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.怀韦拉（Waiwera）地热系统的过度开发，导致该区域天然海滩泉在20世纪60年代停止涌流。作为该区域地热用水的主要运营方，怀韦拉温泉度假村（Waiwera Thermal Resort）于2018年2月关停；如今已有证据表明，该地热系统的压力正快速回升，形成自流工况，致使现有用户的地热钻井与废弃地热钻井均出现溢涌现象。本研究采用搭载热红外（thermal infrared, TIR）相机的无人机（Unmanned Aerial Vehicle, UAV），通过量化海滩热泉的空间分布与温度，并将实测结果与2019年热红外勘测数据进行对比，以验证怀韦拉海滩自流热泉是否已重新开始涌出地热水。此次无人机勘测结果显示，怀韦拉区域的自流工况已促使海滩热泉重新活化。对潮间带平台上涌流的暖水裂隙进行直接观测后，测得热泉水温介于15℃至34.4℃之间。对比2019年10月与2022年5月的热红外勘测结果，部分热泉的水温已出现上升。本次观测到的热异常现象，与雨水排水管的地表径流并无关联。尽管当前水温尚未达到历史观测水平，但通过一些简易的节能手段，或可使这些热泉恢复其历史上的休闲利用价值。怀韦拉区域的重复热红外勘测实践表明，该方法是一种兼具成本效益的管理工具：既有助于解析低温地热系统的自流恢复进程，也展示了在结合地下水位监测的前提下，如何通过重复热红外勘测对地表特征进行持续性管理。