Erosion Control/Damage

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Erosion & Sentiment Control

• Defined by:–Environmental Regulations–State and federal laws–Standard specifications, provisions and

plans–Cooperative agreement with DNR

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Resources

• Reference Documents and training aids–Construction and Materials Manual–Design Manual

• Outside Agencies–DNR–Consultants

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Silt Fence Requirements

• Silt fence is intended to be utilized as a perimeter control to intercept sediment laden runoff.

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Silt Fence Requirements

• ½ acre drainage area• Sheet erosion• 4 inch wide by 6 inch deep trench• 2 feet of fabric above ground• Stakes 2 feet in ground• Stakes 8 feet apart

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Other Sediment Control

• Storm drain inlet protection• Earth dikes• Sediment basins• Pipe slope drains• Vegetative cover

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Backslope Erosion

• Solutions:–Salvaged topsoil–Swale with protection–Intercepting embankment

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Erosion Control

• Silt fences at toe of abutment.• Fabric on slope• Riprap on fabric

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Figure 2: Erosion Control

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Silt Screen

• Prevents siltation• Containment protection• Doesn’t work in heavy flowing water

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Figure 3: Silt Screen

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Silt Fence

• Prevents sediment runoff• Perimeter control

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Figure 3: Silt Fence

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Silt Fence Maintenance

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Steel Sheet Piling

• In place prior to excavation.• Temporary• Heavy riprap will replace• Costly compared to silt screen–No displacement

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Figure 4: Steel Sheet Piling

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Salvaged Topsoil

• Intercepting embankment carries water.• Use Crimped mulching.

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Figure 5: Salvaged Topsoil

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Riprap

• Reduces velocity of water• Steeper grades• Longer runs

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Figure 6: Riprap

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Erosion Mat/Riprap

• Very effective

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Figure 7: Erosion Mat/Riprap

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