💧 Subsurface Beds (AASHTO No. 57 Washed Gravel 40% Void Space, Infiltration Gal/Day)

Subsurface Gravel Storage Bed Calculator

Size underground stormwater infiltration gravel beds and detention galleries placed beneath parking lots: calculate clean double-washed angular stone volume (AASHTO No. 57 / No. 3 with 40% active void space), calculate native soil exfiltration percolation rate (in/hr), prevent groundwater mounding, and civil earthwork margins.

1. Project & Operating Inputs

Required Detention Storage (Cubic Feet e.g. 18,000 Cu Ft Storage)

Native Soil Infiltration Rate (Inches / Hr e.g. 0.85 in/hr Sandy Loam)

Customer Bid Price for Excavated, Lined & Gravel-Filled Bed ($)

AASHTO No. 57 Crushed Stone, Non-Woven Geotextile, Excavator & Labor ($)

2. Financial Breakdown & Yield

GRAVEL INFILTRATION BEDS

Turnkey Subsurface Bed Excavation Profit

Civil Earthwork & Drainage Margin

0.0%

Gross Revenue / Bill

Total Project CapEx

Operating / Direct Cost