The National Framework for Improved Groundwater Management in Australia in 1996 (ARMCANZ, 1996a) set in train subsidiary policies and legislation in the states. Core recommendations were to publicly identify sustainable yield, allocation and use of aquifers as well as limit allocations to sustainable yields. Others included the enablement of trading of groundwater licences; improved integration of surface and groundwaters; management and licensing of high-yielding wells and provision of all drilling data by contractors; provision of funding for investigation in high-priority areas; and the introduction of full recovery of the costs of managing groundwater.
This framework resulted in tangible outcomes in terms of the definition of 72 groundwater provinces, and 538 groundwater management units, with associated water resources assessments and the initiation of groundwater management plans. Preliminary definitions of groundwater provinces and some management units go back to definitions made in the Water Review (1985), but these had only been partially developed. Figure 15.1 shows a summary of the degree of abstraction relative to sustainable yield in the groundwater
Groundwater management unit development categorization by use (2000)
■ Greater than 100% Between 70% and 100% Between 30% and 70% Less than 30% No data Groundwater management units
Data sources: National Land and Water Resources Audit (2000) - Water resource assessment database
Caveat: Data used are assumed to be correct as received from the data suppliers.
Fig. 15.1. Groundwater management units, categorized by use in 2000. (From NLWRA, 2002.)
management units of Australia. The management units are defined on the basis of water availability, water use and aquifer characteristics including depth, thickness and salinity. The NLWRA (2001) reported that more than 50% of the management units were extracting less than 30% of sustainable yield, with a further 19% between 70% and 100%, and 11% exceeding annual sustainable yield. Overall, 83 units (15%) were judged to be overallocated. Three management units, all in Victoria, had developed environmental allocation plans.
The framework is supported by two further national initiatives, and coordinated by the Department of Heritage and Environment - the National Principles for the Provision of Water for Ecosystems (ARMCANZ, 1996b) and the National Water Quality Management Strategy Guidelines for Groundwater Protection in Australia (ARMCANZ, 1995). A summary of groundwater-dependent ecosystems as envisaged in this and other work is given in Box 15.1. There are two further supporting frameworks:
1. Overallocated Groundwater - A National Framework for Managing Overallocated Groundwater Systems has 13 recommendations designed to provide policy guidance for the states grappling with the serious issue of how to reduce the licensed volumes of overallocated groundwater aquifers. Associated with this policy paper is a Best Management Practice Manual, which suggests a broad range of approaches that are available to groundwater managers to reduce allocations and use (NRMMC, 2002a-c).
2. A National Framework for Promoting Groundwater Trading identifies the fundamental requirements for trading of groundwater as well as the impediments to groundwater trading.
The 13 recommendations address both the preconditions for trading and the requirement for a trading regime to operate. Methods to encourage trading are identified, as are the benefits of groundwater trading. The disadvantages of trading in overused systems are also identified. The document also asserts the following:
• The current level of monitoring of groundwater use (through the metering of bores) was low and more comprehensive data were required to correctly estimate sustainable yields.
• Commonly agreed methods for estimating sustainable yields and defining environmental water allocations for groundwater-dependent ecosystems were yet to be developed.
• Some states and territories have released new groundwater management policies; however, generally groundwater management reform was lagging behind those in surface water.
We will now turn to the central issue of sustainable yield: how this is defined, effected by groundwater-dependent ecosystems, and the characteristics of groundwater licensing and trade.
Box 15.1. Definitions of groundwater-dependent ecosystems in Australia.
(Adapted from Hatton and Evans, 1998, 2003.)
• terrestrial ecosystems that show seasonal or episodic reliance on groundwater;
• river base flow systems, which are aquatic and riparian ecosystems in, or adjacent to, streams or rivers depending on the input of groundwater base flows, especially during dry seasons in seasonally dry climates or perennially in arid zones; hyporheic zones;
• aquifer and cave ecosystems, often containing diverse and unique fauna;
• wetlands dependent on groundwater influx for all or part of the year;
• estuarine and near-shore marine ecosystems that use groundwater discharge.
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