Hauraki Gulf BathyTopo Digital Elevation Model

This dataset contains BathyTopo digital elevation models (DEM) of the Hauraki Gulf, New Zealand at a 20 m cell resolution. This is a revised version of that published by Mackay et al. (2012). Not to be used for navigational purposes. Introduction The island-studded Hauraki Gulf is a backdrop to the work and play of New Zealand’s biggest city. Transport hub, commercial port, tourism venue, sailing paradise, marine park, and recreational, customary and commercial _shing ground, this shallow, sheltered sea has been many years in the making. The embayed coastline, estuaries and islands were shaped by volcanism, tectonic upheaval and changing sea levels. The seafloor, revealed here, has a sweeping signature of sediment erosion, transport and deposition. These processes have acted on relict sediments over thousands of years, with input of modern sediment from rivers and biological processes. Typically flat, but for small areas of scour, reefs and rock pinnacles, the seabed is mainly a mosaic of fine-grained muds and sands, with channels and scours filled with shells and gravel. Tides dominate the calm-weather currents of the Gulf, but near-bottom flows quicken in channels, and around islands and pinnacles. Sediment is moved around by these wind, wave, and tide-driven currents. Nestled between the mainland and Coromandel Peninsula, the Gulf region is a trove of biodiversity. Coastal mangrove forests, sea grass beds and reefs support fish, algae and invertebrates. Further offshore, the productive Gulf waters sustain a throng of fish, seabirds, whales and dolphins. Data Sources Bathymetric data are compiled from many sources. Multibeam echo sounder data was sourced from surveys by: · NIWA · Toitū Te Whenua - Land Information New Zealand HYPLAN · Royal New Zealand Navy · Visiting research vessels from USA, France, Germany, and Australia. Single beam echo sounder data was sourced from: · Royal New Zealand Navy sounding sheets, · NIWA surveys · private vessels participating in the International Hydrographic Organization’s Crowd Sourced Bathymetry initiative, notably the Spirit of New Zealand. All bathymetric data have been reduced to Lowest Astronomical Tide (LAT) vertical datum. Topographical elevations were sourced from New Zealand LiDAR 1m DEM from Land Information New Zealand (LINZ, 2025). This layer contains the New Zealand national 1 m DEM which is an amalgamation of the most current LiDAR surveys published as at the date accessed. These data are using the New Zealand Vertical Datum 2016 (NZVD 2016).