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Introduction

This report has been developed as part of the Ministry for the Environment’s environmental reporting programme. As well as producing regular environmental reporting using a set of national environmental indicators, the programme produces a range of occasional reports – such as this one – on topical, national-scale issues. Such reporting provides quantitative information to the resource managers, policy agencies and other decision-makers who manage New Zealand’s natural resources.

Purpose and scope of this report

This report draws together monitoring data from 14 dairy farming1 catchments in New Zealand. The aim is to characterise, in a standardised way, the water quality in these catchments using the latest2 information available from monitoring agencies. As such, this report constitutes a ‘baseline’ report, against which ongoing monitoring information on water quality in the same catchments can be compared in future to identify trends. If care is taken, and consideration given to other monitoring programmes (such as regional council state-of-environment monitoring), these results from the selected catchments can be extrapolated to form a broadly representative nationwide picture of water quality in dairy catchments.

If monitoring in the selected catchments continues, and in some cases intensifies, the data in this report may also be useful for future national-scale assessments of the water-quality outcomes of good practice in on-farm management on dairying land, including implementation of the Dairying and Clean Streams Accord.

There are a number of challenges to providing robust information for national reporting purposes. Although it is not within the scope of this report to determine how such challenges should be overcome, some observations about the existing monitoring programmes are made, as well as recommendations for future data analyses.

Context for this report

The degraded condition of rivers and streams in lowland catchments in New Zealand has been repeatedly described by researchers (eg, Smith et al, 1993; Davies-Colley and Nagels, 2002; Larned et al, 2004) and is recognised by the wider public (Hughey et al, 2008). The public also have a predominantly negative view of the impact of dairying on water quality (Hughey et al, 2008), and council monitoring has shown that dairying is responsible for some of the poorest water quality outside of our urban centres (eg, Perrie, 2007).

Although the current state of water quality in lowland catchments is well understood, it is much more difficult to make general, but definitive, statements about recent trends. Examples of deteriorations in some aspects of water quality in farmed catchments have been reported
(eg, Larned et al, 2004; Scarsbrook, 2006; Parliamentary Commissioner for the Environment, 2004), as have examples of improvements (eg, Larned et al, 2004; Wilcock et al, in press). However, it is significant that Environment Waikato (2008) has recently reported a widespread deterioration in water quality in what is our most intensively farmed region.

The extent to which dairying is responsible for recent and/or continued deteriorations is difficult to quantify. It has been noted by the Parliamentary Commissioner for the Environment (2004), with reference to an earlier researcher’s findings (Larned et al, 2004), that there has been a lack of nationwide assessment of water-quality trends in relation to particular land-use types.

Dairying and water quality

Although dairying is essential to our economy, it has an impact on the natural environment, especially on our waterways (eg, Smith et al, 1993; Davies-Colley et al, 2004).3 High-producing pastures and stock (cows), combined with high stock densities, mean that contaminant losses to fresh water are often greater per hectare of dairy land compared with other land uses. For example, dairying land occupies only 22 per cent of the land area in Waikato, but it is estimated by Environment Waikato to account for 68 per cent of nitrogen and 42 per cent of phosphorus entering the waterways of the region (Environment Waikato, 2008). And although daily faecal loads to land are broadly similar for most types of stock animal (eg, dairy cattle, beef cattle, sheep and deer), the loadings from direct deposition to water are greatest from stock crossings (Wilcock, 2006), which are typically more active on dairy farms.

Contaminants reach waterways from a combination of point and non-point (diffuse) sources. Point-source discharges in dairy catchments are mainly due to the disposal of stock effluent from farm oxidation ponds. These are generally controlled through resource consent conditions, although non-compliant discharges (direct to water) are still a concern (eg, Greater Wellington Regional Council, 2008; Environment Canterbury, 2008). The diffuse pollutants of primary concern are: nutrients from livestock wastes (including urine patches) and fertiliser run-off (eg, Monaghan et al, 2007); microbial contaminants from livestock faeces (eg, Collins et al, 2007); and sediment from eroded banks and paddocks (eg, Niyogi et al, 2007).

