Soil groups

A – well drained sands and gravel, high infiltration capacity, high leaching potential and low runoff potential; B – Moderately drained fine to coarse grained soils, moderate infiltration capacity, moderate leaching potential and moderate runoff potential; C – Fine grained, low infiltration capacity, low leaching potential and high runoff potential; D – Clay soils, very low infiltration capacity, very low leaching potential and very high runoff potential.

That potion of the water precipitated onto a catchment area, which flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

1. A mineral soil separate consisting of particles less than 0.002 millimeter in equivalent diameter. 2. A soil texture class. 3. (Engineering) A fine-grained soil (more than 50 percent passing the No. 200 Sieve) that has a high plasticity index in relation to the liquid limit. (Unified Soil Classification System).