🪨 FHWA HEC-15 / USACE Riprap Armoring (D50 Median Stone Diameter & Layer Depth)

Riprap Rock Slope Protection Calculator

Size quarry rock riprap armor layers for bridge abutments, stormwater drainage channels, and riverbanks under FHWA HEC-15 & USACE EM 1110-2-1601: calculate median stone diameter (D50 inches = 0.001 x V_shear³ / [g x (S_s - 1)] based on water flow velocity), total layer thickness (1.5x to 2.0x D50), nonwoven geotextile underlayment, and civil margins.

1. Project & Operating Inputs

Riprap Armored Surface Area (Square Feet e.g. 24,000 Sq Ft Channel)

Peak Channel Water Velocity (FPS e.g. 12.0 FPS High-Velocity Storm Flow)

Customer Bid Price for Supplied, Placed & Graded Riprap ($ / Sq Ft)

Class II/III Riprap Stone, Heavy Nonwoven Geotextile Fabric, Excavator ($)

2. Financial Breakdown & Yield

FHWA HEC-15 RIPRAP ARMORING

Turnkey Riprap Armoring Profit

Civil Earthwork Contractor Margin

0.0%

Gross Revenue / Bill

Total Project CapEx

Operating / Material Cost