Adelaide
Supporting information for water accounting statements

Introduction

The following set of notes provides consolidated reports for each of the water stores and systems within the Adelaide region during the 2013–14 year. The water stores and systems included in the region are shown in Figure 1.

For more information about the region, please refer to the General description section of the 'Contextual information'.

 

Figure 1 Water stores and systems within the Adelaide region
Figure 1 Water stores and systems within the Adelaide region

 

 

Information on all water flows to and from each water store and system are presented in the following set of notes, including between-store flows and transfers that are not presented in the water accounting statements. The between-store flows and transfers that occur in the region are presented in Figure 2.

 

Figure 2  Between-store flows that occur within the Adelaide region
Figure 2 Between-store flows that occur within the Adelaide region

 

The between-store flows and transfers (Figure 2), which are eliminated from the region's water accounting statements, are shown in italics throughout the following set of notes. The allocation announcement, forfeiture, and allocation remaining items associated with each between-store abstraction (brown arrows in Figure 2) are also shown in italics in the following notes. 

 

Surface water store

Surface water assets

The volume of the surface water assets represents water held in storages (122,502 ML) and water held in river weirs (656 ML). The volume of water in river channels, lakes and wetlands could not be quantified due to a lack of available data; however, the volume of water held in channels and lakes is considered to be relatively small compared to the volume held in storages.

The location of each storage within the Adelaide region and the volume of water in each storage (including dead storage) as a percentage of total storage capacity at the end of the 2013–14 year is shown in Figure 3.

 

Figure 3 Percentage-full volume on 30 June 2014 for each storage
Figure 3 Percentage-full volume on 30 June 2014 for each storage
 

 

The total capacity of the surface water storages in the Adelaide region is 197,871 ML. At the end of the 2013–14 year, total volume held in these storages was at 61%  of capacity, increasing from 44% at the end of the 2012–13 year. The highest gains in storage volumes was observed in Kangaroo Creek and Mount Bold, where volumes increased by over 50% when compared to storage volumes in 2012–13.  

Total volume of water within each storage at 30 June 2014, and at the end of the previous three years (2013, 2012 and 2011) is given in Figure 4.

 

Figure 4 Total volume of water in each storage at 30 June 2014, 2013, 2012 and 2011
Figure 4 Total volume of water in each storage at 30 June 2014, 2013, 2012 and 2011

 

Surface water liabilities

Surface water liabilities in the Adelaide region refer to the volume of surface water allocation remaining on licence entitlements at the end of the 2013–14 year for: 

  • individual users (625 ML)
  • urban water system (0 ML).

The surface water licences in the Adelaide region have a management year which ends on 30 June. In the Barossa Prescribed Water Resources Area (PWRA), licensees for the North Para River and tributaries may carry over the unused portion of their allocation up to a maximum of 30% of the annual allocation, whereas for Little Para Prescribed Water Course (PWC) carry-over is not permitted (Adelaide and Mount Lofty Ranges Natural Resources Management Board 2013).

Allocation remaining for individual users was 625 ML at the end of 2013–14 (Table 1). For the urban water system, the surface water allocation held by SA Water from the Western Mount Lofty Ranges PWRA does not permit any carryover of unused water into the following year; therefore, the allocation remaining is zero (Table 2).

 

Table 1 Volume of surface water allocation remaining for individual users at the end of the 2013–14 year
Account: individual usersVolume (ML)
Opening balance at 1 July 2013574
Surface water allocation announcements3,631
Entitled diversion of allocated surface water to individual users(946)
Adjustment and forfeiture of surface water allocation(2,634)
Closing balance at 30 June 2014625

 

Table 2 Volume of surface water allocation remaining for the urban water system at the end of the 2013–14 year
Account: urban water systemVolume (ML)
Opening balance at 1 July 20130
Surface water allocation announcements143,000
Entitled diversion of allocated surface water to urban water system(66,099)
Adjustment and forfeiture of surface water allocation(76,901)
Closing balance at 30 June 20140

 

Surface water inflows and outflows

A schematic diagram representing all the inflows and outflows associated with the surface water store in the Adelaide region is provided in Figure 5. 

 

Figure 5 Water inflows and outflows for Adelaide's surface water store during the 2013–14 year
Figure 5 Water inflows and outflows for Adelaide's surface water store during the 2013–14 year
 

 

Surface water inflows

Total surface water inflows in the Adelaide region was 539,011 ML. Runoff to surface water contributed the highest volume of inflow with 448,723 ML. Groundwater discharge to surface water was 74,012 ML, this volume included annual baseflow from groundwater to watercourses within the Western Mount Lofty Ranges Prescribed Water Resources Area and baseflow at the Yaldara gauging station on the North Para River. Precipitation on surface water represents rainfall that fell on the major storages within the region and was the smallest volume of natural water inflow contributing 11,209 ML to the surface water store.

