**8. Conclusions**

The purpose of this paper was to review the steps that have been taken to improve the use of the scarce water resources, with a focus on irrigation in Australia but with examples from other countries. We also looked at the challenges that have been encountered and explored opportunities that may lead to improved WUE in the future.

The Australian Federal, State and Territory Governments have facilitated the modernisation and automation of irrigation infrastructure such as distribution channels and improvements on on-farm irrigation hardware. This has led to improved WUE, and some of the water saved has been used for environmental purposes. Improved irrigation scheduling and the real-time control and optimisation have also demonstrated potential for further water savings. The use of remote sensing and communication sensor networks are emerging in the irrigation industry and are expected to contribute to improve WUE. However, challenges lie in the way of enhanced WUE. These include lack of public support, especially when the methods used are not cost-effective, and reluctance of irrigations to adopt new technologies.

The review has demonstrated that the adoption of water-efficient technologies has delivered water savings at the field scale, with some of the savings being released as environmental flows. However, the net water saving at the basin scale is not always achievable. In fact, some studies have demonstrated that a net increase in water consumption, largely due to the reuse of the saved water to expand the area of land under irrigation. Hence, an overall reduction of water consumption at the basin scale is likely to be achieved when water-efficient technologies are used in combination with other measures, such as provision of incentives for water conservation and regulations to limit water allocation.

**Author Contributions:** R.K. conceptualised this review study and produced the first draft of the manuscript. P.L. reviewed the draft, rewrote some sections and formatted the paper.

**Funding:** This research received no external funding.

**Acknowledgments:** We sincerely acknowledge and appreciate the comments and suggestions we received from the anonymous reviewers and editor of this journal.

**Conflicts of Interest:** The authors declare no conflicts of interest.
