Supplementary data for NZJGG Waiwera paper 2024

Over-use of the Waiwera geothermal system caused natural beach springs to cease flowing in the 1960s. The main user of geothermal water in the area, Waiwera Thermal Resort, closed in February 2018, and there is now evidence of the geothermal system rapidly recovering pressure resulting in artesian conditions and causing both existing users’ bores and abandoned bores to overflow. An Unmanned Aerial Vehicle (UAV) mounted with a thermal infrared (TIR) camera was used to verify that artesian beach hot springs have re-started discharging geothermal water by quantify the spatial distribution and temperature of beach hot springs and compare results to a 2019 TIR survey. The UAV study found that the artesian conditions at Waiwera have resulted in the reactivation of the springs at the beach. Direct observations of flowing warm water fractures on the shore platform have measured spring water temperatures of between 15°C and 34.4°C. Some springs have increased in temperature between Oct 2019 and May 2022 TIR surveys. The thermal anomalies observed, are unconnected to overland flow from stormwater drains. While the temperature is not at the level observed historically some simple energy conservation methods may allow the springs to return to their historic recreational use. Repeated TIR surveys demonstrated at Waiwera are a cost-effective management tool, helping to understand the recovery of artesian flow in low temperature systems and shows how repeat TIR surveys can be used in ongoing management of surface features when combined with groundwater level monitoring.