Vegetated drains

Vegetated drains — Key considerations

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• Overview
• Key considerations
• Planning and design
• Construction and operation
• Links and references

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

• 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].

References

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: https://linkinghub.elsevier.com/retrieve/pii/S0167880917301597 [Accessed 26 May 2022].

Last updated: 24 May 2022