Erosion & Sediment Control
Riprap Installation
Riprap is a permanent erosion control measure used wherever concentrated flow or wave action would otherwise erode unprotected soil — pipe outfalls, pond spillways, channel linings, and shoreline edges. LES installs graded riprap sized to the design flow velocity, underlain by filter fabric or bedding stone to prevent the soil beneath it from migrating through the voids between rocks.
What’s Included
- Flow velocity and design-condition assessment for sizing
- Filter fabric or bedding stone underlayment installation
- Graded riprap placement at pipe outfalls and spillways
- Channel lining installation for concentrated-flow areas
- Shoreline and slope riprap for permanent stabilization
Technical Notes
Riprap that isn't properly sized to flow velocity, or installed without a filter layer underneath, will eventually fail as soil washes out from beneath the rock — the riprap stays in place while the slope or channel erodes underneath it. Correct gradation and underlayment are what make the installation permanent rather than temporary.
Frequently Asked Questions
Why does riprap need filter fabric underneath it?
Without a filter layer, soil migrates up through the gaps between rocks under flow, undermining the slope or channel bank even though the riprap itself looks intact. The fabric or bedding stone keeps the soil in place while still allowing water through.
How is riprap size determined?
Rock gradation is selected based on the design flow velocity at that specific location — an outfall handling high-velocity discharge needs larger, heavier rock than a low-flow channel lining.
Request a proposal for riprap installation
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