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Waipa morphological modelling study phase 3: Analysis and modelling

TR 2015/37

Report: TR 2015/37

Authors: Jo Hoyle, Richard Measures and Jo Bind (National Institute of Water & Atmospheric Research Ltd).

About this report

Waikato Regional Council (WRC) has commissioned NIWA to carry out a morphological modelling study on the Waipa River to provide guidance on how the Waipa River channel is likely to adjust in the future as a large volume of bed material moves down the river. This ‘slug’ of bed material is the result of sediment generated from the Tunawaea Landslide, which occurred in 1991, and subsequent erosion of bank and river terrace material induced by raised bed levels resulting from the Tunawaea slip material migrating down the Waipa River. Understanding how the Waipa channel is likely to adjust in the future will help WRC to plan effective river management in response to these adjustments.

Read or download the report

Waipa morphological modelling study Phase 3: Analysis and modelling [PDF, 5.1 MB]

Contents

Executive summary
1 Introduction
1.1 Background
1.2 The Waipa morphological modelling project
1.3 The Tunawaea Landslide
1.4 History of channel works
1.5 Report structure
2 Modelled reach
3 Methodology
3.1 Timeline of events and data availability
3.2 Analysis of historic cross sections
3.3 Analysis of historic aerial photography
3.4 Analysis of landslide and Tunawaea Stream changes
3.5 Morphological modelling approach
3.6 The GRATE model
3.7 Data processing and analysis for model input files
3.8 Model runs
4 Results and Interpretation
4.1 Analysis of historic photographs
4.2 Analysis of historic surveys
4.3 Model calibration results
4.4 Model future run results
5 Discussion
6 Conclusions and Recommendations
7 Acknowledgements
8 References