Editing The Fens (section)

==Background: historical flooding and drainage==
[[File:Wicken Fen Windpump.jpg|thumb|right|A [[windpump]] at [[Wicken Fen]]]]

The Fens are very low-lying compared with the [[chalk]] and [[limestone]] uplands that surround them&nbsp;– in most places no more than {{convert|10|m}} above sea level. As a result of drainage and the subsequent shrinkage of the [[peat]] fens, many parts of the Fens now lie below [[mean sea level]]. Although one writer in the 17th century described the Fenland as entirely above sea level (in contrast to the Netherlands),<ref>H. C. ''A discourse concerning the drayning of fennes and surrounded grounds in the sixe counteys of Norfolk, Suffolke, Cambridge, with the Isle of Ely, Huntington, Northampton and Lincolne''. London: 1629. Reprinted in 1647 under title: ''The Drayner Confirmed, and the Obstinate Fenman Confuted''.</ref> the area now includes the lowest land in the United Kingdom. [[Holme Fen]] in Cambridgeshire, is around {{convert|2.75|metre}} below sea level.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/england/2529365.stm|title=UK's lowest spot is getting lower|publisher=[[BBC]] | date=29 November 2002 | access-date=26 March 2010}}</ref> Within the Fens are a few hills, which have historically been called "islands", as they remained dry when the low-lying fens around them were flooded. The largest of the fen-islands was the 23-square-mile (60&nbsp;km<sup>2</sup>) Kimmeridge Clay island, on which the cathedral city of [[Ely, Cambridgeshire|Ely]] was built: its highest point is {{convert|39|m|ft}} above mean sea level.<ref>[http://www.wheresthepath.com/county_tops/ct_isle_of_ely.htm Isle of Ely] {{Webarchive|url=https://web.archive.org/web/20120307054142/http://www.wheresthepath.com/county_tops/ct_isle_of_ely.htm |date=7 March 2012 }}, Wheres The Path website</ref>

Without artificial drainage and flood protection, the Fens would be liable to periodic flooding, particularly in winter due to the heavy load of water flowing down from the uplands and overflowing the rivers. Some areas of the Fens were once permanently flooded, creating lakes or ''[[Mere (lake)|meres]]'', while others were flooded only during periods of high water. In the pre-modern period, [[agronomy|arable farming]] was limited to the higher areas of the surrounding uplands, the fen islands, and the so-called "Townlands", an arch of [[silt]] ground around [[the Wash]], where the towns had their arable fields. Though these lands were lower than the peat fens before the peat shrinkage began, the more stable [[silt]] soils were reclaimed by medieval farmers and [[embankment dam|embanked]] against any floods coming down from the peat areas or from the sea. The rest of the Fenland was dedicated to [[pastoral farming]], fishing, [[fowling]], and the harvesting of reeds or sedge for thatch. In this way, the medieval and early modern Fens stood in contrast to the rest of England, which was primarily an arable agricultural region.

Since the advent of modern drainage in the 19th and 20th centuries, the Fens have been radically transformed. Today, arable farming has almost entirely replaced pastoral. The economy of the Fens is heavily invested in the production of crops such as grains, vegetables, and some cash crops such as [[rapeseed]] (canola).