APPENDIX C APPENDIX C The Plains - area-wide suburb technical land information Kaiapoi Lakes 1 2 North Kaiapoi Pines Beach Kairaki Beach ! South Kaiapoi Brooklands 3 Bridgend Spencerville Chaneys Ouruhia Belfast 4 5 Styx Harewood Marshland Queenspark Redwood Parklands Casebrook Waimairi Beach Northcote Bishopdale Travis North Mairehau Westhaven New Brighton Burwood Papanui New Brighton Burnside Avonhead Shirley Avondale Yaldhurst Hyde Park 6 7 8 9 Bryndwr St Albans Dallington Bexley Russley Richmond Wainoni Fendalton Merivale Ilam Avonside Aranui Riccarton Park Masham Upper Riccarton Central City North Linwood South New Brighton Templeton Riccarton Phillipstown Hei Hei Bromley Linwood 2012 CanterburyEarthquakes2010and2011-Landreport asat29February COMMISSION: EARTHQUAKE Sockburn Middleton Sydenham Waltham Islington Addington 10 11 St Martins12 13 Hornby Spreydon Woolston Ferrymead Opawa Southshore Hillmorton Somerfield Redcliffs Hoon Hay Beckenham Mt Pleasant St Andrews Hill Westlake Cashmere Oaklands Heathcote Clifton Wentworth Park Sumner Hillsborough Huntsbury Moncks Spur Scarborough Prebbleton 14 Westmorland Halswell Hoon Hay Valley Lyttelton 15 Lincoln Diamond Harbour Governors Bay Tai Tapu Port Levy Notes: DRAWN Road Database supplied by Terralink International Ltd. CHECKED TECHNICAL LAND INFORMATION Rivers, lagoons and coastline licensed under Creative FACT SHEETS Commons Attribution 3.0 New Zealand and sources from LINZ APPROVED ARCFILE Area-wide Suburbs SCALE (AT A3 SIZE) A3 SCALE 1:100,000 1:100,000 0 1 2 3 4 5 (km) PREPARED BY TONKIN & TAYLOR LTD FIGURE No. REV No. PROJECT No. 68 Location Plan 52020.0200 Map Reference Sheet 0 EARTHQUAKE COMMISSION: Canterbury Earthquakes 2010 and 2011 - Land report as at 29 February 2012 87 Factsheet 10 - Hillmorton to Riccarton Hillmorton, Hoon Hay, Riccarton and Upper Riccarton each earthquake, and then on a property-by-property level 10.1 Ground conditions and groundwater Table C10.2 - Summary of ground elevation and groundwater depth (September 2011) Regional geology maps show this area is generally underlain over the following weeks. This mapping was supported by air- Suburb Ground elevation above sea level Groundwater depth by dominantly alluvial sand and silt overbank deposits, with photo analysis for all four main earthquakes, and additional some areas of alluvial gravel, sand and silt of historic river regional or street-level mapping for the earthquakes of Hillmorton Typically 14.2m to 16.3m (Avg 15.1m) Typically 1.7m to 3.0m (Avg 2.3m) flood channels. 13 June 2011 and 23 December 2011. This additional mapping Hoon Hay Typically 9.9m to 13.7m (Avg 11.6m) Typically 0.4m to 1.7m (Avg 0.7m) indicated that the overall pattern of liquefaction and lateral Table C10.1 summarises the area-wide subsurface ground Riccarton Typically 8.6m to 13.5m (Avg 10.9m) Typically 0.5m to 1.8m (Avg 1.2m) spreading for the subsequent earthquakes was generally investigations undertaken by EQC in this area following the Upper Riccarton Typically 15.3m to 23.7m (Avg 20.1m) Typically 1.4m to 5.7m (Avg 3.0m) similar to that observed in the first two main earthquakes. 4 September 2010 and 22 February 2011 earthquakes. These investigations indicate that the near-surface soil Figure C10.1 and Table C10.3 present a summary of the Table C10.3 - Summary of liquefaction and lateral spread observations for residential land, aggregated profile in the area generally comprises loose to dense sands, property-by-property rapid mapping of liquefaction and from mapping undertaken following earthquakes of 4 September 2010 and 22 February 2011 silts and gravel. lateral spread observations in this area. The observations Table C10.2 summarises typical ground elevation and following the 4 September 2010 and 22 February 2011 groundwater depths in the area (the values listed correspond earthquakes have been aggregated by assigning each to the 10th and 90th percentiles and the median). This was property the most severe observation from either of these derived from LiDAR ground elevation survey commissioned two earthquakes. These observed liquefaction and lateral by EQC in September 2011, and a groundwater surface spread mapping colours have completely different developed from recent EQC groundwater monitoring meaning to the colour codes used by the Canterbury Earthquake Recovery Authority (Cera) for residential land in conjunction with historic Environment Canterbury Suburb groundwater data. This area is generally elevated well above zoning and the Department of Building and Housing (DBH) Total residential residential Total property count Not mapped ground No observed or ejected cracking liquefied material cracking, Minor ground ejected but no observed liquefied material but spreading, No lateral quantities