Preventing waterlogging with raised beds
Permanent raised beds are widely used to grow broadacre crops in irrigation country in the eastern states of Australia. They are a practical and economic means of managing particular waterlogged sites in wetter areas of the Western Australian grainbelt.
Raised beds allow excess water to drain out of the beds (horizontal drainage) into open collector drains which then discharge off the paddock.
Raised beds as part of whole-farm surface water management
Three areas need to be included when designing a raised-bed system:
- upslope of the system: if possible, intercept and channel surface water around the raised bed system
- the raised bed system of furrows and drains: this needs to cope with increased run-off and safe disposal
- the downslope disposal points: these need to cope with increased run-off from the raised bed system and have safe discharge. On saline sites, this may require notification to the Commissioner of Soil and Land Conservation.
Are raised beds suitable?
Raised beds are an option where:
- the probability of waterlogging is 50% or more in the wettest months (usually June to August), when the emerging crops are most susceptible. These soils are most commonly shallow sand, high gravel content soils and loam over clay soils
- there are shallow watertables
- hillslopes are less than 3%.
Salinity is likely to be higher on sites suitable for raised beds because of shallow saline watertables and evaporative concentration.
We recommend that you seek professional advice before installing raised beds or investing in the required machinery.
For more information
- Download the Raised bed farming in Western Australia bulletin.
- Check the other raised bed farming pages in the 'See also' links.