Tauranga City Council is being accused of incompetency after slope hazard warnings were added to property files based on outdated and inaccurate information.

Tauranga’s Urban Task Force, who represents the city’s property owners, developers and business communities, says land sales are now falling through and settlements are being withheld on business land until the mapping errors are resolved.

Many property owners are unaware their Land Information Memorandum has now been tagged as having a slope hazard and UTF wrote to council’s commissioners last month to request an urgent meeting.

But Commission Chair Anne Tolley declined, saying it was not a governance issue.

“If council’s governance cannot ensure staff are doing their jobs with a duty of care, based on accurate information, and are being responsible and upholding integrity within our community, then this does fall from the top,” argues UTF Chair Scott Adams.

“There are massive implications if the accuracy of the data is not correct. 

“Some of the areas concerned, such as the new GIB factory in Tauriko, are now flat as a pancake.

“But TCC have put this slope stability clause over the property.

“The maps are clearly wrong and inaccurate, and this extends into the wider Tauriko Business Estate where numerous sites are included on the maps which contain no slopes,” says Scott.

“The slope hazard zone maps referred to are an update of maps created 20 years ago and are an important tool for proactive land use planning,” says Tauranga City Council infrastructure general manager Nic Johansson.

“For the majority of properties in Tauranga, this data already existed on the property LIM and the 2023 data is an update to that.

“Over 13,000 letters were sent to property owners explaining the slope hazard zone updates and Council held drop-in sessions which were very well-attended, providing an opportunity for property owners to talk to a range of technical experts.”

Property owners began receiving letters in early October from council advising that mapping information had been updated and their property was now subject to a slope hazard.

Slope hazard maps identify areas of either existing or potential slope instability.

Landslides could occur in heavy rain or earthquakes, or during land development activities such as earthworks.

Council is required to identify natural hazard risks to support appropriate land use planning and development decisions, and all hazard information must be made available to the public under the Local Government Official Information and Meetings Act 1987.

Notes have therefore been included on affected property’s LIM reports which could affect property values and insurance.

“The updated slope hazard zone maps are based on LiDAR data captured in 2019 as this was the latest available data when the slope angle maps on which the slope hazard zone maps are based were produced,” says Nic.

“The slope hazard zone maps do not supersede Geotechnical Completion Reports or any other site-specific mitigations or geo-professional reports undertaken for the property.

“This is covered in LIM reports with a statement that any further development may need to be supported by a report from a Category 1 Accredited Geo-professional and subject to Storm water Specific Design.”

UTF generally supports the council’s initiative to display known and proven natural hazard records, and to appropriately identify and update slope hazard maps.

“However, our review of this recent mapping leads us to conclude that there are a number of problems with the accuracy of the maps and the duty of care applied by both the consultants and the council staff involved,” says Scott.

“We consider that, if the mapping is to be used, then the council must ensure the mapping is accurate, correct and is based on the most recent and up-to-date information available.”

UTF believes the new maps use outdated data from 2019 which overlooks recent development at places like Tauriko.

“Clearly there is a question to be asked around competency here, as council staff are fully aware that the area has been redeveloped through recent subdivision resulting in significant landform change to create flat residential building sites supported by Geotechnical Completion Reports which certify the lots.”

Commission Chair Anne Tolley says UTF’s criticism of council governance is uninformed.

“The issues UTF has raised are highly technical and should properly be dealt with by geotechnical professionals.

“Council staff with the appropriate professional backgrounds were already scheduled to meet with UTF early in 2024 and the requested meeting would not have achieved any useful outcome.

“Rather than making overblown claims, UTF should focus on working cooperatively with the people who can address and resolve their concerns.”

Scott says these GCR reports contain site-specific information including slope assessment and a description of works and any mitigation measures.

“The GCR reports supersede the slope hazard mapping and should be referred to in the first instance.

“It seems that these have been ignored in relation to all mapping,” he says.

“Slope hazards are also subject to other factors apart from the gradient of the slope.

“Geological profile, vegetation, drainage, and engineered improvements are all relevant considerations which have been ignored instead of being verified through a proper site assessment process.”

Similar concerns were raised by UTF about council’s recent Plan Change 27 to address flooding across Tauranga city.

The accuracy of that data was also questioned, and areas such as Kennedy Ridge at the Lakes is now acknowledged as a ‘reassessment area’.

The same subdivision is now subject to inaccurate slope hazard mapping as well, with UTF calling it a “double whammy” for the developers concerned.

“The property development community is deeply disturbed by these inaccuracies and UTF members now face significant costs as a result, including sales needlessly falling through.

“This is a serious issue which must be urgently addressed.

“Natural hazard mapping must be done with care, using the latest accurate land-based information so people can trust the information on LIM reports is 100 per cent correct.

“We urge council and the commissioners to take responsibility for this issue and immediately fix the problem they have created.”

“For the majority of properties in Tauranga, this data has existed on the property LIM for 20 years and the 2023 data is an update to that,” says Nic.

If someone is selling their property and has concerns about a slope hazard zone on the property, they can email Council at [email protected] or call us on 07 577 7000.