Data

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.

This layer applies the sediment attributes’ classification, per Appendix 2C of the NPS-FM 2020, to the digital River Environment Classification (REC) v2.4 network.

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This layer is meant to support stakeholders in their understanding and implementation of the suspended and deposited sediment attributes, but it does not form part of the regulation; it is not incorporated by reference.

The Stock Exclusion Low Slope Land 2020 layer identifies areas of "low slope land" as defined in the Resource Management (Stock Exclusion) Regulations 2020. The layer shows the land parcels, or part parcels, defined as low slope land. These areas have a mean slope is less than or equal to 10 degrees. Parcels with a parcel intent of "ROAD" are excluded. Areas of lakes, ponds, settlements and urban parkland, as defined in Land Cover Database 5, are also excluded. Areas of low-slope grassland and annual cropland within high-slope parcels are also included in the Stock Exclusion Low Slope Land extent.

This dataset reports modelled mean annual suspended sediment load reduction required to meet suspended sediment attribute bottom lines in the NPS-FM 2020. Results are reported for the REC 2 river reach scale as well as at the “catchment pourpoint average” scale. The dataset includes masks for the DoC estate as well as glacial mountain source of flow.

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During policy development, the Ministry for the Environment tested suspended sediment load reductions required to meet various potential attribute bottom lines. The information from February 2020 reflects the bottom lines in the NPS-FM 2020. For further information on this specific dataset, see “Hicks and Shankar 2020. Contract 23184 Task: Sediment load reductions to meet visual clarity bottom lines”. This report is available on the Ministry for the Environment’s publications website where it is listed as Technical Report 6.

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For further information on the modelling, see Hicks et al. (2019) Sediment load reductions to meet suspended and deposited sediment thresholds. NIWA Client Report No. 2019100CH. Prepared for the Ministry for the Environment. This report is available here: www.mfe.govt.nz/publications/fresh-water/sediment-....

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Note that the river segment and pour point catchment results provided in the 2019 dataset form the basis for the erosion and economic modelling assessment of proposed sediment attributes as reported in Neverman et al. (2019). Impact testing of a proposed suspended sediment attribute: identifying erosion and sediment control mitigations to meet proposed sediment attribute bottom lines and the costs and benefits of those mitigations. Maanaki Whenua Landcare Research Client Report. Prepared for the Ministry for the Environment.

This dataset provides boundaries for catchments that drain to the sea (i.e. sea draining catchments).

It is extracted from the Freshwater Ecosystems of New Zealand (FENZ) v1.0 geodatabase. Ministry for the Environment hosts this copy of this layer for convenience and visibility. For all inquiries please contact Department of Conservation directly.

FENZ requires specialist GIS knowledge for its technical operation and biodiversity knowledge for understanding the content. Because of FENZ’s complexity, DOC is providing advice, briefings and training (where possible) to ensure users understand its strengths, limitations and appropriate applications.

If you would like more information about FENZ or access to any FENZ data sets, email fenz@doc.govt.nz.

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www.doc.govt.nz/our-work/freshwater-ecosystems-of-...

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Variables:

Catch_id - This is a unique identifier that can be used to link to other datasets in the FENZ database, or datasets from other sources that also use a FENZ id.

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Catchment names:

Currently a definitive catchment names dataset does not exist. However for your convenience, an unofficial list has been provided in the attachments ("fenz_catnames.csv") which can be joined to the catchment boundaries to provide names. Feedback on the accuracy or completeness of these names is welcomed.

This set of data sets provides an estimation of groundwater flux. There are three components: Groundwater recharge: development of nationwide mean (daily and seasonal) groundwater recharge data sets through the combination of three pre-existing groundwater recharge models; Groundwater–surface water exchange: development of a national indicative groundwater discharge data set using an existing national groundwater flow model, as well as comparison with a pre-existing gaining/losing stream prediction data set; Groundwater flow: development of a national groundwater flow data set using an existing national groundwater flow model. For more detail on the process and methods, see Westerhoff et al. (2019). New Zealand groundwater atlas: Groundwater Fluxes. Lower Hutt (NZ): GNS Science. 60 p. Consultancy Report 2019/126.

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A national groundwater model was used to estimate near-surface groundwater flow amplitudes and separated into four classes to encompass the uncertainty of the dataset.