A volume of 5,067 ML was discharged to rivers from several wastewater treatment plants, including Angaston, Bird-in-Hand, Hahndorf and Heathfield. It also includes treated wastewater from Victor Harbour wastewater treatment plant which is temporarily stored in Hindmarsh Reservoir during summer before being released to the Inman River in the winter months. 

 

Surface water outflows

Total surface water outflows from the surface water store was 252,377 ML.  River outflow from the region was 166,640 ML and made up 65% of all surface water outflows for the Adelaide region. This includes streamflow from most major rivers that flow to the sea in the region including the Gawler, Torrens, Little Para and Onkaparinga rivers. Evaporation from surface water storages and weirs was 16,954 ML.

Surface water diversions made under other statutory rights were 1,738 ML. Diversions made by individual users under the Western Mount Lofty Ranges Prescribed Resources Area Water Allocation Plan are reported as 'Diversions—other statutory rights'. The majority of entitlements under this plan had not been issued with a licence during the 2013–14 year. Unissued licences are managed under ss 128, 132 and 164N of the Natural Resources Management Act 2004  South Australia). For further information on these authorisations, refer to  Water entitlements and other statutory water rights in the 'Contextual information'.

 

Surface water allocation diversions

The total amount of surface water allocation diversions in the Adelaide region was 67,045 ML. Entitled diversion of allocated surface water to urban water system made up most of this water with 66,099 ML diverted by SA Water from the Western Mount Lofty Ranges PWRA for public water supply. 

 

Figure 6 Surface water allocations and diversions during the 2013–14 year
Figure 6 Surface water allocations and diversions during the 2013–14 year
 

 

Surface water forfeitures

Surface water forfeiture represents the volume of unused allocated water that was not permitted to be carried over at 30 June 2014, and therefore forfeited. For individual users, a volume of 625 ML was able to be carried over in the Barossa PWRA from the North Para River. The remainder of the unused allocation, a volume of 2,634 ML, was forfeited at 30 June 2014.

There are no carryover provisions for SA Water's licence to divert water from the Western Mount Lofty Ranges PWRA for public water supply. Therefore a volume of 76,901 ML was reported as forfeiture from the urban water system.

 

Surface water allocation announcements

Surface water allocation announcements in the Adelaide region during the 2013–14 year refer to surface water supply to:

  • individual users (3,631 ML)
  • urban water system (143,000 ML).

Surface water allocation announcements for individual users represents the volume of surface water (watercourse) licences that are allocated in the Barossa Prescribed Water Resources Area and the Little Para River Prescribed Watercourse.  These licences are issued for a variety of purposes including irrigation (93% of the allocation), industrial (6%), recreational (<1%), and stock and domestic (<1%). Allocation announcements for individual users under the newly commissioned Western Mount Lofty Ranges Prescribed Water Resources Area Water Allocation Plan are not included here as all licences were yet to be fully issued during the 2013–14 year. Figure 7 shows the annual allocation announcement to individual users for each licence purpose for the 2013–14 year.

 

Figure 7 Surface water allocation announcements to individual users for each licence purpose for the 2013–14 year
Figure 7 Surface water allocation announcements to individual users for each licence purpose for the 2013–14 year

 

The surface water allocation announcements for the urban water system represents the volume of water that SA Water is entitled to divert from surface waters within the Western Mount Lofty Ranges within the 2013–14 year. SA water's licence entitles them to divert up to an 143,000 ML annually for the purposes of public water supply.

A more detailed description of surface water allocations and associated water rights in the Adelaide region is given in the Surface water rights note.

 

Surface water balancing item

The balancing item volume represents the difference between the measured opening and closing balances of the surface water store, after physical inflows and outflows have been applied (Table 3). This item is an indication of both the accuracy of the volumes reported and the degree to which the reported water flows represents a complete surface water store balance.

 

Table 3 Balancing item for the surface water store
Account: surface water storeVolume (ML)
Opening balance (at 1 July 2013)87,732
Total surface water inflows539,011
Total surface water outflows(252,377)
Closing balance (at 30 June 2014)(123,158)
Balancing item251,208

 

The calculation of the water balance on the surface water store yielded a balancing item of 251,208 ML. This is larger than the total surface water store volume at the end of the 2013–14 year and approximately 64% of the total surface water inflows during the year. The positive balancing item indicates that either the inflows are too high or the outflows are too low.

There are several reasons for the balancing item:

  • Some items are not quantified, or only partly quantified due to lack of data. This includes evaporation from and precipitation to rivers as well as some surface water/groundwater interactions. River and floodplain losses cannot be quantified in the account. It is likely that these losses are a relatively large source of surface water decrease throughout the region.
  • There is uncertainty associated with the meteorological inputs into the rainfall-runoff model and the model structure, estimated to be in the range of 10–20% (up to +/– 90,000 ML).
  • Quantification of river outflow to sea also contributes to the large balancing item for the surface water asset. River outflow to sea is based on measured flow data collected at the most downstream station along a river. There is no adjustment made for the contributing area below the gauging station. As such, outflow to sea is likely to be underestimated by 10–20% (up to 30,000 ML).

