By Rick Jackson // 2020-08-04
Soils get classified as cohesive or cohesionless. A cohesive soil has an attraction between particles of the same type, origin, and nature. Therefore, cohesive soils are a type of soil that stick to each other. Cohesive soils are the silts and clays, or fine-grained soils. A cohesionless coil (non-cohesive) soil are soils that do not adhere to each other and rely on friction. These soils are the sands and gravels, or coarse-grained soils. The soil type is particularly relevant when it comes to erosion, and stormwater runoff as cohesive soils are less likely to or harder to erode. Hence, cohesive soil particles stick to each other. These soils can be a mix of grain sizes, but are usually primarily fine-grained. The cohesionless soils may be larger grained and erode easier as they do not stick to each other. It is important to know what kind of soils you have on your site to better understand how the soils will react during rain events.