This page provides an overview of the Rotorua Te Arawa Lakes Programme which is restoring the water quality of the Rotorua Lakes (Rotorua, Rotoiti, Ōkāreka and Rotoehu). The programme runs to 2032.
Rotorua, Bay of Plenty
Bay of Plenty Regional Council, Rotorua District Council
Te Arawa Lakes Trust
To restore the Rotorua Lakes (Rotorua, Rotoiti, Ōkāreka and Rotoehu) to address water quality targets agreed by the community, by addressing nutrient run-off into the lakes.
The Rotorua Te Arawa Lakes are of national importance as a tourist destination. Lake Rotorua alone welcomes over half a million international visitors each year. The lakes are also of special importance to the Te Arawa people and the health of the water is essential to their well-being.
Over the past few decades the water quality of the lakes deteriorated dramatically due to:
- sewage discharge from lakeside communities
- changes to land-use practices
- large amounts of nutrients stored in the bottom sediments (from historical practices such as the discharge of treated sewage into Lake Rotorua)
- nutrient enrichment of groundwater aquifers from historical farming practices (which will continue to feed into the lakes over the coming decades).
This has stimulated algal blooms and weed growth. Algal blooms significantly reduce the amenity value of the lakes, pose a risk to human health and regularly result in lakes being closed to swimming and fishing.
In March 2008, the Crown committed $72.1 million for the implementation of the Rotorua Te Arawa Lakes Programme (50 per cent of the project cost) through to 2032. The Ministry for the Environment administers the Crown's funding commitment.
The lakes' water quality issues are being addressed by:
- sewerage reticulation of lake-side communities
- phosphorus-locking (alum-dosing) -an engineering solution
- ongoing harvesting of lake weeds
- construction of floating wetlands
- a planned geothermal nutrient removal plant
- establishment of aeration devices to help stop the release of nutrients from the lake-bed and help prevent algal blooms
- land management change to reduce runoff of sediments and nutrients
- permanent land use change by gorse clearing and conversion of land to low nitrogen land use.
Progress update – February 2017
Water quality in Lake Rotorua continues to improve, due in part to phosphorus-locking (alum-dosing) engineering solutions.
The next steps are to reduce nitrogen entering Lake Rotorua through:
- a change to the Bay of Plenty Regional Council regional plan which introduces rules to enable a reduction of nitrogen from dairy and dry stock farming.
- a $40 million incentives fund to support land owners transition towards permanent low nitrogen land use.
- a $2.5 million fund to support the conversion of land from gorse into trees
- the Tikitere Geothermal Treatment Plant which will remove nutrient inputs from geothermal activities from entering Lake Rotorua.
Water quality has continued to improve in Lake Rotoiti since the installation of the Ōhau diversion wall and sewage system upgrades.
The next step is to secure a new resource consent for the Ōhau diversion wall
Water quality in Lake Rotoehu continues to improve through weed harvesting and phosphorus locking.
The next step is to continue community engagement to explore future water quality initiatives for the Lake Rotoehu catchment
Water quality in Lake Ōkāreka is stable but still below water quality targets following the completion of all interventions approved to date.
The next steps are:
- continued monitoring of lake health
- implementation of the Lake Okareka Land Use Change Programme through the monitoring of nitrogen loss rules, and support of land use change towards low nitrogen loss options.