A site's physical nature can be depicted through mapping physical attributes such as geology, topography, soils, species and ecosystems, and hydrological patterns as illustrated in Figure 11.
Preliminary desktop surveys and site visits may determine the need for further technical assessments, such as a contaminated soils inventory or specialist fauna surveys. Table 1 provides a list of information sources, and the potential for these to direct additional site investigations.
INFRASTRUCTURE SERVICES |
ATTRIBUTE | INFORMATION SOURCE | FACTORS TO CONSIDER |
Drainage systems | GIS databases for wastewater, stormwater, and potable water (AC GIS viewer) | Tie-in locations and overland flow paths Possible CSO issues Existing infrastructure capacity and age Stream daylighting opportunities |
Existing services | Local authority and utility service sheets for power, gas and phone (beforeUdig) Local Authority Code or Subdivision/Infrastructure Standards (AC website) | Fixed costs as immovable infrastructure Potential clashes with earthworks and services Tie-in points |
Existing structures and materials | As-built surveys for landfill areas (contact AC if there is record of a landfill in the area) Extent and location of structures and impervious surfaces (AC GIS Viewer) | Contamination issues Necessity for demolition Potential for re-use of structures or surfaces |
Hazards | City hazard register and LIMs (AC website) Building Code (DBH website) Local Authority Code or Subdivision/ Infrastructure Standards (AC website) | Absolute hazard constraints and appropriate buffers Existing flooding and overland flow paths Erosion issues Resilience of services |
Access | Existing paper roads Predicted road classification and standards Walk, cycle and open space connections Public transport access | Integration with existing streets and entries Existing traffic contribution Priority cycle and pedestrian connections |
ECOLOGY |
Terrestrial environments | Scheduled trees (AC website) Protected Natural Area surveys Land cover database (LENZ) (Koordinates.com) Reserve Management Plans (AC website) Conservation Management Strategies (DOC website) Site survey of lizards, invertebrates, avifauna, and bats (may be required; consult an ecologist) | Vulnerable or valuable habitats to avoid and/or buffer Potential to enhance existing vegetation An environmental framework to augment and connect remnant vegetation |
Freshwater environments | Physical habitat surveys, including Stream Ecological Valuations (SEVs) (may be required; consult an ecologist) Macroinvertebrate and fish surveys (may be required; consult an ecologist) Freshwater fish database (NIWA website) Regional Plan: Air, Land & Water (AC website) Watercourse management plans (contact AC) | Value and sensitivity of freshwater habitats Potential for receiving environments to detain and treat stormwater if enhanced Permanent and seasonal wetlands |
Coastal environment | Regional Plan: Coastal (AC website) Network discharge consents (AC GIS viewer) Coastal and inter-tidal survey (may be required; contact a marine biologist) Marine and estuarine bird surveys (may be required; contact a marine biologist or ecologist) | Value and sensitivity of coastal habitats Effects from coastal inundation and storm surges Marine and diadromous fish spawning areas |
HYDROLOGY |
ATTRIBUTE | INFORMATION SOURCE | FACTORS TO CONSIDER |
Groundwater | Borehole infiltration tests (may be required for detailed design; contact a geologist or geotechnical engineer) Survey spring seepage areas (may be required for detailed design; contact a surveyor) Aquifer maps (available from AC on request) | Seasonal wetlands Water table depth |
Existing impervious extent | Overlay of aerial photographs with curve number values, verified on site for vegetation and soils (AC GIS viewer) | Existing hydrological issues and potential for retrofit of pervious surface or vegetation |
Catchment management | Catchment Management Plans (CMP), Network Discharge Consents (NDC) and Structure Plans (AC GIS viewer) Watercourse Management Plans (WMP) (request from Auckland Council) Flood hazard mapping (AC GIS viewer) Long-term Plan (LTP) stormwater directives (AC website) Annual plan (AC website) Asset Management Plan (AC website) NIWA and archive water quality indicators (may be required; protocol is available from NIWA website) | Upper-catchment contributions Receiving environment sensitivities and values Spatial planning context Catchment-wide stormwater objectives Priority infrastructure Existing flooding issues |
Hydrology | Flood modelling for 2 year, 10 year, and 100 year events (required for detailed design, contact a stormwater engineer or hydrologist) Attenuation targets (AC website) | Model existing capacity Classify streams and water bodies Stormwater discharge targets |
Contaminants | Contaminant Load Model (request from AC) Point source contamination monitoring (may be required for industrial sites; contact an environmental engineer or scientist) Stream Ecological Valuations (SEVs) (required if modifying watercourses; contact an environmental engineer or scientist) | Identify existing contaminant loads and hot spots |
GEOLOGY AND SOILS |
Geology | Fault lines from GNS Science (GNS active fault viewer) | Hazards |
Soils | Land Environments of New Zealand (LENZ) data (Koordinates.com) Auger surveys at recommended distances (Ross, 2007) (may be required for detailed design; contact a geologist or soil scientist) Soil compaction/permeability testing (may be required for detailed design; contact a geologist or soil scientist) Landcare S-mapOnline (smap.landcareresearch.co.nz) | Geotechnical issues Soils prone to surficial erosion Soils as an agricultural resource Organic soils and peats to harvest as a soil media Soils with infiltration and recharge capacity Potential contamination |
TOPOGRAPHY, SLOPE AND ASPECT |
Topography | LIDAR data (AC GIS viewer)
Topographical survey (required for detailed design; contact a surveyor) | Analysis of slope and aspect Sub-catchment definition Hazards and steep slopes Inter-visibility analysis |