A polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity, meaning it has no connection with outside water other than through man operated devices. There are three types of polders: · land reclaimed from a body of water, such as a lake or the sea bed; · Flood planes separated from the sea or river by a dyke; · marches separated from the surrounding water by a dyke and consequentially drained. The ground level in drained marches subsidences over time and thus all polders will eventually be below the surrounding water level some or all of the time.Water enters the low lying polder through: ground swell due to water pressure on ground water, rain fall and transportation of water by rivers and canals. This usually means that the polder has an excess of water that needs to be pumped out or drained by opening sluices at low tide.However care must be taken in not s

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