Oceania Data

"River flow refers to the quantity of water passing a point in the river over a certain amount of time. Different rivers have different flow patterns, such as sharp peak flows following rain with low flows in between, or high spring flows from snow melt. These flow characteristics affect how much water is available for irrigation, drinking water, hydro–electric power generation, and recreational activities such as fishing and boating. River flows are also very important for maintaining the health and form of a waterway.

This dataset relates to the "Geographic pattern of natural river flows" measure on the Environmental Indicators, Te taiao Aotearoa website. "

For more information, refer to the March 2015 report: 'Hydrological indices for national environmental reporting' data.mfe.govt.nz/document/11463-hydrological-indic....

INDEX ONLY: These footprints are the index for the 'Sentinel2 2021 Mainland NZ' mosaic. It has been provided to enable users to explore coverage and capture dates of the component imagery. To enquire about ordering the imagery itself, please e-mail lucas[at]mfe.govt.nz.

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The imagery represented is a 10m, ten-band multispectral, cloud-minimised mosaic of Sentinel 2A and 2B satellite tiles over mainland New Zealand made from scenes captured late-2020/early-2021.

INDEX ONLY: These footprints are the index for the 'Sentinel2 2021 Chatham Islands' mosaic. It has been provided to enable users to explore coverage and capture dates of the component imagery. To enquire about ordering the imagery itself, please e-mail lucas[at]mfe.govt.nz.

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The imagery represented is a 10m, ten-band multispectral, cloud-minimised mosaic of Sentinel 2A and 2B satellite tiles over Chatham Islands made from scenes captured late-2020/early-2021.

This dataset includes three “packages” of information, each with multiple variables. The packages include:

1. Load – results on mean annual suspended sediment load reported by REC 2 river reach scale for various model scenario variations.
2. Lakes – results on sediment inflow, outflow, and entrapment in lakes and reservoirs
3. Coastal – results on sediment inflows, trap efficiency, and sedimentation rates in coastal hydrosystems (estuaries)

For further detail on the modelling methods and discussing results, see Hicks, M., Semademi-Davies, A., Haddadchi, A., Shankar, U., Plew, D. (2019) Updated sediment load estimator for New Zealand. NIWA Client Report No. 2018341CH, prepared for Ministry for the Environment. January 2019. Available online: environment.govt.nz/publications/updated-sediment-...

Note that some portions of this dataset refine and update 2011 modelling on suspended sediment loads across New Zealand, whereas other components, especially the coastal package, report new modelling results.

The StockEx LSL 2021 proposed layer identifies proposed areas of "low slope land" where the Resource Management (Stock Exclusion) Regulations 2020 would apply if the low slope land map was updated as proposed in the "Stock exclusion regulations: Proposed changes to the low slope map" (MfE, 2021) discussion document. The layer shows the area of land defined as low slope land. These areas have a local mean slope is less than or equal to 5 degrees and are below 500m in altitude. Areas of lakes and ponds, estuarine open water, built-up areas, transport infrastructure, depleted grass, tall tussock grassland and urban parkland, as defined in Land Cover Database 5, are also excluded.

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Note: The current regulation layer is 'Stock Exclusion Low Slope Land 2020'

data.mfe.govt.nz/layer/104827

The StockEx LSL 2021 proposed layer identifies proposed areas of "low slope land" where the Resource Management (Stock Exclusion) Regulations 2020 would apply if the low slope land map was updated as proposed in the "Stock exclusion regulations: Proposed changes to the low slope map" (MfE, 2021) discussion document. The layer shows the area of land defined as low slope land. These areas have a local mean slope is less than or equal to 5 degrees and are below 500m in altitude. Areas of lakes and ponds, estuarine open water, built-up areas, transport infrastructure, depleted grass, tall tussock grassland and urban parkland, as defined in Land Cover Database 5, are also excluded.

This dataset shows land parcels within grassland and annual cropping areas which have an average slope of less than 10 degrees. Polygons are attributed into 3 slope classes: less than 5 degrees mean slope; 5 - 7 degrees mean slope; 7 - 10 degrees mean slope.

Full report: Memorandum on implementing a national index for susceptibility to streambank erosion: environment.govt.nz/publications/national-index-st...

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This dataset contains predictions of the susceptibility to streambank erosion for every stream link in the RECv2.5 digital river network. Streambank erosion susceptibility is computed as a dimensionless index (range 0-100) for each stream link based on factors that may influence reach-scale bank erosion. These factors comprise stream power, the extent of riparian woody vegetation, valley confinement, channel sinuosity, and the erodibility of stream banks based on soil texture. The approach for determining streambank erosion susceptibility is described by Smith & Betts (2021) and based on the bank erosion model developed by Smith et al. (2019).

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***Smith HG, Spiekermann R, Dymond J, Basher L 2019. Predicting spatial patterns in riverbank erosion for catchment sediment budgets. New Zealand Journal of Marine and Freshwater Management 53: 338–362.

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***Smith HG, Betts H 2021. Memorandum on implementing a national index for susceptibility to streambank erosion. Technical memorandum prepared for the Ministry for the Environment by Manaaki Whenua – Landcare Research.

The REC groups rivers and parts of river networks that share similar ecological characteristics, including physical and biological. Rivers that share the same class can be treated as similar to one another and different to rivers in other classes. The REC classification system groups rivers according to several environmental factors that strongly influence or cause the rivers’ physical and ecological characteristics (climate, topography, geology and land cover). A catchment is a polygon that defines the upstream watershed of a river system or sub-system. Land cover within the catchment was used to populate the river classification factors (see table 1.1 of the User Guide data.mfe.govt.nz/document/123-rec-user-guide-2010/ ).

Additional metadata can be found at www.mfe.govt.nz/publications/ser/metadata/env-clas...

The New Zealand River Environment Classification (REC) organises information about the physical characteristics of New Zealand's rivers. Individual river sections are mapped according to physical factors such as climate, source of flow for the river water, topography, and geology, and catchment land cover eg, forest, pasture or urban. Sections of river that have similar ecological characteristics can then be grouped together, no matter where they are.

This information is mapped for New Zealand's entire river network - over 425,000 kilometres of river. Different types of rivers respond differently to the pressures placed on them - the REC can be used to highlight the most appropriate management tools and approaches to reduce these pressures for each river type. Information from the classification is used to develop policy, assess the environment, and report on the quality of river water.

Stream order is the numerical position of a tributary or section of a river within the entire network. Headwater streams are assigned a stream order of 1. When two tributaries of the same stream order meet, the order increments by one for the next section downstream. However, if two sections meet where one section has higher order than the other, the next section downstream has the same order as the highest upstream section.

The User Guide is available from data.mfe.govt.nz/document/123-rec-user-guide-2010/ . Additional metadata can be found at www.mfe.govt.nz/publications/ser/metadata/env-clas... .