 

Groundwater store

Groundwater assets

Groundwater in the Adelaide region is described in the Groundwater section in the 'Contextual information'.

There is no information regarding the actual physical volume held in the groundwater aquifers in the Adelaide region. The volume quantified as the groundwater asset refers to the managed groundwater volume reported in relevant water allocation plans. The managed groundwater volume includes groundwater extraction limits and the non-licensed groundwater extractions described by each water allocation plan and does not change from year to year, unless the allocation plan is amended.

The total volume of groundwater assets in the Adelaide region was 86,356 ML at the start and end of the 2013–14 year.

 

Groundwater liabilities

Groundwater liabilities in the Adelaide region refer to the volume of groundwater allocation remaining on licence entitlements at the end of the 2013–14 year for indiviual users only. The groundwater licences in the Adelaide region have a management year that ends on 30 June, and licensees are permitted to carryover up to 30% of their annual water allocation, depending on the management area. There is also provision for a portion of the recharge credit to be carried forward into the following year.

At the end of the 2013–14 year, 6,107 ML was permitted to be carried over, made up of 2,238 ML of groundwater allocation credits and 3,869 ML of recharged water credits.

 

Table 4 Volume of groundwater allocation remaining for individual users at the end of the 2013–14 year
Account: individual usersVolume (ML)
Opening balance at 1 July 20133,941
Groundwater allocation announcements47,483
Entitled extraction of allocated groundwater to individual users(23,559)
Adjustment and forfeiture of groundwater allocation(21,758)
Closing balance at 30 June 20146,107

 

Groundwater inflows and outflows

A schematic diagram representing all the inflows and outflows associated with the groundwater store in the Adelaide region is provided in Figure 8.

 

 

 Figure 8 Water inflows and outflows for Adelaide's groundwater store during the 2013–14 year
Figure 8 Water inflows and outflows for Adelaide's groundwater store during the 2013–14 year

 

Groundwater inflows

Total groundwater inflows from natural sources for the Adelaide region for the 2013–14 year were 261,243 ML. This volume is made up of recharge from landscape, groundwater inflows from outside of the region, leakage from both the urban water system and from off-channel water storages, and a small amount of managed aquifer recharge.

Recharge from landscape contributed around 92% of the total inflows. The volume (243,097 ML) made up of 239,163 ML of rainfall recharge and 3,934 ML of irrigation recharge. Recharge from landscape was 130,331 ML less than the volume reported for the 2012–13 year (373,428 ML). The below average rainfall experienced in the previous year would provide some explanation for the decrease in recharge. There is not often an immediate correlation between rainfall that falls within that year and the amount of groundwater recharge because there is some lag in groundwater movement. This means rain that falls in one year will only contribute to rainfall recharge in subsequent years.  Also, the drier conditions experienced in the 2012–13 year would have dried out the landscape, and rainfall would have to replenish soil moisture levels before infiltrating groundwater aquifers.

Groundwater inflow from outside the region was 21 ML. This represents regional groundwater inflows to the Adelaide region at the northern boundary, through the major sedimentary aquifers in the Adelaide Plains (T1 and T2 aquifers). In general, groundwater flows from the fractured rock aquifers of the Mount Lofty Ranges west towards the Adelaide Plains and Gulf St Vincent (Ellis and Fox 2004). The Adelaide region boundary along the Mount Lofty Ranges is considered a groundwater divide with no groundwater flow across this divide. 

A volume of 1,624 ML was reported as groundwater inflow from outside region at coast through the major sedimentary aquifers in the McLaren Vale PWA (Maslin Sands and Port Willunga aquifers) and the Adelaide Plains (T1 and T2 aquifers). Coastal groundwater inflow may be either fresh or saline groundwater and is not meant to represent sea water intrusion into the Adelaide region aquifers; however, localised cones of depression due to groundwater pumping have been identified as a potential problem, particularly for saline sea water intrusion, in the McLaren Vale PWA (Martin and Hodgkin 2005) and in the Adelaide Plains (Aquaterra 2011). In the McLaren Vale PWA and Adelaide Plains, salinity monitoring suggests some seawater intrusion may be occurring (Martin 1998; Gerges 1999).

Other sources of groundwater inflow was leakage from off-channel water storages (1,131 ML) and leakage from urban water system (15,309 ML). Managed aquifer recharge—urban water system was 61 ML which is 52 ML less than the 2012–13 year. This is the volume of recycled water injected to groundwater as part of the Aldinga Aquifer Storage and Recovery Scheme. Recycled water is supplied from the Christies Beach WWTP and injected to the Port Willunga Formation aquifer for temporary storage and then subsequently supplied to the Willunga Basin Water Company for irrigation (see Irrigation inflows below).

