If a cap or cover lets water in faster than the liner system below lets it out, rain soaks into the waste or fill and has nowhere to go, so the cell fills up like a tub. The same thing happens in lined trenches and pits with poor drainage. It raises the liquid head on the liner and can push leachate out over the rim, so cover and base designs are matched to prevent it.
That old cell is bathtubbing, the cap leaks more than the base drains, and the leachate is up near the rim.
Also heard as
- bathtub effect
- bathtub
Related terms
Cap
Final cover system placed over a closed landfill or waste area to keep water out and control gas.
Composite liner
Barrier made of a geomembrane in direct contact with a low-permeability soil or GCL layer beneath it.
Drainage
Carrying water along the plane of a geosynthetic to an outlet, as in wall backdrains and leak detection layers.