| # As the Soil Grain Size Analysis method is only approved for soils with D10 between 0.1 and 2.5 millimeters, the Hazen formula (below) may be used to calculate the soil permeability (K). Soil | | # As the Soil Grain Size Analysis method is only approved for soils with d<sub>10</sub> between 0.1 and 2.5 millimeters, the Hazen formula (below) may be used to calculate the soil permeability (K). |