Here's where you can find the details of all dangerous, flood-prone or earthquake-prone dams in Taranaki.
A dangerous, flood-prone or earthquake-prone dam is a dam with a medium or high potential impact classification – a measure of how much damage dam failure might cause – that is at risk of failure under certain circumstances. These circumstances are set out in the Building (Dam Safety) Regulations 2022(external link).
Taranaki Regional Council is required through our Dangerous Dams Policy(external link) to notify the public of any dangerous dams and work with dam owners of dangerous dams to develop an action plan to address dam risk. The Council also has powers under the Building Act 2004(external link) to intervene and undertake work if the dam owner does not.
Highlands Park Detention Dam
The Highland Park Flood Detention Dam has been declared a dangerous dam under the Building Act 2004 and has a high potential impact if it was to fail. The dam has been found to be at risk of overtopping and failure in a moderate flood event. The full extent of at risk properties is displayed in the below map. Different properties have very different levels of risk. In particular, the map here(external link) also shows if a dwelling is predicted to be impacted or not.
All persons are advised to not approach the dam during times of heavy rain.
New Plymouth District Council has developed an action plan to address dam risk, which has been approved by Taranaki Regional Council. Work is underway to reduce dam risk.
For further information please contact enquiries@npdc.govt.nz.
NPDC is working on fixing the issues with Highlands Park Dam, starting with investigating the options. We will know the timeline of work once NPDC’s plan of action is confirmed.
NPDC staff monitor the city’s dams every month, and third-party dam experts are engaged to undertake annual inspections and five-yearly comprehensive dam safety reviews. NPDC also has trigger levels to initiate increased monitoring if the dams, including Highlands Park, ever get near to full.
NPDC has a Dam Emergency Action Plan for the Huatoki, Mangaotuku and Waimea dams, and they are amending this to include emergency planning for the Highlands Park area. The action plan is part of an Incident Response Plan that addresses how NPDC will respond in emergencies, which is part of NPDC’s overall strategy to be prepared for any emergency in the district.
NPDC will also be required to include in the land information memorandum (LIM) for affected properties the flood potential in the event of the dam breaking.
An assessment done by Tonkin and Taylor assesses that between 11 and 100 people would be at risk in the event the dam failed, depending on the day and time. Dam failure would put 139 properties downstream of the dam in danger of being flooded to some degree, 53 of them with buildings that would likely be affected. The degree of this risk varies significantly from property to property, this detail is shown in the map.
While NPDC works on bringing the dam up to regulation, it is recommended that residents in affected properties prepare a flood response plan for their family or staff members if a flood alert is raised, so that they know what to do in an emergency. Helpful information is available online here: getready.govt.nz/prepared(external link).
All members of the public should also not approach the dam during periods of heavy rain and be careful downstream of the dam.