🌊 Rational Method Q=CIA, 100-Yr Storm Runoff CuFt & Outlet Control

Stormwater Retention Pond Volume & Orifice Sizing Calculator

Calculate post-development peak stormwater runoff using the Rational Method (Q = C * I * A), size retention/detention pond storage volume (acre-feet / cubic feet for 10-year and 100-year storm events), and size bottom orifice restrictor plates under civil engineering codes.

1. Project & Operating Inputs

Contributing Impervious Drainage Area (Acres)

100-Year Rainfall Intensity (Inches / Hour - I)

Customer Bid Price for Basin Excavation & Outlet ($)

Excavation, Concrete Outlet Structure & Liner Cost ($)

2. Financial Breakdown & Yield

RATIONAL METHOD STORMWATER POND

Turnkey Pond Build Gross Profit

Civil Site Margin

0.0%

Gross Revenue / Bill

Total Project CapEx

Operating / Material Cost