 

Groundwater outflows

Total groundwater outflows for the 2013–14 year was 127,820 ML, excluding water that was abstracted under an allocation. This volume was largely made up of discharge to surface water (74,012 ML) which contributed around 58% of groundwater outflows and was similar to the volume of 72,148 ML in the 2012–13 year. Discharge to surface water quantifies annual average baseflow to watercourses within the Western Mount Lofty Ranges PWRA and baseflow at Yaldara gauging station. A further 25% (32,313 ML) of groundwater outflows was attributed to evapotranspiration from shallow groundwater, reported as discharge to landscape. This was made up of 12,121 ML from Adelaide Plains, 51 ML from McLaren Vale, and 20,141 ML from Western Mount Lofty Ranges Fractured Rocks. This was a substantial decrease on the volume of 108,290 ML reported in the previous year, most likely due to the dry soil moisture conditions in the region as a result of the below average rainfall in 2012–13.  Groundwater outflow to outside region was 383 ML, made up of 43 ML from Adelaide Plains T1, and 340 ML from Adelaide Plains T2 aquifers. Groundwater outflow to outside region at the coast was 972 ML, reporting on outflow from the major sedimentary aquifers in the McLaren Vale PWA (Maslin Sands and Port Willunga aquifers) and the Adelaide Plains (T1 and T2 aquifers).

The volume of 20,079 ML reported for 'Groundwater extraction—other statutory rights' represents non-licensed groundwater extractions in the Adelaide region. A total of 19,017 ML was extracted from the Western Mount Lofty Ranges PWRA and 1,062 ML from the Kangaroo Flat portion of the Northern Adelaide Plains PWA. These extractions are managed by authorisations under ss 128, 132 and 164N of the Act. For further information on these authorisations, refer to Water entitlements and other statutory water rights in 'Contextual information'. A total of 61 ML was supplied to the Willunga Basin Water Company for irrigation under 'Entitled extraction of non-allocated groundwater to irrigation scheme'. This water forms part of the Aldinga Aquifer Storage and Recovery Scheme. The recycled water is supplied from the Christies Beach WWTP and injected to the Port Willunga Formation aquifer for temporary storage.

 

Groundwater allocation extractions

All allocation diversions reported for the Adelaide region are for individual use. The volume of 23,559 ML is water that was extracted from the Barossa PWRA, McLaren Vale PWA, and the Northern Adelaide Plains PWA. No data was available for Dry Creek Prescribed Wells Area. These extractions were made under the following categories:

  • metered extractions
  • metered—recharged groundwater credits extractons
  • non-metered—estimated stock and domestic extractions
  • non-metered—estimated other extractions.

The volume extracted from each management area is shown in Figure 9.

 

Figure 9 Groundwater allocations and abstractions for the Adelaide region during the 2013–14 year
Figure 9 Groundwater allocations and abstractions for the Adelaide region during the 2013–14 year

 

Groundwater forfeitures

Groundwater forfeiture represents the volume of unused allocated water that was not permitted to be carried over at 30 June 2014 and therefore forfeited. A volume of 2,881 ML (see Groundwater liabilities) was able to be carried over in the Adelaide region for groundwater allocation credits and recharged water credits. The remainder of the unused allocation, a volume of 21,758 ML was forfeited at the end of the 2013–14 year. This includes 3 ML of expired groundwater recharge credits at the end of the 2013–14 year.

 

Groundwater allocation announcements

There are currently no groundwater allocation announcements for the urban water system in the Adelaide region; allocation announcements refer only to licences granted for individual users. The volume of groundwater allocated for individual users for the 2013–14 year was 47,483 ML. These licences are granted within the Barossa PWRA, Dry Creek PWRA, McLaren Vale PWA, and the Northern Adelaide Plains PWA. There is a variety of licence purposes in the Adelaide region: around 80% of the total allocation announcement is dedicated for irrigation purposes, 10% for recharge water credits, 8% for industrial purposes, and the remainder for stock and domestic, recreational, industrial and other purposes. Figure 9 shows the annual allocation announcement to individual users for each licence purpose for the 2013–14 year.

 

A more detailed description of groundwater allocations and associated water rights in the Adelaide region is given in the Groundwater rights note.

 

Figure 10 Groundwater allocation announcements to individual users for each licence purpose for the 2013–14 year
Figure 10 Groundwater allocation announcements to individual users for each licence purpose for the 2013–14 year

 

Groundwater balancing item

The calculation of the water balance on the groundwater store yielded a difference of 109,864 ML, approximately 42% of the total groundwater inflows during the 2013–14 year. Whilst this value is approximately 31% less than the previous year's value of 161,087 ML, it represents a slightly higher percentage of inflows than the 2012–13 year.

