A review of the use of remote sensing techniques in assessing irrigation water use

Accurate monitoring of irrigation water use (IWU) is essential for improving irrigation efficiency and countering global water stress. A key technique for monitoring IWU is satellite remote sensing, which observes the Earth ex-situ. This review synthesizes recent studies (2005–2024) to clarify the progress made and challenges in remote sensing of IWU, with a focus on global developments and specific emphasis on Australia, where vast geographic extent, regulatory complexity, and intensive irrigation pose unique challenges. Our objectives were to examine the relationships among methods, sensor types and measured variables, evaluate validation practices and identify study gaps in Australia. We found that studies have predominantly used optical sensors (82 %) to assess IWU while most other sensor types remain underutilized, particularly at regional scales, such as in Australia. Of the studies reviewed, 61 % validated their IWU estimates against field data, 24 % against reference data, 9 % against both reference and field data while 6 % did not perform validation. We highlight the need for strategic integration of remote sensing methods and sensor types to estimate IWU, supported by rigorous validation processes. Australia’s diverse agro-climatic landscape provides a valuable ground for evaluating and comparing different sensor types when used within various methods to estimate IWU. Furthermore, recent technological advances in optical, radar and microwave sensors, and future satellite missions present new opportunities in IWU monitoring. Overall, a coordinated approach within which policy makers are actively involved is essential for strengthening practical applicability of IWU estimates.