina Canal stop bank crest. The bund will Pukehina Beach Road, or 500 m east of the site. The residential lots will be constructed around the site to protect the site from external These locations are less than a 15-minute walk not be connected to town flooding, and will be achieved by surrounding the development from the site and therefore the site would be supply, and reliant on area that connects to the existing canal stop bank and also the evacuate-able. solar power, in addition to 0.1 (1 in Pukehina Beach Road embankment (between the entranceway rain collection tanks and 1000 year and the camp ground). The level of the bund is lower than depth individual effluent Tsunami Insignificant Insignificant Insignificant Minor Insignificant Low Risk tsunami of the modelled 0.04% AEP tsunami and maybe overtopped at disposal fields. No social, event) the current design height. The bund is not overtopped during a cultural or critical 0.2% and 0.1% AEP event. The tsunami will not overtop the built buildings are currently infrastructure and residential building platforms and likely to be proposed. funnelled into the wetlands. The bund may need to be raised at Low-lying areas will least 0.2 m to accommodate the modelled tsunami depth. remain drained to Services for residents post-inundation will not be compromised; maintain ground/surface stormwater, wastewater and effluent will be managed on-site, water levels at ~0.6 m RL and essential services will be elevated above the flood level (i.e. for protection of wetland at least RL 3.5m). Each lot will install rainwater tanks for habitat which are likely to irrigation and possible potable uses. The single watermain rise as an ongoing effect supplying water for firefighting purposes is likely to be adjacent of predicted climate to access roading into the proposed development, which will change. Bunds will be also be raised above the flood level. Minor damage may occur constructed around the along the edges of Pukehina Road, however the functionality is perimeter of the unlikely to be severely compromised and repairable in within 1 development site to help week of the event occurring for a 0.1% and 0.2% AEP event. limit risks from flooding. This may take longer for the 0.04% AEP event where inundation Existing land drains will occurs along the Pukehina Road (albeit shallow i.e. <1 m). It is be filled in. Pukehina anticipated that some damage may be incurred to the bund from Beach Road and tsunami loading, wave actions and scour - we anticipate that Pukehina Canal will works to repair these could be achieved within 6 weeks of an remain. event occurring.

Notes/References 1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 2 Consequences (Refer Appendix L of RPS, Table 21) 3 Overall risk rating (Refer to Risk Screening Matrix, page 374 of RPS) Risk assessment completed in accordance with Appendix L of BOPRC Operative Regional Policy Statement Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833) Earthquake shaking is outside of the requirements of the RPS Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

Table C2 Natural hazard risk assessment (post-development)

Consequences2 Overall risk 3 Development Scenario Natural Probability Social / rating What additional mitigation effects could be 1 Critical Lifelines Health and Qualitative Consideration (proposed site use) Hazard (% AEP) Cultural Buildings (AEP vs. implemented (not currently proposed)? Buildings Utilities Safety Buildings consequence)

Post-development, Aurecon's hydraulic modelling showed that No additional mitigation measures are proposed a 1% AEP resulted in an internal flood level of RL 1.31m within for the site that are above and beyond what is A lifestyle block development the site (ref: 502328-0000-REP-CC-0000). already proposed e.g. elevated building is proposed, with adjacent Secondary analysis for the 0.2% AEP rainfall event is platforms and perimeter bunding. ecological wetland habitat and considered to be within 300-400 mm of the 1% AEP event walking trails. Two ponds will which will still be lower than the proposed platform levels and be constructed within the critical infrastructure levels. wetland, to depths ranging The built infrastructure will be constructed at an elevation of 3.6 between 4 m and 6 m bgl (- m RL or higher, and the design level for the construction of the 0.35 to -0.55 m RL). proposed residential building platforms is currently 4.2 m RL, Residential building platforms which is well above the expected ground water level of RL 0.6m will be constructed on to RL 1.0m, and an internal 100-year flood level (1% AEP). The engineered fill embankments built infrastructure and building platform levels will also be to a minimum RL of 4.2 m. above the Tauranga Harbour Inundation Levels the RCP 8.5 H+ The residential lots will not be value (the BOPRC Policy on this matter is yet to be finalised). connected to town supply, and In addition, a catchment separation bund height is proposed at reliant on solar power, in RL 2.2 m; higher than the Pukehina Canal stop bank crest. The addition to rain collection tanks bund will be constructed around the site to protect the site from and individual effluent disposal 1 (1 in 100 external flooding, and will be achieved by surrounding the fields. No social, cultural or Flooding year rainfall Insignificant Insignificant Insignificant Minor Insignificant Low Risk development area that connects to the existing canal stop bank critical buildings are currently event) and also the Pukehina Beach Road embankment (between the proposed. entranceway and the camp ground). Aurecon's modelling has Low-lying areas will remain shown that accommodate increases in water levels within the drained to maintain site can be accommodated, and as the site will be separated ground/surface water levels at from the surrounding land by a bund, external flood levels are ~0.6 m RL for protection of not increased. The modelling has also shown that the wetland habitat which are construction of a bund will decrease the flood levels for many likely to rise as an ongoing storm scenarios. effect of predicted climate Services for residents post-flooding will not be compromised; change. Bunds will be stormwater, wastewater and effluent will be managed on-site, constructed around the and essential services will be elevated above the flood level perimeter of the development (i.e. at least RL 3.5m). Each lot will install rainwater tanks for site to help limit risks from irrigation and possible potable uses. The single watermain flooding. Existing land drains supplying water for firefighting purposes is likely to be adjacent will be filled in. Pukehina to access roading into the proposed development, which will Beach Road and Pukehina also be raised above the flood level. Minor damage may occur Canal will remain. along the edges of Pukehina Road, however the functionality is unlikely to be severely compromised and repairable in within 1 week of the event occurring.

Notes/References 1 Probability (in terms of % AEP) (Refer Appendix L of RPS, Table 20) 2 Consequences (Refer Appendix L of RPS, Table 21) 3 Overall risk rating (Refer to Risk Screening Matrix, page 374 of RPS) Risk assessment completed in accordance with Appendix L of BOPRC Operative Regional Policy Statement Volcanic hazards, fault rupture, landslips excluded from natural hazard assessment in agreement with BOPRC Modelling indicates that the site is not impacted by coastal erosion and coastal inundation, therefore risk assessment not completed for these hazards (refer to Tonkin & Taylor, April 2015, ref: 851833) Earthquake shaking is outside of the requirements of the RPS Ash fall hazard for the site is not well-defined, and therefore not be considered further. Furthermore, the effect of ash fall on buildings and infrastructure is not considered in the New Zealand Building Code or other relevant codes pertaining to the proposed development

Project number 502328 File 502328-0000-GG-0002[2].docx, 2019-04-08 Revision 2

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