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Soil and Practice Effects. Bare. Mulch + Grass. Silt Fence. Sediment Trap. R. A. McLaughlin. NCSU Soil Science. Ground Covers: Protect From Droplets. R. A. McLaughlin. NCSU Soil Science. Mulch Doesn’t Work In Ditches. Mulch piled up at rock check dam. R. A. McLaughlin.
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Soil and Practice Effects Bare Mulch + Grass Silt Fence Sediment Trap R. A. McLaughlin NCSU Soil Science
Ground Covers: Protect From Droplets R. A. McLaughlin NCSU Soil Science
Mulch Doesn’t Work In Ditches Mulch piled up at rock check dam. R. A. McLaughlin NCSU Soil Science
Erosion – Even on Flat, Sandy Sites! R. A. McLaughlin NCSU Soil Science
Soft Armor for Gentle Slopes R. A. McLaughlin NCSU Soil Science
Hard Armor for Steep Slopes R. A. McLaughlin NCSU Soil Science
Field Runoff: Bypass Through Buffer Crop Field StreamBuffer Bypass In Ditch R. A. McLaughlin NCSU Soil Science
Field Runoff: Spread Across Buffer For Treatment Crop Field Spreader StreamBuffer Sheet Flow R. A. McLaughlin NCSU Soil Science
Silt Fence: Works but Needs Maintenance! R. A. McLaughlin NCSU Soil Science
Dissipated Flow Deposits Sediment R. A. McLaughlin NCSU Soil Science
Sediment control fabric Backfill 1.5-in PVC pipe 3 -5 in. 2ft. rebar 2 ft. Level Spreaders Can Dissipate Flow: Example Level & On Contour Flow R.A. McLaughlin NCSU Soil Science
Simple Math for Sedimentation • V=((4/3)pi(r3)*(d1-d2)*g)/(2pirz3) • OR…larger particles fall faster once flow is slowed/stopped. R.A. McLaughlin NCSU Soil Science
Sedimentation: Size Matters Coarse Clay Silt Fine sand R.A. McLaughlin NCSU Soil Science
Sediment Trap (full) R. A. McLaughlin NCSU Soil Science
Sediment Deposit at Basin Inlet R. A. McLaughlin NCSU Soil Science
In Conclusion... • Sediment is the #1 cause of surface water degradation. • Soil has to become detached to erode: cover it up! • Water always gathers and becomes more erosive: protect those waterways! • Slow water holds less sediment than fast water: keep the flows low and ponded wherever possible! R.A. McLaughlin NCSU Soil Science