Prediction of Contaminant Accumulation in the Upper Waitemata Harbour

109 Pages·2005·1.69 MB·English

Prediction of Contaminant
Accumulation in the Upper
Waitemata Harbour – Methods

June 2004 Technical Publication 261

Auckland Regional Council
Technical Publication No. 261, June 2004
ISSN 1175 205(cid:31), ISBN 1-877-353-79-5
www.arc.govt.nz
Printed on recycled paper

Prediction of Contaminant
Accumulation in the
Upper Waitemata Harbour –
Methods

Malcolm Green
Mike Timperley
Robert Collins
Alastair Senior
Russell Adams
Andrew Swales

Bruce Williamson and Geoff Mills
(Diffuse Sources Ltd)

Prepared for
Auckland Regional Council, North Shore City Council, Rodney District
Council, Waitakere City Council, and Transit New Zealand.

NIWA Client Report: HAM2003-087/1
June 2004

NIWA Project: ARC03210

National Institute of Water & Atmospheric Research Ltd
Gate 10, Silverdale Road, Hamilton
P O Box 11115, Hamilton, New Zealand
Phone [phone], Fax [phone]
www.niwa.co.nz
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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
Acknowledgements
This report was prepared for the Auckland Regional Council, the North
Shore City Council, the Rodney District Council, the Waitakere District
Council and Transit New Zealand by the National Institute of Water and
Atmospheric Research (NIWA).

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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
Contents

Executive Summary 1
1. Introduction 5
1.1 Strategic Fit 5
1.2 Study Development 5
1.3 Project Aim 6
1.4 Study Approach 7
2. Overview – Hydrology of the Upper Waitemata Harbour 11
2.1 General 11
2.2 Bathymetry 13
2.3 Tide 13
2.4 Currents 14
2.5 Sediments 14
3. Overview – Catchment of the Upper Waitemata Harbour 17
4. Explanation of the Prediction Scheme 19
4.1 Introduction 19
4.2 Principal Outputs of the Prediction Scheme 23
4.3 General Constitution of the Model 25
4.3.1 “Core” models 25
4.3.1.1 Catchment model 25
4.3.1.2 Estuary model 27
4.3.1.3 Generation of contaminants. 28
4.3.2 Prediction during a single event 29
4.3.2.1 Delivery 29
4.3.2.2 Dispersal 30
4.3.3 Prediction between any two events 38
4.3.3.1 Redispersal by waves and currents 38
4.3.3.2 Bioturbation 41
4.3.4 Prediction across many events 43
4.4 Model Verification 44
5. Conclusions 47
REFERENCES 49
APPENDIX A. Prediction Scheme Details 51

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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
A.1 Prediction During a Single Event 51
A.2 Prediction Between Any Two Events 54
A.2.1 Redispersal 54
A.2.2 Bioturbation 56
A.3 Prediction Across Many Events 58
A.3.1 Prediction of contaminant concentration in surface sediment 59
A.3.2 Prediction of sediment-deposition rate 59
A.3.3 Origin of sediments and contaminants that deposit in each subestuary 60
A.3.4 Fate of sediments and contaminants that originate in each
subcatchment 62
APPENDIX B. Estuary Hydrodynamics and Particle-Tracking Model 65
B.1 Introduction 65
B.1.1 DHI model suite 65
B.1.2 Bathymetric grid 66
B.2 Calibration 66
B.2.1 Field study 66
B.2.2 Hydrodynamic calibration 68
B.2.3 Particle transport calibration 73
B.3 Analysis of Catchment Model Results 75
B.4 Hydrodynamic Simulations 79
B.4.1 Warm-up simulation 79
B.4.2 Flood event simulations 79
B.5 Particle Analysis Simulations 79
B.6 References 80
APPENDIX C. Contaminant Concentration Profiles in Lucas Creek 81
C.1 References 84
APPENDIX D. Calibration and Verification of GLEAMS 85
D.1 References 86
APPENDIX E. Verification of Model Predictions: Annual Average
Sedimentation Rates 87
E.1 Introduction 87
E.2 Hellyers Creek 88
E.3 Lucas Creek 89
E.4 Paremoremo and Rangitopuni Creeks 89
E.5 Brighams Creek 89
E.6 Rarawaru and Waiarohia Creeks 90
E.7 Main Body 90
E.8 Comment on Bioturbation Depth 90

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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
E.9 Comment on Bathymetry 90
E.10 References 91
APPENDIX F. Verification of Model Predictions: Contaminant Concentration
Profiles in Lucas Creek 93
F.1 Introduction 93
F.2 Development History of the Lucas Catchment 93
F.3 Validation Results 96
F.4. References 98
APPENDIX G. Summary of Principal Outputs of the Prediction Scheme 99

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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261
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Prediction of Contaminant Accumulation in the Upper Waitemata Harbour – Methods TP 261