Irrigation systems must be properly designed to ensure good uniformity of water application.
- Excess irrigation on horticultural properties will infiltrate past the root zone and leach nutrients which may pollute groundwater.
- Nitrogen, is held weakly by all sandy soils of the coastal plain and is easily leached by excess irrigation or heavy rainfall. Phosphorus is ‘fixed’ or held by most soils and is not readily leached, except for the Bassendean sands which have poor phosphorus retention ability.
- Proper design and efficient operation of irrigation systems are essential for efficient water use and to minimise nutrient leaching.
It is recommended that all irrigation systems are designed by an irrigation designer. A list of certified irrigation designers for agricultural sprinkler and drip irrigation systems can be found on the Irrigation Association of Australia's web site www.irrigation.org.au.