Rotomā/Rotoehu lake levels
Road closure at Rotoehu
High lake level at Rotomā
Unprecedented rainfall this year has caused flooding and rising lake levels at Rotomā and Rotoehu.
Data shows the lake levels for Rotomā and Rotoehu are the highest since 1972 and are approaching records set in 1971.
This has impacted residents and resulted in flooding of roads and slips around certain areas of both lakes.
The situation has caused flooding of areas at Rotomā (Manawahe, camp ground in particular) and reserves and some properties at Rotoehu and raised the risk of other properties also being flooded. It has impeded access to properties (including due to flooding of the Rotorua end of Manawahe Road).
It has also resulted in infrastructure like jetties and ramps becoming submerged or floating and navigation aids have moved, creating hazards in/on the water.
Unlike other lakes, there are no river outlets in lakes Rotomā or Rotoehu and no outlet infrastructure in place.
There is a natural surface outlet from Rotomā into Rotoehu where water from the former would overflow into Rotoehu.
This has not happened in recorded history but is a possibility and this would cause flooding of land and dwellings at Rotoehu and potentially cut off access via Manawahe Road.
Longer term solutions will need to be considered but the immediate focus is on providing any assistance residents may require with people’s safety the primary concern.
The situation is being closely monitored and those who require assistance are being put in touch with Rotorua Lakes Council via an Incident Management Team set up to provide a single port of call for support for residents.
The Rotorua Te Arawa Lakes Programme partners, Toi Moana (Bay of Plenty Regional Council), Rotorua Lakes Council and Te Arawa Lakes Trust) are collaborating to provide any immediate assistance they can, alongside the Rotorua Lakes Community Board which is assisting with and facilitating community engagement and communications.
Waka Kotahi, local iwi and Whakatane District Council are also involved in providing support.
Residents who need assistance or have concerns or questions should call Rotorua Lakes Council on 07 348 4199.
15 September 2023
A reminder that road closures remain in place (update from Council Group Manager Infrastructure and Environmental Solutions, Stavros Michael):
Rotorua Lakes Council has determined that parts of Manawahe Road and Pongakawa Valley Road need to remain closed to all traffic until further notice for the public’s safety.
While the water level has receded, the fact they have been under water since June is likely to have compromised the structural integrity of these roads.
While Council appreciates that local residents are keen to have the roads re-opened as soon as possible, until the foundations of the road can be checked, which cannot happen until they are no longer under water, we cannot be certain that they are safe for traffic.
While the surface of the road may appear to be fine, we cannot currently check what is happening in the foundations.
The roads cannot be properly inspected and have any structural damage repaired until the lake levels fall below the level of the road.
It would be irresponsible of the council to re-open these roads until we can be certain they are safe. We would ask for your ongoing patience regarding this situation.
If you have any further questions or concerns please call (07) 348 4199.
17 August 2023
Council to consider rates remission applications for properties affected by high lake levels and deemed uninhabitable. There have been 9 applications received to date: Council meeting preview - Rotorua Lakes Council
23 August 2023
Council approves 100% rates remissions for properties affected by high lake levels that meet remissions criteria. More here from today’s Council meeting: Council decisions - Rotorua Lakes Council
- Bay of Plenty Regional Council presentation that was presented at a community meeting in May 2023 for residents of Rotomā and Rotoehu: Water Level: Lake Rotomā and Rotoehu (boprc.govt.nz)
- Rotorua Lakes Council provides information on its website about current road closures: Road Closures - Rotorua Lakes Council
- Waka Kotahi provides information on its website relating to state highway conditions and closures: Highway conditions for Bay of Plenty | Waka Kotahi Journey Planner (nzta.govt.nz)
- Bay of Plenty Regional Council collects environmental data from around the region to help inform decision-making and resource management: Maps and data | Bay of Plenty Regional Council | Toi Moana (boprc.govt.nz)
Please see FAQs below for further information. More will be added to these if/as needed.
Two groups have been established to manage the issues caused by the extremely high levels at Rotoehu and Rotomā.
