The relative terms used to describe natural drainage and corresponding types of soils are as follows: (1) Excessive: Excessively drained soils are commonly very porous and rapidly permeable, and have low water-holding capacity; (2) Somewhat Excessive: Somewhat excessively drained soils are also very permeable and are free from mottling throughout their profile; (3) Good: Well drained soils that are nearly free of mottling and are commonly of intermediate texture; (4) Moderately Good: Moderately well drained soils that commonly have a slowly permeable layer in or immediately beneath the solum. They have uniform color in the surface layers and upper subsoil, and mottling in the lower subsoils and substrata; (5) Somewhat Poor: Somewhat poorly drained soils are wet for significant periods, but not all the time. They commonly have a slowly permeable layer in their profile, a high water table, additions through seepage, or a combination of these conditions; (6) Poor: Poorly drained soils are wet for long periods of time. They are light gray and generally are mottled from the surface downward, although mottling may be absent or nearly so in some soils.
DRAINAGE CLASS, SOILS
Meaning of DRAINAGE CLASS, SOILS in English
Environmental engineering English vocabulary. Английский словарь экологического инжиниринга. 2012