AgriMetSoft


SCS-CN Curve Number Table

We are developing a tool for calculating the runoff by using SCS-CN Curve Number method so we collected the SCS-CN Curve Number Table. You can find the SCS-CN Curve Number Table in below.

SCS Curve Number

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IDF Curve Tool

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SCS Curve Number Table

Cover description Curve numbers for hydrologic soil group
Cover type Treatment Hydrologic condition A B C D
Cultivated agricultural lands
Fallow Bare soil --- 77 86 91 94
Crop residue cover (CR) Poor 76 85 90 93
Good 74 83 88 90
Row crops Straight row (SR) Poor 72 81 88 91
Good 67 78 85 89
SR + CR Poor 71 80 87 90
Good 64 75 82 85
Contoured (C) Poor 70 79 84 88
Good 65 75 82 86
C + CR Poor 69 78 83 87
Good 64 74 81 85
Contoured & terraced (C&T) Poor 66 74 80 82
Good 62 71 78 81
C&T + R Poor 65 73 79 81
Good 61 70 77 80
Small grain SR Poor 65 76 84 88
Good 63 75 83 87
SR + CR Poor 64 75 83 86
Good 60 72 80 84
C Poor 63 74 82 85
Good 61 73 81 84
C + CR Poor 62 73 81 84
Good 60 72 80 83
C&T Poor 61 72 79 82
Good 59 70 78 81
C&T + R Poor 60 71 78 81
Good 58 69 77 80
Close-seeded or broadcast legumes or rotation meadow SR Poor 66 77 85 89
Good 58 72 81 85
C Poor 64 75 83 85
Good 55 69 78 83
C&T Poor 63 73 80 83
Good 51 67 76 80
Developing urban areas
Newly graded areas (pervious areas only, no vegetation) 77 86 91 94
Fully developed urban areas (vegetation established)
Open space (lawns, parks, golf courses, cemeteries, etc.) Poor condition (grass cover <50%) 68 79 86 89
Fair condition (grass cover 50 to 75%) 49 69 79 84
Good condition (grass cover >75%) 39 61 74 80
Impervious areas Paved parking lots, roofs, driveways, etc. (excluding right of way) 98 98 98 98
Streets and roads Paved; curbs and storm sewers (excluding right-of-way) 98 98 98 98
Paved; open ditches (including right-of-way) 83 89 92 93
Gravel (including right of way) 76 85 89 91
Dirt (including right-of-way) 72 82 87 89
Western desert urban areas Natural desert landscaping (pervious area only) 63 77 85 88
Artificial desert landscaping (impervious weed barrier, desert shrub with 1- to 2-inch sand or
gravel mulch and basin borders)		 96 96 96 96
Urban districts Commercial and business (85% imp.) 89 92 94 95
Industrial (72% imp.) 81 88 91 93
Residential districts by average lot size 1/8 acre or less (town houses) (65% imp.) 77 85 90 92
1/4 acre (38% imp.) 61 75 83 87
1/3 acre (30% imp.) 57 72 81 86
1/2 acre (25% imp.) 54 70 80 85
1 acre (20% imp.) 51 68 79 84
2 acres (12% imp.) 46 65 77 82
Other agricultural lands
Pasture, grassland, or range-continuous forage for grazing.A Poor 68 79 86 89
Fair 49 69 79 84
Good 39 61 74 80
Meadow-continuous grass, protected from grazing and generally mowed for hay. - 30 58 71 78
Brush-brush-weed-grass mixture with brush the major element.B Poor 48 67 77 83
Fair 35 56 70 77
Good 30 48 65 73
Woods-grass combination (orchard or tree farm).D Poor 57 73 82 86
Fair 43 65 76 82
Good 32 58 72 79
Woods.E Poor 45 66 77 83
Fair 36 60 73 79
Good 30 55 70 77
Farmsteads-buildings, lanes, driveways, and surrounding lots. - 59 74 82 86
Arid and semiarid rangelands
Herbaceuous-mixture of grass, weeds, and low-growing brush, with brush the minor element Poor - 80 87 93
Fair - 71 81 89
Good - 62 74 85
Oak-aspen-mountain brush mixture of oak brush, aspen, mountain mahogany, bitter brush, maple, and other brush Poor - 66 74 79
Fair - 48 57 63
Good - 30 41 48
Pinyon-juniper-pinyon, juniper, or both; grass understory Poor - 75 85 89
Fair - 58 73 80
Good - 41 61 71
Sagebrush with grass understory Poor - 67 80 85
Fair - 51 63 70
Good - 35 47 55
Desert shrub-major plants include saltbush, geasewood, creosotebush, blackbrush, bursage, palo verde, mesquite, and cactus. Poor 63 77 85 88
Fair 55 72 81 86
Good 49 68 79 84
Woods and Forests:
Poor (small trees/brush destroyed by over-grazing or burning) 45 66 77 83
Fair (grazing but not burned; some brush) 36 60 73 79
Good (no grazing; brush covers ground) 30 55 70 77
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