New Zealand’s fresh waters: Values, state, trends and human impacts

Abstract

Fresh water provides us with considerable natural advantage. It is abundant and supports our economy, our environment, our recreation and our national identity. There are many values associated with fresh water for all New Zealanders, and particularly for Māori. Moreover, the state of our fresh water is the environmental issue of highest public concern. In recent years there has been an increasingly complex and at times confusing public discourse about fresh water. It is clear that fresh water is an issue on the minds of many New Zealanders. Accordingly, following discussion with Prime Minister Key, I undertook to produce a paper explaining the issues surrounding the state of fresh water in New Zealand, and this is something that my Office has been working on independently for some time. Until relatively recently the issues of conservation and issues of economic development have been largely seen in isolation. We have been proud of our environment as reflected in our extensive portfolio of national parks and the conservation estate. However, waters outside these areas have been seen primarily through the lens of development. Now, the need for more holistic and integrated practices of ecosystem management – something long-recognised by Māori – is more generally understood. But such management practices do create challenges in dealing with legacy issues: to ensure the quality of our freshwater estate on one hand, while balancing development interests on the other. These scientific and policy challenges are compounded by the inherent complexities of freshwater-associated ecosystem maintenance and enhancement. It is these complexities and challenges that the reports that follow are intended to elucidate. The recent release of the Government’s ‘Clean Water’ discussion document and proposed new standards for the swimmability of our fresh waters has brought some of the issues to the fore. Therefore I have accelerated completion of this paper so that it might assist those who wish to engage in the consultation on those proposals. The report is in two sections. The first is a summary report written from my Office with the assistance of the Departmental Science Advisors from the Department of Conservation and the Ministry for the Environment. This overview avoids technical detail but tries to explain the core issues of public concern that have implications for policy development. The main body of the report is a more technical and scientifically referenced document that reviews the state of fresh water in New Zealand and issues related to restoration. The initial draft of the technical report was prepared by the Freshwater Group from NIWA, and was then subjected to iterative review assisted by a number of academics, the Departmental Science Advisors and my Office. The final draft has also undergone external peer review. I want to acknowledge the extraordinary amount of work done by Dr Bryce Cooper and his team at NIWA. We are lucky that New Zealand has a large number of world-class scientists in both the CRI and university sectors who have extensive knowledge from diverse perspectives on the challenges presented by our diverse catchments, lakes, rivers, estuaries and wetlands. These issues extend from geomorphology and hydrology to understanding the ecology of our native plants, fish, insects and birds, and consideration of our vi pastoral agricultural system and the impact of urbanisation and industrialisation. The likely impacts of climate change are a further and critical concern. It has been inevitable since humans and their accompanying animals and plants came to New Zealand and altered land use that there would be impacts on the quality of fresh water. This has been particularly so since the arrival of Pakeha and the rapid expansion of pastoral farming. The latter, and particularly its very rapid intensification in recent years, creates enormous challenges. On one hand it is at the core of our economy, on the other it has led to rapid changes in land use, particularly through dairy expansion, with concomitant major and adverse impacts on the quality of our fresh water estate. Agriculture and horticulture are also creating some supply-side issues in some catchments – that is, there are places and times where there simply is not enough water to meet everyone’s needs. The urbanisation of New Zealand is a further source of reduced water quality. Accompanying issues are created by the impact of hydroelectric and geothermal power, industrialisation and the arrival of exotic invasive species that have all had further impacts on our fresh water and its associated biota. There are many measures of water quality – reflecting its physical, chemical and biological characteristics. However, no single measure is sufficient to understand the state of fresh water and the analysis is further complicated by gaps and inconsistency in the monitoring regimes. This is reflected in the current confusion over the proposed new water standards, which this paper seeks to explain. There is an inherent and pragmatic logic in having nuanced definitions that take into account what is an acceptable risk, consideration of the seasonal changes, the relationship to extreme weather events etc., but the impacts of such complexity must be interpreted and communicated clearly. Water monitoring in New Zealand is imperfect, with sampling site distribution not fully representative of the environmental variation that occurs, sub-optimal site density in places, and variable quality of sampling and analysis protocols. Despite these challenges, the data very clearly shows that water quality and quantity is being adversely affected primarily by changes in land use and the diffuse contamination arising from pastoral farming and urbanisation. While the public understandably might hope for rapid restoration of water quality across all rivers and lakes in New Zealand, this is unrealistic and scientifically impossible. In some cases we are dealing with contamination that occurred decades ago, and the legacy effects may take a similar time to flush from the system. Moreover there are no silver bullets in water restoration – multiple actions are needed, requiring partnerships between central and local authorities, iwi, citizens and businesses including farmers. Climate change can only put additional pressures on our freshwater ecosystems. In a number of regions drought will become more common requiring either better water management and/or changes in land-use. Considerable research is needed to pre-emptively identify the strategies to employ. Freshwater research has certainly been accelerated by the National Science Challenge processes, and water issues have been highlighted further in the recently released Conservation and Environment Science Roadmap. These issues will also be referenced in the soon-to-be-released Primary Sector Science Roadmap. The linkage between these two roadmaps highlights the intertwined nature of the challenges ahead. The brief Q&A section and the two papers that follow are intended primarily to inform the public and policy makers regarding the associated science rather than to point to specific policy vii initiatives. There are clearly very complicated trade-offs between public expectations, economic drivers and recreational considerations in protecting our fresh water. This will require sustained commitment by governments, industry, local authorities and community groups, and an ongoing commitment to monitoring and research across multiple modalities. I hope that this report will be of value in enhancing public and policy understandings of the opportunities and challenges ahead.