What is the difference between silt/clay and sand/gravel in the Tier I Look Up Table?
A coarse grained soil (sand/gravel) is defined as material having greater than 50% (by dry weight) particles equal to or larger than 75 microns (200 mesh) in diameter. Materials with less than 50% sand-sized particles are considered fine-grained soil (silt/clay). If no seive data is available, then the lowest applicable number should apply until a seive test is performed.
