INTRODUCTION

1 Water Account Australia presents information on the supply and use of water in the Australian economy in 2008–09, compiled in accordance with the System of Integrated Environmental and Economic Accounting. In successive sections Water Account Australia provides additional information on key industries' (agriculture, mining, manufacturing, water supply, sewerage and drainage, households) water use and consumption practices. This additional information presents physical supply and use tables for the Murray-Darling Basin.


METHODS FOR CALCULATING WATER SUPPLY AND USE IN THE MURRAY-DARLING BASIN (MDB)

2 These notes are intended as a general guide to the method use to calculate estimates of water supply and use. For more detail on the methods please refer to the Explanatory Notes for the national Water Account Australia or contact the Director, Environmental Accounts and Water (EAW), Australian Bureau of Statistics.

3 For Water Supply, Sewerage and Drainage Services;

• Water utilities from the Water Supply Survey were were identified within the MDB, based on geographic spatial coding of address information contained within the Australian Business Register, Local Government Area (LGA) boundaries and meshblock population estimates.
• Of the 151 water utilities supplying to the MDB region:
  • 119 water utilities supplied water exclusively within the MDB region, accounting for approximately 57% of the total MDB water supply.
  • 3 water utilities supplied water to specific rivers systems that are exclusively inside or outside of the MDB, accounting for 42% of the total MDB water supply.
  • 29 water utilities operated on the boundary of the MDB region, supplying to regions within and immediately surrounding the MDB. The water supplied into the MDB region from these utilities accounts for 1% of the total MDB water supply.

• For the 29 water utilities operating on the MDB boundary, water supply was allocated into the MDB on the basis of population density within Local Government Areas (LGA's). Where the percentage of the served population was above 85%, the supplier was deemed to be supplying totally inside the MDB. Where the percentage of the served population was below 15% inside the MDB, the supplier was deemed to be supplying totally outside of the MDB.

4 For Agriculture;

• The MDB data (physical supply and use tables) presented in this publication are similar but slightly different to those data presented in Water Use on Australian Farms, 2008–09 (cat. no. 4618.0) (ABS 2010), for several reasons:
  • the multiple data sources used in the 2008–09 Water Account Australia, compared to the single source of ABS survey data used for Water Use on Australian Farms, 2008–09;
  • an industry view of agriculture is provided in the 2008–09 MDB physical supply and use tables presented in this publication, whereas Water Use on Australian Farms presents an activity view. In an industry view, all businesses are coded to an industry according to the Australian and New Zealand Standard Industrial Classification (ANZSIC 2006). An industry view provides direct links to the economic information in the System of National Accounts. This enables data such as industry value added to be compared to water consumption. The Agriculture industry view presents only the agricultural activity that occurs in businesses where the primary income producing activity (i.e. the activity with value added that exceeds the value added of any other activity carried out by the same business) of the business is agricultural production. Businesses which undertake some agricultural activity but for which other activities provide most of the income are excluded from the Agriculture industry view. For example, a business which generates most of its income from transporting agricultural produce, but also grows some agricultural commodities would be classified to the industry Transport, Postal and Warehousing. The agricultural production is still counted but is attributed to the Transport, Postal and Warehousing industry.
  • water use estimates for Victoria and the Victorian region of the MDB were supplemented with information from the Victorian Water Register (Department of Sustainability and Environment, State Government Victoria, 2010);
  • the location of agricultural businesses was geo-coded (latitude and longitude) to provide estimates for the MDB. The MDB data used in Water Use on Australian Farms, 2008–09 were derived from a concordance of Natural Resource Management (NRM) regions falling mostly within the MDB. This difference between the two methodologies results in only very small differences in the estimates (less than 0.2%), compared to the other differences described in the dot points above.

5 For Mining;

• The source of water use data for Mining, the 2008–09 Energy, Water and Environment Survey (EWES), completely enumerated all mines within the MDB and volumes used were directly applied in the supply and use tables. Mining businesses were identified within the MDB, based on geographic spatial coding of address information contained within the Australian Business Register.

6 For Manufacturing;

• Data for manufacturing businesses were collected via the 2008–09 EWES. Business units were mapped to the MDB based on geographic spatial coding of address information contained within the Australian Business Register. The EWES survey is designed on the basis of a national sample, therefore there may be some non-sampling error associated with these estimates at the regional level. This non-sample error is not quantifiable, however the ABS is currently investigating a refinement to this estimation process.

7 For Electricity and Gas Supply;

• Water information for electricity generators was obtained via the ABS Electricity Generators Survey, which was based on a complete enumeration of all electricity generators at the power plant level. These survey units were identified within the MDB, based on geographic spatial coding of address information contained within the Australian Business Register.

8 For Other industries (see Glossary for list of industries included in this category);

• Data for businesses in Other industries were collected via the 2008–09 EWES. Business units were mapped to the MDB based on geographic spatial coding of address information contained within the Australian Business Register. The EWES survey is designed on the basis of a national sample, therefore there may be some non-sampling error associated with these estimates at the regional level. This non-sample error is not quantifiable, however the ABS is currently investigating a refinement to this estimation process.

9 For household water use;

• Household volumes were derived from the Water Supply methodology of populations served by suppliers fully or partially located inside the MDB.

ENVIRONMENTAL FLOWS

10 Environmental flows are not separately identified within the Murray-Darling Basin as some water utilities do not measure all environmental flows and there is subsequent uncertainty around the level estimate. The environmental flows that were reported in surveys are presented within the estimates for distributed, reuse water and in-stream water used by the water supply and electricity generation industry. Consumption for these industries is not affected by this treatment of environmental flow volumes.

DATA QUALITY AND RELIABILITY

11 All water information presented in this additional information were collected by the ABS and validated with other data sources (i.e. estimates for the water supply; electricity, gas, water and waste services; mining; manufacturing; and agriculture industry at the ANZSIC Division Level).

12 Data relating to the following categories can be used with a high degree of confidence:

• total water use
• water use by Agriculture
• water use by Electricity and Gas Supply industry
• water use by Mining industry
  

13 Data relating to the following categories should be used with some caution:

• water use by the Manufacturing industry
• water use by the amalgamation of all Other industries.

NEXT EDITION

14 Physical and monetary supply and use tables for the MDB will be published in the next edition of Water Account Australia (reference period 2009–10) scheduled for release in November 2011.