NZ Estuarine Environments Classification

The classification differentiates estuaries at 3 levels of detail. Level 1 differentiates global scale variation based on differences in climatic and oceanic processes, which are discriminated by the factors: latitude, oceanic basins and large landmasses. Level 2 differentiates estuaries into 8 categories (or estuary types ) on the basis of variation in estuary hydrodynamic processes, which are discriminated by estuary basin morphometry, river and oceanic forcing. Level 3 differentiates variation among estuaries that are due to catchment processes, which are discriminated by catchment geology and catchment land cover. Estuaries are assigned class membership at each level of the classification by applying criteria in the form of decision rules to the database of assignment characteristics. GIS is then used to map the estuaries with classes being defined by colour at any level of the classification. The resulting map showing the distribution of various classes of estuaries around New Zealand provides a multi-scale spatial framework that is suitable for many environmental or conservation management applications. NZCoast was developed as part of the “Reducing Impact of weather related hazards” programme and funded by FRST under contract C01X0401. Purpose: This project aims to build on Terry Hume's morphological classification of estuaries (Hume and Herdendorf, 1988) The Estuary Environment Classification (Hume et al. 2007; 2003) provides a framework for classifying New Zealand’s estuaries. This controlling factors classification is based on broad scale physical components of the landscape or ‘controlling factors’ such as climate, oceanic and riverine conditions, and catchment characteristics that cause or ‘control’ differences and similarities in the physical and biological characteristics of estuaries. The classification can be used to simplify the complexity of estuaries, so that differences and similarities can be characterised and ordered systematically and thereby providing an objective basis for treating different locations in a similar manner, extrapolating the results of studies between estuaries, and stratifying environments on the basis of their susceptibility and vulnerability to effects of development.

National

All estuaries in the Waikato Region (project has a national focus)

The classification was derived from a database populated with physical variables descriptive of climate, oceanic water mass, basin morphometry, oceanic forcing (tides), river forcing (freshwater inflow), characteristics of the contributing catchment (including topography, geology and land cover), and factors that vary within an estuary including depth, tidal currents, and wind waves. Further information is available at the link below.

scale limitations, wont define habitats within estuaries. Data quality: Varied

Data is available through NIWA's "Coastal Explorer" - see link below. Digital Format: Available through Coastal Explorer website at link below.

Freely available to public good end-users with a resource management or conservation focus. Sensitivity/Confidentiality: Contact NIWA

Complete

Related information: NZ Beach Classification