 

Table 5 Balancing item for the groundwater store
Account:  groundwater storeVolume (ML)
Opening balance (at 1 July 2013)86,356
Total groundwater inflows261,243
Total groundwater outflows(151,379)
Closing balance (at 30 June 2014)(86,356)
Balancing item109,864

 

There are several reasons for the balancing item:

  • The actual physical volume in the groundwater asset is not quantified, but represents the average long-term groundwater volume available for extraction, without adversely impacting the system. It is essentially constant from year to year.
  • The omission of some items such as recharge from surface water to groundwater and discharge to off-channel water storage due to a lack of data.
  • There is uncertainty associated with the meteorological inputs into the model and the model structure, estimated to be in the range of 10–20% (up to +/– 60,000 ML).
  • Groundwater discharge to surface water was the average annual baseflow and does not necessarily represent the flux during the year.

 

Urban water system

Urban water assets

Adelaide's urban water system comprises of three subcomponents:

  • urban water supply system (1,414 ML)
  • wastewater supply system (133 ML)
  • recycled water system (17 ML).

The volume stated for the urban water asset includes water held in pipes that were part of the potable, wastewater and recycled pipe network, storage tanks and wastewater treatment lagoons. The volume of 1,414 ML stated for the urban water supply system includes 630 ML held in the pipe network, 616 ML in balancing tanks, and 168 ML held in process tanks. The wastewater supply system includes water held in pipes and treatment lagoons, and the 17 ML stated for the recycled water system is the volume of water held in recycled water mains pipes.

The closing balance reported for the urban water system varied very little compared to 2012–13. In the absence of substantial expansion of the pipe networks, the volume of water held in the urban water system is not expected to vary much between years.

 

Urban water claims

Adelaide's urban water system holds two claims to water:

  • urban claim on surface water within the region (0 ML)
  • urban inter-region claim on River Murray water (0 ML).

Table 6 details the opening and closing balance as well as increases and decreases to the urban claim on surface water during the 2013–14 year. The urban claim on surface water is facilitated by a licence issued to SA Water to harvest and divert water from surface water storages within the Western Mount Lofty Ranges PWRA for the purposes of public water supply. The annual maximum diversion volume of 143,000 ML was assumed to equal the annual allocation. The volume of water diverted (66,099 ML) was slightly less than 50% of the annual allocation. The remaining water (76,901 ML) was forfeited because licence conditions do not allow carryover of unused water at the end of the water year, resulting in a closing balance of zero for the urban claim on surface water.

Table 7 details the opening and closing balances and also increases and decreases to the urban claim on inter-region water during the 2013–14 year. The urban claim on inter-region water is facilitated by a Class 6 water access entitlement (WAE) held by SA Water to 130,000 shares in the River Murray for the purposes of public water supply. On 1 July 2013, the South Australian Minister for Sustainability, Environment and Conservation announced a 100% allocation of 1 kL/unit share for the Class 6 WAE, resulting in an allocation increase of 130,000 ML for the 2013–14 year. The volume of water diverted (32,149 ML) was approximately 25% of the annual allocation. The remaining water (97,851 ML) was forfeited as WAE conditions do not allow carryover of unused water at the end of the water year, resulting in a closing balance of zero for the urban claim on inter-region water.

 

Table 6 Volume of urban claim on surface water at the end of the 2013–14 year
Account: surface water
Volume (ML)
Opening balance at 1 July 20130
Surface water allocation announcements143,000
Entitled diversion of allocated surface water to urban water system(66,099)
Adjustment and forfeiture of surface water allocation(76,901)
Closing balance at 30 June 20140

 

Table 7 Volume of urban inter-region claim on water at the end of the 2013–14 year
Account: inter-region
Volume (ML)
Opening balance at 1 July 20130
Increase of inter-region claim on water from urban water system130,000
Delivery of water to urban water system under inter-region agreement(32,149)
Adjustment and forfeiture of urban inter-region claim on water(97,851)
Closing balance at 30 June 20140

 

Urban water system inflows and outflows

A schematic diagram representing all the inflows and outflows associated with the urban water system in the Adelaide region is provided in Figure 11.

 

Figure 11 Water inflows and outflows for Adelaide's urban water system during the 2013–14 year
Figure 11 Water inflows and outflows for Adelaide's urban water system during the 2013–14 year

 

Urban water supply system inflows

In the Adelaide region, water for urban supply comes from three sources:

  • allocated surface water harvested from the Western Mount Lofty Ranges PWRA (66,099 ML)
  • allocated River Murray water imported via the Mannum–Adelaide, Murray Bridge–Onkaparinga, and Swan Reach–Stockwell pipelines (32,149 ML)
  • desalinated water received from the Adelaide Desalination Plant (60,950 ML).

During 2013–14 there was a small decrease (approximately 2%) in the total volume of water supplied to the urban water system, from 162,173 ML in 2012–13 to 159,198 ML in 2013–14.

