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. (See References for trees)
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