This table shows guidelines for filter strip pre-treatment sizing
Link to this table
Parameter Impervious Parking Lots Residential Lawns
Maximum Inflow Approach Length (ft)
35
75
75
150
Filter Strip Slope =<2% >2% 2% 2% 2% 2% 2% 2%
Filter Strip Minimum Length 10' 15' 20' 25'0' 10' 12' 15' 18'