Managing freshwater quality

Report 1: land use and nutrient pollution

This report updates a 2013 report on the same topic and focuses on the impacts of land use on water quality. It follows an earlier investigation into the relationship between land use and two nutrient pollutants – nitrogen and phosphorus. It presents new information about the recent changes in farm productivity and mitigation methods and discusses the resulting trends in nutrient concentration and water quality.

The report recognises the range of mitigation techniques increasingly used on dairy farms to reduce nutrient losses, especially on the management of shed effluent and bridging and fencing waterways. In other areas, such as keeping stock out of wetlands, progress has been much slower. The report notes that experiments on research farms have shown that it is possible to reduce nitrogen losses by as much as 50%, but the most effective techniques are generally expensive. It cites an example of the Future Farmlet in Waikato where nitrogen losses were reduced by 40-50% by using less nitrogen fertiliser, a lower stocking rate, with cows that excrete less nitrogen in their urine and are taken off pasture for defined periods. However, these techniques are still in development and are a long way from being suitable for widespread adoption.

Report 2: examining the 2014 national policy statement

This second report examines the current NPS. This sets a national direction for freshwater management which includes managing land use and development activities that affect freshwater. It is considered a first step to improving freshwater management at a national level.

The report identifies aspects of the NPS that are absent or unclear and makes six recommendations about how it could be improved.

As currently drafted, a key water quality objective refers to maintaining and improving the 'overall' quality of fresh water within a region. The report considers that this lends support to an 'unders and overs' approach. It recommends that the word 'overall' be deleted and 'maintaining and improving' should be defined as at least staying within the same band in the national objectives framework.

The report considers that criteria should be provided for dividing regions into freshwater management units (FMU). These units are the basis for measuring water quality, setting limits and choosing objectives, and the lack of any criteria means that these FMU could be set in a way that leads to inappropriate management and monitoring.

The policy on exceptions to national bottom lines needs clarification. Amendments to the NPS are suggested so an exception can only be made for existing infrastructure if it is the reason for water quality being below the bottom line.

Regional councils should be required to prioritise the protection of vulnerable water bodies and catchments. Councils have until the end of 2025 to implement the NPS. However, certain water bodies need focussed efforts and priority action taken.

The NPS should be amended to include the management of estuaries under the national objectives framework. Estuaries are vulnerable water bodies, and according to the report, water catchments cannot be managed in an integrated way while estuaries are excluded.

The Minister for the Environment has said that the ministry already has work underway on four of the six recommendations, and the other two will be considered over the coming months.

• Rachel Devine, is a partner at interEllisonRuddWatts specialising in all aspects of environmental and resource management law. Kathy Wilson a senior associate at MinterEllisonRuddWatts advising on all aspects of environmental, planning and related legal issues.