EXECUTIVE SUMMARY

Marlborough District Council (MDC) is reviewing their regional plans. MDC require advice on standards appropriate for point source discharges into the marine receiving environment.

Water quality classifications are provided in Schedule 3 of the Resource Management Act 1991 (RMA), and are used in a range of ways by different councils. General requirements for the impact of discharges on water quality are defined in Sections 70 and 107 of the RMA and other requirements are stated in the New Zealand Coastal Policy Statement (NZCPS).

Under MDC's current plans, all marine waters are classified for Shellfish Gathering (SG). MDC has requested guidance on standards for the (SG) and Contact Recreation (CR) classes for the marine environment. Council recognise that the SG and CR classes do not incorporate broader requirements of the RMA and NZCPS.

Many difficulties in setting standards and monitoring impacts stem from the variability of water column characteristics in the marine environment. Our approach has been to identify standards and indicators that are relevant to the class in question, and consistent with approaches taken by other councils in New Zealand. Some commonly-used standards, such as dissolved oxygen saturation, are likely to be exceeded by background variation. Difficulty in directly attributing changes to a particular cause means that use of standards as trigger values for further investigation is often more appropriate than setting fixed points beyond which an activity is deemed non-compliant.

Suitable methods for monitoring the parameters, for which standards have been set, are also given. Often high-resolution data is required to separate impacts of an activity from background variation. Improvements in monitoring technology mean that moored instrumentation is becoming a more feasible approach to consent monitoring.