Allocated surface water harvested from the Western Mount Lofty Ranges PWRA was the region's primary source of urban water (42%) during the 2013–14 year; 38% was sourced from desalinated water; and the remaining 20% was sourced from the River Murray (Figure 12).

The volume of surface water sourced for the urban water system increased by approximately 15% in the 2013–14 year. This is most likely a result of the region's average to above-average rainfall and increased inflows into surface water storages over the year. The shift towards greater production and use of desalinated water continued, rising from 36, 472 ML in the 2012–13 year to 60,950 ML in the 2013–14 year. The volume of River Murray water imported into the region during the 2013–14 year decreased by more than 50% compared with the 2012–13 year, possibly reflecting the increased capacity of resources within the region to meet the urban water needs.

 

Figure 12 Water sources used in Adelaide's urban water system and total volume for the years ending 30 June 2012, 2013 and 2014
Figure 12 Water sources used in Adelaide's urban water system and total volume for the years ending 30 June 2012, 2013 and 2014

 

Wastewater system inflows

Total wastewater collected during the 2013–14 year was 95,560 ML, a small increase (5%) from the previous year. The volume of wastewater collected at each treatment plant and subsequently discharged following treatment is given in Figure 13.

 

Figure 13 Wastewater inflows and outflows at each wastewater treatment plant
Figure 13 Wastewater collected and outflows from each wastewater system
(source)

 

Urban water supply system outflows

Potable and nonpotable water consumption within the Adelaide region was 132,547 ML during the 2013–14 year and was the largest outflow from the urban water supply system. It made up around 97% of the 137,027 ML reported as urban water use for both potable and recycled water. 

Smaller volumes of potable water were transferred out of the region via normal operations in SA Water's service area (4,150 ML) and discharged to South Para Reservoir from the Swan Reach–Stockwell pipeline (2,681 ML). Losses from the urban water supply system included leakage to groundwater (15,309 ML) and other non-revenue water (1,325 ML).

Overall, there was very little change in the outflows from the urban water supply system in the 2013–14 year compared with the 2012–13 year. The volume of water supplied to customers for each use category (commercial, industrial and municipal, residential, agriculture/irrigation and other use) was similar to the volumes reported in the 2012–13 year. A small decrease in consumption of potable water was evident and consistent with a small decrease in overall supply (inflows) to the urban water supply system during the 2013–14 year.

Urban water supply system use does not include recycled water use. Refer to Wastewater and recycled water system outflows for the additional volume of recycled and advanced treated water supplied for urban and non-urban water consumption.

 

Wastewater and recycled water system outflows

Total outflows from Adelaide’s wastewater and recycled water system was 93,835 ML and is presented in Figure 14.

 

Figure 14 Wastewater and recycled water outflows from Adelaide's wastewater system during the 2013–14 year
Figure 14 Wastewater and recycled water outflows from Adelaide's wastewater system during the 2013–14 year

 

The majority of treated wastewater in the Adelaide region was discharged to sea (64,399 ML) during the 2013–14 year. The remaining treated wastewater was either discharged to rivers (2,386 ML), lost to evaporation during wastewater treatment processes (3,821 ML) or recycled for use.  Recycled water uses included delivery to the region's irrigation schemes (18,684 ML), supply for urban consumption (4,480 ML), and a very small volume (61 ML) which was injected to groundwater for later use (managed aquifer recharge).

Recirculation of treated wastewater and recycled water occurs in the system which may be subjected to additional treatment and/or re-use on site. The reported outflows exclude any such recirculated volumes in the system.

 

Urban water system balancing item

The balancing item volume represents the difference between the measured opening and closing balances of the urban water system, after physical inflows and outflows have been applied (Table 8). This item is an indication of both the accuracy of the volumes reported and the degree to which the reported water flows represents a complete urban water system balance.

 

Table 8 Balancing item for the urban water system
Account:  urban water systemVolume (ML)
Opening balance (at 1 July 2013)1,553
Total urban water system inflows254,758
Total urban water system outflows(249,843)
Closing balance (at 30 June 2014)(1,564)
Balancing item4,904

 

The calculation of the water balance on the urban water system yielded a balance item of 4,904 ML. This is 1.9% of the total urban water system inflows during the year 2013–14 year. The misbalance can mainly be attributed to the urban water supply system. Inflows to the urban water supply system were reported as the licensed diversion from the River Murray and the licensed diversion from surface waters within the region. These volumes do not match the total water treatment plant intake within the Adelaide region, thus resulting in a misbalance. The misbalance may also be due to a number of other factors, such as metering inaccuracies, unaccounted losses and inaccuracies in the estimation of certain volumes.

 

Irrigation scheme

Irrigation water assets

The volume of water reported as the irrigation store water asset (29 ML) represents the volume of water held within the pipe and tank infrastructure from Barossa Infrastructure Limited (BIL) and Virginia Pipeline Scheme (VPS) at 30 June 2014. As Willunga Basin Water Company (WBWC) drain all its pipes and tanks from May to October the volume within their storage system is assumed to be zero.

