Santamaria Cerrutti, M.E.; Mourot, F.; Westerhoff, R.S. 2021 Inventory of available data for hydrogeological investigations of the Aupōuri Peninsula, Northland. Aqua Intel Aotearoa report 2021/05; (GNS Science consultancy report 2021/98). 54 p. https://doi.org/10.21420/JQJR-CQ20
Abstract
This report has been co-developed by Aqua Intel Aotearoa (AIA; a collaboration between GNS Science (GNS) and the Kānoa Regional Economic Development & Investment Unit [Kānoa])and Northland Regional Council (NRC) for investigations of water storage and aquifer mapping in Northland. This Northland-based work is part of a larger project called ‘Aqua Intel Aotearoa Regional Water Storage Investigations’. Phase 3 of the AIA Regional Water Storage Investigations includes the assessment of the feasibility of airborne electromagnetic (AEM) geophysical surveying for aquifer characterisation in the Aupōuri Aquifer, Northland. This report informs the feasibility study by establishing an inventory of existing data available in the Aupōuri Peninsula and compiles relevant geological, hydrogeological and geophysical data, guided by four key features of interest in the study area established by NRC: presence of shell beds; depth to hydrogeological basement; groundwater–surface water interaction; and location and geometry of the freshwater–saline interface. GNS made a first assessment of the data from other projects, including Phases 1 and 2 of the AIA Regional Water Storage Investigations. Missing data was requested and provided by NRC. GNS also complemented NRC’s data with additional literature gathered via the GNS library or online. The obtained information comprises geological information (basement, structure, presence of shell beds or iron pans, lithological bore logs or relevant maps), hydrogeological information (aquifer hydraulic properties, groundwater levels, hydrochemistry, groundwater recharge, groundwater discharge, groundwater flows, freshwater–saline interface and groundwater and surface water interactions) and geophysical information (geophysical methods). A GIS workspace was developed using ArcGIS. Datasets were grouped into two main types, local and national, and into geological, hydrogeological and geophysical sub-categories. National datasets are relevant when local data is scarce or absent. The GIS workspace can be utilised in later project stages and updated when new information becomes available. It is recommended that NRC keeps this data inventory up to date with new references and other information not included in this work to (i) ensure that all of the available and new data is organised systematically, (ii) ensure that the state of knowledge for the Aupōuri Peninsula is well understood by interested parties, (iii) help prioritise new studies to fill information gaps and (iv) allow easy access to the information. It is also recommended that NRC’sexisting and new well logs are collected, digitised and stored under a standard approach, e.g. as developed in the National Bore Database Project, considering that lithological logs are important information for most geological, hydrogeological and geophysical investigations. (auth)
