Estuaries spatial database

The New Zealand estuaries spatial database is an interactive map that allows you to explore data related to estuaries, rivers, river catchments, and the marine environment.

New Zealand estuaries spatial database.

Use the drop-down menus and tick boxes to display the information you’re interested in.

Some examples of the maps you can create include:

seagrass extent and coastal turbidity
wetlands and protected areas in vulnerable catchments
estuary eutrophication as measured by chlorophyll, river water quality total nitrogen, and natural river and stream cover
inanga spawning sites and natural river and stream cover.

Data layer descriptions and sources

In this section:

Water quality, sediment and river flow
Catchment and land cover
Estuary plants and animals
Estuary classifications and descriptions
Wetlands
Bathymetry and tides
Management areas

Catchment and land cover

Vulnerable catchments

Includes all river and stream catchments that are classified as vulnerable. Vulnerable means showing signs of stress but have not yet reached a tipping point, where it becomes much more costly and more difficult to return water bodies to good health.

Source and management: Ministry for the Environment, see Freshwater Improvement Fund.

Sea-draining catchments

Includes all river and stream catchments that drain to the in the River Environment Classification database.

Source: Freshwater Ecosystems of New Zealand. Managed by Department of Conservation

Land cover

This database classifies land cover into 35 categories using satellite imagery. The database is used to monitor the natural environment at regional and national scales. Previous versions record past land cover and can be used to track changes over time.

Source and management: Manaaki Whenua - Landcare Research, see New Zealand Land Cover Database, version 6.0.

Natural river and stream cover

This database shows the proportion of native vegetation cover alongside rivers and streams, derived from satellite imagery. Natural cover ranges from 0 to 1, where 1 has the highest proportion of native vegetation.

Source: NIWA, managed by DOC.

Human pressures on rivers and streams

This is an assessment of human pressures on the ecological integrity of rivers and streams along their length. The overall pressure index was calculated from individual pressures:

clearance of native vegetation
imperviousness
stream nitrogen loads
mine and industrial discharges
upstream and downstream dam effects, and
introduction of pest fish.

The index ranges from 0 to 1, where 0 has the most severe pressure.

Source: NIWA, managed by DOC.

Estuary plants and animals

Mangroves

Mangroves are mapped with the most recent data from regional councils, DOC and other agencies.

DOC maintains the New Zealand mangroves and seagrass database, which provides a comprehensive nationwide spatial and temporal habitat layer for this species. Information from other agencies is added as it becomes available.

See New Zealand mangroves and seagrass database.

Seagrass

Seagrass (Zostera muelleri) is mapped with the most recent data from regional councils, DOC and other agencies.

See New Zealand mangroves and seagrass database.

Inanga spawning sites

Records of spawning sites are drawn from iNaturalist as submitted by the public and include historical and recent records. This dataset relies on public observations that are moderated by a subject matter expert, so the data may not be complete or accurate.

Source: iNaturalist inanga spawning sites project. Managed by Shane Orchard.

Email: shane.orchard@canterbury.ac.nz

Estuary classifications and descriptions

Ecological districts

To survey New Zealand’s protected natural areas, 268 ecological districts were identified, based on landscape and ecological features. The districts were further grouped into 85 ecological regions. Ecological regions and districts highlight the similarities of composition, form and function within and between the natural ecosystems inside their boundaries.

Source: Ecological regions and districts of New Zealand (PDF, 506K)

Estuary environment classification

This classification system classifies estuaries into different types based on their climate, catchment characteristics, and ocean and river conditions.

Estuarine Classification: Niwa

Source: NIWA.

Coastal hydrosystem classification

Coastal hydrosystems is a collective term for coastal lakes and wetlands, lagoons, river, estuarine and marine environments. This resource uses a standard set of criteria to classify each hydrosystem based on its physical characteristics.

Classification of New Zealand's coastal hydrosystems.

Source: Ministry for the Environment.

Marine habitats

This dataset maps marine habitats in the New Zealand territorial sea based on surrogates including depth, substratum, exposure and biogenic habitats.

Coastal marine habitats and marine protected areas in the New Zealand Territorial Sea: a broad scale gap analysis.

Managed by DOC.

Wetlands

Current wetland extent (2013)

Wetlands are mapped at 1:50,000 to a minimum size of 0.5 hectares. A combination of satellite imagery and recent survey data was used to map 7 wetland classes:

bog
fen
inland saline
marsh
pakihi/gumland
seepage
swamp.

Source: Manaaki Whenua - Landcare Research. Managed by Stats NZ and Ministry for the Environment.

Historical wetland extent

The extent of wetlands before human arrival is mapped at 1:50,000 to a minimum size of 0.5 hectares. The extent is predicted from the national fundamental soil layers (FSL) database, which is used to identify wetland soils from their drainage properties.

Source: Manaaki Whenua - Landcare Research. Managed by Stats NZ and Ministry for the Environment.

Bathymetry and tides

Mean high water springs

Mean high water springs (MHWS) is the averaged highest level that spring tides at full moons reach over many years – often the last 19. It is close to the high water mark where debris accumulates on a tidal shore on about 2 days per year, 6 months apart.

MHWS level is used as the dividing line between land and sea in the Resource Management Act 1991 and the Foreshore and Seabed Act 2004.

Bathymetry (depth)

This dataset is compiled from hydrographic bathymetry datasets sourced from LINZ nautical charts at three scales:

1:22,000–1:90,000
1:90,000–1:350,000, and
1:350,000–1:500,000.

The finest scale, 1:22,000–1:90,000, is used first where it exists. Missing areas are filled with the 1:90,000–1:350,000 then the 1:350,000–1:500,000 datasets.

Some gaps between the coastline and the bathymetry remained, so values from the 1:22,000–1:90,000 polygons were extrapolated into the 1:350,000–1:500,000 polygons where they touched the coastline.

Source: Land Information New Zealand and DOC. Managed by DOC.

Management areas

Public conservation areas

A spatial database of all areas of public conservation land and waters managed by DOC. These include marine mammal sanctuaries, marine reserves and wildlife reserves.

Source and management: DOC.

Type 2 marine protected areas

A spatial database of areas that have restrictions on fishing, mining, aquaculture and dredging to maintain and improve marine biodiversity and protect submarine cables and pipelines. These are managed by the Ministry for Primary Industries, Ministry of Transport and Tāngata Tiaki/Kaitiaki.

Source and management: DOC and Ministry for Primary Industries.

DOC operations regions and districts

DOC has 11 operations regions and 46 operations districts within them. The boundaries were implemented in February 2016 and replaced the previous services regions boundaries.