If you can get bentonite, till it in at proper proportions to a minimum 12 inch depth, moisten and then compact.

Just be sure to tie the new repairs in to the lower level clay or the water could continue to leak under the repairs.

It would be a great time to add stucture, shelves, ditches or any other contour changes you might like.

Benotonite expands and contracts a great deal and is most effective when it remains compacted and under water. Drying out will make it shrink considerably and could create cracks that leak badly, so proper mixing with other soils is critcal.

Last edited by Rainman; 08/27/10 10:56 AM.