biomat

plural biomats

1. subsoil hydraulicsA clogging layer of typically densely packed decaying organic matter which impedes the downward flow of water.

   This may be an artifact of the aerobic conditions used which would not favor the growth of any anaerobic bacteria that may exist in the low oxygen regions within the biomat.

   1999, Bruce C. Alleman, Andrea Leeson, Natural attenuation of chlorinated solvents, petroleum hydrocarbons, and other organic compounds, Volume 5

2. A restrictive layer that develops beneath the distribution lines of the soil absorption system of septic tanks at the gravel-soil or bed-soil interface.