Recommended values for porosity, field capacity and wilting point for different soils.1
Link to this table.
| Soil | Hydrologic soil group | Porosity 2 (volume/volume) | Field capacity (volume/volume) | Wilting point (volume/volume) | Porosity minus field capacity (volume/volume)3 | Field capacity minus wilting point (volume/volume)4 |
|---|---|---|---|---|---|---|
| Sand | A (GM, SW, or SP) | 0.43 | 0.17 | 0.025 to 0.09 | 0.26 | 0.11 |
| Loamy sand | A (GM, SW, or SP) | 0.44 | 0.09 | 0.04 | 0.35 | 0.05 |
| Sandy loam | A (GM, SW, or SP) | 0.45 | 0.14 | 0.05 | 0.31 | 0.09 |
| Loam | B (ML or OL) | 0.47 | 0.25 to 0.32 | 0.09 to 0.15 | 0.19 | 0.16 |
| Silt loam | B (ML or OL) | 0.50 | 0.28 | 0.11 | 0.22 | 0.17 |
| Sandy clay loam | C | 0.4 | 0.07 | |||
| Clay loam | D | 0.46 | 0.32 | 0.15 | 0.14 | 0.17 |
| Silty clay loam | D | 0.47 to 0.51 | 0.30 to 0.37 | 0.17 to 0.22 | 0.16 | 0.14 |
| Sandy clay | D | 0.43 | 0.11 | |||
| Silty clay | D | 0.47 | 0.05 | |||
| Clay | D | 0.47 | 0.32 | 0.20 | 0.15 | 0.12 |
1Sources of information include Saxton and Rawls (2006), Cornell University, USDA-NIFA, Minnesota Stormwater Manual
2Soil saturation is assumed to be equal to the porosity.
3This value may be used to represent the volume of water that will drain from a bioretention media.
4This value may be used to estimate the amount of water available for evapotranspiration
