Step 1:

Enter Square footage of drainage area:  sf

Step 2:

Choose the 25 Year Rainfall (see rainfall map):  in/hr

Step 3:

Choose coefficient of Runoff  

Step 4:

Select EZ-Drain Size  

Step 5:

Press the Calculate button for results:


0 cubic feet per second
0 gallons per minute
Gallons to be stored: 0 gallons
Length of trench required: 0 ft
# EZ-Drain of bundles required: 0
Gallons of storage provided: 0 gallons

Storage Volume (Gallons per 10-ft bundle): 0
Flow Capacity (GPM at 1%): 0

Note: First Flush is defined as first 15 minutes of runoff. 15 minutes is the minimum length of time to be stored.
The first flush contains all the oil, fertilizer, pesticides, etc. that get washed away with the rain.