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National Water Account 2015

Perth: Water resources and systems

Perth city from the Swan Brewery (iStock © s_porter01)

Introduction

The following set of notes provides water accounting statements for each of the water stores and systems within the Perth region during the 2014–15 year. Information on all water flows to and from each water store and system are presented in this note, including between-store flows and transfers that are not presented in the consolidated water accounting statements (which are shown in italics).

For more information about the region, please refer to the General description section of the 'Contextual information'. For more information on between-store flows and transfers that occur in the region, please refer to the Supporting information note.

 

Surface water

Statement of Water Assets and Water Liabilities

The Statement of Water Assets and Water Liabilities presents the volume of water assets and water liabilities at the start and end of the reporting year.

Surface water assets of the region include physical water assets (e.g., storages and rivers) and rights or claims to water. Surface water liabilities include commitments to deliver water to users at the end of the year. The closing net water assets are the volume of surface water assets in the region minus the surface water liabilities at the end of the reporting year (Figure N18).

 

Figure N18 Schematic diagram of surface water assets and surface water liabilities for the region at 30 June 2015
Figure N18 Surface water assets and surface water liabilities for the region at 30 June 2015

 

Details on the region's surface water assets and surface water liabilities for the 2014–15 year are also provided in Table N26.

 

Table N26 Statement of Water Assets and Water Liabilities as at 30 June 2015 for the surface water store
 2015
ML		2014
ML
Water assets  
Storages202,362204,898
Unregulated river––
Regulated river––
Lakes and wetlands––
Total water assets202,362204,898
   
Water liabilities  
Allocation remaining: individual users8,43712,587
Allocation remaining: urban system00
Allocation remaining: irrigation scheme22,87712,718
Total water liabilities31,31425,305
   
Opening net water assets179,593135,154
Change in net water assets(8,545)44,439
Closing net water assets171,048179,593

 

Statement of Changes in Water Assets and Water Liabilities

The Statement of Changes in Water Assets and Water Liabilities presents the changes in water assets and water liabilities that occurred during the reporting year.

This statement is prepared on an accrual basis. Figure N19 shows the transactions that changed the surface water assets and surface water liabilities of the region, including:

  • accrual (non-physical) transactions, indicated by the glass-of-water symbols
  • actual water flows (both natural and engineered), indicated by the arrows.

 

Figure N19 Schematic diagram of changes in surface water assets and surface water liabilities for the region during the 2014–15 year
Figure N19 Changes in surface water assets and surface water liabilities for the region during the 2014–15 year

 

Details on the changes in surface water assets and surface water liabilities for the 2014–15 year are also provided in Table N27.

 

Table N27 Statement of Changes in Water Assets and Water Liabilities for the 2014–15 year for the surface water store
 2015
ML		2014
ML
Water asset increases  
Precipitation21,23825,009
Discharge: groundwater291,896283,158
Runoff549,983787,143
Point return: irrigation––
Delivery: inter-region1,8582,539
Discharge: urban supply74,17259,469
Total water asset increases939,1471,157,318
   
Water liability decreases  
Adjustment and forfeiture: individual users4,0455,219
Adjustment and forfeiture: urban system128,301142,071
Adjustment and forfeiture: irrigation11,5065,807
Total water liability decreases143,852153,097
   
Water asset decreases  
Evaporation46,05233,600
Outflow380,925555,390
Recharge: groundwater00
Leakage: landscape150196
River and floodplain losses––
Total water asset decreases427,127589,186
  
Water liability increases  
Allocation: individual users38,55633,958
Allocation: urban system247,950247,950
Allocation: irrigation54,62346,481
Total water liability increases341,129328,389
   
Balancing item—surface water(323,288)(348,401)
   
Change in net water assets(8,545)44,439

 

Statement of Water Flows

The Statement of Water Flows presents the actual water inflows and outflows associated with the water stores of the region that occurred during the reporting year.

Figure N20 shows the actual surface water flows, including flows corresponding to the accrual transactions shown in Figure N19 above (red arrows).

 

Figure N20 Schematic diagram of surface water flows for the region during the 2014–15 year
Figure N20 Surface water flows for the region during the 2014–15 year

 

Details on the surface water flows for the 2014–15 year are also provided in Table N28.

