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 79 Factsheet 6 - Ilam to Bishopdale Bishopdale, Bryndwr, Burnside, Fendalton and Ilam over the following weeks. This mapping was supported by air- 6.1 Ground conditions and groundwater Table C6.2 - Summary of ground elevation and groundwater depth (September 2011) Regional geology maps show this area is generally underlain photo analysis for all four main earthquakes, and additional by dominantly alluvial sand and silt overbank deposits. regional or street-level mapping for the earthquakes of Suburb Ground elevation above sea level Groundwater depth 13 June 2011 and 23 December 2011. This additional mapping Bishopdale Typically 16.4m to 18.2m (Avg 17.8m) Typically 2.1m to 2.9m (Avg 2.5m) Table C6.1 summarises the area-wide subsurface ground indicated that the overall pattern of liquefaction and lateral Bryndwr Typically 11.3m to 16.7m (Avg 14.5m) Typically 0.7m to 2.5m (Avg 1.8m) investigations undertaken by EQC in this area following the spreading for the subsequent earthquakes was generally 4 September 2010 and 22 February 2011 earthquakes. Burnside Typically 17.4m to 22.2m (Avg 19.8m) Typically 2.0m to 3.6m (Avg 3.0m) similar to that observed in the first two main earthquakes. These investigations indicate that the near-surface soil Fendalton Typically 9.3m to 13.6m (Avg 11.4m) Typically 0.4m to 1.4m (Avg 0.9m) profile in the area generally comprises very loose to dense Figure C6.1 and Table C6.3 present a summary of the Ilam Typically 13.7m to 18.2m (Avg 16.3m) Typically 1.4m to 4.1m (Avg 2.6m) sands and silts. property-by-property rapid mapping of liquefaction and lateral spread observations in this area. The observations Table C6.2 summarises typical ground elevation and Table C6.3 - Summary of liquefaction and lateral spread observations for residential land, aggregated following the 4 September 2010 and 22 February 2011 groundwater depths in the area (the values listed correspond from mapping undertaken following earthquakes of 4 September 2010 and 22 February 2011 to the 10th and 90th percentiles and the median). This was earthquakes have been aggregated by assigning each derived from LiDAR ground elevation survey commissioned property the most severe observation from either of by EQC in September 2011, and a groundwater surface these two earthquakes. These observed liquefaction and developed from recent EQC groundwater monitoring lateral spread mapping colours have completely different in conjunction with historic Environment Canterbury meaning to the colour codes used by the Canterbury groundwater data. This area is generally elevated well above Earthquake Recovery Authority (Cera) for residential land sea level with a shallow to moderate depth to groundwater. zoning and the Department of Building and Housing (DBH) for technical categories. The ground conditions and groundwater in this area are Suburb generally similar to most of the southern, central and Table C6.4 summarises the change in ground elevation 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 northern suburbs of Christchurch. inferred from the LiDAR survey. The total change in ground Bishopdale 3680 28% 48% 13% 11% 0% <1% 0% elevation which has occurred is a combination of regional While ground surface disturbance has occurred in some Bryndwr 3010 29% 49% 2% 19% 0% 1% 0% uplift or subsidence due to fault movements (tectonics) areas (e.g. settlement, cracking and ejection of material), Burnside 2247 94% 6% 0% <1% 0% <1% 0% the underlying ground which liquefied appears to have now and local ground subsidence due to liquefaction and related Fendalton 2699 2% 46% 5% 36% <1% 10% <1% returned to its pre-earthquake strength. effects. The LiDAR is of limited accuracy (about ±100mm). This means that the LiDAR is more suitable for measuring Ilam 2335 73% 25% <1% 1% <1% <1% 0% 6.2 Post-earthquake observations large changes in ground elevation (greater than about 100 Rapid mapping of liquefaction and lateral spreading to 200mm), and may not accurately represent areas where observations was undertaken following the 4 September Table C6.4 - Changes in ground elevation inferred from LiDAR survey only minor changes in ground elevation have occurred. 2010 and 22 February 2011 earthquakes, first on a regional Suburb Change in ground elevation from July 2003 to September 2011 and street-by-street level in the days immediately after Table C6.5 summarises the extent and severity of observed (positive values are uplift, negative values are subsidence) liquefaction and lateral spread. each earthquake, and then on a property-by-property level Bishopdale Typically -400mm to -150mm (Average -250mm) Bryndwr Typically -350mm to -150mm (Average -250mm) Table C6.1 - Area-wide geotechnical investigations undertaken by EQC (December 2011) Burnside Typically -250mm to +0mm (Average -150mm) Suburb Number of cone Number of Number of groundwater Length of MASW penetration tests boreholes standpipes geophysical testing (m) Fendalton Typically -400mm to -100mm (Average -250mm) Bishopdale 9 - 6 - Ilam Typically -100mm to +50mm (Average +0mm) Bryndwr 14 2 8 - Burnside - - - - Fendalton 26 7 14 - Ilam - - - - ENVIRONMENTAL AND ENGINEERING CONSULTANTS EARTHQUAKE COMMISSION: Canterbury Earthquakes 2010 and 2011 - Land report as at 29 February 2012 80 Factsheet 6 - Ilam to Bishopdale Bishopdale, Bryndwr, Burnside, Fendalton and Ilam Table C6.5 - 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 Bishopdale Minor to moderate liquefaction in several areas, causing sand ejection and settlement. Bryndwr In the surrounding areas, settlement and minor ground cracking observed without any obvious surface evidence of liquefaction, likely due to minor liquefaction occurring at depth below the surface but not SAWYERS ARMS ROAD ATSONS ROAD being ejected. W Casebrook TUCKERS ROAD GLASNEVIN DRIVE HIGHSTED ROAD For the remainder of the suburb, no surface evidence of liquefaction or related land effects was observed. HAREWOOD ROAD CAVENDISH ROAD Burnside Most of this suburb was not mapped at a property-by-property level, however street-level mapping and AINTREE STREET GARDINERS ROAD VEITCHES ROAD CROFTON ROAD air photo analysis found no surface evidence of liquefaction or related land effects. OLDWOOD STREET Northcote PADDINGTON STREET Fendalton Extensive areas of minor to moderate liquefaction (severe liquefaction on a small number of properties), NORTHCOTE ROAD IAN PLACE COTSWOLDAVENUE causing sand ejection and settlement. WOOLDRIDGE ROAD Moderate to major lateral spreading towards streams and watercourses in many areas, but generally HIGHSTED ROAD VAGUES ROAD localised to the immediately adjacent properties. TRAFFORD STREET BECMEAD DRIVE SKYEDALE DRIVE For the remainder of the suburb, no surface evidence of liquefaction or related land effects was observed. BAINTON STREET SAWYERS ARMS ROAD Bishopdale PRIMROSE STREET RALEIGH STREET OAKLAND STREET Ilam Minor to moderate liquefaction in several small localised areas, causing sand