IMP 4, a three cell system, collects seepage from a reclaimed slurry pond with a pretreatment anoxic limestone drain. RT 2 collects seepage from a reclaimed strip mine. It consists of a pond followed by two wetland cells. Water parameters are described in Table 1 . Sediment samples and water column depth measurements were taken at each node of the grid.
Sediment consists of two visually distinct floc layers.
The compaction rate of the fluffy layer is unknown. This study assumed a conservative one-year compaction rate. Samples were collected June - August 1993. In summer 1993 northern Alabama received a significant decrease in average annual rainfall. As anticipated, excepting cell 3, IMP 1 CF and FF volume decreased in successive cells.