 

Table N28 Statement of Water Flows for the 2014–15 year for the surface water store
 2015
ML		2014
ML
Water inflows  
Precipitation21,23825,009
Discharge: groundwater291,896283,158
Runoff549,983787,143
Point return: irrigation ––
Delivery: inter-region1,8582,539
Discharge: urban supply74,17259,469
Total water inflows939,1471,157,318
   
Water outflows  
Evaporation46,05233,600
Outflow380,925555,390
Recharge: groundwater00
Leakage: landscape150196
River and floodplain losses ––
Allocated diversion: individual users38,66133,861
Allocated diversion: urban system119,649105,998
Allocated diversion: irrigation32,95834,466
Total water outflows618,395763,511
   
Balancing item—surface water(323,288)(348,401)
   
Opening water storage204,898159,492
Change in water storage(2,536)45,406
Closing water storage202,362204,898

 

 

Groundwater

Statement of Water Assets and Water Liabilities

The Statement of Water Assets and Water Liabilities presents the volume of water assets and water liabilities at the start and end of the reporting year.

Groundwater assets of the region include physical water assets (e.g., water table aquifer and underlying aquifers) and rights or claims to water. Groundwater liabilities include commitments to deliver water to users at the end of the year. The closing net water assets are the volume of groundwater assets in the region minus the groundwater liabilities at the end of the reporting year (Figure N21).

 

Figure N21 Schematic diagram of groundwater assets and groundwater liabilities for the region at 30 June 2015
Figure N21 Groundwater assets and groundwater liabilities for the region at 30 June 2015

 

Details on the region's groundwater assets and groundwater liabilities for the 2014–15 year are also provided in Table N29.

 

Table N29 Statement of Water Assets and Water Liabilities as at 30 June 2015 for the groundwater store
 2015
ML		2014
ML
Water assets  
Water table aquifer––
Underlying aquifers––
Total water assets––
   
Water liabilities  
Allocation remaining: individual users109,093116,430
Allocation remaining: urban system00
Total water liabilities109,093116,430
   
Opening net water assets(116,430)(124,858)
Change in net water assets7,3378,428
Closing net water assets(109,093)(116,430)

 

Statement of Changes in Water Assets and Water Liabilities

The Statement of Changes in Water Assets and Water Liabilities presents the changes in water assets and water liabilities that occurred during the reporting year.

This statement is prepared on an accrual basis. Figure N22 shows the transactions that change the groundwater assets and groundwater liabilities of the region, including:

  • accrual (non-physical) transactions, indicated by the glass-of-water symbols
  • actual water flows (both natural and engineered), indicated by the arrows.

 

Figure N22 Schematic diagram of changes in groundwater assets and groundwater liabilities for the region during the 2014–15 year
Figure N22 Changes in groundwater assets and groundwater liabilities for the region during the 2014–15 year

 

Details on the changes in groundwater assets and groundwater liabilities for the 2014–15 year are also provided in Table N30.

 

Table N30 Statement of Changes in Water Assets and Water Liabilities for the 2014–15 year for the groundwater store
 2015
ML		2014
ML
Water asset increases  
Inter-region inflow45,21852,788
Inter-region coastal inflow00
Recharge: landscape1,304,5301,937,932
Recharge: surface water00
Leakage: urban system21,15521,005
Leakage: irrigation––
Managed aquifer recharge: urban system198614
Discharge: urban system1,5921,648
Total water asset increases1,372,6932,013,987
   
Water liability decreases  
Adjustment and forfeiture: individual users13,63714,172
Adjustment and forfeiture: urban system6,8917,203
Total water liability decreases20,52821,375
   
Water asset decreases  
Inter-region outflow23,43930,164
Inter-region coastal outflow341,881433,999
Discharge: landscape378,114622,737
Discharge: surface water291,896283,158
Non-allocated extraction: individual users79,61073,249
Total water asset decreases1,114,9401,443,307
   
Water liability increases  
Allocation: individual users287,753287,262
Allocation: urban system129,019132,054
Total water liability increases416,772419,316
   
Balancing item—groundwater145,828(164,311)
   
Change in net water assets7,3378,428

 

Statement of Water Flows

The Statement of Water Flows presents the actual water inflows and outflows associated with the water stores of the region that occurred during the reporting year.

Figure N23 shows the actual groundwater flows, including flows corresponding to the accrual transactions shown in Figure N22 above (red arrows).

 

Figure N23 Schematic diagram of groundwater flows for the region during the 2014–15 year
Figure N23 Groundwater flows for the region during the 2014–15 year

 

Details on the groundwater flows for the 2014–15 year are also provided in Table N31.

