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A methodology for chlorophyll and visual clarity modelling of the Waikato and Waipa River

TR 2018/60

Report: TR 2018/60

Author: Sharleen Yalden, Sandy Elliott (NIWA)

About this report

This report was commissioned by the Technical Leaders Group for the Healthy Rivers Wai Ora Project Report No. HR/TLG/2015-2016/2.3

This report, one in a series commissioned by the Healthy Rivers/Wai Ora Technical Leaders Group, describes the methodology used to estimate changes in chlorophyll concentrations and visual clarity in the Waikato and Waipa Rivers in response to changes in nutrient concentrations and sediment loads under various scenarios of land management and land use change. The scope of the report is limited to the development of the methodology – the actual modelling of changes to chlorophyll concentrations and visual clarity will be undertaken as part of the scenario modelling used to assess both the water quality improvements and the costs associated with each scenario (to be reported elsewhere).

Read or download the report

A methodology for chlorophyll and visual clarity modelling of the Waikato and Waipa River [PDF, 2 MB]

Contents
Executive summary
1 Introduction
1.1 Preamble
1.2 Background Information
1.3 Scope
2 Visual Clarity of the Waikato and Waipa Rivers
2.1 Background Information
2.2 Current Visual Clarity and Constituent Contributions
3 Estimating Changes to Chlorophyll Concentrations and Visual Clarity
3.1 Outline
3.2 Nutrient-Chlorophyll Relationships
3.3 Sediment Routing
3.4 Changes to Visual Clarity
4 Limitations and Recommendations for Futher Work
5 Summary
6 Acknowledgements
7 References
Appendix A - Plots of Nutrient-Chlorophyll Relationships