Table 1 Curve number (CN) values derived for hydrological soil groups (A, B, C, and D) for plant functional types (PFT) and their matches in National Engineering Handbook – Part 630 Hydrology land cover classes (NEH-630).

From: GCN250, new global gridded curve numbers for hydrologic modeling and design

PFT NEH-630 classes (hydrologic condition) CN for hydrological soil group
A B C D
Tree Broadleaf Evergreen Woods (good) 30 55 70 77
Tree Broadleaf Deciduous Woods (average CN of fair and good condition) 33 58 72 78
Tree Needleleaf Evergreen Woods (average CN of fair and good condition) 33 58 72 78
Tree Needleleaf Deciduous Woods (poor) 45 66 77 83
Shrub Broadleaf Evergreen Average CN of Desert shrub (good), and Brush (good) 40 58 72 79
Shrub Broadleaf Deciduous Average CN of Desert shrub (good), and Brush (fair) 42 62 75 81
Shrub Needleleaf Evergreen Average CN of Desert shrub (good), and Brush (fair) 42 62 75 81
Shrub Needleleaf Deciduous Does not exist in ESA LC types
Natural grass Grassland (good) 39 61 74 80
Managed grass (rainfed) Average CN of good hydrologic conditions for all cropland types 57 68 75 78
Bare soil Fallow (bare soil) 77 86 91 94
Water (for wetlands only) 100 100 100 100