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Vegetated drains

Vegetated drains — Key considerations

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What makes an effective vegetated drain for treating run-off?

Figure 2 Cross-section of a vegetated drain, showing a flat base and a gentle or gradually sloping batter with dense vegetation

  • Gentle batters to promote vegetation growth and minimise erosion.
  • Dense vegetation (grass and reeds) in most of the drain (or sections) to promote uniform water flows and facilitate sedimentation and denitrification.
  • Relatively flat gradient to slow water flows, minimise erosion and maximise residence time for nitrogen removal.
  • Sized to convey required water flow, accounting for the increased friction associated with the vegetation.

Treatment processes

Suitability and limitations

Vegetated drains are suitable in almost all agricultural and aquaculture production systems and climates. Drains are common throughout farms in Queensland, providing opportunities to improve water quality by modifying and managing drains to encourage and retain vegetation.

Residence time will influence the effectiveness of vegetated drains in removing nutrients and toxicants. Therefore, vegetated drains will be more effective if water flow is relatively slow, maximising the time water is in contact with vegetation. Vegetated drains with extended residence times act as linear wetlands, promoting nutrient and toxicant removal[1].


In addition to the standard disclaimer located at the bottom of the page, please note the content presented is based on published knowledge of treatment systems. Many of the treatment systems described have not been trialled in different regions or land uses in Queensland. The information will be updated as new trials are conducted and monitored. If you have any additional information on treatment systems or suggestions for additional technologies please contact us using the feedback link at the bottom of this page.


  1. ^ Soana, E, Balestrini, R, Vincenzi, F, Bartoli, M & Castaldelli, G (June 2017), 'Mitigation of nitrogen pollution in vegetated ditches fed by nitrate-rich spring waters', Agriculture, Ecosystems & Environment. [online], vol. 243, pp. 74-82. Available at: [Accessed 26 May 2022].

Last updated: 24 May 2022

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2022) Vegetated drains — Key considerations , WetlandInfo website, accessed 18 March 2024. Available at:

Queensland Government
WetlandInfo   —   Department of Environment, Science and Innovation