AL ENGINEERING TABLE 4-4 Selected runoff coefficients Description of area or Runoff character of surface coefficient 0.70 to 0.95 0.50 to 0.70 Business Downtown Neighborhood Residential Single-family Multi-units, detached Multi-units, attached Residential (suburban) Apartment Industrial Light Heavy 0.30 to 0.50 0.40 to 0.60 0.60 to 0.75 0.25 to 0.40 0.50 to 0.70 Description of area or Runoff character of surface coefficient Railroad yard 0.20 to 0.35 Unimproved 0.10 to 0.30 Pavement Asphaltic and concrete 0.70 to 0.95 Brick 0.70 to 0.85 Roofs 0.75 to 0.95 Lawns, sandy soil Flat, 2 percent 0.05 to 0.10 Average, 2 to 7 percent 0.10 to 0.15 Steep, 7 percent 0.15 to 0.20 Lawns, heavy soil Flat, 2 percent 0.13 to 0.17 Average, 2 to 7 percent 0.18 to 0.22 Steep, 7 percent 0.25 to 0.35 0.50 to 0.80 0.60 to 0.90 0.10 to 0.25 0.20 to 0.35 Parks, cemeteries Playgrounds Extracted from ASCE, 1969. AL ENGINEERING TABLE 4-4 Selected runoff coefficients Description of area or Runoff character of surface coefficient 0.70 to 0.95 0.50 to 0.70 Business Downtown Neighborhood Residential Single-family Multi-units, detached Multi-units, attached Residential (suburban) Apartment Industrial Light Heavy 0.30 to 0.50 0.40 to 0.60 0.60 to 0.75 0.25 to 0.40 0.50 to 0.70 Description of area or Runoff character of surface coefficient Railroad yard 0.20 to 0.35 Unimproved 0.10 to 0.30 Pavement Asphaltic and concrete 0.70 to 0.95 Brick 0.70 to 0.85 Roofs 0.75 to 0.95 Lawns, sandy soil Flat, 2 percent 0.05 to 0.10 Average, 2 to 7 percent 0.10 to 0.15 Steep, 7 percent 0.15 to 0.20 Lawns, heavy soil Flat, 2 percent 0.13 to 0.17 Average, 2 to 7 percent 0.18 to 0.22 Steep, 7 percent 0.25 to 0.35 0.50 to 0.80 0.60 to 0.90 0.10 to 0.25 0.20 to 0.35 Parks, cemeteries Playgrounds Extracted from ASCE, 1969