The Rotorua Lakes Council-led Rotoehu – Rotomā Response Team (RRRT) is focused on;
- Coordinating the response for requests for assistance from impacted residents, such as requests for sandbags or rates relief.
- Providing a ‘single point of contact’ for residents and property owners in Rotoehu and Rotomā. All requests should be made to Rotorua Lakes Council (07-348 4199). Council staff will triage calls and ensure callers are linked up with the appropriate service or agency, depending on their needs.
- Maintaining an overview of day-to-day, impacts and operational matters in respect of high lake levels in Rotoehu and Rotomā catchment.
The team is following Coordinated Incident Management System (CIMS) principles in terms of the structure of the response effort.
Another working group has been established by the Te Arawa Lakes Strategy Group which oversees the Rotorua Te Arawa Lakes Programme [CLICK HERE to see more about the lakes programme] at its quarterly meeting in June 2023 approved the establishment of a group to scope foreseeable climate change effects on lake levels, to explore a range of possible interventions/approaches and based on a set of criteria including cost/benefit analysis develop adaptation and mitigation options for the Te Arawa lakes communities.
This group comprises representatives from the lakes programme partners Te Arawa Lakes Trust, Rotorua Lakes Council and Bay of Plenty Regional Council, plus regional leads for Crown agencies such as Waka Kotahi and representatives from local iwi groups.
The scope and terms of reference for this working group will be reported to the Strategy Group in September and its on-going progress reported regularly to the partners in the Strategy Group.
Heavy rainfall causes flooding and other water quality issues, such as nutrients flushed and leached off land, which can impact lakes negatively.
Winter is usually when a natural increase of lake levels occurs, however a wet summer and multiple cyclones have made them higher than usual. Climate change will likely make these extreme weather events more common.
Persistent high lake levels are generating a range of issues including:
- Erosion at the lake margins;
- Raised groundwater levels;
- Undermining of embankments and road foundations;
- Increased infiltration of water into the wastewater network;
- Increased flood risk due to higher tail water (at river mouths and upstream of elevated lake levels).
High lake levels raise the groundwater table in areas near the periphery of the lake. This has the following implications:
- Increased water infiltration into the wastewater network, creating challenges with effective treatment and final disposal costs;
- Reduction in the rainfall infiltration capacity of the land where the groundwater table is elevated, resulting in higher volumes of rainfall runoff at higher concentration velocities during storm events and reduction in infiltration rates for any soakage systems;
- Groundwater coming into contact with wastewater disposal fields for septic tanks which can cause contamination;
- Can cause challenging geotechnical issues such as rate of settlement or dampness under buildings and foundations;
- Warm water has been coming to the surface in some areas as Lake Rotomā has risen. There has been so much rainfall, that the saturation of the groundwater is forcing warm water to the surface. There is naturally geothermal activity in this area at depth and the high rainfall and high lake levels have recharged groundwater in the area to saturation, which forces the warm water to the surface. The warm water is also bringing other minerals up from deeper areas, evident by orange coloration that is typical of water containing high levels of iron.
Implications on flooding and stream processes
High lake levels reduce the velocity of the stream flows entering the lake. This encourages sediment to be deposited at the stream mouth, further reducing the hydraulic capacity and potentially worsening flooding.
Sustained high lake levels increase the risk of shoreline erosion due to wind waves. Uncertainty in the range of lake levels is a factor in landowners (including RLC) opting to construct hard erosion protection structures such as rock revetments.
Bay of Plenty Regional Council data shows us that the current lake levels for Rotomā and Rotoehu are the highest they have been since 1972 and records set in 1971. This is due to the recent cyclones and ongoing rainfall.
Some lakes, such as Lake Tarawera, have a natural surface outlet and can handle rainfall without large increases in level. Lakes without a natural surface outlet do not have the same ability to drain and they respond to rainfall by rising in level.
Lake Rotomā has a natural surface outlet to Rotoehu, but the lake would need to reach a higher level than previously observed, before it will flow. The height of the surface overflow is a natural land formation.
Lakes Rotomā and Rotoehu do not have river outlets and therefore can have large lake level fluctuations. Rotomā can fluctuate in response to wet and dry seasons.
