Spate irrigation can also be referred to as floodwater harvesting. It is a method of random irrigation using the floodwaters of a normally dry system. It is practised by building earthen diversion banks across a dry watercourse. The floods - or spates- are diverted into embanked fields, where the water is pounded until total infiltration. These systems are in general characterised by very large upstream watershed and have an important “catchment area: cultivated area” ratio.