page_title: River bank failure
section_title: Sacks/Blocks
hierarchical_section_title: River bank failure / Solutions / Sacks/Blocks
caption_attribution_description: Français&#160;: construction en Tunisie
context_page_description: River bank failure can be caused when the gravitational forces acting on a bank exceed the forces which hold the sediment together. Failure depends on sediment type, layering, and moisture content.
  All river banks experience erosion, but failure is dependent on the location and the rate at which erosion is occurring.
  River bank failure may be caused by house placement, water saturation, weight on the river bank, vegetation, and/or tectonic activity. When structures are built too close to the bank of the river, their weight may exceed the weight which the bank can hold and cause slumping, or accelerate slumping that may already be active. Adding to these stresses can be increased saturation caused by irrigation and septics, which reduce the soil's strength. While deep rooted vegetation can increase the strength of river banks, replacement with grass and shallower rooted vegetation can actually weaken the soil. Presence of lawns and concrete driveways concentrates runoff onto the riverbank, weakening it further. Foundations and structures further increase stress.
context_section_description: Sacks and blocks may be used during flooding, where sacks are filled with material, allowing for blocks to encourage drainage and vegetation growth. This method requires increased man labor and larger amounts of filler material, as all sacks and blocks should be of the same size.
caption: Gabion au rive
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