River Lea

The River Lea in England originates in Marsh Farm, Leagrave, Luton in the Chiltern Hills and flows generally southeast, east, and then south through east London where it meets the River Thames, the last section being known as Bow Creek. It is one of the largest rivers in London and the easternmost major tributary of the Thames. Its valley creates a long chain of marshy ground along its lower length, much of which has been used for gravel and mineral extraction, reservoirs and industry. Much of the river has been canalised to provide a navigable route for boats into eastern Hertfordshire, known as the Lee Navigation. While the lower Lea remains somewhat polluted, its upper stretch and tributaries, classified as chalk streams, are a major source of drinking water for London. A diversion known as the New River, opened in 1613, abstracts clean water away from the lower stretch of the river for drinking. Its origins in the Chilterns contribute to the extreme hardness (high mineral content) of London tap water.EtymologyThe name of the River Lea was first recorded in the 9th century, although is believed to be much older. Spellings from the Anglo-Saxon period include Lig(e)an in 880 and Lygan in 895, and in the early medieval period it is usually Luye or Leye. It seems to be derived from a Celtic (brythonic) root lug-meaning 'bright or light' which is also the derivation of a name for a deity, so the meaning may be 'bright river' or 'river dedicated to the god Lugus'. A simpler derivation may well be the Brythonic word cognate with the modern Welsh "Li" pronounced "Lea" which means a flow or a current.