Response to claims about the impact of improved water infrastructure on environmental outcomes in the MDB (27 July 2017)

The Department of Agriculture and Water Resources administers a number of successful programs to return water to the environment in the Murray-Darling Basin, with a priority focus on improving the efficiency of irrigation infrastructure.

Recent claims that more efficient irrigated agriculture damages the environment by reducing ‘return flows’ to rivers are spurious.

Return flows are when excess water from irrigation runs off the surface and back into the river system or leaks into the ground. The claim made is that more efficient water infrastructure means there is less excess water and therefore there is less return flows available for the environment.

Following this line of thinking would promote less efficient irrigation, in order to maximise these return flows.

The Department disagrees with this view.

While ‘return flows’ can be reduced by more efficient irrigation infrastructure, this is usually a good thing. ‘Return flows’ can cause environmental damage, particularly where:

  • irrigation surface run-off contains high levels of nutrients, salt or other pollutants; or
  • seepage due to inefficient watering causes rising water tables and salinisation of our rivers and landscape.

The Australian Government’s irrigation efficiency programs recover at least 50 per cent of water savings as water entitlement held by the Commonwealth Environmental Water Holder (CEWH). The CEWH is able to use this water when and where it can have the most benefit to the environment. This represents a much better environmental outcome than ‘return flows’, which are invariably of poor quality and by their nature are not able to be directed to best environmental effect.

As we have seen over time, irrigators who strive to improve their efficiency have less wastage and reduced salinity and water quality issues. Irrigators could fund these efficiency improvements themselves and retain all of the water savings. Instead, through Australian Government-funded programs, we are ensuring that water savings are shared between farmers and the environment.

To date, water entitlement yielding almost 2100 gigalitres annually (on average) has been recovered or is contracted, and will deliver on an ongoing basis significant environmental benefits across the Basin.

Implementing the Basin Plan is a major long-term undertaking. Early benefits are already apparent, and should provide all Australians with confidence that the enduring triple-bottom line outcomes envisaged by the Plan are being delivered. ​