mississippi

Cards (17)

  • Mississippi River
    • Largest drainage basin in USA and parts of Canada
    • Located in SE of USA
  • Uses of the Mississippi River
    • Shipping channel
    • Recreation
    • Hydroelectric power
    • Drinking water
  • The Mississippi River is hard to engineer
  • Levee engineering
    1. Raised 15m
    2. Strengthened to enclose channel for 3,000km
  • Levees failing
    Riverbed silting up
  • Hard engineering is more effective in the short term but less sustainable
  • New floodplain ends below risen river bed in New Orleans, which is 4.3m
  • Less alluvium deposited
    Soil less fertile, artificial fertilisers needed
  • Dams on main tributaries
    1. 100 dams controlling tributaries
    2. Expensive to construct and maintain
    3. Unsustainable
  • River straightening
    1. Meanders cut through stretch of 1,750km
    2. Creates fast flowing channel
    3. May cause floods downstream
  • Soft engineering: Afforestation
    • Trees planted in upper course to intercept (Tennessee)
    • Not applied over wide enough area
    • Trees haven't grown large enough to be effective
  • Soft engineering: Safe flood zones
    • Housing bought by country and demolished to allow flooding
    • Some states still developing housing on floodplains e.g. St Louis
  • Soft engineering: Washlands
    1. Morganza spillway opened in 2011 to flood 12,000 km² of farmland
    2. 2011 flood showed lack of washland
  • US conservation spent £25 million buying farmland
  • hard engineering methods
    levees
    dams
    river straightening
  • soft engineering methods
    afforestation
    safe flood zones
    washlands
  • river outside british isles : mississippi