 

Table N31 Statement of Water Flows for the 2014–15 year for the groundwater store
 2015
ML		2014
ML
Water inflows  
Inter-region inflow45,21852,788
Inter-region coastal inflow00
Recharge: landscape1,304,5301,937,932
Recharge: surface water00
Leakage: urban system21,15521,005
Leakage: irrigation––
Managed aquifer recharge: urban system198614
Discharge: urban system1,5921,648
Total water inflows1,372,6932,013,987
   
Water outflows  
Inter-region outflow23,43930,164
Inter-region coastal outflow341,881433,999
Discharge: landscape378,114622,737
Discharge: surface water291,896283,158
Non-allocated extraction: individual users79,61073,249
Allocated extraction: individual users281,453281,518
Allocated extraction: urban system122,128124,851
Total water outflows1,518,5211,849,676
   
Balancing item—groundwater145,828(164,311)
   
Opening water storage––
Change in water storage00
Closing water storage––

 

 

Urban water system

Statement of Water Assets and Water Liabilities

The Statement of Water Assets and Water Liabilities presents the volume of water assets and water liabilities at the start and end of the reporting year.

Urban water system assets of the region include physical water assets (e.g., water within the urban supply, wastewater and recycled water systems) and rights or claims to water. The total net water assets are the sum of the physical water assets in the system and the water claims at the end of the reporting year (Figure N24).

 

Figure N24 Schematic diagram of urban water assets and urban water claims for the region at 30 June 2015
Figure N24 Urban water assets and urban water claims for the region at 30 June 2015

 

Details on the region's urban water systems assets and urban water claims for the 2014–15 year are also provided in Table N32.

 

Table N32 Statement of Water Assets and Water Liabilities as at 30 June 2015 for the urban water system
 2015
ML		2014
ML
Water assets  
Supply system7,1027,002
Wastewater––
Recycled water––
Claims: surface water00
Claims: groundwater00
Total water assets7,1027,002
   
Opening net water assets7,0026,878
Change in net water assets100124
Closing net water assets7,1027,002

 

Statement of Changes in Water Assets and Water Liabilities

The Statement of Changes in Water Assets and Water Liabilities presents the changes in water assets and water liabilities that occurred during the reporting year.

This statement is prepared on an accrual basis. Figure N25 shows the transactions that change the urban water system assets and urban water claims of the region, including:

  • accrual (non-physical) transactions, indicated by the glass-of-water symbols
  • actual water flows (both natural and engineered), indicated by the arrows.

 

Figure N25 Schematic diagram of changes in urban water assets and urban water claims for the region during the 2014–15 year
Figure N25 Changes in urban water assets and urban water claims for the region during the 2014–15 year

 

Details on the changes in urban water system assets and urban water claims for the 2014–15 year are also provided in Table N33.

 

Table N33 Statement of Changes in Water Assets and Water Liabilities for the 2014–15 year for the urban water system
 2015
ML		2014
ML
Water asset increases  
Wastewater collected140,771141,024
Supply system delivery: inter-region1,9222,121
Delivery: desalinated water119,457113,060
Claims: surface water247,950247,950
Claims: groundwater129,019132,054
Total water asset increases639,119636,209
   
Water asset decreases  
Leakage: groundwater21,15521,005
Supply system delivery: urban users232,537234,774
Recycled water delivery: urban users8,0358,203
Supply system discharge: surface water74,17259,469
Discharge: sea125,025124,900
Discharge: landscape5,9625,673
Managed aquifer recharge198614
Discharge: groundwater1,5921,648
Supply system transfer: inter-region24,79620,797
Claims: surface water128,301142,071
Claims: groundwater6,8917,203
Other supply system decreases10,01610,005
Total water asset decreases638,680636,362
   
Balancing item—urban water system(339)277
   
Change in net water assets100124

 

Statement of Water Flows

The Statement of Water Flows presents the actual water inflows and outflows associated with the water stores of the region that occurred during the reporting year.

Figure N26 shows the actual urban water system flows, including flows corresponding to the accrual transactions shown in Figure N25 above (red arrows).

 

Figure N26 Schamatic diagram of urban water flows for the region during the 2014–15 year
Figure N26 Urban water flows for the region during the 2014–15 year

 

Details on the urban water system flows for the 2014–15 year are also provided in Table N34.

