NZ Coastal Hydrosystems

Coastal hydrosystems describe coastal features that span a gradient from near coast freshwater lakes/wetlands (lacustrine/palustrine environments) to marine. The term 'coastal hydrosystem' avoids the common error of referring to all such features as estuaries, mislabelling the numerous types that are non-estuarine and have different behavioural characteristics and management sensitivities from any truly estuarine environment. It also encompasses the coastal systems that do not represent end-of-river environments (e.g., some pocket beaches and embayments) or are so large and complex as to be fed by several freshwater drainage features (rivers, streams, wetlands) but which are dominated by none (e.g., some harbours, fjords, sounds and coastal-lacustrine systems). It also incorporates the multiple aspects of each system, including beaches, spits, barriers, river mouths, wetlands, saltmarshes and other geomorphic, ecological and hydrological features.

The New Zealand Coastal Hydrosystem classification (NZCH) is a classification of coastal hydrosystems within New Zealand including some offshore islands. The coastal hydrosystems classification is based on a hierarchical view of the abiotic components that comprise the environments of coastal hydrosystems. This classification presents detail at the geomorphic class level because this level is particularly important for coastal management and conservation needs at national and regional scales.

The primary GIS is the point layer. Supporting files (attached) include: a CSV database of environmental variables; GIS polygon layer; and Google Earth (.kmz) point and polygon exports.

The database, GIS and Google Earth files should be used in conjunction with the Classification of New Zealand's Coastal Hydrosystems report (Hume et al. 2016) (also attached) which documents a full description of the database, the calculation procedures and limitations to the variables.

The spreadsheet comprises a database of 500 New Zealand coastal hydrosystems and their associated environmental variables developed for the report.

The GIS point file comprises 500 New Zealand coastal hydrosystems and their associated environmental variables developed for the database. The environmental variables are mapped at 1:50,000 scale.
NOTE: Within the point attribute file -9999 represents the environmental variables with no data as shown in the spreadsheet as a blank cell. Make sure to exclude these values from analyses.

The polygon files comprise 420 New Zealand coastal hydrosystems depicting their general shape of the water body basin at high tide and upstream limit.

The .kmz files are derived from the NZCH GIS point and polygon layers for use with Google Earth.

The report provides a classification of coastal hydrosystems within New Zealand including some offshore islands. The coastal hydrosystems classification reconciles and clarifies coastal hydrosystem terminology and produces a hierarchy and classification of coastal wetland, riverine, estuarine and marine types. This report identifies and provides a list of environmental variables that describe the characteristics and properties of about 500 discrete coastal hydrosystems that can be used to provide national and regional statistics on coastal hydrosystems. An Identification Key is provided to guide the determination of the classes.