Greater Wellington (GW) routinely monitors water quality in two lakes in the Wellington Region, Lake Wairarapa and Lake Ōnoke. Monitoring in Lake Wairarapa commenced in 1994 and the programme remained largely unchanged until 2012/13 when changes in monitoring frequency and some site locations and variables were implemented (see Cockeram & Perrie 2013 and Cockeram & Perrie 2014). Water quality monitoring in Lake Ōnoke was established in 2009. Additional shorter-term targeted water quality monitoring and “one-off” sampling, including zooplankton communities, has also been undertaken in other lakes in the Wellington Region (see Perrie & Milne 2012; Perrie et al. 2015; Duggan 2022; Perrie & Royal 2022).
In 2011 assessments of ecological condition, based on submerged macrophyte community structure and composition, were introduced for Lakes Kohangapiripiri, Kohangatera and Pounui. Assessments of macrophyte communities, termed LakeSPI (Submerged Plant Indicator) have since been expanded to other lakes and lagoons in the Wellington Region: Bartons Lagoon, Boggy Pond, Lake Nganoke, Lake Ngarara, Lake Waiorongomai, Matthews Lagoon and Turners Lagoon (de Winton et al. 2022). LakeSPI assessments are planned to occur every three-five years.
Drag and scroll on the map to move and zoom in on areas of interest and hover on the site circles to see more information. See the methods pages for the Trophic Level Index (three-year; 2020-2023) and LakeSPI assessments for details on how the classes in each hover label are assigned.
State assessments presents current lake status as assessed by the Trophic Lake Index (TLI), GW Natural Resources Plan (NRP), and National Policy Statement for Freshwater Management National Objectives Framework (NOF). Links are provided with each for more information.
Trend assessments estimates the rate of change and direction of key lake water quality data at each site over periods of 5-, 10-, 15-, and all available- years.
LakeSPI assessments includes assessments of submerged aquatic plant communities using measures of diversity from the presence of key plant communities, the depth of vegetation growth, and the extent that invasive weeds are represented.
Supplementary data provides annual summaries of dissolved oxygen, water temperature, pH, conductivity, visual clarity, turbidity, suspended solids, chlorophyll a, and dissolved and total nutrients.
Our web report may be cited as: Greater Wellington (GW). 2023. Lake water quality and ecology annual report 2022/23 – Web report. Downloaded from https://www.gw.govt.nz/environment/environmental-data-and-information/water-monitoring/.
A static PDF version of this report can be viewed and downloaded here. Previous years’ PDF reports are available in the GW document library.