 

Table N34 Statement of Water Flows for the 2014–15 year for the urban water system
 2015
ML		2014
ML
Water inflows  
Wastewater collected140,771141,024
Supply system delivery: inter-region1,9222,121
Delivery: desalinated water119,457113,060
Allocated diversion: surface water119,649105,998
Allocated extraction: groundwater122,128124,851
Total water inflows503,927487,054
   
Water outflows  
Leakage: groundwater21,15521,005
Supply system delivery: urban users232,537234,774
Recycled water delivery: urban users8,0358,203
Supply system discharge: surface water74,17259,469
Discharge: sea125,025124,900
Discharge: landscape5,9625,673
Managed aquifer recharge198614
Discharge: groundwater1,5921,648
Supply system transfer: inter-region24,79620,797
Other supply system decreases10,01610,005
Total water outflows503,488487,088
   
Balancing item—urban water system(339)277
Opening water storage7,0026,759
Change in water storage100243
Closing water storage7,1027,002

 

 

Irrigation scheme

Statement of Water Assets and Water Liabilities

The Statement of Water Assets and Water Liabilities presents the volume of water assets and water liabilities at the start and end of the reporting year.

Irrigation scheme assets of the region include physical water assets (i.e., water within the supply system) and rights or claims to water. The total net water assets are the sum of the physical water assets in the system and the water claims at the end of the reporting year (Figure N27).

 

Figure N27 Schematic diagram of irrigation water assets and irrigation water claims for the region at 30 June 2015
Figure N27 Irrigation water assets and irrigation water claims for the region at 30 June 2015

 

Details on the region's irrigation scheme assets and irrigation water claims for the 2014–15 year are also provided in Table N35.

 

Table N35 Statement of Water Assets and Water Liabilities as at 30 June 2015 for the irrigation scheme
 2015
ML		2014
ML
Water assets  
Supply system390390
Claims: surface water22,87712,718
Total water assets23,26713,108
   
Opening net water assets13,1086,900
Change in net water assets10,1596,208
Closing net water assets23,26713,108

 

Statement of Changes in Water Assets and Water Liabilities

The Statement of Changes in Water Assets and Water Liabilities presents the changes in water assets and water liabilities that occurred during the reporting year.

This statement is prepared on an accrual basis. Figure N28 shows the transactions that change the irrigation scheme assets and irrigation water claims of the region, including:

  • accrual (non-physical) transactions, indicated by the glass-of-water symbols
  • actual water flows (both natural and engineered), indicated by the arrows.

 

Figure N28 Schematic diagram of changes in irrigation water assets and irrigation water claims for the region during the 2014–15 year
Figure N28 Changes in irrigation water assets and irrigation water claims for the region during the 2014–15 year

 

Details on the changes in irrigation scheme assets and irrigation water claims for the 2014–15 year are also provided in Table N36.

 

Table N36 Statement of Changes in Water Assets and Water Liabilities for the 2014–15 year for the irrigation scheme
 2015
ML		2014
ML
Water asset increases  
Claims: surface water54,62346,481
Total water asset increases54,62346,481
   
Water asset decreases  
Leakage: groundwater––
Delivery31,42633,622
Return flow: surface water––
Claims: surface water11,5065,807
Total water asset decreases42,93239,429
   
Balancing item—irrigation scheme(1,532)(844)
   
Change in net water assets10,1596,208

 

Statement of Water Flows

The Statement of Water Flows presents the actual water inflows and outflows associated with the water stores of the region that occurred during the reporting year.

Figure N29 shows the actual irrigation scheme flows, including flows corresponding to the accrual transactions shown in Figure N28 above (red arrows).

 

Figure N29 Schematic diagram of irrigation water flows for the region during the 2014–15 year
Figure N29 Irrigation water flows for the region during the 2014–15 year

 

Details on the irrigation scheme flows for the 2014–15 year are also provided in Table N37.

 

Table N37 Statement of Water Flows for the 2014–15 year for the irrigation scheme
 2015
ML		2014
ML
Water inflows  
Allocated diversion: surface water32,95834,466
Total water inflows32,95834,466
   
Water outflows  
Leakage: groundwater ––
Delivery31,42633,622
Return flow: surface water––
Total water outflows31,42633,622
   
Balancing item—irrigation scheme(1,532)(844)
   
Opening water storage390390
Change in water storage00
Closing water storage390390