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Lake Taupo long term monitoring programme - 2016-2017

TR 2018/16

Report: TR 2018/16

Author: Piet Verburg and Anathea Albert (NIWA).

About this report

WRC began monitoring the water quality of Lake Taupō in 1994. The large size of the lake means that specialized equipment and procedures are needed to survey its condition. Furthermore, its generally excellent water quality means that non-standard laboratory methods must be used to analyse samples collected from the lake. As a result, the monitoring continues to be carried out by the same specialist contractor (NIWA Hamilton).


The contract with NIWA requires that a report be produced each year describing the results observed in the previous 12 months. This report, covering 2016–17, is the latest in this series—the twenty-third. These annual reports are routinely-published in the council’s Technical Report series. The results are also incorporated in our annual water quality indicator for Lake Taupō. They are also included here, describing (1) the current water quality of the lake, and (2) whether it has changed since the council’s plan to protect the lake took effect.


The water quality of the open waters of Lake Taupō is generally excellent. Over the past 22 years (1995-2016) concentrations of the plant nutrients total nitrogen and total phosphorus have increased, at rates of 1.7 per cent per year and 0.6 per cent per year, respectively. Average concentrations of algae, however, have been stable. The increases in total nitrogen were anticipated in the Waikato Regional Plan (section 3.10), and are consistent with legacy effects in groundwater in the catchment which are expected to eventually stabilize at year 2000 levels.

Read or download the report

Lake Taupo long term monitoring programme - 2016-2017 [PDF, 5.1 MB]

Contents
1 Introduction
2 Methods
2.1 Report contents
2.2 Statistical evaluation
3 Results and discussion
3.1 Temperature and mixing
3.2 Dissolved oxygen
3.3 Secchi depth
3.4 Phytoplankton
3.5 Nutrients in the upper water layer
3.6 Vertical profiles
3.7 Nutrient accumulation in the hypolimnion
4 Summary
5 Acknowledgements
6 Glossary of abbreviations and terms
7 References