abare.gov.au - research report 08.9

2	Methodology

The Murray-Darling Basin is the largest catchment for irrigation activities in Australia. In 2005-06, around 65 per cent per cent of the total area irrigated in Australia was situated within the Basin (ABS 2008). A wide range of irrigated agricultural enterprises are undertaken within the Basin, including vegetable crops, perennial tree and vine crops, pastures for grazing, rice, cotton and a variety of cereal, pulse and oilseed crops. Some of these enterprises, such as rice, rely entirely on the availability of irrigation water. Other activities, such as cereal crops, pasture and cotton, use irrigation water when available but can also be grown under dryland conditions. The major users of irrigation water within the Basin are dairy farms (mainly for pasture, hay and silage production), rice, cotton and horticulture (including both perennial and annual crops) (ABS 2008).

The ABARE survey was designed to provide good coverage of broadacre (including rice and cotton growers), dairy and horticulture irrigation farms within ten regions throughout the Murray-Darling Basin (table 1). The survey regions were chosen to cover the major irrigation regions in the Basin and were based on those defined by CSIRO in its ‘Sustainable Yields Project’ (CSIRO 2007a), namely: Condamine–Balonne; Border Rivers; Namoi; Macquarie–Castlereagh; Lachlan; Murrumbidgee; Murray; Goulburn–Broken; Loddon–Avoca; and Eastern Mount Lofty Ranges (map 1). Some of the CSIRO regions were not covered by the survey because of relatively small numbers of irrigation farms.

The survey was conducted by ABARE in two stages between October 2007 and March 2008. Irrigation farms in the southern part of the Basin were surveyed from October to December 2007 while farms in the remaining regions were surveyed between February and March 2008.

Sample farms were selected on the basis of data provided by the Australian Bureau of Statistics. Using these data, target farms were identified by an irrigation flag (defined as farms that irrigated in 2005-06), location (in terms of statistical local area), and industry classification. An advantage of this method is that benchmark data can be used to weight individual farm data in producing averages so surveyed farms are representative of an industry in a particular region. Summary results are provided at appendix A.

1	Population of irrigation farmsa and survey coverage, by region, 2006-07

population

sample

Condamine–Balonne

1 135

Border Rivers

585

Namoi

777

Macquarie–Castlereagh

658

Lachlan

834

Murrumbidgee

1 926

129

Murray

5 218

324

Goulburn–Broken

1 720

107

Loddon–Avoca

912

Eastern Mt Lofty Ranges

445

Total

14 210

900

a Defined as those farms in the dairy, horticulture or broadacre industries that irrigated in 2005-06.

In most regions, the farms surveyed in each industry were relatively homogeneous in terms of enterprise mix, but there was considerable variability across farms for individual estimates (appendix B).

The survey was conducted by ABARE field officers using face-to-face interviews to obtain physical and financial details of the farm business for the 2006-07 financial year. The questionnaire was designed to collect comprehensive data on land area and value; broadacre crop production and sales; tree and vine crop production and sales; irrigation water use by crop type and pasture; livestock production and sales; farm receipts and costs; labour use; debts and assets; and market values of farm capital. The survey also included questions on types of water licences held (see box 1); irrigation water use in 2006-07; water trading; types of irrigation infrastructure; basis for irrigation scheduling decisions; and future intentions.

An indication of the reliability of the estimates is given by relative standard errors; that is, estimates of standard errors expressed as a percentage of the estimate. Relative standard errors for each estimate are shown in parentheses in the tables. Detailed information on the survey methodology is provided at appendix C.

box 1

Defining water rights/entitlements

Irrigators may hold a number of water licences, as well as different types of water licences. Data on these licences were collected separately for individual farms. However, there is wide variation in the terminology used by each state to describe irrigation rights and entitlements. Also, in some irrigation districts, an irrigation corporation (eg Murray Irrigation Ltd) holds the access licence and individual irrigators within the area have access to a share of the water entitlement held by the irrigation corporation. For the purposes of collecting data in the survey, the following definitions were adopted:

Rights and entitlements

A right (also referred to as a water access entitlement or simply an entitlement) is the legal right to take water under conditions stipulated by an irrigation water management authority (usually a state government department). Water taking rights are either long-term (usually referred to as permanent rights) or short-term (often termed seasonal or temporary rights). Water rights are also mostly associated with a water source (that is, surface water, groundwater or overland flows).

New South Wales: Water licences generally apply to either a regulated river system (general security, high security and supplementary licences), unregulated river systems (unregulated river licence), or to groundwater (groundwater or aquifer access licence).

Victoria: All rights to take surface water in 2006-07 were called a water right. Some licence holders have access to sales water (this is periodically made available to irrigators when water storages have sufficient water to meet the current year’s and next year’s requirements). Groundwater users require a groundwater right.

South Australia: There is only one type of water right in South Australia called a water licence, although this will normally specify the source (either surface water or groundwater).

Queensland: There are a variety of terms used in Queensland depending on the region. Generally, these apply to surface water, harvesting of overland flows, or groundwater.