How does water get to it in clay soil?
How does water get to it in clay soil?
Most clay soils are permeable, although at a significantly lower rate than granular soils. The ability of a subsurface drain to drain clay soils is a function of the clay soil’s permeability – i.e. the ability of the soil to transmit water to the drainage trench. Groundwater interceptor drains can work in these soils if designed properly. Groundwater interceptor drains in low permeable soil applications require a minimum of 4” of suitable fill material, course sand, placed above the drainage bundle and brought to grade. This can also be achieved with minimum of 2” of an overlying permeable strata, such as a low clay topsoil, mulch or decorative landscape stones over a minimum of 2” of course sand (see drawing). The interceptor drain should daylight to prevent saturation of the surrounding clay soils and to prevent the drain system from 'bath tubbing'.
