Water warning for Rotorua as stream flows drop

The Ngongotahā Stream has reached its lowest recorded flow, for this time of the year, since records began in 1975. Photo / Andrew Warner.

The Bay of Plenty Regional Council is warning a water shortage may be impending in parts of Rotorua, with one stream hitting record low flows and others also drying.

The council has implemented Level 2 of its "water shortage event standard operating procedure" for some streams with headwaters in the west-southwest of Rotorua, and says water restrictions may follow.

The council said in a statement central and western parts of the region were experiencing dry conditions.

This had resulted in several streams near Rotorua experiencing very low flows. The Ngongotahā Stream has reached its lowest recorded flow, for this time of the year, since records began in 1975.

Both the Ngongotahā Stream and Paraiti (Mangorewa) River have had declining flows for some time.

The regional council is responsible for caring for the region's waterways and ensuring people's use of water is sustainable.

The Rotorua focus zone. Image / Bay of Plenty Regional Council

Bay of Plenty Regional Council water shortage event manager Steve Pickles said the region entered 2021 with lingering drought conditions from long-term rainfall deficits starting in early 2019.

"We came into this summer on the back of last year's drought, which we never recovered from, so there was always a high chance of low stream flows this year," he said.

"If we do not get some decent rain in the near future there is a risk that stream flows will shortly reach critical levels, and we may have to impose water restrictions on consented water users.

"The most affected area in the Bay of Plenty is currently waterways with their headwaters near the Mamaku ranges. It is most likely that the same processes affecting those streams are also reflected by decreased groundwater levels within the Rotorua geothermal system too," he said.

Under Level 2 of the water shortage procedure, the regional council will take additional flow measurements in affected waterways, increase assessment, analysis and reporting for the focus area, and talk to affected stakeholders.

The Bay of Plenty Regional Council's dry weather procedure. Graphic / BOPRC

"As advised last year, water users need to be preparing and planning for water restrictions if the dry weather conditions continue," Pickles said.

"Even though our initial focus is in the Rotorua area, other streams over the wider Bay of Plenty region are also dropping. So it is important that all water users plan for some possible disruption to their water supply this summer. This included all consented and unconsented water takers.

"Summer water restrictions may be needed in the near future; to protect our local waterways and the wildlife they support from harm during record low stream flows."

Across the region, everybody can also do their part to help to care for local waterways. Water users should check for leaks in their systems, and take steps to always use water as efficiently as possible to avoid wasting it.