For Rotomā to surface flow into Rotoehu, it would need to rise around 750mm further to follow the natural overland flow path between the lakes. This has not happened in recorded history and is likely to further significantly impact the levels of Rotoehu.
Options for control of lake levels were investigated in the 1970s, but due to the challenges and cost of options, they were not taken forward.
- Remove items from your property now, including sentimental or valuable items. If people live in your property, they will need to consider where they will go should the property become uninhabitable and/or access be impeded.
- If you require assistance with finding somewhere to live, please contact Rotorua Lakes Council. Phone (07) 348 4199 or email email@example.com
- Please avoid contact with the water, if you need to have contact with lake water take reasonable precautions to protect your health. Rotoehu dwellings are not connected to sewerage reticulation and many septic tanks are now under water.
- Consider now whether temporarily raising your house is an option and consider talking to your insurer. Regional Council can recommend floor levels for raising your house. Please do not hesitate to contact Council staff or Phill Thomass (Lakes Community Board Chair) using the contact details below to discuss your concerns, we will assist as we can to meet your specific needs.
- Rotorua Lakes Council contractors have closed parts of Manawahe and Pongakawa Valley Roads to all traffic until further notice. Local residents looking for alternative routes can use Maniatutu/Rotoehu Roads or the usable part of Pongakawa Valley Road via SH2.
- Follow (1) Waka Kotahi NZ Transport Agency Waikato BoP | Facebook for all roading and access updates. Plan your journey before you go by using (www.journeys.nzta.govt.nz/journey-planner).
- Be aware that infrastructure in the lakes has become submerged, creating new underwater hazards and leaving some ramps unusable. What were fences, seats and signs are now underwater hazards. Boat users planning to head to the lakes must check if ramps are open ahead of time.
- The high water has moved many navigation aids such as the 5 knot buoys. Toi Moana Maritime team are working to get these reinstated, but while this is happening, please remember to observe the 5-knot rule within 200m of shore and to keep your eyes peeled for unexpected hazards.
- When putting your boat in the water, take care not to hit signs and supporting structures. While navigating the lake edge, keep an eye out for sunken structures. Keep an eye out for floating debris, including logs and broken structures.
- Consider how your wake is affecting property, as many areas are suffering flooding and erosion from wave action.
Remissions are possible from both Bay of Plenty Regional Council and Rotorua Lakes Council if your house is uninhabitable. Applications are considered on a case-by-case basis.
Please contact Helen Creagh at Bay of Plenty Regional Council for regional council remissions (firstname.lastname@example.org or 0800 884 880.
Contact Rotorua Lakes Council via the customer contact centre - phone 07 348 4199 or email email@example.com
Please note that the councils will share information to ensure a consistent approach.
If you can stay in your property but cannot use the septic system, check with your insurer about the possibility of providing a port-a-loo.
Yes, please contact Rotorua Lakes Council. Please note, however, that sandbags will not be effective in all situations. Please contact the Council to discuss.
We do not believe so as they are sealed systems. We know some people are concerned that water can get in and out of them, and RLC is carrying out inspections of properties where lake levels are close to inundating these systems. If you have specific concerns about your system, please contact Rotorua Lakes Council to arrange an inspection of your system to ensure it is working as it should.
The Rotorua Lakes Council building compliance team is considering its responsibilities in terms of the Building Act.
Bay of Plenty Regional Council has been undertaking testing of water at Kennedy Bay and Ōtautū Bay for e-coli to make a basic assessment of the risk and the effect that the inundated septic tanks may be having.
Initial results have not shown reason for concern. However, this could change so we recommend people take reasonable precautions if they must enter the lake by washing hands and clothing after contact.
The sewer mains and pump stations are installed for a reticulated system at Rotoehu. However, more funding is required for the installation and connection of the on-site systems at each property to the mains so the connection cost for individual properties is affordable.
No, there is no evidence of this. The regional council believes that the overflow point is the natural landform level. Erosion protection was installed downstream of this overflow point in the early 1970s (when the lakes were previously this high) to protect from erosion and scouring if an overflow occurs.
