Publications: Research reports and publications

Advice for the NCC Whakamahere Whakatu Nelson Plan: water quality

28 October, 2016
Cawthron Report 2937. Prepared for Nelson City Council under Envirolink contract CAWX1603.


Nelson City Council (NCC) is reviewing the operative Nelson Resource Management Plan (NRMP), and preparing its successor, the Whakamahere Whakatu Nelson Plan. The consent status of activities in the Coastal Marine Area (CMA) is defined in part by the activities’ ability (or otherwise) to comply with the relevant standards and limits of this plan. However, this is not the only purpose for standards; they ‘provide a framework for managing water quality and water resources…[and] classification also provides an indication of general water quality objectives’ (Forrest et al. 1994). The current standards were reviewed to determine whether they remain fit for purpose. Consideration was given to requirements of the New Zealand Coastal Policy Statement (NZCPS, DoC 2010), approaches taken by other councils, national guidance, and the availability of local water quality information.

Development of comprehensive regionally-appropriate standards for a range of parameters is not achievable given the limited state of the environment information available in the region. Moreover, where other councils have identified guidance on acceptable values for a range of parameters, they are employed for definition of water quality categories or as target quality standards, rather than as obligatory standards.

The standards in the extant NRMP are largely suitable for inclusion in the new Whakamahere Nelson Plan, however minor changes are recommended to:

  •  align faecal indicator bacteria standards with current Ministry of Health/Ministry for the Environment guidelines
  •  allow for assessment of the Shellfish Gathering standard in shellfish flesh (as well as water samples)
  •  extend the Shellfish Gathering class across the whole CMA
  •  extend the Contact Recreation class to include the Horoirangi Marine Reserve
  •  remove reference to ‘shellfish gathering season’ and ‘bathing season’.

The present criteria governing the determination of mixing zones and discharge criteria appear to be generally appropriate. We suggest a minor amendment to incorporate risks of cumulative and/or persistent effects.

NZCPS requirements regarding water quality include managing the effects of activities on land, but do not necessarily require monitoring the impact of these activities on the state of the marine receiving environment. Furthermore, NZCPS requirements cannot be met solely by the setting of consent conditions, but require other monitoring or management (independent of consented activities) from council. Accordingly, acceptance of our recommendations is insufficient to fulfil all the requirements of the NZCPS regarding marine water quality.

Instituting a marine monitoring programme may also be required to move towards fulfilment of some NZCPS obligations. Monitoring should also consider opportunities for maximising value from existing data collection in the NCC area and adjacent CMAs, and the opportunities emerging as a result of technology advances such as satellite imagery and high-frequency data-collection with moored instrumentation.