Levees

Levees

1. Levees are raised banks of sediment alongside a river at its OLD STAGE due to deposition.

2. River Mississippi.

3. Rivers deposit their load when they lose speed or when the gradient is reduced.

   • Levees occur at the old stage of a river where its energy and ability to erode and transport material are reduced.
     • The river then drops its load.
       • Flooding may occur because of an increased volume of water.
         • The river looses its energy as it is flowing over a wider floodplain.
           • Its speed and ability to transport are therefore reduced.
             • Heavy material is deposited first and lighter material flows downstream.
               • Over time, the deposition of coarser material along the riverbanks lead to the formation of levees.
                 • These levees can act as natural barriers to floodwater and back swamps can form behind them.
                   • Artificial levees have been built along the courses of some rivers to prevent flooding.

4. Deposition

Bilder und Dateien der Mindmap