Channel Evaporation Mitigation

The project will develop the application of monolayers to reduce evaporation from irrigation channels.

It links with current CRC Irrigation Futures and CRC Polymers evaluation and development of monolayers for evaporation reduction. Within Goulburn-Murray Water (G-MW) alone there are potential water savings of 11 GL/year, at competitive prices. The effectiveness and economics of monolayers in controlling evaporation will be assessed in closed channel (i.e. with no through-flow), and flowing channel situations. The suitability of application equipment and techniques will also be assessed.


  • To develop rigorous methods to determine evaporation rates from channels
  • To determine the efficacy of monolayers when used on channels.
  • To develop application methods to apply evaporation suppressants to channels.
  • To better understand the control measures that should apply to minimise environmental impacts when using monolayers in irrigation channel systems.


At the estimated cost of $200-800/ML/year, evaporation control using monolayers has an application in channel systems, particularly in years when allocations are low. Determination of the potential savings and commercial costs, will allow more effective assessment of this technology.

Based on a 30% reduction in evaporation loss and 50% adoption, the potential benefit within the jurisdiction of G-MW is;

  Potential Water Saving (GL/year) Potential Value (at $2,000/ML water saved)
Storages 48.0 $ 96.0 Million
Channels 11.0 $ 22.0 Million
Farm Storages 0.5 $ 0.5 Million
Total 59.5 $ 118.5 Million

Given that G-MW constitutes about 20% of gravity irrigation systems nationally, the benefit to the water industry nationally is considered to be a factor of 5-10 greater that outlined above.

Another outcome is improved measurement of evaporation losses in channels and storages, which is an issue in current water savings projects. The project will therefore reduce the uncertainty associated with estimating evaporation losses.


Water in open channels is subject to high evaporative losses. Some 66GL/annum of water is lost through evaporation from channels in Northern Victoria.

Research by University of Southern Queensland (USQ) has shown that applying small quantities of chemicals to form a surface film on water bodies is a cost-effective method of suppressing evaporation. Initial findings suggest that monolayers reduce evaporation by 35% at a cost between $200-800/ML/year, and that there is potential to further improve product performance to reach a target of $80/ML water saved. The potential water saving from the use of such monolayers on G-MW channels is approximately 11GL/year (assuming 30% evaporation suppression and application to 50% of channels).



National Program for Sustainable Irrigation

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id: 2636 / created: 10 September, 2008 / last updated: 09 February, 2011