Izzard

Where:

• I= Rainfall intensity (in/hr)
• K= Length of overland flow (ft)
• qe= 0.0000231 I L (cfs/ft)
• s= Surface slope (ft/ft)
• C= 0.046 (bluegrass turf)

Value of C are:

Very smooth asphalt	0.007
Tar & sand pavement	0.0075
Crushed slate roof	0.0082
Tar & gravel pavement	0.017
Closely clipped sod	0.046
Dense Bluegrass	0.06