7.3 Issues and Objectives
Inefficient take, use and discharge can unnecessarily accelerate the rate of depletion of the Regional Geothermal Resource.
Take, use and discharge of geothermal energy and water can adversely affect Significant Geothermal Features.
Some land and water use practices in the vicinity of Significant Geothermal Features can cause significant adverse effects on the features.
Large takes of geothermal energy and water from any geothermal system may cause adverse effects on other natural and physical resources including overlying structures (the built environment), such as those resulting from subsidence and land instability.
The discharge of geothermal energy and water can contaminate fresh water to an extent that reduces its suitability for other uses and may significantly adversely affect the health and intrinsic value of fresh water ecologies generally.
A lack of information and knowledge about the Regional Geothermal Resource and effects of its use can create uncertainty for management of the resource.
Where geothermal energy and water is taken, it shall be used and managed efficiently.
In Development Geothermal Systems, significant adverse effects on Significant Geothermal Features arising from the take of geothermal energy and water to be remedied or mitigated within the Regional Geothermal Resource
In all Limited Development, Research, Protected, and Small Geothermal Systems, significant adverse effects on Significant Geothermal Features arising from the take of geothermal energy and fluid are to be avoided.
Significant adverse effects on Significant Geothermal Features arising from land use and the take, use and discharge of non-geothermal water to be avoided.
In Development Geothermal Systems, adverse effects on other natural and physical resources including overlying structures (the built environment), such as those resulting from subsidence and land instability, arising from the take, use, and discharge of geothermal energy or water to be avoided, remedied or mitigated.
In Limited Development Geothermal Systems, significant adverse effects on other natural and physical resources including overlying structures (the built environment) such as those resulting from subsidence and land instability, arising from the take, use, and discharge of geothermal energy or water to be avoided, remedied or mitigated.
Significant adverse effects on fresh water and land arising from the discharge of geothermal energy and water avoided.
Increased knowledge about the Regional Geothermal Resource, and better understanding of the effects of using the resource and effects of other activities on the resource.
Principal Reasons for Adopting the Objectives
In order to provide for the energy needs of current generations and the reasonably foreseeable needs of future generations, it is necessary to ensure that all the readily accessible geothermal energy is not wasted on inefficient and inappropriate uses, and that future generations have equitable access to the resource. Particular regard should be given to using the resource efficiently, otherwise more resources will be demanded, and additional environmental costs may occur. Once used in a primary process such as electricity generation, a geothermal resource may be of value to secondary uses, such as commercial, industrial and/or domestic processes. Such a cascaded use of the resource may contribute to the efficient use and development of that resource. Reinjection of used geothermal energy and water, where practicable, may also assist in ensuring that the remaining energy and water are not lost from the system and that reservoir pressures are sustained.
Objectives 2 and 3
Objectives 2 and 3 recognise that the take, use, and discharge of geothermal energy and water can have a significant adverse effect on Significant Geothermal Features. Distinctly different management approaches are required for those geothermal systems that are subject to development and those that are to be protected.
Objective 2 recognises that large-scale use of Development Systems may result in significant adverse effects on Significant Geothermal Features and requires remediation or mitigation of those effects. Remediation and mitigation can be undertaken on the Significant Geothermal Feature affected or on another geothermal feature of the same type in any geothermal system.
Objective 3 focuses on protection of the Significant Geothermal Features of Limited Development, Research, Protected, and Small Geothermal Systems. In order to maintain the extent and variety of the valued regional geothermal characteristics, it is appropriate to protect Significant Geothermal Features in Limited Development, Protected, and Small Geothermal Systems from significant adverse effects arising from the extraction of energy and water from these systems. In Research Systems, a precautionary approach must be applied to protect known and unknown features within each system and within any Protected System that may later prove to be hydrologically connected to it.
Objective 4 recognises that land uses and uses of non-geothermal water can have a significant adverse effect on Significant Geothermal Features, and seeks to avoid these effects. Historically, for example, the establishment of the Waikato River hydroelectric system artificially submerged a range of Geothermal Features such as most of the geysers at Orakeikorako, which are now under water as a result of the creation of the hydroelectric lake Ohakuri. Whilst the hydroelectric system has significant regional and national benefits, such effects on Significant Geothermal Features should be avoided for any future activities. For instance, some land uses have adverse effects on characteristics of the geothermal resource. For example, at Reporoa, land drainage for farming has caused some sinter-depositing springs to cease discharging. Forestry in geothermal areas can lead to geothermal features being damaged by trees falling into them and harvesting machinery destroying delicate sinter terraces. Allowing livestock or vehicles access to geothermal features, or using geothermal features as rubbish dumps can lead to a range of adverse effects including the crushing of fragile sinters and rare native plants, animals and micro-organisms.
In most cases, surface features that are part of a tourism venture are better cared for than those found in land that has other uses such as forestry and farming. Tourism can also increase appreciation of the resource and awareness of its fragility and rarity. However, extensive tourist use can lead to vandalism, wearing away of paths, and contamination of sinter by gravel and rubbish. Draining a feature or diverting its flow to protect paths can cause destruction of the feature and its ecosystem.
Objectives 5 and 6
Objectives 5 and 6 recognise that the take, use, and discharge of geothermal energy and water can have adverse effects on overlying structures (the built environment) and other natural and physical resources. These objectives achieve integration between the Geothermal and other Modules of this Plan and are implemented through policies and methods throughout the Plan.
In Development and Limited Development Systems it is important to ensure that adverse effects arising from the take, use, and discharge of geothermal resources are avoided, remedied, or mitigated, and that the cost of these actions falls on those who cause the adverse effects.
Objective 7 recognises that discharges of geothermal energy and water can have an adverse effect on fresh water resources from a water quality and ecological perspective. This objective achieves integration between the Geothermal and Water Modules of this Plan. It is consistent with the Water Module Section 3.2.3 Policy 3. Discharges to freshwater or land are not inconsistent with this objective if they are sufficiently remedied or mitigated so as to avoid significant adverse effects on the receiving environment.
Objective 8 recognises that where surface features exist, they provide only a very small indication of the extent of the resource and its hydrodynamic characteristics. Geophysical and geochemical techniques, as well as an understanding of the local geology, must be applied to enable understanding of the resource. Sustainable management of geothermal systems requires inputs from these disciplines, reservoir modelling and other disciplines to provide a useful model of system dynamics.
It is important that information be made available to support regional decision-making and policy direction, and to ensure that significant adverse effects on valued geothermal system characteristics are avoided, remedied or mitigated as appropriate.