Lake Okareka

Lake Okareka

Lake Okareka

Its name means "the lake of sweet food". In early times, Maori grew sweet potatoes or kumara around the outside of the lake. The lake is now a very popular recreational resource and residential area.

Lake Okareka has reasonably clear, clean water and is used extensively for recreation such as boating, swimming and fishing. However, the quality of the water has been affected, over time, by land use in the catchment. Nutrients have been introduced to the lake from surrounding farmland, residential septic tanks and from the release of existing and accumulated nutrients from sediments on the lake bed. These nutrients have affected lake water quality.

At a Glance  
Lake size: 340 ha
Catchment area:  1980 ha
Elevation: 355 m
Average depth: 20 m
Deepest point: 34 m
Formed:  19,000 years ago
Drains to Lake Tarawera via Waitangi Springs and an artificial surface channel  

 

Water Quality Status

Water quality for Lake Ōkāreka has improved as a result of completing actions specified in the Lake Ōkāreka Action Plan for the lake, including sewerage reticulation and land use change. While the lake does have stable water quality, it has remained slightly above its target Trophic Level Index of 3, at 3.3 for a number of years now. The University of Waikato is currently undertaking further modelling to determine the reductions required to bring the lake to its target Trophic Level Index.

 

Catchment Map

Click here to view image of map

 

Target and Results

To meet community expectations for Lake Okareka's nitrogen inputs need to reduce by a total of 2,500 kilograms and phosphorus to reduce by 50 kilograms per year.

Water Quality target 

3.0

2015 result

3.3

2016 result

3.2 

 

 

 

 

 

Total Annual Nutrient Reductions Required (according to current Action Plan)

 

Nitrogen

Phosphorus

Target

2.5 Tonnes

80 Kilograms

 

 

 

 

Nutrient information

  Nitrogen Phosphorus
Total load 10.5 Tonnes 130 Kilograms
Target 8 Tonnes 80 Kilograms

Actions and achievements

Water quality for Lake Ōkāreka is stable. 

All actions have been completed and the nutrient reductions required by the Lake’s Action Plan have been achieved. However, the lake stubbornly remains slightly above its target Trophic Level Index and further work is being done by the University of Waikato to establish further required nutrient reductions in the catchment. In the mean-time the Regional Council has allocated funding between 2016 and 2019 to achieve further nutrient gains from land use change the catchment. Staff will shortly be commencing a project to confirm current nutrient loss from land use in the catchment and look for further opportunities for reducing this through voluntary agreements with landowners. Staff will be talking to the community about this project over the last six months of 2016.

Action

Achieved as at June 2016 (Annually)

Status

Land use

1.18 T N
0.22 T P

Agreements in place and monitored.

Sewerage reticulation

2.84 T N
0.24 T N

Sewerage reticulation is complete.

Action Plan Progress

The reductions in nutrients from land use change and sewerage reticulation outlined above have exceeded those targets set in the Lake Ōkāreka Action Plan (also outlined above). However, the lake remains stubbornly above its target Trophic Level Index and the Programme is committed to removing more nutrient from the lake over the next three years from 2016, with the aim of improving the lake further to achieve its target Trophic Level Index of 3.

Read Lake Okareka Action Plan