Indicator: IW-44 Sustainable yield determination

Data

Developed yield is the average annual volume of water that can be diverted for use with the existing infrastructure. The developed yield demonstrates the extent to which surface water assets are, or can be, used.

Surface water stocks - 2000
	NSW	Vic.	Qld	SA	WA	Tas.	NT	Aust.
Mean annual run-off (ML/yr)	41 926 000	20 188 300	157 208 576	1 936 800	43 133 800	45 582 113	75 428 200	385 923 826
Developed yield (ML)	6 010 171	6 326 240	3 244 024	750 808	856 754	3 542 690	54 383	20 870 270

Source: Australian Bureau of Statistics 2004, Water Account Australia 2000-2001, Australian Bureau of Statistics, viewed 16 Nov 2005, http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/D828F04237840B07CA256F4C007155B3, Table 10.9, p. 98.

Sustainable yield (in Megalitres) of groundwater, by level of salinity - 2000
Level of salinity	NSW	Vic	Qld	SA	WA	Tas	NT	Aust
Volume (ML) Less than 1500 mg/L Less than 500 mg/L 500–1000 mg/L 1000–1500 mg/L Total	698215 3927969 34000 4660184	193560 827000 386357 1406917	1373040 994530 119460 2487030	55850 228640 679515 964005	1898876 1061380 995171 3955427	1585388 766705 449 2352542	4412001 287238 454972 5154211	10216930 8093462 2669924 20980317
1500 mg/L and over 1500–3000 mg/L 3000–5000 mg/L 5000–14000 mg/L More than 14000 mg/L Total	812450 1550 440400 — 1254400	243735 707133 200750 797000 1948618	113540 29750 62730 — 206020	252645 600 761900 — 1015145	1467640 588568 841195 370668 3268071	178230 — — — 178230	139306 182917 — — 322223	3207547 1510518 2306975 1167668 8192707

Total sustainable yield	5 914 584	3 355 535	2 693 050	1 979 150	7 223 498	2 530 772	5 476 434	29 173 024

Proportion (%) Less than 1500 mg/L 1500 mg/L and over	79 21	42 58	92 8	49 51	55 45	93 7	94 6	72 28

Sustainable yield is the level of extraction measured over a specified planning time frame that should not be exceeded to protect the higher value social, environmental and economic uses associated with the aquifer.

What the data mean

In 2000 developed yield was approximately 20 870 GL, representing 5.4% of Australia's mean annul runoff.

There are approximately 29 173 gigalitres of groundwater available in Australia but it is not all of equal quality. Dissolved salt concentrations vary and determine the suitability of water use, e.g. a salinity level above 1500 mg/L is not suitable for irrigation.

Data Limitations

Groundwater sustainable yield data, reported in 2001, has not been updated.

Variations in calculating sustainable yields occur between States and Territories.

Issues for which this is an indicator and why

Inland Waters — Human response - policy and management - Management of surface and groundwaters

The sustainable yield of a groundwater or surface water system refers to the volume and/or rate of water that can be extracted from that system while maintaining an acceptable level of aquatic ecosystem health. The sustainable yield can indicate environmental stress on an aquatic ecosystem if water extraction is greater than the sustainable yield. Sustainable yield can also be used to help identify aquatic systems where water use can be increased in a sustainable manner.