April 9, 1829: The Polish city of Gdańsk is flooded when the dike breaks, killing 1,200 people. Gdańsk, also known as Danzig, is an ancient city in Poland located on the Baltic Sea at the mouth of the Motlawa River. The city was first established in the 10th century and was given city rights in 1263. Today, there are nearly 458,000 people calling it home and over 1 million in the greater metropolitan area. The city is famous for being the birthplace of the Solidarity movement begun by Lech Wałęsa.
Dikes have been used to hold back rising waters since 2600 BC. These early barriers were constructed in the Indus Valley protecting the Harappan people. The word “dijk” is from the Netherlands, a land associated with lowlands surrounded by water and needing protection. We also call them levees. Not all levees are manmade. Mother Nature herself helps build up walls of sediment left behind as rivers flood. These rising lands build up and protect the rest of the floodplain except in extreme cases. During high floods when the waters crest over the sediment levees, it leaves new deposits and raises the height of the embankment once again.
Water can inundate an area by breaching the dike or levee. The water can actually displace a portion of the dike allowing the water to pour in – as was seen in New Orleans during the Katrina Hurricane of 2005. Water can also “boil” through or under the dike and resurface on the landside – which usually results in enough material being carried away to form a true breach. Dikes can also fail when water rises high enough to flow over the top.
Early civilization needed water nearby, so they built cities around places with the needed commodity. This led to the possibility of flooding from rain, storm surges, tsunamis or any combination thereof. In order to protect themselves, early people built earthen dikes to hold back the waters. Humanity’s love/hate relationship with water continues to this day, with humans trying to control the rising seas and not always winning.
“No individual raindrop ever considers itself responsible for the flood.” – unknown
“By gnawing through a dike, even a rat may drown a nation.” – Edmund Burke
“Nothing is as soft as water, yet who can withstand the raging flood?” – Lao Ma
“No man drowns if he perseveres in praying to God; and can swim.” – Russian proverb– https://patriciahysell.wordpress.com/2010/04/09/water-water-everywhere-2/