Technical and scientific considerations when setting measurable objectives and limits for water management

Executive Summary

Introduction

The Ministry for the Environment (MfE) commissioned NIWA to provide a report containing: i) background on the technical and scientific aspects of setting measurable water management objectives and limits in resource management; and ii) technical discussion on concepts such as allocation and assimilative capacity in relation to water quality.

The purpose of this report is to assist, from a science perspective, with development of knowledge on the wider topic of setting limits in water management, which comes under the Water Quality Limits Project that is part of Government’s New Start for Fresh Water Officials’ Work Programme. The ideas in this report are from the authors’ perspective as water resource scientists working in the resource management industry. This could form a basis for discussion on limit setting with people that have other perspectives, such as those working in law, policy, planning and other technical fields.

Background

The need for limits in water management has been widely discussed recently. For example the Government’s Cabinet paper proposing a New Start for Fresh Water (Offices of the Minister for the Environment and Minister of Agriculture [ME & MA] 2009) stated: “… New Zealand is approaching some water resource limits, which can be seen in areas with deteriorating water quality, water demand outstripping supply, and constrained economic opportunities.” In particular the Cabinet paper
identified that “water resource limits” were needed “to shape actions on quantity and quality” and also identified the importance of “supplementary measures to address the impacts of land use intensification on water quality, and manage urban and rural demand”.

Terminology

Setting limits for water management requires multiple disciplines including various science fields (e.g., climatology, hydrology, hydrogeology, geomorphology, chemistry, ecology, earth and agricultural sciences, social and cultural sciences, and economics), as well as law, policy and planning expertise. Ideas for setting limits are evolving across these multiple disciplines, creating significant integration and communication challenges, and particularly problems with inconsistent use of terminology. We have defined and used consistent terminology in this report with the hope that our ideas may be more easily integrated with ideas from work in other disciplines (see Glossary at the end of this Executive Summary). Terms defined in the Glossary are underlined throughout the remainder of this report.

Integration of science, planning and law

There is a need to integrate expertise from the science, planning and legal disciplines. While bridging these disciplines has always been important in resource management, the approach suggested in this report places an even greater emphasis on interdisciplinary communication for regional planning. This is because the approach represents a shift in thinking from a reactive mode (i.e. concentrating on regulating the effects of new activities) to a pre-emptive planning mode (i.e. identifying the capacity for use of resources and setting limits). This requires greater use of scientific knowledge by planners, thinking at more expansive scales by scientists and more creative use of legal tools.

Structure of the main report

The purpose of the report and terminology are provided in Section 1. Section 2 contains an overview of the need for measurable objectives and why defining these allows a range of limits such as water quality standards to also be justifiably set. Section 3 describes how science can be used to help overcome a range of challenges and to set measurable objectives and limits. Section 4 describes how science can help implement measurable objectives and limits strategically under the Resource Management Act (RMA), and specifically through regional plans. Section 5 describes the benefits of setting measurable objectives and limits, and illustrates the benefits with examples. Section 6 summarises the challenges and refers back to solutions identified throughout previous sections. Section 7 contains our conclusions.

Last updated: December 2010