Canterbury Wetlands

Description

How to use this map

The easiest way to find out if you have a wetland on your property is to use the search bar in the top right corner.

1. Type in your full address or choose from the suggested addresses
2. Zoom into your property by scrolling with your mouse or using the zoom buttons on the left.
3. Click on the wetland (blue areas) to view aerial/ground survey information

Description:

This geodatabase collates wetland location and extent information for Canterbury Region. Information comes from a variety of sources and has varying levels of detail or precision on wetland location, type, condition and significance.

Database coverage over most of Canterbury Region was completed in March 2019. However, wetland mapping is less comprehensive for land over 900m in some parts of the region.

The Canterbury Wetlands GIS Layer distinguishes between ‘ground survey’ and ‘aerial survey’ wetlands. Most of the mapped wetlands are in the ‘aerial survey’ category. ‘Ground survey’ and ‘aerial survey’ methodologies are described below.

Methodology:

“Ground survey” wetlands have been field inspected and mapped/described in some detail. Ground surveys have been carried out by Environment Canterbury staff, or wetland ground survey information provided by other agencies such as the Department of Conservation and New Zealand Defence Force. Wetlands that have been ecologically surveyed and mapped as part of Resource Consent Applications may also be included in this category.

For vegetated wetland survey areas, wetland boundaries were delineated where more than 50% of the dominant plant species from all vegetation strata are ‘Obligate’, ‘Facultative Wetland’ or ‘Facultative’ (i.e. the plant community is considered hydrophytic – Clarkson 2013). Descriptions of wetland hydrosystems, wetland class and vegetation types listed in the attributes tables for ground surveyed wetlands follow Johnson and Gerbeaux (2004), while assessment scores for wetland condition and threat follow Clarkson et al. (2003).  An assessment of ecological significance against Canterbury Regional Policy Statement criteria is also provided for most ground surveyed wetlands.

“Aerial survey” wetlands have been mapped by delineating the outline of known and likely/potential wetland habitats from the latest high-resolution aerial imagery available at the time of mapping. Characteristic vegetation types, colours, patterns, presence of visible water were used to identify wetlands on aerial photos; with hydrological and topographical information also considered. Note that precision limitations and uncertainties mean that there may be errors or omissions in this part of the dataset.

Where available, existing ecological information for ‘aerial survey’ wetlands is noted in the attributes and the source referenced. However, for most ‘aerial survey’ wetlands, apart from date of base imagery and data capture, no further information is provided in the attributes.

Currency:

Current at time of survey date for “ground survey” sites and current to date of aerial imagery for “aerial survey” sites.

Data owner:

Environment Canterbury

Data interpretation and limitations:

The Canterbury Wetlands GIS Layer is not a ‘schedule’ in a plan and has not been tested through a statutory planning process. The GIS layer is not comprehensive, nor does it attempt to systematically apply the Canterbury Land and Water Regional Plan definition of ‘wetland’.  It is not ‘locked in’ and can potentially be changed or updated with more information.

Attributes of the Canterbury Wetlands Layer

(Note: the attributes tables will only be complete for ground surveyed wetlands)

OBJECT ID

Default GIS polygon identification number

AREA NAME

Name of wetland or survey area.

HYDROSYSTEM

Wetland ecosystems are differentiated by landform and hydrological setting, and by water salinity, chemistry and temperature. Estuarine, riverine, lacustrine and palustrine hydrosystems have been recorded for ground-surveyed wetlands in Canterbury.

SUBSYSTEM

Hydrosystems can be further described according to the water regime. Periodicity of inundation is the main feature e.g. permanent, seasonal, tidal, non-tidal, ephemeral.

WETLAND CLASS

Main wetland classes for Canterbury are swamp, marsh, fen, bog, seepage, shallow water, ephemeral wetland and saltmarsh.

WETLAND FORM

Landforms that wetlands occupy, and forms they create or contain.

VEGETATION TYPE

Dominant vegetation type(s) within wetland. A general description of the growth form (or structure) and composition of the vegetation. For example: raupō reedland, saltmarsh herbfield, willow forest.

SURVEY TYPE

‘Ground survey’ or ‘Aerial survey’.

SURVEY DATE

Date of wetland ground survey or delineation by aerial survey.

IMAGERY DATE

Date of imagery used when delineating wetlands by aerial survey method.

RECORD NO

Record number of wetland assessment reports for ground-surveyed wetlands. Stored in Environment Canterbury’s HP Content Manager.

ECOLOGICAL SIGNIFICANCE

Assessment of ecological significance for ground surveyed wetlands against Canterbury Regional Policy Statement (CRPS) criteria and associated guidelines (Wildland Consultants, 2013). Three level score:

High:               Meets one or more significance criteria; Regionally, Nationally or Internationally Significant

Moderate:      Meets one or more significance criteria; Locally Significant

Low                  Does not meet any CRPS ecological significance criteria

 

References

Clarkson, BR, Sorrell BK, Reeves PN, Champion PD, Partridge TR, Clarkson BD. 2003. Handbook for monitoring wetland condition. Coordinated monitoring of New Zealand wetlands. A Ministry for the Environment SMF funded project. Ministry for the Environment, Wellington. 74pp.

Clarkson, BR. 2013. A vegetation tool for wetland delineation in New Zealand. Landcare Research contract report prepared for Meridian Energy Limited. 62pp.

Johnson P. Gerbeaux G. 2004. Wetland Types in New Zealand. Department of Conservation. Wellington. 184pp.

Wildlands Consultants. 2013. Guidelines for the application of ecological significance criteria for indigenous vegetation and habitats of indigenous fauna in Canterbury Region. Contract Report No. 2289i.

Map Credits

Access and Use Constraints

This work is licensed under a Creative Commons Attribution 3.0 New Zealand License