Actions to reduce the impacts of dairying include fencing to keep stock from waterways, riparian planting, improved control of effluent discharges, bridging and culverting of streams, wintering off stock, and adopting fertiliser management plans and nitrification inhibitors. Some of these actions have been formalised and given target measures in the Dairying and Clean Streams Accord (see next section), which applies to streams that are “wider than a stride, deeper than a redband gumboot, and permanently flowing”. Others actions are part of day-to-day council advocacy work (eg, farmer-assisted riparian planting programmes).

However, some contaminant sources and pathways, particularly diffuse ones, are notoriously difficult to manage. For example, small headwater streams can make substantial contributions to the overall pollutant loading of a stream but can also be hard to isolate from farm activities
(by fencing and planting) because of their number and the extent of the drainage area.

The Dairying and Clean Streams Accord

In 2003, the Dairying and Clean Streams Accord was adopted in 15 of the 16 regions in New Zealand, in effect comprising a national non-regulatory programme for the dairying sector. The Accord is centred around a number of objectives and national targets, each of which is recognised as a best practice management action on dairy farms, although there are many additional best practice management actions not covered by the Accord. (See Box 1 for more details about the Accord, its objectives and its national targets.)

Box 1: The Dairying and Clean Streams Accord

The Dairying and Clean Streams Accord (the Accord) was agreed between Fonterra Co-operative Group Ltd (which comprises over 95 per cent of New Zealand’s dairy industry), the Minister for the Environment, the Minister of Agriculture, and regional authorities in May 2003. The Accord reflects a non-legally binding commitment by these parties to improve the environmental performance of dairying, and has a goal of achieving “clean healthy water in dairying areas”. The parties to the Accord agreed to work together to develop practical solutions to protect and enhance water quality in dairying areas.

The Accord comprises a number of objectives and national targets, as summarised in the following table.

Accord objective Accord national targets
Dairy cattle are excluded from streams, rivers, lakes and their banks. Dairy cattle are excluded from 50% of streams, rivers and lakes by 2007, and from 90% by 2012.
Regular (more than twice a week) crossing-points have bridges or culverts. 50% of regular crossing-points have bridges or culverts by 2007, 90% by 2012.
Farm dairy effluent is appropriately treated and discharged. 100% of dairy farm effluent discharge complies with resource consents and regional plans immediately.
Nutrients are managed effectively to minimise losses to ground and surface water. 100% of dairy farms have in place systems to manage nutrient inputs and outputs by 2007.
Existing regionally significant or important wetlands (as defined by regional councils) are fenced and their natural water regimes are protected. 50% of regionally significant wetlands are fenced by 2005, 90% by 2007.

The Accord is operational in 15 out of the 16 regions in New Zealand. The Accord does not operate in the West Coast region, where Westland Dairy Milk Products operates. Thirteen of the 15 Accord regions have significant numbers of Fonterra dairy suppliers in their region. The two exceptions are the Gisborne District and Nelson City, which have very little dairying.

Progress towards the Accord targets set out in the table above is reported annually by the Accord partners in the Snapshot of Progress reports. Up to June 2009, there have been five Snapshot of Progress reports published. The majority of data in these reports is supplied by regional authorities (effluent compliance figures) and Fonterra (through their annual On-farm Environment and Animal Welfare Assessment surveys).

The main reporting commitment associated with the Accord is an annual Snapshot of Progress (eg, Ministry of Agriculture and Forestry, 2009). The Snapshot of Progress is produced by Accord partners and reports on progress towards each Accord objective and target. However, the Snapshot does not provide information about what environmental outcomes – including improved water quality – are being achieved in dairying catchment waterways.

Monitoring water quality in dairy catchments: this report

There are many routine sampling programmes in New Zealand that aim to monitor water-quality changes in intensively used catchments. However, there has been no nationally concerted effort to draw data together from a wide range of predominantly dairy catchments to try to establish a broadly representative New Zealand-wide picture of water quality in these environments. That is the aim of this report, which has been guided by a monitoring and reporting strategy published by the Ministry for the Environment in 2006 (A Monitoring and Reporting Strategy for Measuring the Environmental Outcomes of the Accord).

