Table 1 shows that there is a surplus (111,488 ML) of available water assets, expected future inflows and future water rights over water liabilities and future water commitments that are expected to be settled within 12 months of the reporting date. It should be noted that Table 1, with the exception of desalinated water, does not include expected water inflows for 2011–12 due to lack of appropriate data and a suitable quantification approach.
The volumes reported for future water rights and future water commitments are indicative only. The volumes presented in Table 1 were estimated from the average diversions and extractions in the previous two years. The actual volume of water delivered under these future water rights and future water commitments will depend on climatic conditions and demand.
Above-average rainfall was experienced in the Adelaide region in both 2009–10 and 2010–11, increasing water availability and corresponding to a reduction in demand on water resources. These conditions suggest that diversions and extractions during these two years are likely to underestimate expected diversions and extractions in an average rainfall year.
During 2009–10 and 2010–11 the average volume of water diverted and extracted under water liabilities for water resources within the Adelaide region was approximately 40% of the allocated volume. Similarly, the wetter conditions experienced between 2009 and 2011 reduced demand on River Murray water. The volume of water diverted from the River Murray by SA Water (under the Class 6 water access entitlement) was approximately 30% of the volume allocated; and by Barossa Infrastructure Limited, the volume of water diverted was approximately 50% of the volume allocated under their entitlement to River Murray water.
Preliminary climate data suggest that 2011–12 was wetter than the previous two years. If similar conditions to 2009–10 and 2010–11 persist, the future prospects suggested in Table 1 may be a reasonable estimate of what to expect in 2011–12.
Although it was not possible to quantify future inflows such as precipitation, runoff and groundwater recharge, using recent data (previous two years) as an approximation, future inflows are expected to be greater than 1,200,000 ML in 2011–12 and are expected to meet the demands of future water commitments. Inflows will be further supplemented by desalinated water (as indicated in Table 1), which could be as high as 50,000 ML. Therefore it is likely that future demands on the Adelaide region's water resources will be sufficiently met.
|Total water assets as at 30 June||227,174|
|Less water assets not available to be accessed, taken or delivered|
|Less total water liabilities as at 30 June|
|Carryover of groundwater allocation||3,5613|
|Less future water commitments expected to be settled within 12 months of the reporting date|
|Expected non-licensed surface water diversions||3,1144|
|Expected allocation diversion of surface water||1,1505|
|Expected non-licenced groundwater extractions||36,7006|
|Expected allocation extraction of groundwater||17,6777|
|Expected urban water use||128,0978|
|Expected irrigation schemes water use||14,7899|
|Surplus/deficit of available water assets over water liabilities and future commitments expected to be settled within 12 months of the reporting date||19,979|
|Add future water rights expected to be realised within 12 months of the reporting date|
|Urban inter-region claim to River Murray water||49,16810|
|Irrigation scheme inter-region claim to River Murray Water||2,30111|
|Add expected inflows within 12 months of the reporting date|
|Surplus/deficit of available water assets, expected future inflows and future water rights over water liabilities and future commitments expected to be settled within 12 months of the reporting date||111,488
2. Conveyance water is water held in potable pipes reported at 3.1 Urban water supply system
3. Carryover of groundwater allocaiton reported at 6.1 Groundwater allocation remaining
4. Average of 2009–10 and 2010–11 surface water diversions reported at 17.6 Diversions - other statutory rights
5. Average of 2009–10 and 2010–11 surface water diversions reported at 17.11 Surface water allocation diversion
6. Average of 2009–10 and 2010–11 groundwater extractions reported at 18.7 Extraction - other statutory rights
7. Average of 2009–10 and 2010–11 groundwater extractions reported at 18.11 Groundwater allocation extraction
8. Average of 2009–10 and 2010–11 urban water use reported at 19.4 Delivery to urban water system users
9. Average of 2009–10 and 2010–11 irrigation schemes water use reported at 20.4 Delivery to irrigation scheme users
10. Average of 2009–10 and 2010–11 River Murray water diverted reported at 11.9 Delivery of water to urban water system under inter-region agreement
11. Average of 2009–10 and 2010–11 River Murray water diverted reported at 12.6 Delivery of water to irrigation scheme under inter-region agreement
12. As of October 2011 customers were receiving desalinated water from the first 50,000ML plant. 40,000 ML was estimated as a proportion of the maximum volume that might be delivered from the desalination plant in 2011–12. For further information see the SA Water website.
Contingent water assets and water liabilities
Contingent water assets
The non-extractable portion of groundwater in the Adelaide region:
The Adelaide and Mount Lofty Ranges Natural Resources Management Board develops water allocation plans for the prescribed water resources within the Adelaide region. A water allocation plan describes the capacity of the groundwater resources to meet demand. The non-extractable portion of the groundwater asset is a contingent water asset because it is possible that a change in circumstances, such as legislative or regulatory changes that alter the extraction limits, would result in further portions of the groundwater becoming available for extraction. There is no estimate available of the total volume stored in the aquifers of the region.
Contingent water liabilities
Groundwater and surface water allocations in the Western Mount Lofty Ranges Adelaide region
The Adelaide and Mount Lofty Ranges Natural Resources Management Board have drafted a water allocation plan for the water resources (surface water and groundwater) within the Western Mount Lofty Ranges. The water allocation plan provides for the allocation and use of water within the region. The draft plan was released for public consultation in late 2010 and is expected to be adopted in 2012. The approval and adoption of the water allocation plan for the Western Mount Lofty Ranges by the South Australian Government is outside the control of the management of the Adelaide region. Therefore, the allocations detailed in this plan are considered a contingent water liability.
The extraction limits outlined in the draft plan indicate an approximate volume of the contingent liability if the resources are fully allocated. The underground water extraction limit is 70,000 ML and the surface water (main watercourse) extraction limit is 97,000 ML.
Water for urban use
SA Water supplies urban water to residential customers throughout the Adelaide region. SA Water maintains water within its distribution pipes for the delivery of water to the city, but the actual delivery of water is determined by the customers when they turn on the tap. Therefore, the delivery of urban water to customers within the Adelaide region is considered a contingent liability. During the 2010–2011 year, 126,000 ML of urban water was supplied to residential customers within the Adelaide reporting region. Notwithstanding any major changes, it is estimated that a similar volume of water will be required to be delivered in the next reporting period.