Climate change impact on groundwater resources in Australia: Summary Report

[摘要] Over the past few decades, much of Australia has experienced increasing pressure on groundwater resources due to a drier climate and increased scarcity of surface water. In 2004 the Council of Australian Governments agreed to form a National Water Initiative (NWI) to ensure the implementation of a transparent planning framework that would avoid over-allocation of water resources, including groundwater. Under the NWI it is necessary to incorporate risks associated with climate change and variability in water management plans. In response to these issues, the National Water Commission established a project, ‘Investigating the impact of climate change on groundwater resources’, within the National Groundwater Action Plan (NGAP). The primary objective of the project was to determine how projected climate change will impact on groundwater recharge and groundwater resources across different aquifer types in different climatic types across Australia. The project was undertaken by CSIRO in collaboration with SKM.Climate change is of most concern where aquifers are heavily allocated or particularly vulnerable to changes in recharge. In these systems a reduction in water availability due to climate change may impact on groundwater use and entitlements. The impacts of climate change are also likely to be more profound for unconfined aquifer systems, which may respond rapidly to changes in the recharge regime. The relationship between climate and confined aquifer systems is often muted. In addition to consumptive use in many regions, a rich biodiversity of both national and international significance is associated with groundwater-dependant ecosystems, which may also be impacted by changes to groundwater resources due to the effect of a changing climate.This summary report covers the main findings of the project and discusses the historical climate in Australia, its effect on diffuse recharge, future climate projections and their likely effect on renewable resources (both diffuse and localised recharge), sensitivity of the Australian aquifers to climate variability and changes, and modelling the future climate change impact on groundwater resources. Key challenges in providing a national contextual statement on groundwater resources and climate change include: sparse information on aquifers; poor understanding and quantification of recharge and discharge mechanisms; lack of spatial appreciation of the connectivity to streams; and unknown interactions with groundwater-dependent ecosystems. Most groundwater management is based on long-term average recharge to the system. The effect of short- and long-term climate variability on groundwater resources is even less clear, both in terms of groundwater recharge and discharge, which includes the groundwater uptake by vegetation. This variability is compounded by potential climate change, which is currently not considered in regional development plans.

[发布日期] 2011-07-01 [发布机构] CSIRO

[学科分类] 地球科学(综合)