| Abstract |
The Bay of Plenty Regional Council (BOPRC) is in the process of reviewing its inventory of natural geothermal resources of the region and their geographical extent. This work provides the science base-knowledge for identifying and mapping the systems for the sustainable management of the geothermal resources through its planning framework, as well as to inform work for other Council areas like Consents and Compliance. This work identifies the key sources of information publicly available and outlines the methodology developed to identify and propose the geothermal system’ extent of the Bay of Plenty region. Two types of extents are suggested, tailored to the level of certainty around their geographical extent. Approximate extents are suggested when there is a reasonable level of certainty around its location, and inferred extents for when the level of certainty is moderate or low. Those different levels of certainty arise from variable levels of data availability, data quality and appropriateness of the data available for the purpose of this mahi. A high certainty is not considered achievable given the intrinsic complex hydrodynamics of geothermal systems and gradual lateral transition into cold groundwater systems, therefore none of the systems are proposed to be mapped with accurate extent. A distinction between geothermal systems and geothermal occurrences is also proposed and recommended, as well as the inclusion, exclusion and merging of some of the geothermal systems identified in the planning framework of the Bay of Plenty Regional Natural Resources Plan and Regional Policy Statement. This paper also highlights that a significant heterogeneity in the level of knowledge and data availability exists across the various geothermal systems of the region. Geothermal systems with high commercial and scientific interest like Kawerau, Rotorua and Waimangu, for example, have been extensively studied over time, while a lower level of knowledge exists for some of the other systems, like the offshore Moutohorā Island (Whale Island), the low-temperature systems like the TaurangaMount Maunganui (Mauao)-Pāpāmoa-Maketū system and, to some extent, most systems with significant environmental constraints for development, like Tikitere. |