grab samples

SECTION 5
PHYSICAL ANALYSIS
Particle size and settling rate are required in the physical analysis section of four of the five permit
application forms. Although the application requires the percentage by volume of each of the gravel, sand, silt
and clay-colloids fractions which make up the sample, most commonly used methods of sediment analysis
calculate proportions by weight. These components of the sediment are defined by individual particle size
(Wentworth Classification) as follows:
Gravel ... . >2 mm
Sand ..... ...... .......... . 2 mm - 0.0625 mm
Silt 0.0625 mm - 0.0039 mm CO2 -5 - 3 'yr'
Clay and Colloids ..