Assessment of the Waikato River estuary and delta for whitebait habitat management: field survey, GIS modelling and hydrodynamic modelling

TR 2014/35
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Report: TR 2014/35

Author: HFE Jones and DP Hamilton (University of Waikato: Environmental Research Institute)

About this report

The University of Waikato was contracted by Waikato Regional Council to develop a hydrodynamic model of the Waikato River delta, to aid with the assessment of whitebait spawning habitat.

A three-dimensional hydrodynamic model was applied to the Waikato River estuary and delta under a range of conditions (i.e. varying tidal heights and river flows). In addition, GIS modelling was used to identify potential whitebait spawning habitat in the floodplain surrounding the estuary and delta.

The models developed in this study were designed to provide a basis for future research and modelling, which may be used to determine opportunities to enhance native fish habitat, and reduce available habitat for pest fish, in the lower Waikato River.

Rehabilitation of habitat for native fish, especially whitebait, has been a recent focus of management and restoration of the lower Waikato River. For example, the Waikato River Authority has recently provided significant funding for riparian planting, wetland restoration and for research into restoration of whitebait habitat.

This study aims to provide information that may guide and assist with future restoration efforts.

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Assessment of the Waikato River estuary and delta for whitebait habitat management: field survey, GIS modelling and hydrodynamic modelling [PDF, 7 MB]

Contents
General introduction 
Background
Whitebait
Waikato River estuary and delta
Study objectives
Waikato River estuary and delta field survey: spatial and temporal variability in ecologically relevant parameters
Introduction
Methods
Data logger deployment
CTD and BiofishTM surveys
Results and discussion
Logger deployment
CTD and BiofishTM surveys
Limitations and recommendations
Conclusions
GIS modelling of potential whitebait spawning habitat using a Digital Elevation Model for the Waikato River estuary, delta and floodplain
Introduction
Methods
Development of a Digital Elevation Model for the Waikato River estuary, delta and floodplain
GIS modelling of potential whitebait spawning habitat
Results and discussion
Digital Elevation Model of the Waikato River estuary, delta and floodplain
Potential whitebait spawning habitat
Limitations and recommendations
Conclusions
Hydrodynamic modelling of the Waikato River estuary and delta: inundation and salinity distributions under varying tidal and river discharge condtions
Introduction
Methods
Delft3D model description and set-up
Delft3D calibration and validation
Influence of river flow on water levels and salinity
Results and discussion
Delft3D calibration and validation
Influence of river flow on water levels and salinity
Limitations and recommendations
Conclusions
General conclusions and recommendations
References
Appendix 1: Water level at Hoods landing
Appendix 2: CTD profiles