Murray-Darling Basin water market catchment dataset 2021

The MDB water market catchment dataset covers the period of July 2000 to June 2021 and includes catchment regions in the MDB. The MDB is split into northern (nMDB) and southern (sMDB).  The nMDB covers QLD and northern NSW, while the sMDB covers southern NSW, ACT, Vic. and SA.

In preparing the data, ABARES focussed on providing consistent time series data for key catchments and irrigation activities in the basin. Supply data has been collected for all MDB regions in NSW, Vic. and SA, but was not collected for QLD regions. Irrigation activity data has been compiled for all catchments within the basin.

The list of regions in the Basin is outlined in Table 1, as well as if they are included in the demand and supply dataset.

Source: ABARES

The MDB water market catchment dataset offers several improvements over previous datasets released by ABARES. For example, the supply file includes additional variables, such as forfeited water (split by during year, and end of year), which allows for more accurate estimations of total water supply. The irrigation activity file provides a time series of catchment level data, which is the result of close collaboration with the ABS.

The construction of the MDB water market catchment dataset involved considerable effort, given the large number of data sources and various inconsistencies between them. A number of data imputations, assumptions and regression estimations were required, in addition to filling gaps through external data sources in order to generate time series data for a consistent set of regional and industry definitions.

The MDB water market catchment dataset draws from various sources, which are further detailed in the metadata spreadsheets accompanying this product. The construction of rainfall, commodity prices, allocations and carryover volume variables use the same methods as detailed in Gupta et al. 2018. All deflation adjustments use the Consumer Price Index as reported by the ABS (ABS 2021a).

Irrigation activity

The irrigation activity dataset has been split into an ‘area and water use’ dataset and a ‘production and value’ dataset due to differences in the scope of the underlying data. Each of the variables included in the irrigation activity datasets is listed in Table 2 and Table 3.

The area and water use dataset has been built from unit-record data collected through various agricultural censuses and surveys and provides irrigation activity data for catchment regions between 2010–11 and 2017–18. For the period 2005–06 to 2010–11 and from 2018–19 onwards, ABARES apportioned Natural Resource Management (NRM) level data to catchment regions, using methods previously described in Gupta et al. 2018. The apportioning method was further calibrated using data sourced from the ABS for 2010–11 to 2012–13.

The production and value dataset has also been built from unit-record data for catchment regions between 2005–06 and 2017–18 for selected commodities. For Almonds, Cotton, Grapevines and Rice, a custom dataset was created from ABS unit-record data for 2010-11 to 2017-18. For all other commodities, and from 2018–19 onwards, ABARES apportioned NRM level data to catchment regions.

Source: ABARES

Table 4 and Table 5 list the irrigation activities considered, which are based on ABS industry classifications. A significant feature of the MDB water market catchment dataset is that it separately reports data for the almonds industry, which is elsewhere part of the combined fruit and nut category reported by the ABS.

Table 4 shows the irrigation activities for the area and water use data. Revisions have made to the irrigation activities reported based on updates made by the ABS (ABS 2021b). The All other crops category is the aggregation of the previously reported Other broadacre, Other cereals and Other crops categories. The Pastures – Grazing category is the aggregation of previously reported Pastures for grazing and Dairy categories. See the metadata for additional information on how these series were constructed (Table 6).

Table 5 shows the irrigation activities for the production and value data. The key differences are the reporting of disaggregated Other cereals and Other broadacre categories, as well as Dairy and Pastures – Grazing categories (which continue to be reported by the ABS for production and value).

Source: ABARES

Source: ABARES

For regions within the MDB where data was missing (for example, due to ABS confidentiality constraints) ABARES has estimated values. ABARES has used a variety of methods to impute missing data, as listed in Table 6. All imputed data points are marked in additional columns in the dataset (denoted with the "meta" suffix) and remain subject to further refinement.

Source: ABARES

The supply file was compiled using data from the MDBA, state water agencies (NSW Department of Planning, Industry and Environment, Goulburn-Murray Water, Northern Victorian Resource Manager and the South Australian Department for Environment and Water), BOM and the Department of Agriculture, Water and the Environment (DAWE). Water price data has been compiled and cleaned by ABARES using the GAM price cleaning method described in Sanders et al. 2019.

Each of the variables included in the supply file are briefly described in Table 7, which contains data for catchments in the MDB from 2000–01 to 2020–21.

For 2020–21, data for water forfeits has not yet been published by NSW and has been estimated by ABARES based on the carryover rules applied in that state.

The volume of entitlements on issue reported in the supply file is based on 2020-21 data. As a result, some structural changes over the past two decades (such as the introduction of low reliability entitlements in Victoria) are smoothed over, as the data is intended to support modelling and analysis of forward-looking scenarios.

ABS 2021a, Consumer Price Index, Australia, cat. no. 6401.0, Australian Bureau of Statistics, Canberra, accessed 28 June 2021.

ABS 2021b, Water use on Australian farms, cat. no. 4618.0, Australian Bureau of Statistics, Canberra, accessed 14 May 2021.

Gupta, M, Hughes, N & Wakerman-Powell, K 2018, A model of water trade and irrigation activity in the southern Murray-Darling Basin, paper presented at the Australasian Agricultural & Resource Economics Society 2018 Annual Conference, Canberra, February, accessed 20 February 2020.

Sanders, O, Hughes, N & Gupta, M 2019, Measuring water market prices; Statistical methods for interpreting water trade data, ABARES research report, Canberra, February, CC BY 4.0, DOI: 10.25814/5c5388a92260d, accessed 24 February 2020.