Fresh Water Data

Summary

Water quality for swimming categories for rivers 4th order and above. This dataset was used to compose the current state for water quality for swimming.

Note this data is under review and will be updated in due course. This information is based on modelled and measured data using the approach outlined at www.mfe.govt.nz/fresh-water/freshwater-management-... .

The modelling methods used are outlined in Snelder et al. (2016) Strategic assessment of New Zealand’s freshwaters for recreational use: a human health perspective. LWP Client Report 2016-011 www.mfe.govt.nz/publications/fresh-water/strategic...

Versions

This dataset is the geometric version of this: data.mfe.govt.nz/table/53620-river-water-quality-f...

This dataset has now been superseded due to consultation with local authorities, and this is the latest version: data.mfe.govt.nz/layer/95555-river-water-quality-f...

Column headings:

NZREACH: NZREACH from the River Environment Classification Version 1

ORDER: Strahler stream order

Category: Water quality for swimming category see www.mfe.govt.nz/fresh-water/national-targets-swimm...

PrGT540: percentage of samples that exceeded 540 E.coli per 100mL

PrGT260: percentage of samples that exceeded 260 E.coli per 100mL

Median: median E.coli per 100mL

Q95: 95th percentile E.coli per 100mL

Note: blank cells are reaches where a prediction was not possible because of missing predictor variables.

This dataset is a result of Random Forest modelling to predict cyanobacterial biovolume in lakes nationally, which included spatial modelling of chlorophyll a, TN, TP, Secchi depth, Trophic Level Index, and Cyanobacterial biovolume.

More information about the methods used to create this dataset can be found here: www.mfe.govt.nz/publications/fresh-water/strategic...

LID - FENZ Lake ID

Name - Name of lake (where available)

RegionalCo - Regional council name

CHLA - Chlorophyll a (mg/L)

TN - Total nitrogen (mg/m3)

TP - Total phosphorus (mg/m3)

SECCHI - Secchi disc depth (m)

TLI3 - Trophic Level Index (unitless)

CyanoBioVo - Cyanobacterial biovolume (mm3/L)

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.

This dataset relates to the March 2018 report National E. coli modelling - Supplementary material to support setting draft regional targets for swimmable rivers.

Scenario 1 represents the level of stock exclusion and riparian planting for the nominal year 2030
when the CWP rules have been implemented assuming that the effects of the measures have been realised and water quality has attained a new attribute state. Scenario 1 also includes the impact of regional committed work (that is, work already committed to by councils in their policy plans, or planned infrastructure investment) in regions that have committed to mitigation beyond the CWP.

The geometries are based off REC1, and the field 'Swimability_band' defines the modelled E. coli attribute state NPS-FM human health for recreation value. The rest of the fields come from the River Environment Classification.

This dataset relates to the March 2018 report National E. coli modelling - Supplementary material to support setting draft regional targets for swimmable rivers.

It represents Scenario 0, baseline (i.e. 2017) including the current level of on-farm fencing and land use - further details available in the above report.

The geometries are based off REC1, and the field 'Swimability_band' defines the modelled E. coli attribute state NPS-FM human health for recreation value. The rest of the fields come from the River Environment Classification.

This dataset reports modelled mean annual suspended sediment load reduction required to meet proposed suspended sediment attribute bottom lines. 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. For further information, 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.

Note that the river segment and pour point catchment results provided here (in the attached folders with the same names) 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 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: www.mfe.govt.nz/publications/fresh-water/updated-s...

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.

This dataset reports erosion modelling results regarding annual mean sediment load reductions required to meet proposed suspended sediment attribute bottom lines. For more detail on the modelling process and methods, see 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.

Results of modelled mitigations are reported at catchment scale and at the REC2 river reach scale. The modelled on-farm mitigations (per economic optimisation as reported in Neverman et al. (2019) are also mapped.

This dataset shows land that would be covered by the option 1 of section 8.4 Immediate action to reduce nitrogen loss.

This web map has been developed by the Ministry for the Environment to support policy proposals in the Action for Healthy Waterways discussion document. The proposals are currently being consulted on.

It provides extra detail on Option 1 in section 8.4 of the discussion document (Immediate action to reduce nitrogen loss). The map indicates the pastoral catchments and sub-catchments specified as high-nitrate in Option 1, where regional rules are not already in place or proposed, and shows the land considered to be low-slope.

Low-slope is defined in this option as land parcels with an average slope of less than 5, 7 or 10 degrees. We are seeking feedback on the appropriate slope threshold to use.

The catchments are those with the highest 10% of nitrate levels in the MfE Environmental Reporting River Water Quality dataset found here. Catchments where the predominant sources of nitrate are non-pastoral in origin are excluded.

Under Option 1, a per-hectare cap, or threshold, for nitrogen losses will be set for each sub-catchment with similar soil type and rainfall. This threshold will be based on a ranking of nitrogen losses from farms within each sub-catchment, and could be set at the 90th percentile, or the 70th, or a point between. Feedback is sought on where this threshold should be set.

This is only one of the options being consulted on, The areas indicated are provisional and may not equate to areas included in regulation.