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Final Report: Inflow monitoring of Lake Mangakaware and the Rotopiko lakes 2014

TR 2014/15

Report: TR 2014/15

Author: G Tempero and D Hamilton (Environmental Research Institute and University of Waikato)

About this report

Waikato Regional Council has identified several lake catchments in the Waikato region where water quality improvements may be possible with the development of farm nutrient budgets. These lake catchments currently include the Rotopiko (Serpentine) lakes and Lake Mangakaware.

Following the development and implementation of nutrient budgets for properties within the Rotopiko and Mangakaware catchments, the University of Waikato was contracted to monitor representative inflows to these lakes, with the objectives of

  • tracking changes in nutrient run off following the implementation of farm nutrient budgets
  • providing an indication of seasonal variation in discharge, sediment and nutrient concentrations; and
  • obtaining data on the magnitude of changes in discharge, sediment and nutrient concentrations occurring during heavy rainfall events.

This report provides details on the selection of representative inflows into the Rotopiko lakes and Lake Mangakaware, and includes the results from two years of base-flow monitoring as well as from high-frequency monitoring of four major rainfall events during this period. This information is used to provide recommendations for future data collection, monitoring and modelling to underpin management actions to reduce sediment and nutrient inputs to the lakes.

Read or download the report

Final Report: Inflow monitoring of Lake Mangakaware and the Rotopiko lakes 2014 [PDF, 2.3 MB]

Contents
Executive summary 3
Introduction 9
Methods 10
Site descriptions 10
Inflow monitoring 14
Storm event sampling 15
Water level loggers 15
Results 17
Discharge 17
Base-flow monitoring 20
Storm flow monitoring 22
Discussion 36
Recommendations 40
Acknowledgments 41
References 42
Appendix 1 44
Appendix 2 46
Appendix 3 52