What is a hydrologic soil group?

“Hydrologic group” is a group of soils having similar runoff potential under similar storm and cover conditions. Soil properties that influence runoff potential are those that influence the minimum rate of infiltration for a bare soil after prolonged wetting and when not frozen.

How do you identify a hydrologic soil group?

The depth and hydraulic conductivity of any water im- permeable layer and the depth to any high water table are used to determine correct hydrologic soil group for the soil. The property that is most limiting to water movement generally determines the soil’s hydrologic group.

What are the different hydrologic soil groups?

Hydrologic Soil Groups

• Group A is sand, loamy sand or sandy loam types of soils. It has low runoff potential and high infiltration rates even when thoroughly wetted.
• Group B is silt loam or loam.
• Group C soils are sandy clay loam.
• Group D soils are clay loam, silty clay loam, sandy clay, silty clay or clay.

What is a Type B soil?

Type B soil has medium unconfined compressive strength; between 0.5 and 1.5 tons per square foot. Examples of Type B soil include angular gravel, silt, silt loam, and soils that are fissured or near sources of vibration, but could otherwise be Type A. Type C soil is the least stable type of soil.

How do you classify soil types?

The United States Department of Agriculture defines twelve major soil texture classifications ( sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay). Soil textures are classified by the fractions of sand, silt, and clay in a soil.

How many soil groups are there?

The Six Types of Soil. There are six main soil groups: clay, sandy, silty, peaty, chalky and loamy.

What does hydrologic soil group D mean?

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet.

What is Type D soil?

Group D soils are clay loam, silty clay loam, sandy clay, silty clay or clay. This HSG has the highest runoff potential. They have very low infiltration rates when thoroughly wetted and consist chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near…

What is hydraulic soil?

Hydric Soils – Introduction. Definition. The definition of a hydric soil is a soil that formed under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part.

What is a soil group?

soil group. noun. one of a number of soil classes having the same kinds of horizons in the same sequence and under similar moisture and temperature regimes.