Sunday, January 6, 2013

Aquatic Systems

Water is the driving force of all nature -- Leonardo Da Vinci 



Here are some things I learned about aquatic systems: 
  • Wetlands:  A Wetland is any land that is wet for at least 5-7 days commonly called swamp or marsh.
  • A canal that curves is better than one that runs straight.  If it curves, then the speed of water slows down.  This reduces soil erosion. 
  • We need to plant vegetation around the waterways to reduce soil erosion.
  • Water cycle:  The ones I was already familiar with were: Evaporation, Condensation, Precipitation and Surface Runoff.  The new ones I learned were: Percolation, Transpiration, Infiltration and Ground water.    

Levees

I also learned about levees.  Levees are man- made hills that stretch at least 1 mile and prevent floods from happening.  But levees can also break down. For example, in 1992, there was a lot of snow in Montana.  This snow melted and flowed down the rivers and piled up in the Missouri river. Along the way, the snow melted and became water. There was so much water that the water broke through the levee and was a huge disaster in St. Louis. This was called the flood of 1993.

The probability of a levee breaking is given a number. The probability that a 500 year levee will break increases by 0.2% every year.  Therefore, in 300 years, the probability of it breaking is 60%. A hundred year levee’s probability of breaking increases by 1% every year.  Therefore, a 500 year levee prevents more floods than a 100 year levee.





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