Managing Our Estuaries
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Managing our estuaries August 2020 This report has been produced pursuant to subsections 16(1)(a) to (c) of the Environment Act 1986. The Parliamentary Commissioner for the Environment is an independent Officer of Parliament, with functions and powers set out in the Environment Act 1986. His role allows an opportunity to provide Members of Parliament with independent advice in their consideration of matters that may have impacts on the environment. This document may be copied provided that the source is acknowledged. This report and other publications by the Parliamentary Commissioner for the Environment are available at pce.parliament.nz. Parliamentary Commissioner for the Environment Te Kaitiaki Taiao a Te Whare Pāremata PO Box 10-241, Wellington 6143 Aotearoa New Zealand T 64 4 471 1669 F 64 4 495 8350 E [email protected] W pce.parliament.nz August 2020 ISBN 978-0-947517-20-5 (print) 978-0-947517-21-2 (electronic) Photography Cover images: Waimea Estuary, NelsonNZ, Flickr; Purerua Peninsula, Hazel Owen, Flickr; Whāingaroa Harbour, Hannah Jones. Chapter header seagrass and seaweed images: Peter de Lange, iNaturalist; Melissa Gunn, iNaturalist; Erasmo Macaya, iNaturalist; and Emily Roberts, iNaturalist. Managing our estuaries August 2020 Acknowledgements The Parliamentary Commissioner for the Environment is indebted to a number of people who assisted him in conducting this review. Special thanks are due to Dr Sophie Mormede who led the project, supported by Leana Barriball, Greg Briner, Dr Maria Charry, Dr Stefan Gray, Dr Anna Hooper, Shaun Killerby, Megan Martin, Dr Susan Waugh and Dr Helen White. The Commissioner would like to acknowledge the following organisations for their time and assistance: • Bay of Plenty Regional Council • Te Ao Marama Inc. • Department of Conservation • Waikato District Council • Environment Southland • Waikato Regional Council • Greater Wellington Regional Council • Wellington Regional Public Health • Invercargill City Council • Wellington Water Limited • Marlborough District Council • Western Bay of Plenty District Council. • Ministry for Primary Industries • Ministry for the Environment • New Zealand Transport Agency • Porirua City Council • Tauranga City Council The Commissioner wishes to thank the following individuals for reviewing earlier drafts of the report: • Dr Anthony Chariton (Macquarie • Dr Wayne Landis (Western Washington University) University) • Dr Marie A. Doole (The Catalyst Group) • Dr Melissa Robson-Williams (Manaaki • Dr Paul Gillespie (Cawthron Institute) Whenua – Landcare Research) • Dr Anne-Marie Jackson (University of • Ra Smith (Ngāti Kahungunu ki Otago) Wairarapa). • Helen Kettles (Department of Conservation) Finally the Commissioner wishes to thank the following organisations for their support on the case studies: Ballance, Cawthron Institute, DairyNZ, Davidson Environmental, e3 Scientific, Tauranga Harbour estuary care groups, Federated Farmers, Southland Fish & Game Council, Fruition Horticulture, GNS Science, Kitson Consulting Ltd, Land and Water Science, Lincoln University, Marine Farming Association, Marlborough Forest Industry Association, New River Estuary Forum, Ngāti Kuia, Ngāi Tahu ki Murihiku iwi, Ngāti Toa Rangatira, National Institute of Water and Atmospheric Research, Otatara School students, Porirua educators group, Porirua Harbour and Catchment Community Trust, Rayonier Matariki Forests, Robertson Environmental Ltd, Salt Ecology, Tainui Āwhiro, Te Rūnanga a Rangitāne o Kaituna Inc., University of Waikato, Whāingaroa Environment Centre, Whaingaroa Harbour Care, and the many others who took time to talk to us. Contents Overview 3 1 Tirohanga whānui 11 1 The challenge of managing estuaries 19 2 What do estuaries suffer from? 31 3 How are estuaries managed? 41 4 Hurdles to good estuary management 57 5 A shortlist of initiatives that could make a difference 81 6 Looking forward 89 7 Appendices 99 Appendix 1: New River Estuary 99 Appendix 2: Pelorus Sound/Te Hoiere 115 Appendix 3: Tauranga Harbour 133 Appendix 4: Te Awarua-o-Porirua Harbour 151 Appendix 5: Whāingaroa Harbour 167 Appendix 6: Methodology 181 8 Glossary of Māori terms 185 References 189 2 Cystophora retroflexa Overview This report makes two modest recommendations. They are set out in chapter five. The first is that all estuaries should be included in freshwater management units under the National Policy Statement for Freshwater Management. Currently we apply a distinct management framework to freshwater up to the point where it enters something known as the coastal marine area. That area starts at the high tide mark (technically known as mean high water springs) and goes all the way out to 12 nautical miles from the coast. It is managed under the New Zealand Coastal Policy Statement. The following figure from chapter four visually describes the complexity that surrounds the management of a single interconnected ecosystem that we have sliced and diced for all manner of managerial and bureaucratic reasons. Overview Coastal environment Coastal