Thermal UAS survey of reactivated hot spring activity in Waiwera, New Zealand

Abstract

Abstract. The utilization of geothermal reservoirs as alternative energy source is becoming increasingly important worldwide. Through close-range aerial photogrammetry realized by unmanned aircraft systems (UAS), this study investigates the surface expression of a leaking warm water reservoir in Waiwera, New Zealand, that has been known for many centuries but remained little explored. Due to overproduction during the 1960s and 1970s the reservoir has suffered significant pressure reduction, which resulted in the loss of artesian conditions and led to the desiccation of the hot springs in close succession. However, shortly after the recent shutdown of the primary user (Waiwera Thermal Resort & Spa) renewed artesian activity was reported by locals but no hot spring activity has been observed so far. Therefore, this study was carried out in October 2019 to assess the actual conditions of thermal activity in the area of the former hot springs. UAS with coupled thermal infrared cameras were used for thermal mapping and the obtained data show renewed activity of the hot springs on the beachfront of Waiwera. Faults and fractures were identified as important fluid pathways, as well as individual fluid conducting lithologies.

Geographic Information System (GIS) as a basis for the next generation of hydrogeological models to manage the geothermal area Waiwera (New Zealand)

“…Within the presented study, we used QGIS, a free and open-source cross-platform desktop GIS (QGIS 2022, QGIS Geographic Information System, QGIS Association, http://www.qgis.org, last access: 4 November 2022). The available information in the form of data from previous studies (especially ARWB, 1980;Kühn and Stöfen, 2005;Kühn and Altmannsberger, 2016;Kühn and Schöne, 2017;Präg et al, 2020) has been extracted and integrated into the new hydrogeological model. Furthermore, geospatial datasets such as groundwater recharge and the delineation of hydrogeological units outcropped at the surface are retrieved from the database by the Ministry for the Environment (MfE, https://environment.govt.nz/, last access: 4 November 2022) of New Zealand and subsequently processed in the system.…”

“…However, shortly after the primary user (Waiwera Thermal Resort & Spa) shut down in 2018, local residents reported overflowing bores to the Auckland Council. Furthermore, there is indication for a renewed activity of the hot springs on the beach (Präg et al, 2020). This implies a progressing recovery of the geothermal system including the return to artesian conditions.…”

Deconvolution well test analysis applied to a long-term data set of the Waiwera geothermal reservoir (New Zealand)

“…As a consequence, the water level recovered over the following years and the initial problem of overexploitation became obsolete. With unmanned aircraft systems and coupled thermal infrared cameras data were retrieved which show a renewed activity of the hot springs on the beachfront of Waiwera (Präg et al, 2020).…”