Purpose

The main purpose of this management practice is to identify changes in groundwater table levels. It is primarily carried out in irrigation cropping and by those who feel or are at risk from dryland salinity.

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In a recently completed national study on salinity indicators (NLWRA and BRS 2007), 'depth to groundwater' was generally identified and accepted as one of the most useful indicators of land salinity. Monitoring of groundwater tables can provide an indication of current risk of land salinity and also offer an early warning of changing catchment hydrology that might lead to the development of soil salinity (NLWRA and BRS 2007). Specifically, changes in the rate and magnitude of water table rises or falls can be used to estimate the potential for land salinisation, timeframes for groundwater system responses and the effectiveness of mitigation measures (NLWRA 2007).

While high and rising ground water tables are indicative of increased potential risk of dryland or irrigation-induced soil salinity and water logging, falling ground water tables can be caused by prolonged drought or be a response to mitigation strategies (e.g. planting of deep-rooted perennial pastures, trees and shrubs; pumping of water from aquifers) and static water tables indicate that recharge to the aquifer is equal to discharge. Therefore, monitoring 'water table depth and trend patterns can assist in, prioritise and inform management decisions' (NLWRA 2007).

Components that may be affected:        Biodiversity conservation.

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Some characteristics of monitoring water tables as a sustainable management practice were investigated by Cary et al. (2002). The results are presented in Table 1.

Table 1: Characteristics of sustainable management practices as assessed by Cary et al. (2002)

Sustainable practice	Geographic applicability	Relative advantage	Risk	Complexity	Compatibility	Trialability	Observability
(Ideal rating)	(high)	(high)	(low)	(low)	(high)	(high)	(high)
Regularly monitor water tables	medium	medium (locality)	low	low	low	high	medium

• Geographic applicability—refers to relative appropriateness of a practice, in terms of whether it is effective or adapted to only specific localities or, more universally, across many localities.
• Relative advantage—relates to the financial advantage or other convenience or personal advantage to the farm business or the adopter.
• Risk—refers to uncertainty about likely benefits or costs associated with a sustainable practice, the effectiveness of the practice, when the benefits might be realised and the social acceptability of the practice.
• Complexity—implies that a practice comprises more than one or two simple elements and that its elements interact with each other and, in sometimes complicated ways, with elements of the farming system into which it is to be incorporated.
• Compatibility—refers to the extent to which a practice fits in with existing farm practices, knowledge or social practice.
• Trialability—where practices can be implemented on a small or pilot scale, decisions can be more easily made about the value of a new practice without the risks associated with full implementation.
• Observability—practices where the impact or advantage is easily observable or the outcome quickly realised are more likely to be adopted.

Indicator

Percentage of farmers monitoring water tables on a regular basis.

Results

The 2001-02 Resource Management Survey, carried out by the Australian Bureau of Agricultural and Resource Economics (ABARE), estimated that 26 per cent of broadacre and dairy industry farm operators regularly monitored the water table on their property in 2001-02 (ABARE 2002). The The survey is carried out intermittently and may be repeated in the future (Nelson et al. 2004). Additional survey data from research and development corporations and grower groups may be available.

Table 2: Estimated percentage of farms using the management practice

^{Source- ABARE 2001-02 Resource Management Survey.} 

^{Note: RSE = Relative standard error; Population (farms) = 38502,  Sample (farms) = 579}

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VARIABLE	DESCRIPTION
Population	Estimated number of broadacre and dairy industry farms in the selected category with an EVAO greater than $22 500.
Sample	Number of broadacre and dairy industry farms that responded to questions in the 2001-02 Resource Management supplementary in the selected category.
Regularly monitor water tables	Regularly monitor water tables is part of farm management practices (wheat-sheep and high-rainfall zone only)

 

References

ABARE (2002) 2001-02 Resource Management Survey: Data Package 2001-02. Australian Bureau of Agricultural and Resource Economics, Canberra. Website- http://www.abareconomics.com/ame/lrm2/lrmalt.asp. Accessed 14/05/2007.

Cary, J. Webb, T. and Barr, N. (2002) Understanding landholders capacity to change to sustainable practices: Insights about practice adoption and social capacity for change. Bureau of Rural Sciences, Canberra, p. 17.

Nelson, R., Alexander, F., Elliston, L. and Blias, A. (2004) 2001-02 Resource Management Survey:Natural Resource Management on Australian Farms report. australian Bureau of Agricultural and Resource Economics, Canberra. Website- http://abareonlineshop.com/PdfFiles/PC12675.pdf. Accessed 14/05/2007.