As the title suggests, the Strategy’s intent was to provide a monitoring approach to measure the water quality outcomes of the Accord. However, the Strategy document also stated that there are a number of significant challenges4 to discriminating between the water-quality outcomes of
on-farm management practice changes resulting from the Accord and all the other activities occurring in a particular catchment. These challenges have since been emphasised by Harris Consulting (2008) in the mid-term stocktake of the Accord, who stated:

  • ... the Accord itself is not likely to have an impact on water quality outcomes that is discernible against all the other changes that are going on in the operating, regulatory and voluntary environment ...

  • ... it would seem appropriate, given the (methodological) difficulties of monitoring the Accord on its own, to integrate the Accord monitoring with other monitoring programmes being undertaken nationally; that is ... it may be more useful to have an overall monitoring programme ... to assist in determining the impact of the whole suite of initiatives rather than just focusing on the Accord.

Given the challenges just described, the Ministry for the Environment considers that the Strategy better represents a ‘whole-of-catchment’ monitoring strategy rather than an Accord-focused strategy, and it will be further implemented (and interpreted) in the future as such.

The Strategy recommended making use of data from existing monitoring programmes in selected dairy catchments and implementing a small number of new monitoring programmes (see Box 2 below) with a view to producing standardised reporting on water quality in monitored dairying catchments at regular intervals. Such reporting would take the form of a baseline report in the first instance (ie, this report), followed by subsequent follow-up reports every five years.

Box 2: Implementing the monitoring and reporting strategy

The monitoring and reporting strategy for measuring the environmental outcomes of the Accord (Ministry for the Environment, 2006) recommended using monitoring information from two primary sources to assess the environmental outcomes of the Accord. These are given below and are the basis for the information provided in this report.

Existing best practice (Tier 1) catchments

Concern about increasing degradation of soil and water quality and the long-term sustainability of dairy farming led to the New Zealand dairy industry initiating the Best Practice Dairy Catchments Project in 2001, in which four dairying catchments were chosen for long-term monitoring. These catchments were chosen as being generally representative of some of the challenges of water-quality management in each of the regions.

The goal of the project was to establish an environmental baseline in each catchment against which the effects of the adoption of best management practices can be measured over time.

The catchments are located in two traditional dairy farm areas of the North Island (Waikato and Taranaki), and two areas of the South Island that have only relatively recently undergone conversion to dairy farming (South Canterbury and Southland). Monitoring of a fifth catchment at Inchbonnie on the West Coast of the South Island began in June 2004 (in a waterway known as Pigeon Creek).

Additional (Tier 2) catchments

In addition to the best practice catchments, a further nine predominantly dairying catchments were selected for long-term water-quality monitoring, with a specific focus on assessing how Accord actions can affect water quality. These catchments were chosen to represent New Zealand dairy catchments in which best management practice is generally not as far advanced as in the Tier 1 catchments. Regional councils undertake the monitoring and reporting in these Tier 2 catchments.

All of the Tier 1 and five of the Tier 2 monitoring programmes discussed above have been in place since at least 2002. Four of the Tier 2 catchment programmes were established specifically to generate additional monitoring data in line with the monitoring and reporting strategy, which is why the majority of that data was collected during 2006/07.

 


1 In terms of land area, dairy farming is the dominant single land-use type in 12 of the 14 catchments. In two catchments dairying is not dominant by land area but is considered to be an important determinant of overall water quality.

2 For the purposes of this report, ‘latest water quality’ information refers to average water-quality information calculated using the most recent data available for each monitored catchment at the time this report was compiled: generally this means either a 2001–2006 average or a 2006/07 average. See the introduction of the ‘Water-quality Baseline’ section for more detail on monitoring time periods.

3 Intensive farming, including dairying, is known to have an impact on unconfined groundwater aquifers
(eg, Hayward and Hanson, 2004). However, investigating this is not within the scope of this report.

4 See further explanation of these challenges in the ‘Data limitations and constraints’ section.