Movie:Sand Boil behind Levee
Information Page: Sand Boil behind Levee
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Sand Boil near Levee
Key Attributes
| Domain: | terrestrial, hydrology |
| Keywords: | levee |
| Keywords: | groundwater |
| Keywords: | seepage |
| Keywords: | flood risk |
| Model name: | Animation model name |
| Name: | chris, leefish/overeem |
| Where: | Bennington Levee |
| When: | March 2011 |
Short Description
Grade level: Middle (6-8), High (9-12), Under graduate (13-16), Graduate / Professional
Statement: sand boil results from seepage under levee
Abstract: This show the bubbling of sand near a levee in the lowlying farmlands, the sand seepage results from the pressure gradient that is caused by high river stage in flood conditions. This example is near Bennington Levee, Indiana, where the White River was at flood stage in March 2011. The sand boil was an indicator of the underminng of the levee and a 25 ft breach did happen during this same flood.
Theory
High river water that does not overtop a levee yet, can still create a tremendous water pressure. This pressure creates a potential for groundwater seepage of the water, through the underlying, permeable aquifer into the lowlands that are protected from direct flooding by an largely impermeable levee. Sand and water start bubbling up on the floodplain; usually indicating that undermining of the levee is going on.
