Drivers for Change in Groundwater Management

There has been an increasing realization that surface and groundwater resources are inextricably linked - which is obvious at one level and yet quietly under-recognized, perhaps due to the relatively low historical use of groundwater.

Groundwater exploitation has risen in tandem with competition for surface water resources. The development of groundwater as a 'back-up' supply for irrigation properties is additionally increasing the demand for groundwater development in existing irrigation areas, in NSW and Victoria. Table 15.5 shows that groundwater use has tripled between 1983/84 and 1996/97 in NSW, Victoria and western Australia. Abstraction in Queensland actually declined, largely as a result of a programme to cap all the bores in the Great Artesian Basin, many of which had been flowing freely for years, gradually reducing artesian pressure and causing concern about 'senseless' wastage.

Although western Australia and the NT have the greatest reliance on groundwater, the primary users in these jurisdictions are urban, rural (town, stock and domestic) and mining. The capital of western Australia, Perth (population 1.5 million), is the largest groundwater-dependent city in Australia.

Despite various earlier initiatives to quantify water resources in Australia, it was progressively realized that, as a lot of groundwater use was neither licensed nor measured, steps would have to be taken to bring this in line with surface water management. Historically, the British riparian tradition of landowner access to groundwater had continued long after surface water had been declared

Table 15.5. Changes in mean annual groundwater use, 1983/84 to 1996/97. (From National Land and Water Audit, 2002.)

Total use 1983/84 MCM

Total use 1996/97 MCM

% change in groundwater use

NSW

31 8

1008

21 7

VIC

206

622

202

QLD

1 1 21

831

-26

WA

373

1 1 38

205

SA

542

41 9

-22

TAS

9

20

1 22

NT

65

1 28

97

ACT

n/a

5

-

Total

2634

4171

58

Table 15.6. The extent of metering of groundwater use in 2000 in Australia. (From National Land and Water Audit, 2002.)

Not known

Total

Total

8 28 40 15

5 22

50 79 107 174 53 17 55 3

a state (and peoples') resource to be allocated through licensing. Table 15.6 shows that only a small number of groundwater management units were metered before 2000, although it is important to note that the majority of large agricultural abstractors, especially those operating within the large surface irrigation schemes were licensed and metered by this time.

Coupled with the lack of detailed knowledge on abstraction, the rising trends in total groundwater use prompted the introduction of legislation and initiatives designed to respond to three major principles of ecologically sustainable development of groundwater:

• Water level and pressure should be maintained within agreed limits and should not diminish.

• There should be no degradation of water quality.

• Environmental water needs should be determined and sustained.

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