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.
Page section
Subsection
SCS Curve Number
IDF Curve Tool
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 | ||

