section_path: Geography/Floods
section_name: Floods
paragraph_text: Floods
  
  Over the centuries, the Dutch coastline has changed considerably as a result of natural disasters and human intervention.
  
  On 14 December 1287, St. Lucia's flood affected the Netherlands and Germany, killing more than 50,000 people in one of the most destructive floods in recorded history. The St. Elizabeth flood of 1421 and the mismanagement in its aftermath destroyed a newly reclaimed polder, replacing it with the 72 km (28 sq mi) Biesbosch tidal floodplains. The huge North Sea flood of February 1953 caused the collapse of several dikes in the southwest Netherlands; more than 1,800 people drowned. The Dutch government subsequently instituted a large-scale programme, the " Delta Works ", to protect the country against future flooding, which was completed over a period of more than 40 years.
  
  The impact of disasters was, to an extent, increased through human activity. Relatively high-lying swampland was drained to be used as farmland. The drainage caused the fertile peat to contract and ground levels to drop; groundwater levels were lowered to compensate, causing the underlying peat to contract further. Additionally, until the 19th century peat was mined, dried, and used for fuel, further exacerbating the problem. Even in flooded areas, peat extraction continued through turf dredging.
  
  To guard against floods, a series of defences against the water were contrived. In the first millennium AD, villages and farmhouses were built on hills called terps. Later, these terps were connected by dikes. In the 12th century, local government agencies called " waterschappen " ("water boards") or " hoogheemraadschappen " ("high home councils") started to appear, whose job it was to maintain the water level and to protect a region from floods; these agencies continue to exist. As the ground level dropped, the dikes by necessity grew and merged into an integrated system. By the 13th century windmills had come into use to pump water. The windmills were later used to drain lakes, creating the famous polders. In 1932 the Afsluitdijk ("Closure Dike") was completed, blocking the former Zuiderzee (Southern Sea) from the North Sea and thus creating the IJsselmeer (IJssel Lake). It became part of the larger Zuiderzee Works in which four polders totalling 2,500 square kilometres (965 sq mi) were reclaimed from the sea.
  
  The Netherlands is one of the countries that may suffer most from climate change. Not only is the rising sea a problem, but erratic weather patterns may cause the rivers to overflow.