Irrigation currently uses 70% of all the world's freshwater withdrawals. Given the increasing demands for water from all other sectors of the economy, including the environment, irrigation is going to have to give up some of its water and improve its water use efficiency to produce more product with less water. This means that every litre of water made available to irrigated agriculture needs to be used productively and that any potential ‘water losses’ need to be prevented or at least minimised. Seepage/leakage losses from water distribution channels are variable but have been measured to be 3 to 24 mm/day and as high as 50 to 400 mm/day. These are significant losses that waste money and reduce crop production, but the water losses can be reduced by lining water distribution channels with clay liners, concrete liners, geomembrane and/or other ‘plastic’ liners.

Various methods are now available to identify the locations where seepage losses occur and to help quantify losses from water distribution channels. We have visited and/or held conversations with water authorities, grower organisations and growers in four different irrigation schemes around the country including Harvey Water in the south west corner of Western Australia, the Ord Irrigation Scheme in the north east of Western Australia, the Burdekin Haughton Water Supply Scheme in north Queensland and Murray Irrigation in southern New South Wales. Our aim in doing this was to learn from experiences in each of the four irrigation schemes in (i) dealing with seepage/leakage losses from water distribution channels, and (ii) to see if water managers would be interested in having access to a commercially available sprayable polymer channel liner to help reduce seepage/leakage. We also carried out a literature search and explored the web to gain an understanding of seepage/leakage losses from water distribution channels and the current channel liner products and their use. The results of this scoping study has confirmed that there is strong interest from one of the four irrigation schemes for a cost-effective commercially available fit-for- purpose sprayable channel liner for use on large regional water distribution channels. There is also interest from some of the other irrigation schemes in having access to a sprayable channel liner for use in small on-farm water distribution channels and on-farm water storages. If a cost-effective, practical, durable and fit-for-purpose sprayable polymer channel liner was developed and commercialised successfully it would have the potential to increase irrigation water availability substantially. Use of a technology like this would improve the cotton industry’s water use efficiency and yield potential by minimising seepage/leakage losses from water distribution channels.