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Editorial: Coastal risk information should be on land reports once science is robust

high tide in Southshore June 2013  (by

Scientists rate highly in the annual surveys of the most trusted professions, not far behind stalwart teachers, pilots, health professionals and firefighters and a long way above the ignominiously ranked politicians and journalists.

If the public are to believe in scientists, and science, they need to trust their work is accurate and robust. The implications of science can have major repercussions on our lives.

The fallout from the Tonkin & Taylor report on Christchurch's likely coastal hazards is an example of what can happen when science is rushed, underfunded or badly communicated. In this case, conclusions from what has become a controversial document could affect thousands of city residents.

For residents of the 6000 homes classified as susceptible to erosion and the 18,000 at risk from inundation over the next 50 to 100 years, such figures added to their Land Information Memorandum (LIM) reports will have a huge impact on their ability to sell properties and may also affect future insurance premiums. This is what the Christchurch Coastal Residents United (CCRU) group has been railing against since July 2015's Tonkin & Taylor study.

In December, the Christchurch City Council appointed five experts to peer review that study, after those residents voiced concerns about the quality of the science. That panel of specialists has now endorsed parts of the report, albeit with significant caveats, saying given the city council only allowed Tonkin & Taylor 20 days to complete it within a limited budget, "simplifying assumptions" was only to be expected.

The panel, however, is critical of the report's mapping of coastal erosion hazard zones, fearing they could be "legally unsound" and has recommended extra research be done to produce new maps before they can be used for planning purposes.

Significantly, for residents, the panel told the council removing these initial maps from residents' LIMs was the best thing to do until more comprehensive ones were completed.

Generally you get what you pay for. For Tonkin & Taylor to get just 20 days to prepare a report with potentially such far-reaching consequences seems extraordinary. Notably, the review panel said the engineering company's researchers had for most of the assessment followed industry best practice. They had also based their work on generally conservative assumptions.

The residents' group is understandably cock-a-hoop at the panel's suggestion to remove the maps from LIMs. Spokesman Darrell Latham says the findings have justified the CCRU's appeal for "due process and fair procedure" and also confirmed the document did not constitute robust science.

Removing less-than-robust details from those residents' LIMs is the right thing to do. But once maps based on more rigorous research are produced, they should certainly be put on to land reports. Potential purchasers need clear, unequivocal guidance of all the risks that come with buying any property. Transparency is critical, as is an understanding that the risk, once established, does not disappear regardless of whether it appears in paperwork.

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