Deep drainage varies considerably depending on soil properties and irrigation management, and is not necessarily ‘very small’ - 50-100 mm/yr is typical, though 0 to 900 mm/yr has been observed. Soils used for irrigated cotton have much more diverse properties and management requirements than the simple description ‘clay soil’ suggests. Some drainage, or leaching fraction, is needed to avoid salt build up in the soil profile, but only where more saline water is used. This may be particularly relevant for CPLM and drip systems where the leaching fraction may not be provided by rainfall. The consequences of deep drainage are distinctly different where underlying groundwater can be used for pumping (fresh water, high flow rate) and where it cannot (saline water or low flow rate). Near saturated conditions can be found 2 to 6 metres under irrigated fields, conditions which do not exist under native vegetation.