Groundwater-dependent ecosystems: the where, what and why of GDEs

TLDR: Groundwater resource managers commonly ask how much water can be taken from the aquifer while still maintaining a low level of risk to GDEs, and recommendations are generally made by defining the acceptable level to which groundwater can be allowed to fall, while maintaining important environmental values.

Abstract: Until the early 1970s, the management of water resources in Australia was predominantly concerned with the assessment, development and harnessing of new water resources for irrigation, urban and industrial, stock and domestic water supply. The consequences of excessive and unsympathetic groundwater abstraction on groundwaterdependent (phreatophytic) vegetation, such as tree decline and mortality, have been observed throughout Australia (Arrowsmith 1996; Hatton and Evans 1998; Clifton and Evans 2001). With increasing demand for water and a changing climate regime, the need to mitigate the environmental impacts of groundwater development is increasing. Current borefield operation in Australia is largely responsive to consumption demand and often in conflict with environmental needs for groundwater, resulting in drought stress and sometimes death of phreatophytic vegetation and other impacts on GDEs. Groundwater resource managers commonly ask how much water can be taken from the aquifer while still maintaining a low level of risk to GDEs. This requires quantified information on the relationship between the health of a GDE and groundwater depth (or other parameter; see Eamus et al. 2006a). Recommendations are generally made by defining the acceptable level to which groundwater can be allowed to fall, while maintaining important environmental values (see Murray et al. 2006). The Council of Australian Governments (COAG) endorsed reforms in 1994 to achieve a sustainable water industry that included allocations for the environment