Water erosion control structures are engineered systems designed to protect land surfaces from the destructive forces of flowing water and safely manage runoff. These structures aim to reduce soil loss and prevent environmental damage.
Types of Water Erosion Control Structures
Here are some common types of structures used for water erosion control:
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Water and Sediment Control Basins (WASCOBs): These are earthen embankments built across drainage areas to trap sediment and control runoff. They typically include:
- Retention basins: Depressions that temporarily store water, allowing sediment to settle out.
- Standpipe inlets (drop pipe inlets): Structures that convey water to a subsurface drainage system, releasing it at a controlled rate.
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Terraces: Level platforms constructed along slopes to intercept and redirect runoff, reducing its velocity and erosive power. Different types include:
- Bench terraces: Wide, level platforms separated by steep slopes.
- Contour terraces: Terraces that follow the contour of the land.
- Grassed Back Slope Terraces: Terraces with grass on the back slope to further prevent erosion
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Diversion Ditches/Channels: Channels constructed to divert runoff away from vulnerable areas, such as steep slopes or unstable soils.
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Check Dams: Small barriers placed across drainage channels to reduce water velocity and promote sediment deposition. They can be made of various materials like:
- Rock
- Concrete
- Wood
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Drop Structures (Grade Stabilization Structures): Structures designed to safely convey water down steep slopes, preventing channel erosion.
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Culverts: Pipes or box structures that allow water to flow under roads, embankments, or other obstructions.
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Vegetative Covers (Bioengineering): Using plants to protect soil from erosion. This includes:
- Cover crops: Planted to protect soil when primary crops are not growing.
- Contour Buffer Strips: Narrow strips of vegetation planted along the contour of the land.
- Riparian Buffers: Vegetated areas along streams and rivers to filter runoff and stabilize banks.
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Retaining Walls: Structures designed to hold back soil and prevent landslides or erosion on steep slopes.
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Energy Dissipaters: Structures placed at the outlets of culverts or other drainage structures to reduce the velocity of the water and prevent erosion.
Function of Erosion Control Structures
Erosion control structures serve to:
- Reduce Runoff Velocity: Slowing down the flow of water reduces its erosive force.
- Trap Sediment: Allowing sediment to settle out of runoff prevents it from being transported and deposited elsewhere.
- Divert Runoff: Directing water away from vulnerable areas protects them from erosion.
- Stabilize Slopes: Preventing landslides and soil movement.
- Improve Water Quality: Filtering pollutants and sediment from runoff.
By strategically implementing these structures, it's possible to significantly reduce the impact of water erosion and protect valuable land resources.
