What kind of soils are not considered gravely?

Soils with less than 15% rock fragments are considered not gravely based on soil classification standards. The classification of soils into categories such as sandy, loamy, or gravely largely depends on the proportion of mineral fragments present, specifically rock fragments. When soils contain 15% or more rock fragments, they are typically classified as gravely, meaning they have a significant amount of coarse material that affects drainage, aeration, and the way water moves through the soil.

By contrast, soils that contain less than 15% rock fragments do not have enough coarse material to be classified as gravely. Instead, they can fall into other categories such as clay, loam, or sandy soils, depending on their composition of finer particles and organic matter. These classifications are crucial for understanding soil behavior in septic system installations, as different soil types affect absorption rates, percolation, and suitability for septic systems. Thus, recognizing soils with lower rock fragments ensures proper assessment of soil conditions for septic system implementation.