 

Irrigation scheme claims

In the Adelaide region there is an irrigation scheme claim on water under an inter-region agreement that equates to the volume of River Murray water allocated to BIL under class 3a water access entitlement.  Water that has not been used by 30 June is not able to accessed in the following year. Therefore the allocation remaining at 30 June 2014 was zero.

 

Table 8 Volume of irrigation scheme claim on inter-region agreement at the end of the 2013–14 year
Account: irrigation schemeVolume (ML)
Opening balance at 1 July 20130
Increase of irrigation scheme inter-region claim on water6,294
Delivery of water to irrigation scheme under inter-region agreement(6,221)
Adjustment and forfeiture of irrigation scheme inter-region claim on water(73)
Closing balance at 30 June 20140

 

Irrigation scheme inflows and outflows

A schematic diagram representing all the inflows and outflows associated with the irrigation scheme in the Adelaide region is provided in Figure 15. Around 75% of the 25,576 ML of inflows to the irrigation scheme is the delivery of recycled water. A volume of 18,684 ML was delivered to VPS and WBWC from Bolivar, Christies' Beach and Aldinga WWTPs. A further 610 ML was delivered through community wastewater management systems during the 2013–14 year, 254 ML to BIL from Nuriootpa, and 346 ML to WBWC from Willunga.

 

Figure 15 Water inflows and outflows for Adelaide's irrigation scheme during the 2013–14 year
Figure 15 Water inflows and outflows for Adelaide's irrigation scheme during the 2013–14 year
 

 

Groundwater extraction was 61 ML, which is almost half of the 112 ML extracted in the 2012–13 year. This water is also recycled water injected to groundwater as part of the Aldinga Aquifer Storage and Recovery Scheme. Recycled water is supplied from the Christies Beach Wastewater Treatment Plant and injected to the Port Willunga Formation aquifer for temporary storage and then subsequently supplied to the WBWC for irrigation.

A volume of 6,221 ML was delivered to BIL through the import of River Murray water under their Class 3a WAE in 2013–14. This is 1,145 ML less than the volume imported for the previous year. River Murray water is delivered either via the Mannum-Adelaide pipeline, or the Swan Reach–Stockwell Pipeline. The Mannum–Adelaide pipeline is the preferred route, it conveys untreated water abstracted from the River Murray and then discharges it into Warren Reservoir. The Swan Reach–Stockwell pipeline conveys water abstracted from the River Murray and treated at Swan Reach water treatment plant.

Application of water for irrigation for the 2013–14 year was 24,149 ML. This is made up of 6,557 ML from BIL, 13,900 ML from VPS, and 3,692 ML from WBWC.

 

Decrease of irrigation scheme claims

The portion of irrigation scheme claim that has not been abstracted at the end of the water year is forfeited, that is, there is no carry-over of entitlements into the next water year.

The adjustment and forfeiture of the irrigation scheme inter-region claim on water (73 ML) during the 2013–14 year occured on 30 June 2013 and is the irrigation inter-region claim that was not abstracted by BIL from the River Murray.

 

Increase of irrigation scheme claims

The volume reported (6,294 ML) represents the volume of River Murray water allocated to BIL under their Class 3a WAEs during the 2013–14 year. This volume is made up of the ministerial allocation announcement and the allocations traded. More detail on the irrigation scheme water allocation and associated water rights is given in the Surface water rights note.

 

Irrigation scheme balancing item

The balancing item volume represents the difference between the measured opening and closing balances of the irrigation scheme, after physical inflows and outflows have been applied (Table 9). This item is an indication of both the accuracy of the volumes reported and the degree to which the reported water flows represents a complete irrigation scheme store balance.

 

Table 9 Balancing item for the irrigation scheme
Account:  irrigation schemeVolume (ML)
Opening balance (at 1 July 2013)29
Total irrigation scheme inflows25,576
Total irrigation scheme outflows(24,149)
Closing balance (at 30 June 2014)(29)
Balancing item1,427

 

The calculation of the water balance on the irrigation scheme yielded a balancing item of 1,427 ML, which is approximately 5% of the total irrigation scheme inflows for the 2013–14 year.

The balancing item may be due to:

  • Different methods of measuring flows to and from the irrigation scheme for different data suppliers.
  • Inconsistent time periods for measurement: The irrigation year is October–September and customer meters are not read on 30 June. Therefore, the volume reported for delivery to irrigation scheme users for the Virginia Pipeline Scheme was the metered volume of water at their pumping station, not at customer meters.
  • There is no reporting of evaporation and precipitation on the irrigation scheme or leakage to groundwater, due to lack of available data.

 

Unaccounted-for difference

The volume recognised in the water accounting statements 367,403 ML represents the total unaccounted-for difference for the Adelaide region for the 2013–14 year.

