This classification is being developed to allow managers and researchers to appropriately apply estuarine research and monitoring results to areas beyond those of the original investigations.

The structure of the classification is still being developed and is likely to include the following levels:

Types of estuaries will be defined using physical parameters and processes. These are likely to include: tidal flow, salinity stratification, and wave action.

Because different processes are important for different types of estuaries, the physical processes will be treated as one level in the hierarchy of the classification. The product of this level of the classification is likely to be a fixed number of estuary types that are depicted visually as well as being described. Within each estuary type broad habitat classes will be defined and key attributes described. Information on the sensitivity of estuary types and the biota(?) to sedimentation will be used to identify the estuary sensitivity to sedimentation.

At this stage it is unclear how the catchment parameters (e.g. area of catchment) will be included in the classification system. It is also unclear how anthropogenically derived changes such as the removal of a river from an estuary (e.g. removal of the Kaituna River from Maketu Estuary) will be addressed.

The classification is being developed using a top down approach (identifying dominant processes)and a bottom up approach to test the validity of the classification).

• digital topographical database (e.g. Measurements of catchment size, estuary area)
• NIWA estuary database
• various biological data sets including those for Manukau and Maharangi.