Characteristics of Groundwater Irrigation Development in Australia

Groundwater development for irrigation has not received the significant subsidies characteristic of surface water irrigation. The process for irrigation development of groundwater has evolved directly from policies put in place to ensure that groundwater development processes could readily accommodate the high priority of remote town, as well as stock and domestic, supplies. The typical process has been for an irrigator to nominate preferred bore sites on a property, and apply for a groundwater licence. Assessments of nominated sites are made, and licences issued according to bore yield and need. The full cost of infrastructure (installation, operation and maintenance) is borne by the irrigator. In practice, bore owners have generally been fairly free to go about their business. Lack of a linear supply system (river or channel) limits natural centralization, which encourages communication between groundwater stakeholders.

By the very nature of this decentralized development, groundwater users are characterized as being highly independent, autonomous and protected by:

1. ownership of infrastructure located on private land;

2. limited detail of scientific understanding of cause-and-effect relationships between resource availability and resource use.

The private investment and operation of infrastructure make changes to groundwater management difficult and highly dependent on social willingness to comply (see case study 2).

Australian groundwater irrigation development is a natural response to surface water availability, markets and the expanding politics and compliance overheads of surface water development. In many established irrigation areas, groundwater development has been characterized by a tangible trade-off between poorer water quality and enhanced supply security. Table 15.4 summarizes resource and institutional differences between surface and groundwater irrigation.

Table 15.4. Characteristics distinguishing surface water and groundwater.

Characteristic

Primary nature of development Infrastructure funding

Management of flow

Public awareness

Security of supply

Water quality

Physical extraction limit

Capacity to enforce legal limits

Monitoring and reporting

Primary financial costs of water use and entitlement

Markets

Ease of monitoring and building resource data

Surface water

Centralized (Historically) publicly subsidized Linearly regulated High Low

High (managed) Volume in storage High (linearly regulated)

Regulatory and centralized Levies

Well established and widely available Relatively high

Groundwater

Decentralized Private

Unregulated Low High Variable

Bore capacity, draw-down Variable (private infrastructure on private land)

Variable, generally less than surface water Infrastructure installation, maintenance and operation Wide range. Generally developing Low

Salinity management and extractive use have dominated public awareness of groundwater. Salinity management has been the dominant issue to date, given the significance of irrigation-induced salinity problems, particularly in the state of Victoria. Irrigation-induced salinity largely occurs because of rise in water table due to progressive accessions from irrigated fields and water supply infrastructure, where the groundwater is naturally saline or intersects naturally saline soils and rock formations.

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