The unaccounted–for difference is the volume necessary to reconcile the opening water storage and closing water storage with the total water inflows and total water outflows reported in the water accounting statements (Table 10).

 

Table 10 Calculation on unaccounted-for difference for the 2013–14 year
Account: water storageVolume (ML)
Opening water storage (at 1 July 2013)175,670
Total water inflows901,295
Total water outflows(498,455)
Closing water storage (at 30 June 2014)(211,107)
Unaccounted-for difference367,403

 

The unaccounted–for difference can also be calculated by summing the volumes necessary to reconcile (balance) the opening and closing storage with the water inflows and outflows of each of the separate water stores of the region, as shown in Table 11.

 

Table 11 Balancing volumes of the water stores of the Adelaide region for the 2013–14 year
Balancing itemVolume (ML)
surface water store251,208
groundwater store109,864
urban water system store4,904
irrigation scheme store1,427
Unaccounted-for difference367,403

 

Table 11 shows that the unaccounted-for difference is largely made up of the balancing items for the surface water and groundwater stores. 

The balancing item may be due to several reasons:

  • Some items are not quantified, or only partly quantified due to lack of data. This includes evaporation from and precipitation to rivers as well as some surface water/groundwater interactions. Also, river and floodplain losses cannot be quantified in the account. It is likely that these losses are a relatively large source of surface water decrease throughout the region.
  • There is uncertainty associated with the meteorological inputs into the rainfall-runoff model and the model structure, estimated to be in the range of 10–20% (up to +/– 90,000 ML).
  • Quantification of river outflow to sea also contributes to the large balancing item for the surface water asset. River outflow to sea is based on measured flow data collected at the most downstream station along a river. There is no adjustment made for the contributing area below the gauging station. As such, outflow to sea is likely to be underestimated by 10–20% (up to 30,000 ML).
  • The actual physical volume in the groundwater asset is not quantified but represents the average long-term groundwater volume available for extraction without adversely impacting the system. It is essentially constant from year to year.
  • The omission of some items such as recharge from surface water to groundwater and discharge to off-channel water storage due to a lack of data.
  • Groundwater discharge to surface water was the average annual baseflow and does not necessarily represent the flux during the year.

 

Off-channel storages

Off-channel storages refer to farm dams or other landscape catchment storages used to harvest runoff, floodwater or collected rainwater. Water held in off-channel water storages is considered to be taken from the shared pool of water resources and, as such, is not included as part of the region's water assets (see more on off-channel storages under Water resources in  'Physical information').

Water held in and abstracted from off-channel water storages is used for a combination of purposes including industrial, irrigation, and stock and domestic purposes. In the Barossa, water from off-channel water storages is predominantly used for irrigation purposes (Barossa Precribed Water Resources (PWRA) Water Allocation Plan: p26), whereas throughout the rest of the Adelaide region the majority of off-channel water services stock and domestic purposes (Western Mount Lofty Ranges PWRA Water Allocation Plan: p72)

This note provides additional information about water that has been harvested from the landscape into off-channel water storages and; therefore, did not contribute to groundwater recharge or runoff into surface water.

 

Off-channel water store

The volume of water held in off-channel water storages increased from 14,913 ML to 17,223 ML during the 2013–14 year.

 

Off-channel inflows and outflows

A schematic diagram representing all the inflows and outflows associated with the off-channel water store in the Adelaide region is provided in Figure 16.

 

Figure 16 Water inflows and outflows for Adelaide's off-channel water store during the 2013–14 year
Figure 16 Water inflows and outflows for Adelaide's off-channel water store during the 2013–14 year
 

 

The volumes presented in Figure 16 only relate to off-channel water storages that are filled primarily by rainfall-runoff capture. Off-channel water storages in the region that are filled by groundwater extractions, surface water diversions or recycled water transfers are not included here as these inflows cannot be quantified due to a lack of available data; however, these volumes are considered to be relatively small as these types of off-channel water storages make up only a small portion of the total number of off-channel storages in the region.

The total volume of runoff harvested by off-channel storages during the 2013–14 year was 15,095 ML. Given the total runoff into surface water during the year was 448,723 ML (see Surface water note), it can be assumed that runoff harvesting reduced streamflow in the Adelaide region by less than 1%.

 

Balancing item

The balancing item volume represents the difference between the measured opening and closing balances of the surface water store, after physical inflows and outflows have been applied (Table 12). 

 

Table 12 Balancing item for the off-channel water store for the 2013–14 year
AccountVolume (ML)
Opening balance at 1 July 201314,913
Total off-channel water inflows27,860
Total off-channel water outflows(25,549)
Closing balance at 30 June 2014(17,223)
Balancing item1

 

The calculation of the water balance on the off-channel water storages yielded a balance of 1 ML. This is less than 0.1% of the total off-channel water storage volume at the end of the 2013–14 year.