biomat

Noun

 * 1)  A clogging layer of typically densely packed decaying organic matter which impedes the downward flow of water.
 * 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.
 * 1) 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.