marine area 4 Territorial sea Resource Management Act 1991 Draft National Policy Statement for Indigenous Biodiversity National Policy Statement for Freshwater Management 2020* New Zealand Coastal Policy Statement 2010 Regional policy statements Regional plans Regional coastal plans District plans 12 Landward Mean high Mean low nautical boundary** water springs water mark miles * The application is variable as regional councils can decide whether to manage lakes and lagoons that are intermittently open to the sea and coastal wetlands as coastal or freshwater. ** The landward boundary of the coastal environment varies according to local geography. Source: PCE Figure 4.3: Areas where different RMA instruments apply in the coastal space. Needless to say, the plants and animals that inhabit this space are strangers to our thinking. What comes off the land ends up in the estuary so unless we manage this in a genuinely integrated way we will always have things falling between the cracks. The report’s second recommendation is even more banal: I am recommending that estuaries and the catchments that feed into them need to be robustly monitored so that we know what is going on and can take management decisions that are informed decisions. Faced with a 200-page report, any reader could reasonably ask why two simple recommendations required such a big report to support them. Is this a case of a huge whale of an enquiry begetting a minnow? I don’t mind admitting that this has been a very difficult report to land. The more we read, and the more we talked to estuary managers, the more we felt that in some ways there was little new to say. It is not as though the problems facing our estuaries and the shortcomings of the ways we manage them have not been 5 documented. On the contrary. Absolutely everyone agrees that estuaries are on the receiving end of numerous different pressures and that they have to be managed in an integrated way. The trouble is, there is nothing naturally integrated about the wide range of activities that go on in a catchment, the conflicting interests of businesses, recreationists and residents whose lives impinge on these places. Many conversations with well-motivated and well-informed groups of people striving to clean up our estuaries ended with the reflection that finding a way forward is all very complicated. A report that tells people what they already know – that these are complex ecosystems with complicated and conflicting human demands on them – is of limited value. And that may ultimately be a fair judgement of this report. I believe that really good information about what’s going on and an insistence that we manage estuaries as part of catchments would make a difference. But I can’t claim that these are original proposals or that there is some hidden secret to galvanising action. There are a lot of entities, communities and governance arrangements to be navigated. My best hope is that this report describes the forces at work (or not at work) in a fresh way, and encourages people to ask themselves, once more, whether we are likely to make useful progress continuing on the track we are on. It may be that we are doing as well as it is humanly possible, although I doubt it. But before we conclude that, let’s at least look at the state of things as they exist. There will be readers who ask why they should read a report if the author himself describes its two recommendations as modest. The answer is that the report gathers much that is fascinating about how our estuaries come to be in the state they are in. It is not just an environmental assessment. It is a human and cultural assessment. It had to be. Estuaries are where humans have tended to cluster from the very first arrival of Māori on these shores. The way they have been treated has reflected the values of estuary dwellers – values that have changed over time and are still changing. There are over 400 estuaries of different shapes and sizes in Aotearoa New Zealand and they are obviously not all in the same state. Those found in national parks or remote and relatively untouched corners of the country will be as close to pristine as anything can be in the twenty-first century. But many more are disfigured by reclamations and foreshore hardening for residential and commercial developments and transport arteries. Overview The overwhelming majority are receiving sediment at many times pre-settlement levels. Sediments smother shellfish and seagrass and make the water cloudy. Nutrients from agriculture and wastewater treatment plants can trigger algal blooms and reduce the level of dissolved oxygen in the water. Pesticides, heavy 6 metals, anti-fouling paints, timber treatment substances, plastics, household detergents, solvents and pharmaceuticals all find their way into our estuaries and combine to form a cocktail whose consequences can persist long after their use has ceased. Any one of these pressures would be a matter for concern. But it is the cumulative effects that make them particularly worrying – especially when in many cases we know very little about cause and effect.