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Indicators for <i>Our fresh water 2017</i>

Published By   /   April 20, 2017  /   Comments Off on Indicators for <i>Our fresh water 2017</i>

MIL OSI – Source: Statistics New Zealand – Release/Statement

Headline: Indicators for Our fresh water 2017

This page provides an overview of the new and discontinued fresh water indicators for New Zealand’s Environmental Reporting Series: Our fresh water 2017, which Stats NZ and the Ministry for the Environment (MfE) will publish on 27 April 2017. Apart from the report, we will also publish an infographic, raw data accessible from MfE’s website, and indicator pages with dynamic maps and graphs on Stats NZ’s website.

The Environmental Reporting Act 2015 requires Stats NZ and MfE to publish regular reports about the state of the environment. We publish a report on one of the five domains every six months – air, atmosphere and climate, land, fresh water, and marine – and a synthesis report on the state of New Zealand’s environment as a whole every three years.

New indicators

Since Environment Aotearoa 2015, we added 11 new indicators for the fresh water domain.

  • Selected barriers to freshwater fish in Hawke’s Bay will report on the known barriers to fish in the region, such as culverts, weirs, and stormwater pump stations, for 2002–10.
  • Consented freshwater takes will discuss two measures of the pressure on our river flows. The first outlines the key variables regulated through consents to take water – location, use, source, maximum allowable instantaneous rate, and maximum allowable annual volume. The second shows the potential impact of consented freshwater takes on river flows across New Zealand. The data, sourced from regional councils, covers the July 2013–14 year.
  • Conservation status of native freshwater fish and invertebrates represents the risk of extinction for our native freshwater fish and invertebrates. We will report on the conservation status from 2013, and most-recent change in status, of freshwater fish and invertebrates.
  • Trends in freshwater fish will include national trends for 11 freshwater fish species (nine native and two exotic) covering the period 1977–2015 using data from the New Zealand Freshwater Fish Database.
  • Groundwater pesticides data is sourced from a 2014 survey by Environmental Science and Research.
  • Lake submerged plant index will combine information on ecological condition, and the diversity and extent of both native and invasive plants, for 210 lakes for the period 2007–16.
  • Urban stream water quality will report on six measures: zinc, copper, E.coli, ammoniacal nitrogen, nitrate-nitrogen, and dissolved reactive phosphorus for Auckland, Wellington, and Christchurch covering the 2008–15 period.
  • Four indicators will show the impact of the state of our fresh water on our society, economy, and culture, with three providing information on the impact on Māori:
    • Kaitiakitanga of the Waikouaiti catchment
    • Tau kōura: freshwater crayfish traditional fishing method
    • Cultural health index for freshwater bodies
    • Value of water resources for hydroelectric generation quantifies the economic impact of using water for electricity, to help us understand the importance of our natural resources to the economy. We estimated these values for the 2007–15 period.

Key methodological updates

To measure the current state of river water quality (macroinvertebrate community index, clarity, E.coli, nitrogen, and phosphorus) we will complement regional council information with nationally representative maps derived through modelling. This will allow us to provide estimates for locations where monitoring is not undertaken. Information on climate, land use, land form, and source of flow is used in this modelling.

We will expand the number of sites we are reporting on for both river and groundwater quality by using data from regional councils, and NIWA and GNS Science, respectively.

Measuring swimmability

We are assessing whether modelled E.coli data can be used as a suitable indicator to track the risks of infection over a time period when swimming in water bodies.
Although this is still in development, we recognise the topic is of great interest so we will provide an update on the initial results of this work. In future we will expand this work to include lakes.

Improved presentation

We will combine the presentation of some indicators from 2015 (see Environmental indicators Te taiao Aotearoa: Fresh water) in one page to show a more cohesive story. For example, we will combine state and trend indicators for nitrogen, phosphorus, and clarity (river water quality); and for nitrogen and phosphorus (groundwater quality).

Indicators not updated

We will not update some indicators presented in Environment Aotearoa 2015. This is so that we could balance the cost of procuring additional data (and the time available to analyse, quality assure, and update the products) against the benefit of new information. In some cases, new data were not available.

We considered that it would add more value to provide a more comprehensive analysis of existing indicators and fill topic gaps over updating datasets with one or two years of new information. For example, we will increase the number of river water sites we are reporting on to about 750, and will extend coverage to about 560,000 modelled river segments.

These indicators will not be updated:

  • Trends in nitrogen leaching from agriculture
  • Geographic pattern of natural river flows
  • Geographic pattern of agricultural nitrate leaching
  • Groundwater physical stocks
  • Streambed sedimentation
  • Wetland extent
  • Location and extent of New Zealand’s aquifers
  • Participation in recreational fishing
  • Freshwater pests.

We will investigate the viability of updating all indicators for the 2019 synthesis report.

Discontinued indicators

We will replace two indicators:

  • Value of water resources used for hydroelectric generation replaced Contribution of hydroelectricity to total electricity generation is replaced
  • Trends in freshwater fish replaced Freshwater fish communities.

The discontinued indicators will still be available from the archived indicator pages on Stats NZ’s website but will no longer be updated with new data.

Supplementary information

In addition to the indicators described above, we will draw on scientific literature to provide context to and explain our findings.

Remaining data gaps

We identified data gaps in our national reporting on the freshwater environment. These data gaps relate to pressure, state, and impact, and fall under three themes: water quality; water quantity and flows; and ecosystems, habitats, and species. Specific data gaps are discussed further in the report.

How we selected the indicators

Stats NZ and MfE undertook the selection and quality assurance process in August 2015.

Initial considerations involved how we could fill information gaps (such as topics not informed by indicators in Environment Aotearoa 2015), and specific gaps pointed out in Environment Aotearoa 2015 which we said we would report on this time.

We then put together all the existing indicators to be updated with the new indicators and prioritised them by considering:

  • what value the measure adds to the story
  • the feasibility of updating or creating the measure within the required timeframes.

We collected data from December 2015 to June 2016.

Quality assurance

The Statistical Methods team and the Environmental Statistics team of Stats NZ undertook a quality-assessment process to ensure the statistics and their methodology are robust.

This work, which took place between June–October 2016, was supported by technical and scientific advice from MfE and data providers.

We assessed all indicators against the six criteria from the data quality framework (as outlined in the Principles and Protocols for Producers of Tier 1 Statistics): relevance; accuracy; timeliness; coherence and consistency; accessibility; and interpretability.

We classified the measures based on data quality into three categories: national indicator, case study, or supporting information. See Good practice guide for environmental reporting for more information on quality assurance and the classification of measures.

Following quality assurance, we completed the first draft of the report in November 2016. From November 2016 to March 2017 we sought expert reviews on the choice and interpretation of the indicators used in the report and associated products. Peer review included technical advisers from central government, regional councils, Crown research institutes, and two independent peer reviewers.

Indicators for Our fresh water 2017

For a list of the indicators in table format, see the PDF in the Available files box on the right-hand side of this page. If you have problems viewing the files, see opening files and PDFs.

Published 20 April 2017

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