Is Bay of Plenty Regional Council activating the consent from the 1970s to lower the level of Lake Rotomā by altering the level of the surface overflow point from Rotomā?
No. That consent (Water Right) has a condition which says it cannot be activated if the level of Lake Rotoehu is not under control, so the consent will not be used. There is no evidence that the level of surface overflow from Lake Rotomā has been modified, therefore if Lake Rotomā does overflow, it does not require a resource consent as there has not been human intervention in that.
The overflow point has been cleared and inspected by an engineer who has advised some remedial works including further rock armouring and vegetation clearance. Pictured below; BOPRC staffer working on clearing overflow point.
From springs (groundwater), presumably fed by Lake Rotomā. There is currently no surface overflow (ie overflow from the lake itself).
Once Lake Rotomā gets to the natural point of overflow and starts a surface overflow to Lake Rotoehu, is it expected to get any higher than that?
No, we expect that at or about RL 318.21m is the maximum height of Lake Rotomā, at which point it will start to overflow over the natural landform height to Rotoehu.
Due to the rising lake levels at Rotoehu, Rotorua Lakes Council contractors have closed parts of Manawahe Road and Pongakawa Valley Road to all traffic until further notice.
Residents looking for alternative routes can use Maniatutu Road/Rotoehu Road or the usable part of Pongakawa Valley Road via SH2.
Yes, all local emergency services are aware that parts of Manawahe and Pongakawa Valley roads have been closed and have put contingency plans in place accordingly.
Local police, fire and ambulance commanders have also confirmed they will proactively take the situation in Rotomā and Rotoehu into consideration when deciding on the fastest way to deploy emergency staff to these areas.
However, as the staff working in call centres for emergency services are based outside of Rotorua, we recommend that if a resident from Rotomā or Rotoehu needs to make a 111 emergency call they mention the road closures.
Personal preparedness for an emergency is also vital, particularly for those living in non-urban locations. You should have a list of contact numbers for nearby neighbours who might be able to help or may need help.
Ensure you have working smoke alarms and basic firefighting equipment such as a fire blanket and fire extinguisher.
If you are on medication ensure your prescriptions are up-to-date and refill these well in advance of running out.
Keep relevant medical documents such as a recent discharge summary or advance care plan, readily accessible and close to hand. Store all of this information in a safe but prominent place. It is recommended keeping this information on the fridge door or alongside your medication.
Hato Hone St John area operations manager Hōri (George) Clicquot recommends that Rotomā and Rotoehu residents consider undertaking a community First Aid course, or CPR course. Effective CPR is the foundation to saving lives during a cardiac arrest. A defibrillator is the next layer of intervention,but does not supersede high quality CPR.
Waka Kotahi, which manages state highways, will do its best to keep this route open. There are some complex remedial issues. The safety of those using the Highway is of utmost importance. Please follow signage, drive carefully and be patient.
Legislation protects the right of trucks to use roads.
This is currently being rectified.
Yes. Waka Kotahi and Council will make sure that schools and the community are advised of road/highway closures. We recommend people join the Lake Rotomā Community Facebook page as it is a useful way to get information in a timely manner and for residents to help and support each other.
Fulton Hogan has been asked by Rotorua Lakes Council to keep this road well maintained. Some of it is maintained by Western Bay of Plenty District Council as it is the boundary of the two Districts and the Western Bay of Plenty District Council contractor is different. Rotorua Lakes Council will follow up with Western Bay of Plenty District Council about this. Please raise any issues directly with the Councils.
Only the first section of Hamilton Road is a public road administered by Rotorua Lakes Council. The purpose of this 'no exit' road is to provide access to Department of Conservation (DoC) land, so people can enjoy the amenity of the native reserve. The track that carries on through the DoC land is a 'private road' for use by DoC staff and is neither designed or intended to be a public thoroughfare.
Yes. Rotorua Lakes Council will continue to ensure the water supply is treated to the required standard and will let the community know if this changes at any time.
Lake water should not be consumed without treatment. Speak to a water treatment company to install treatment.