Impervious Surface Values and Sources


Land Use Percent Impervious Cover Source
Forest 1 Center for Watershed Protection 1998 (p.6-3)
Urban/Suburban Open Land 3 Center for Watershed Protection 1998 (p.6-3)
Low Density Residential (0.5 units/acre) 12 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Low Density Residential (1 units/acre) 20 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Medium Density Residential (2 units/acre) 25 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Medium Density Residential (3 units/acre) 30 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Medium Density Residential (4 units/acre) 38 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
High Density Residential (5-7 units/acre) 40 Puget Sound – AquaTerra 1994 as reported in Center for Watershed Protection 1998 (p. 6-7)
Multifamily Townhouse (>7 units per acre) 65 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Commercial 85 NRCS – USDA 1986 as reported in Center for Watershed Protection 1998 (p. 6-7)
Parking – Unpaved 90 expert opinion of Lee Sutton, Georgia NEMO
Roads/Paved Parking 100 expert opinion of Lee Sutton, Georgia NEMO

Center for Watershed Protection. 1998. "Rapid Watershed Planning Handbook"