minor to moderate of ejected material spreading, No lateral quantities of but large ejected material to major Moderate ejected spreading, lateral often observed material spreading, lateral Severe often ejected material observed sea level with a shallow to moderate depth to groundwater. for technical categories. Hillmorton 543 1% 59% <1% 38% <1% 1% 0% The ground conditions and groundwater in this area are Table C10.4 summarises the change in ground elevation Hoon Hay 2957 13% 55% 1% 31% <1% <1% 0% generally similar to most of the southern, central and inferred from the LiDAR survey. The total change in ground Riccarton 3689 57% 36% <1% 6% 0% <1% 0% northern suburbs of Christchurch. elevation which has occurred is a combination of regional Upper Riccarton 3487 100% 0% 0% 0% 0% 0% 0% While ground surface disturbance has occurred in some uplift or subsidence due to fault movements (tectonics) areas (e.g. settlement, cracking and ejection of material), and local ground subsidence due to liquefaction and related the underlying ground which liquefied appears to have now effects. The LiDAR is of limited accuracy (about ±100mm). Table C10.4 - Changes in ground elevation inferred from LiDAR survey returned to its pre-earthquake strength. This means that the LiDAR is more suitable for measuring Suburb Change in ground elevation from July 2003 to September 2011 large changes in ground elevation (greater than about 100 to (positive values are uplift, negative values are subsidence) 10.2 Post-earthquake observations 200mm), and may not accurately represent areas where only Hillmorton Typically -150mm to +50mm (Average -50mm) Rapid mapping of liquefaction and lateral spreading minor changes in ground elevation have occurred. observations was undertaken following the 4 September Hoon Hay Typically -200mm to +50mm (Average -50mm) 2010 and 22 February 2011 earthquakes, first on a regional Table C10.5 summarises the extent and severity of observed Riccarton Typically -250mm to +0mm (Average -150mm) and street-by-street level in the days immediately after liquefaction and lateral spread. Upper Riccarton Typically -200mm to +50mm (Average -100mm) Table C10.1 - Area-wide geotechnical investigations undertaken by EQC (December 2011) Suburb Number of cone Number of Number of groundwater Length of MASW penetration tests boreholes standpipes geophysical testing (m) Hillmorton 5 - 2 - Hoon Hay 25 3 9 - Riccarton - - - - Upper Riccarton - - - - ENVIRONMENTAL AND ENGINEERING CONSULTANTS EARTHQUAKE COMMISSION: Canterbury Earthquakes 2010 and 2011 - Land report as at 29 February 2012 88 Factsheet 10 - Hillmorton to Riccarton Hillmorton, Hoon Hay, Riccarton and Upper Riccarton Table C10.5 - Liquefaction and lateral spread observations Unmapped, no observations (uncoloured) No lateral spreading but large quantities of ejected material No observed ground cracking or ejected liquefied material Moderate to major lateral spreading; ejected material often observed Suburb Observations Minor ground cracking but no observed ejected liquefied material Severe lateral spreading; ejected material often observed No lateral spreading but minor to moderate quantities of ejected material Territorial Authority suburb boundary Hillmorton Minor to moderate liquefaction in several areas (severe liquefaction on a small number of CREYKE ROAD WEKA STREET Hoon Hay properties), causing sand ejection and settlement. KOTARE STREET Riccarton ROCHDALE STREET Minor to moderate lateral spreading towards the Heathcote and Avon Rivers in several small ARTS ROAD CORFE STREET ATHOL TERRACE HARAKEKE STREET areas, but localised to the immediately adjacent properties. STREET TUI CLYDE ROAD KAHU ROAD For the remainder of these suburbs, no surface evidence of liquefaction or related land effects HOMESTEAD LANE MATAI STREET EAST WAIMAIRI ROAD ILAM ROAD was observed. PURIRI STREET SISKA PLACE BALGAY STREET KILMARNOCK STREET HINAU STREET Upper Riccarton This suburb was not mapped at a property-by-property level, however street-level mapping and KAURI STREET AYR STREET KIRKWOOD AVENUE RATA STREET STRAVEN ROAD air photo analysis found no surface evidence of liquefaction or related land effects. BRODIE STREET PEER STREET BOWEN STREET HANRAHAN STREET TOTARA STREET PAEROA STREET For further area-wide geotechnical information, refer to the technical data reports RUDLEIGH AVENUE RICCARTON ROAD BROCKWORTH PLACE EUSTON STREET MANDEVILLE STREET on the EQC website, at http://canterbury.eqc.govt.nz/news/reports Upper Riccarton DALLAS STREET WHARENUI ROAD PICTONAVENUE LOCHEE ROAD Riccarton PEVEREL STREET WAINUI STREET HAYNES AVENUEHANSONS LANE MATIPO STREET OWENS TERRACE TIKA STREET SUVA STREET MIDDLETON ROAD ELIZABETH STREET VICKI STREET MAYFAIR STREET PUNA STREET LYNDON STREET TYNE STREET JANET STREET