A web-accessed classification of New Zealand's coastal environment

A GIS-based web-accessed classification and database has been developed for the New Zealand coast that provides basic information on the open coast shoreline and estuaries needed to understand and manage environmental change and coastal hazards. NZCoast and the Coastal Explorer web tool (http://www.niwa.co.nz/our-science/natural-hazards/tools-and-resources) classify shores, beaches and estuaries and identify hazards such as rips, wave runup, wave climate, wind erosion and overtopping by waves, along with related geomorphological metrics such as exposure, coastal landform type, foreshore sediment type, hinterland characteristics, beach type and other geomorphological features that have control on coastal processes. Data extracted using GIS and other techniques are stored in a spatial database. The geographic coverage includes the New Zealand mainland and offshore islands at a basic scale of 1:50,000. The Coastal Explorer tool provides a beach type classification which groups New Zealand beaches into 14 types based on the Wright-Short model. These types are products of the wave, tide and beach morphology and sediment characteristics. There is a beach hazard rating associated with each beach type for modal (most commonly occurring) wave conditions. It takes into account hazards such as rips, surf zone currents, deep water nearshore and how changing breaker height affects the hazard rating for each type. Beach report cards for c. 500 beaches provide a high level (first cut) risk/survey assessment tool for Surf Life Saving New Zealand who have collaborated with the classification and mapping. Coastal Explorer also provides report cards for c. 435 estuaries and key statistics on water body and catchment characteristics such as area, depth, tide range, tidal prism and freshwater inflow. The coastal database and classification have been developed through data mining, generous inputs from regional council staff and local experts, university staff and consultants, and classification and mapping by expert panels.