Thames Land Subsidence Threat Ignored

While Dunedin Takes Action For Lesser Threat 

Parts of the foreshore of Thames are sinking at rates between 8 mm and 13 mm a year.  Thames Coromandel District Council and Waikato Regional Council are fully aware of the added risk from sea level rise this poses to low-lying subdivision suburbs such as Moanataiari.  But no further research has been undertaken.  Contrast this with Dunedin where the Councils have begun a comprehensive drilling program after discovering subsidence rates of just 1mm – 2 mm.


Here is a copy of the GNS Science letter to the Dunedin City Council requesting the drilling program.  With this key extract….

2mm a year

One of the keys questions the drilling would answer is “deep groundwater conditions and gradients of groundwater flow, and potential impacts on ground surface elevation, in regard to possible engineering options? For example, dewatering can cause compaction and exacerbate sea level rise effects, and upwards flow can make dewatering a difficult engineering challenge”

The issue even made TVNZ’s news bulletin in 2016 which cited the “dire consequences” for South Dunedin arising from the land subsiding at just 2mm a year and the added risk of sea level rise.


Meanwhile, Thames continues to sink at a rate 5 times faster than Dunedin and TCDC and the Waikato Regional Council have yet to take any steps to investigate this critical problem for the town. 

Months ago, I wrote to TCDC’s Chief Executive suggesting that the Council could ask for a local investigation of subsidence to be undertaken by taking advantage of an $8M government-funded “SeaRise” program which is researching vertical land movement and sea level rise around the New Zealand coast.  My request was “noted”.  My letter to local National MP Scott Simpson making a similar request has not been answered.

These are serious issues and require a serious response from our political leaders.  Sadly, at the moment they are looking the other way.